The Analytical Engine (CHAC newsletter!)
jo...@cs.uiowa.edu
by sec...@kxovax.enet.dec.com (Strong datatypes for weak minds.):
>
> Thank you for posting the Computer History Association of California
> information. Would you post the rest of the newsletter, please ?
Here it is:
--------------------------------------------------------------------
Analytical Engine V1#1, July 1993 Page 1
The ANALYTICAL ENGINE
Newsletter of the Computer History Association of California
ISSN pending
Volume 1, Number 1, July 1993
Kip Crosby, Managing Editor
Jude Thilman, Telecommunications Editor
-------------------------------------------------
EDITORIAL
Welcome to the Analytical Engine, volume one, number one.
This document has three purposes: To present a small sample of
computer history. To convince you that computer history is
worth exploring and preserving. To persuade you that a modest
commitment of your time or money, or both, will help build an
institution and protect some of the most important scientific
information in the world today.
Let me give you one concise example. Remember the Pong machine?
It wasn't much to look at; a black-and-white CRT in a squat,
screaming-yellow plywood box, with a couple of black knobs. But
in the early Seventies it introduced thousands of people -- and,
beyond them, the world -- to the interactive video game. It was
one of the first computer-driven devices to become a memorable
part of our culture.
Of the perhaps 15,000 Pong machines that Atari built, _there are
fewer than a dozen left_ and they are substantially priceless.
Collectors compete to buy them. What happened to the others?
They were displaced, replaced, thrown away. Junked.
Ever since the days of ENIAC, the rallying cry of computing has
been _Let's chuck the old stuff to make room for the new
stuff!!_ and hardware is scrapped, with the hardware goes the
documentation, goes the information, leaving only the thin
thread of memory which snaps too. Leaving aside dubious
precursors, electronic computing is fifty-five years old,
microcomputing is less than twenty years old, and we're shedding
the pertinent history by the dumpsterful. The history of
digital computing -- one of the newest core sciences in the
world -- is being destroyed as fast as it's being made.
Nor can we depend on the voices of the pioneers to fill gaps.
Many of the originators of electronic computing, like Alan
Turing, Atanasoff and Berry, John Mauchly, Wallace Eckert,
Admiral Hopper, and even Bob Noyce and William Shockley, can no
longer be interviewed. The British journalist Chris Evans, who
wanted to be _the_ popular historian of the microcomputer, died
with one of his books half-finished. Computer science has
become a freestanding discipline comparable in stature to almost
any other physical science, and yet its public record lags far
behind the evolving fact. Worthy exceptions like the BBC Press
Analytical Engine V1#1, July 1993 Page 2
book The Dream Machine (reviewed next issue) only underscore the
scale of the general flow into oblivion. A handful of concerned
organizations, like the Association for Computing Machinery, and
individual historians -- Ted Nelson, Jon Palfreman, James
Cortada, for example -- are trying to preserve an irreplaceable
historical record, and frankly fighting a losing battle.
On April 19, 1993, a few people decided to take a stand by
founding the Computer History Association of California, an
organization that exists to do these things:
* Create awareness of the history of computing as a real,
evolving and valuable phenomenon.
* Prevent the destruction of historically significant
hardware, software and documentation.
* Strengthen the cooperation among existing institutions
that safeguard the history of computing.
* Begin discussions among developers and computer-related
manufacturers about setting up an overall archive -- or at
least agreeing on archiving conventions.
* Ultimately, to help build a coalition that can build and
endow a library and museum for the history of computing in
California.
A tall order! But the people who attended the first meeting
left, thought it over, and told friends. The idea went out in
CompuServe mail and Internet mail and voice. And within days we
had --
Projects.
Urgent messages about hardware slated to be scrapped, software
in filing cabinets in storerooms, manuals on pallets waiting to
be recycled.
Right now, today, we have almost no space, almost no money, a
few members, a lot of work to do and a lot of enthusiasm. The
Computer History Association of California could take off and do
its part for the history of science. Or it could end up as a
good idea in a filing cabinet in a storeroom. The difference is
up to me, to us, and to you.
If we can make a good case for ourselves, we won't be alone.
Companies and managers who share our wish to preserve this
history -- their history -- will lend a hand to a serious
effort. The wider public will contribute through annual dues or
subscriptions to this newsletter.
Our potential membership is large, and growing. Computing --
personally and institutionally -- is moving from a
Analytical Engine V1#1, July 1993 Page 3
devil-may-care adolescence to a maturity that embraces social
responsibility. Recycling, waste control, power consumption and
other "green" issues are developing broad constituencies. These
people are the same ones who will recognize, in and through our
Association, steps that can be taken now to prevent a lot of
regret in the next century. The sooner we can alert them to the
need for preservation, the more we can accomplish.
To those of you who want to share in that accomplishment, the
Computer History Association of California makes five promises:
* We will be non-partisan and nonjudgmental. We will strive
to be accurate, interesting and innovative. Our aim must be to
enrich the history of science without distorting it.
* We will work to preserve hardware, software and
documentation, as it becomes available to us, from the full
spectrum of the history of computing.
* We will make the Association's property accessible to all
interested parties as a professional and educational resource.
* We will aggressively pursue funding from the corporations
that made the computer into a fact of modern life -- inviting
them to safeguard the history that they themselves created.
* We will have professional counsel on how to build up and
broaden this organization; how to make time and money most
effective; how to choose and manage exhibits and resources,
and protect them for future generations.
If we succeed in these ambitions, we will do our small part of a
big -- of a great -- job. We will help to affirm the history
of a core science while we live surrounded by its turbulent
origins. Someday, when our descendants respect the pioneers of
computing as they do Galileo, Edison and Goddard, that
affirmation will pay off.
But we are those pioneers. We know this story as no one else
ever will. And we must keep it as our children's heritage --
and as our own.
-------------------------------------------------
PROGRAMMING THE 1401:
An Interview with Leo Damarodas
by Roger Louis Sinasohn
[Author's note: Leo Damarodas has been a programmer since the
days of room-sized computers filled with vacuum tubes. We
first met in the mid '80s when we both worked for Noesis
Computing Company, then known as one of the premier software
Analytical Engine V1#1, July 1993 Page 4
houses in the Hewlett-Packard marketplace.
Today, Leo is an independent consultant, and lives on a sailboat
south of San Francisco. I was recently able to pin him down
and convince him to reminisce about his work with one of the
earliest commercially available mid-size computers, the IBM
1401. ]
_When and how did you get into computers?_
Let's see.... My actual first job was in 1965. I started off
from high school as an electronic technician in the early
'60s,when they were a dime a dozen, and in a period of three
years, I was laid off 18 months. I got a job in one of the
local mills, and went to school nights studying computer
programming, circuitry and design, figuring that if I got a job
in either maintenance or programming, that's where I'd work.
And the mill that I was working at knew of my interest in
computers and moved me into their office as a programmer, once I
graduated.
_Over the years, what have been the biggest changes in the
computer industry?_
(Laughs) Well, let's see. Going from vacuum tubes to
solid-state magnetic core memory -- this is where the
expression core memory comes from. Another big one's
interactive programming; getting away from punched cards. It
affected the way I was working, anyway.
_What has stayed the same?_
The need for programmers. That's never changed. And I don't
think it's ever going to.
_Why do you say that?_
Because I've been hearing as long as I've been in this business
that computers would start programming themselves in the near
future. It hasn't happened yet. I don't really think it will.
_You don't think that artificial intelligence will become
intelligent enough?_
Not with the way computers are being built currently. I mean,
programmers will be put out of business when computers become
sentient. They're going to have to know what they're doing, and
machines don't. It's as if we worried about cars driving
themselves around the streets. Even artificial intelligence
requires programming.
_When I've been working, I've cursed my computer for not doing
what I wanted it to..._
Analytical Engine V1#1, July 1993 Page 5
(Laughs) You want my poem? Is that what you're asking for?
[Quotes:]
"I really hate this gosh-darned thing, I think I'm gonna sell it.
It never does just what I want, but only what I tell it."
_In that connection you've said that you shouldn't want it to start
guessing what you want. You want it to do what you tell it._
Right.
_Why do you say that?_
If it starts trying to second-guess me, and it guesses
wrong....if anything goes wrong with the computer, I'd rather
blame myself than the computer, because to me the computer is a
tool -- nothing more than a glorified screwdriver. And when the
tools start running themselves, then it's time to worry.
Because if computers start doing what they think we want done,
the next step is them doing what they think is best for us. It
is getting to the point where computers become intelligent, but
with present-day circuitry, no matter how many processors you
hook up, it still can't think for itself. It still needs a
program to run.
_You worked on the IBM 1401._
Yeah.
_What was that like?_
Well, at the time, it seemed great, because it was the only
thing I knew -- the first computer I ever worked on. It was a
hundred per cent vacuum tubes....the logic circuitry, the
memory, everything was vacuum tubes. The addressing structure
of the machine only allowed for 16K of memory, and there was no
operating system in the modern sense.
The way into the machine was through reading the machine
instructions. Each instruction portion was a letter, a
readable character, and they made sense. Take some examples, M
was Move; W was Write a print line; P was Punch a card; R was
Read a card. When you executed these instructions, you didn't
need an address, because the card read/punch always worked
memory locations 1 through 80. And the printer always used
memory locations 101 through 232 as the I/O buffer. It was a
really simple machine to work with and a lot of fun in a way.
The only way you could get the machine to do something was put a
deck of cards in the card reader and hit the start button. And
that would read the card deck, load the program into memory, and
Analytical Engine V1#1, July 1993 Page 6
start executing it. It was slow; there was no multi-processing,
no nothing. Just a really simple machine.
_So it was basically one thing at a time, and mostly written in
machine language._
Basically, yeah, but we had ways around that. There was a COBOL
compiler on the program, but we tried to avoid using it,
because to compile a 16K program and get a program deck out
would take something like an hour. But because we could read
the machine instructions, if we had an error, we didn't really
have to go through the compilation. You could take the program
deck and modify the actual machine code, load the program and
run it again. It saved a lot of time.
We also had a language called Autocoder which was a kind of
assembler. It expanded the machine instructions out to more
readable mnemonics, and allowed you to use labels for addresses
and stuff -- use real names. It made the programming a lot
easier. The thing that was really interesting was the COBOL
compiler, which was the only other language, that I knew about
-- I think there was a FORTRAN available too, but I coded
business applications, so FORTRAN wasn't used that much. One of
the features of the COBOL was an ENTER instruction, so that
while you were writing your COBOL code, you could say ENTER
AUTOCODER and start writing Autocoder code right in your COBOL
source, then say ENTER COBOL and start writing COBOL code again.
This was possible because the COBOL compiler didn't generate
machine language -- it generated Autocoder code, and then called
the Autocoder, which converted the COBOL output into machine
language. So it just substituted the Autocoder code in your
COBOL source for the output.
_What sort of applications were you working on?_
Payroll, Accounts Payable, Accounts Receivable, General Ledger
-- straight business applications. And it was next to
impossible to write any major program without going over 16K.
So you either broke it down into steps -- 16K steps, or you
wrote program overlays. There were instructions that would
allow you to read in the next part of the program. But the
overlays had to be set up in such a way that you performed one
step for all the data, loaded the next step and performed it for
all the data. You couldn't go back and forth between overlays
because the programs had to run from card decks. Data resided
on disk, but not programs. All the data would come in initially
on cards, be transferred to the disk drives on the system, and
the programs could process disk.
_So, for example, a run to print the payroll, how long would it
take that program to produce checks?_
Honestly I don't remember, but a long time, because the only
time we could use for testing was between midnight and eight in
Analytical Engine V1#1, July 1993 Page 7
the morning. The machine was being used the rest of the day to
do production work, and about all they were doing was Accounts
Receivable, Accounts Payable, General Ledger, payroll and some
inventory. Not too much more than that.
_What happened if you had a deck that's data to be input, and you
have a deck that's a program -- what happens if you mix them
up? That is, you put the data in as if it were a program?_
One of the things that would happen, if you tried to load the
data in without having the program loaded, was that it would
choke on the first card. You've got to remember there was no
operating system, and this machine's just sitting there, waiting
for a bootstrap program that had to be in the first card. When
you pressed the start button on the console, it read the
bootstrap card and branched to location one. If there wasn't a
valid instruction there for it to execute, it wouldn't do a
thing. The bootstrap program read the rest of the cards in, and
when it got an end-of-cardfile, it branched to the location
where the program was loaded; I forget exactly what part of
memory that was.
_Punched cards had 80 columns, so you could, in theory, have up
to eighty instructions per card. Is that correct?_
In theory you could, if they were instructions that didn't
require addresses. They were single-byte instructions.
_So a small program might fit on a single card?_
Yes, in fact the bootstrap program didn't even take a whole
card. The bootstrap program was about a dozen characters long.
Somewhere I have a framed white poster, about four inches high
and ten or twelve inches long, with that program written on it.
I got it at an HP user group meeting where I walked by a booth
with a sign outside that said "If you know what this is, you're
showing your age." It was the 1401 bootstrap program. It
looked familiar but I couldn't quite remember what it was, and I
said "I don't know what it is, but I should." The guy who was
running the booth knew me and my background, and he said "I
know you should." Maybe three or four weeks after the meeting,
the poster showed up in my mailbox.
_How long did you work with the 1401?_
Only about a year, and I think the machine I worked on was
actually a 1410. 1410's were the ones that had disk drives. I
came in just as they were doing a conversion from the 1401
series to an IBM 360.
_And 360's are still being used today._
I would imagine so. [Editor's note: Our best information is
that at least two System/360s are currently used in California,
Analytical Engine V1#1, July 1993 Page 8
both by private corporations in Greater Los Angeles.] As for
the 1401 series, last I heard, the Department of the Navy was
still running an application on a 1410 a good eight or nine
years ago... In the early eighties, anyway.
[Concluded next issue]
-------------------------------------------------
I Played the ORIGINAL Video Game!
a recollection by Scott Robinson
I went to work at Bolt Beranek and Newman (no comma, please) in
the summer of 1966, as an instrumentation engineer. In those
days the company's activities were roughly equally divided
between acoustics -- both architectural and underwater -- and
computer science. The computer group's main machine was a
PDP-1, which consisted of about six 6 foot racks full of
hardware. It may have had a Remington Rand Fastrand drum
memory; I'm not sure. The company certainly had one of these
beasts later on, a drum about five feet long and two feet in
diameter with a large number of heads. All this was housed on
the lower floor of the (then) new split-level building, adjacent
to the kitchen and the reception area.
The control console for this machine was on the end of the row
of racks; it had a monochrome CRT, about 12 or 14 inch size,
and a row of miniature metal-handled toggle switches to enter
data and addresses when necessary. These switches were used as
the controls for Spacewar. This game was not a time-shared
activity; I suspect that we used the whole machine!
When a game was started, the screen would light up with two
different ship icons against a random background of stars.
There could, optionally, be a sun in the middle exerting
gravitational influence on matter. The gravitational constant
was also players' choice, I think in two steps, "fast" or
"slow." The screen was topologically connected side-to-side and
top-to-bottom; if you exited screen left, you reappeared screen
right, and so on.
Each ship could be rotated clockwise or counterclockwise, fire
reaction engines that eventually ran out of fuel, and fire
missiles of finite range and finite number. The ship obeyed
Newton's laws, accelerating and decelerating under the influence
of its engines and of solar gravitation, if any. Rotation could
be either easy to control (when you had a switch on, the ship
rotated,) or more difficult and realistic (the switches applied
angular acceleration, so that rotation increased or decreased
gradually depending on switch settings). The object, of course,
was to blow the other ship up.
If you were hit, you were dead meat! Falling onto the sun was
comparably ill-advised. Collision of two ships produced a
Analytical Engine V1#1, July 1993 Page 9
vivid, graphically depicted explosion on screen, and both
players were out, whereupon the game restarted.
For those in desperate circumstance, faced perhaps with a
barrage of missiles incoming and too close to dodge, there was
an escape...hyperspace! By rotating in both directions
simultaneously, the ship could be made to vanish and reappear
with unpredictable position and velocity. Your situation might
be improved...but with a catch. The ship might explode upon
re-entry into normal space, and the likelihood increased each
time hyperspace was invoked. I don't think I ever saw anyone
use hyperspace four times in one game without blowing up.
The display was a vector-type CRT and the quality of the
graphics exceptional. The motion was perfectly smooth, with no
aliasing artifacts noticeable.
Although I and others spent many enjoyable evenings playing
Space War, the test word toggle switches used as controls
enjoyed the game much less than we did, and failed with some
regularity. Ultimately the computer folks got tired of
replacing the switches and threw us off the machine.
Nonetheless I take a certain satisfaction in having played one of
the first computer games, an innovative and engaging game with
rigorous simulation of physics in action. As for the hyperspace
feature, haven't you ever felt that you were about to go off
into hyperspace when you tried to rotate both directions at
once?
-------------------------------------------------
NEXT ISSUE * NEXT ISSUE * NEXT ISSUE * NEXT ISSUE
INITIATIVE 1999: Why a lot of hardware will be scrapped at the
turn of the century. Why six years is barely long enough to
prepare for the consequences. Plus: Programming the 1401,
part 2. Smalltalk Then and Now. Palfreman and Swade's Dream
Machine. More....
Downloadable October first -- don't miss it!
-------------------------------------------------
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Analytical Engine V1#1, July 1993 Page 10
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Douglas W. Jones,201H MLH,3193350740,3193382879
1) The IBM 1401 was not a vacuum tube machine! It was transistorized.
2) Pong was not a computer game! It was a video game implemented with
TTL logic, with no computer.
3) Spacewar wasn't a video game! Video encoding of data was not used to
paint the image on the face of the CRT. Instead, the software drove
a pair of ADC's to handle deflection in the X and Y directions, and
the software painted each dot on the screen. The resolution was far
better than standard video, but the number of dots that could be
painted without causing flicker was limited.
(By the way, I have played spacewar myself on a DDP 224 computer at the
University of Michigan -- that machine was a nice 24 bit minicomputer,
and their version of spacewar used two joysticks on the graphics display.)
In any case, the folks at CHAC clearly have their hearts in the right
place, and the kinds of errors they made in their newsletter only serve
to prove the point of their opening editorial! History is indeed being
lost and forgotten at an impressive rate!
Doug Jones
jo...@cs.uiowa.edu
William Tyler
>Here it is:
>
>--------------------------------------------------------------------
> Analytical Engine V1#1, July 1993 Page 1
>
>
> PROGRAMMING THE 1401:
> An Interview with Leo Damarodas
>
> by Roger Louis Sinasohn
>
.........
> _You worked on the IBM 1401._
>
> Yeah.
>
> _What was that like?_
>
> Well, at the time, it seemed great, because it was the only
> thing I knew -- the first computer I ever worked on. It was a
> hundred per cent vacuum tubes....the logic circuitry, the
> memory, everything was vacuum tubes. The addressing structure
> of the machine only allowed for 16K of memory, and there was no
> operating system in the modern sense.
This is incorrect. The 1401 used discrete transistors. (I also worked
on one, and know whereof I speak.)
.........
> _How long did you work with the 1401?_
>
> Only about a year, and I think the machine I worked on was
> actually a 1410. 1410's were the ones that had disk drives. I
> came in just as they were doing a conversion from the 1401
> series to an IBM 360.
Disk drives were actually also available on the 1401. Mine had two.
Bill Tyler
--
Bill Tyler wty...@adobe.com
Adam Justin Thornton
>2) Pong was not a computer game! It was a video game implemented with
> TTL logic, with no computer.
Hey. Enough TTL _is_ a computer. Just 'cause it didn't have an LSI
CPU...sheesh. I think I still have my old home version of _Super Pong_ (4
whole games!); I wonder if I clean the crud from the battery case if it'll
still work.
Adam
--
ad...@rice.edu | These? Rice's opinions? Yeah, right. | "Might there have
been fewer crimes in the name of Jesus, and more mercy in the name of Judas
Iscariot?"--Thomas Pynchon | Overheard in Waco: "This is not an assault."
Save the Choad! | Win/NT: Yesterday's technology tomorrow. | 64,928 | Fnord
Douglas W. Jones,201H MLH,3193350740,3193382879
by ad...@owlnet.rice.edu (Adam Justin Thornton):
> In article <1993Aug31....@news.uiowa.edu>
> jones@pyrite (Douglas W. Jones,201H MLH,3193350740,3193382879) writes:
>
>>2) Pong was not a computer game! It was a video game implemented with
>> TTL logic, with no computer.
>
> Hey. Enough TTL _is_ a computer. Just 'cause it didn't have an LSI
> CPU...sheesh.
And I collect computers made with TTL without an LSI CPU; I have three
of them sitting in my study right now at home! Still, Pong isn't a
computer game because it doesn't have a computer! I'm using the standard
definition of a computer -- that is, a general purpose machine capable
of executing a program provided by the user. The logic inside a Pong
game is a special purpose controller with a single fixed (but fairly
complex) program that does only one thing.
The border between computers, calculators and controllers can get fuzzy,
for example, ENIAC was clearly a programmable calculator, but was it a
computer? You could reprogram it with a patch panel change, and it was
powerful enough that someone could have programmed a patch panel to make
it interpret a stored program, but to my knowledge, nobody did it.
You can't make that kind of quibble about Pong though. There were no
provisions for even rudimentary programmability.
Doug Jones
jo...@cs.uiowa.edu
David Hembrow
>The border between computers, calculators and controllers can get fuzzy,
>for example, ENIAC was clearly a programmable calculator, but was it a
>computer? You could reprogram it with a patch panel change, and it was
>powerful enough that someone could have programmed a patch panel to make
>it interpret a stored program, but to my knowledge, nobody did it.
Not a quibble, but possibly the start of a new interesting thread:
Is this in fact true ? If you know enough about the way in which ENIAC
was put together, could you provide some details of what it was in fact
capable of ? I'd be interested in knowing something about the workings
of some of these early computers ( especially the programmable ones ).
ie.
o Amount of memory
o Instruction set
o I/O capabilities
I'm afraid there isn't a lot I can contribute to this, I know only
what I've read in various books. They tend to give information like
the number of valves ( tubes ) in each machine and make some statement
about the number of operations a second it was apparently capable of
but little more.
David.
Douglas W. Jones
by dav...@harlequin.co.uk (David Hembrow):
>
> I'd be interested in knowing something about the workings
> of some of these early computers
That's why I prepared the alt.sys.pdp8 faq (and I'm still working
on improving it). Eventually, I'd like to see similar faq files
for a number of other old machines. The next one I'd like to hammer
down is the IBM 701, a 1953 gem for which I happen to have the
principles of operation book. If you like such things, here's a
brief summary:
Computer: The IBM 701
Date: 1953
Technology: Vacuum Tubes!
Size: CPU -- about 9 to 10 feet wide, 6 feet high, 2.5 feet deep.
Main Memory -- 4 or 5 feet wide; depth and height as above.
Main memory: 2048 words, 36 bits each, Williams tube technology.
Addressing: word and half-word addressable.
even negative numbers address words.
even positive numbers address left-half-words.
odd positive numbers address right-half-words.
Registers: Accumulator -- 37 bits.
two extra bits are provided for magnitude overflow.
MQ (multiplier-quotient) -- 38 bits.
half-word loads and stores use the high 18 bits of registers.
Number system: Signed magnitude
Arithmetic assumes 35 bits right of the point.
Instruction: 18 bit (half word) instructions, formed as:
sign of address | 6 bit opcode | 12 bit address
Instruction set:
mnemonic opcode
R ADD 10 reset and add memory to accumulator.
ADD 09 add memory to accumulator.
ADD AB 11 add absolute value of memory to accumulator.
R SUB 06 reset and subtract memory from accumulator.
SUB 05 subtract memory from accumulator.
SUB AB 07 subtract absolute value of memory from accumulator.
STORE MQ 14 store MQ in memory.
ROUND 19 round accumulator by most significant bit of MQ.
MPY 16 multiply MQ by memory giving result in AC-MQ.
MPY ROUND 17 multiply followed by round
DIV 18 AC-MQ div memory; MQ gets quotient, AC gets rem.
A RIGHT 23 Accumulator shift addr field places right.
A LEFT 22 Accumulator shift addr field places left.
L RIGHT 21 AC-MQ shift address field places to the right.
L LEFT 20 AC-MQ shift address field places to the left.
TR 01 Transfer control to the given address.
TR + 03 Transfer on accumulator positive.
TR 0 04 Transfer on accumulator zero.
TR OV 02 Transfer on overflow and reset overflow indicator.
STOP 00 Stop, transfer to given address on restart.
STORE A 13 Store address field from high halfword of AC.
READ 24 Prepare to read one unit record from device.
READ B 25 Prepare to read one unit record backward.
WRITE 26 Prepare to write one unit record to device.
WRITE EF 27 Write end of file to mag tape unit.
REWIND 28 Rewind tape unit.
SET DR 29 Set drum address of next unit record to read/write.
COPY 31 Copy one data word to or from unit record.
SENSE 30 Signal device and conditional skip on result.
Notes on instructions:
Note the lack of procedure call instructions or provisions for
array addressing! The STORE A instruction was provided to allow
easy construction of self-modifying code, and with careful self-
modification, both could be accomplished.
Note the lack of logical operations. The importance of shifting
was understood, but if you wanted to mask something, you had to
shift one way and then the other, letting bits fall off the ends
of the accumulator to clear them, and keeping in mind the extra
two magnitude bits on the accumulator.
Note that the mnemonics weren't designed for processing by an
assembler. Assemblers weren't routinely used yet, and programmers
generally programmed in binary and then punched their programs
in absolute binary on punched cards! The manual includes a
bootstrap loader that will load a single card image into memory,
and then it includes a loader that fits on one-card to load a card
deck full of code into memory.
I have one used coding form from the MIT Digital Computer Laboratory
that was apparently for this machine, and I have Diazo copies of
other similar forms. They never use the mnemonics given above!
instead, they use cryptic two-letter abbreviations.
Unit record formats:
80 column punched cards were handled as 12 rows of 72 columns, with
each column stored in two consecutive memory locations, reading
from the bottom of the card to the top. A patch panel determined
which columns the printer and punch would handle.
The printer had 120 columns, with a character set of 48 characters.
Output was in card image format, so no more than 72 characters
could be printed per line. A patch panel determined which 72.
The magnetic tape drives stored data in 6 channels, with a 7th
channel added for parity, all on half-inch wide tape with 1400
feet of tape per reel. This was the first computer to use this
format, a format that lasted through the 1960's.
The magnetic drum system stored 2048 words per drum, addressed
by even integers as in main memory. Words on drum are randomly
accessable (within the limits of latency), with a set-drum-address
command used to specify the starting drum address of each transfer,
followed by a sequence of copy instructions to move the data.
I/O instructions, particularly the copy instruction, were blocking,
and would hang the CPU until the transfer was complete.
da...@gilly.uucp
>Stories like this seem to cut down on some of the CHAC story about there
>being only a few of them left?
>
>cj "owner of less than 4,000,000 PDP-8's"
Chill out dude, there's a difference between the coin-operated arcade
games that article was about, and the home version that you can get
anywhere these days for $15. Arcade games are "upgraded" to new games
by swapping the guts and putting new stickers on the outside, so most
of the early one are extremely rare now.
------------------------ uunet!quack!gilly!dave ------------------------
================= Dave Fischer - Nature's Perfect Food =================
----------------------- dave%gi...@speedway.net ------------------------
Ethan Dicks
: Correct, Pong from Atari is a hard-wired TTL controller that plays a true
: video game using digital techniques to accomplish all the features. Contrast
: that with the earlier Magnavox Odyssey which wasn't even a digital device.
I just unpacked my old Magnavox, complete with the plastic colored screen
overlays (in two sizes) for adding boundaries and other features to the games.
I have dissected in more than once (and it still works :-), and can confirm
personally that it is a strictly analog device. The motherboard is populated
with edge-card connectors which are filled with 2"x2" circuit boards to perform
things like horizontal timing, vertical timing, dot generation, drift, etc.
The specifics of the game (control of the ball, display of paddles, response
on collision detection, etc.) are selected by plugging in a "cartridge". This
cartridge contains no active components, but rather jumpers various pins of
the 44 pin connector, turning on or turning off various features. To play
a game, you tape the correct colored overlay to the screen and plug in the
correct cartridge.
Stone knives and bearskins.
-ethan
Travis Corcoran
>2) Pong was not a computer game! It was a video game implemented with
> TTL logic, with no computer.
Hey. Enough TTL _is_ a computer. Just 'cause it didn't have an LSI
CPU...sheesh. I think I still have my old home version of _Super Pong_ (4
whole games!); I wonder if I clean the crud from the battery case if it'll
still work.
My aptmate <mike...@analog.com> is the proud owner of a *WORKING* Pong
game. Over the last few months we've played more Pong than...well,
we've played a lot of Pong...;) Somehow the classics never go out of
style... <attention marketeers: inser picture of
(Coke|chinos|jeans|etc.) here.>
--
__
TJIC (Travis J.I. Corcoran) Corc...@ICD.teradyne.com
opinions(TJIC) != opinions(employer(TJIC))
"It's like the '64 Air Force mission to the moon-you want to be on the
cutting edge, you gotta live with the secrecy."
"What Air Force mission to the moon?"
"See?" -'In the Hole w/ the Boys w/ the Toys' G.Landis IAFSM Oct 93
Charles Lasner
Douglas W. Jones,201H MLH,3193350740,3193382879 <jones@pyrite> wrote:
>From article <CCr2r...@rice.edu>,
>by ad...@owlnet.rice.edu (Adam Justin Thornton):
>
>> In article <1993Aug31....@news.uiowa.edu>
>> jones@pyrite (Douglas W. Jones,201H MLH,3193350740,3193382879) writes:
>>
>>>2) Pong was not a computer game! It was a video game implemented with
>>> TTL logic, with no computer.
>>
>> Hey. Enough TTL _is_ a computer. Just 'cause it didn't have an LSI
>> CPU...sheesh.
>
>And I collect computers made with TTL without an LSI CPU; I have three
>of them sitting in my study right now at home!
And I (and Doug) collect computers that don't even have TTL in them, or even
the forerunner DTL chips either, or even RTL! The original PDP-8, LINC-8,
various peripheral controllers, etc., are all made out of discrete components
meaning transistors, diodes, resistors, capacitors, a few pulse transformer
coils, a few oscillator crystals hooked to analog oscillator circuits made
of additional discrete components (years before the concept of the "oscillator
in a can"), etc. Hundreds of little boards each stocked with a significant
quantity of some of all of the above only.
And surprisingly, the PDP-8/i, made mostly of TTL, isn't that much smaller,
in large part because the little boards are the limiting factor. Most of the
M-series cards are empty real-estate, because for most cards, all of the
card-edge fingers are used up by the functionality of 3 TTL chips. In the
R-series modules, even with 1/2 the fingers, the connectivity to density ratio
was more favorable. Until DEC went to much larger modules, the fingers were
a long-standing bottleneck, etc.
cjl
Travis Corcoran
>2) Pong was not a computer game! It was a video game implemented with
> TTL logic, with no computer.
Hey. Enough TTL _is_ a computer. Just 'cause it didn't have an LSI
CPU...sheesh. I think I still have my old home version of _Super Pong_ (4
whole games!); I wonder if I clean the crud from the battery case if it'll
still work.
My aptmate <mi...@analog.com> is the proud owner of a *WORKING* Pong
Charles Lasner
Travis Corcoran <corc...@icd.teradyne.com> wrote:
>My aptmate <mike...@analog.com> is the proud owner of a *WORKING* Pong
>game. Over the last few months we've played more Pong than...well,
>we've played a lot of Pong...;) Somehow the classics never go out of
>style... <attention marketeers: inser picture of
>(Coke|chinos|jeans|etc.) here.>
Hmm...
Robert Bernecky
Yup. 1401s had disk drives (the mighty 1311). See "IBM 1311 Disk Storage Drive,
Form A24-3086".
It also was most certainly a discrete transistor machine, with nary a tube
in sight.
Bob
Robert Bernecky r...@yrloc.ipsa.reuter.com
Snake Island Research Inc (416) 203-0854
18 Fifth Street, Ward's Island
Toronto, Ontario M5J 2B9
Canada
Charles Lasner
Yes, as several people pointed out. I have an additional criticism:
I truly believe in the intended cause the CHAC people are attempting, and
I really hope they succeed, but unfortunately, they seem to be victims of
their own predictions. In order for such an organization to succeed, it
must *flawlessly* pursue its subject matter.
Towards that end, I would suggest that groups such as alt.sys.pdp8 act
as super-proof-readers of such material, i.e., post draft copies here first
and allow us pedantic pdp-8'ers and other interested hanger-outers to tear
apart their articles for technical accuracy, all in the interest of upping
the quality of the product, etc.
As it stands now, it's a little too revisional for me, although admittedly
only a little. Forgive me for saying it, but from my vantage point, someone
who happened upon a 1401 in 1965 ain't a pioneer! This is only marginally
before my time, and I already knew enough to know the mistakes pointed out
elsewhere, and I consider myself "second generation", not a true pioneer in
the industry, etc.
>
>1) The IBM 1401 was not a vacuum tube machine! It was transistorized.
Amen!
And it always had all of the core memory present. There was a jumper to
make half of the stack go away if the customer didn't pay for field service
for it! (And sometimes a friendly tech could put it back in!)
>
>2) Pong was not a computer game! It was a video game implemented with
> TTL logic, with no computer.
Correct, Pong from Atari is a hard-wired TTL controller that plays a true
video game using digital techniques to accomplish all the features. Contrast
that with the earlier Magnavox Odyssey which wasn't even a digital device.
Further, there is no provision to reprogram the device that Pong is, although
you can get into a grey area if something akin to a patch panel or even a
control ROM is used to transiently change the controller's exact function.
In any case, it still ain't a computer, since it lacks a program that can
be stored, nor has the storage itself to do such a thing either. This is
also far afield from a true computer with a ROM-based program that as provided
cannot be changed without changing the ROM, because the ROM *could* be changed
if need be, and the changes could bring about either of two effects: 1) the
program could run the same way with totally different contents because it's
usually possible to program any reasonable task using entirely different
algorithms thus different, yet equivalent program sequences, or 2) The program
will run materially different if small changes to the code are made. The
complications arise when a feature of the program is to sense external options
such as DIP switches or perhaps even semi-random input devices to determine
just what to do. (Meaning that it's possible to use a computer to simulate
a hard-wired controller whose wiring gets patched, etc.)
>
>3) Spacewar wasn't a video game! Video encoding of data was not used to
> paint the image on the face of the CRT. Instead, the software drove
> a pair of ADC's to handle deflection in the X and Y directions, and
> the software painted each dot on the screen. The resolution was far
> better than standard video, but the number of dots that could be
> painted without causing flicker was limited.
This point is particularly galling as it's getting increasingly difficult
to explain to people that just because a screen lights up, it ain't gonna
necessarily be video!
The great thing about oscilloscope graphics is the random access aspect
of it. Without having to rigorously display in raster order, you totally
avoid the jaggies, and most of these tubes use 12-bit D-A convertors to
make matters even better. But when you don't use raster order, and instead
draw points where you want/need them, the jaggies just don't happen. This
is why DEC has made various displays that were adequate with as little as
8-bits D-A convertors, and not the slightest aliasing visible on the
typical 'scopes used with them. (Such as the LINC-8 or the AX08 with
various Tektronix scopes attached, etc.)
>
>(By the way, I have played spacewar myself on a DDP 224 computer at the
>University of Michigan -- that machine was a nice 24 bit minicomputer,
>and their version of spacewar used two joysticks on the graphics display.)
The description of the PDP-1 spacewar, clearly the first version, entirely
matches the 4K w/EAE PDP-8 version attributable to Richard Lary, Herb Jacobs,
and Rod Dorman, etc., which is usually distributed with P?S/8, which is able
to load it on a 4K PDP-8 it can run from, etc.
>
>In any case, the folks at CHAC clearly have their hearts in the right
>place, and the kinds of errors they made in their newsletter only serve
>to prove the point of their opening editorial! History is indeed being
>lost and forgotten at an impressive rate!
Yes, if those who are committed to wanting to preserve history can't quite
get it together, we can't possibly succeed! We must help these folks get
their act together completely. All of us have a part to play to get it
correct, before the entire history of computing is personally attributed
to Bill Gates, now sometimes erroneously attributed to as the author of the
original BASIC among other things!
>
> Doug Jones
> jo...@cs.uiowa.edu
cjl
Edward Rice
RB> Yup. 1401s had disk drives (the mighty 1311). See "IBM 1311 Disk
RB> Storage Drive, Form A24-3086".
Right. We had one o' them, late in the life of our 1401's.
RB> It also was most certainly a discrete transistor machine, with nary a
RB> tube in sight.
There was no tube in the 1401 per se, but I think there may have been in the
1402 Card Reader/Punch unit. I forget what it was used for, but I have a
vague recollection that if you jammed it up enough that you needed your card
gouge/file and had to rip the machine apart to get at the punch dies, that
there was one (or were a very small number) of tubes in there. Can't remember
what they were for.
corn...@eisner.decus.org
> Charles Lasner (las...@watsun.cc.columbia.edu) wrote:
>
> : Correct, Pong from Atari is a hard-wired TTL controller that plays a true
> : video game using digital techniques to accomplish all the features. Contrast
> : that with the earlier Magnavox Odyssey which wasn't even a digital device.
>
> I just unpacked my old Magnavox, complete with the plastic colored screen
> overlays (in two sizes) for adding boundaries and other features to the games.
>
> I have dissected in more than once (and it still works :-), and can confirm
> personally that it is a strictly analog device. The motherboard is populated
> with edge-card connectors which are filled with 2"x2" circuit boards to perform
> things like horizontal timing, vertical timing, dot generation, drift, etc.
If it's putting dots on the screen (and if it contains TTL!), it's probably not
an analog device. I suspect you mean that it does not contain a microprocessor
or a semblance thereto.
Douglas W. Jones,201H MLH,3193350740,3193382879
by corn...@eisner.decus.org:
>
> If it's putting dots on the screen (and if it contains TTL!),
> it's probably not an analog device. I suspect you mean that
> it does not contain a microprocessor or a semblance thereto.
No, the point is that the Magnavox Odyssey used analog techniques
to drive the logic of the game. No doubt there were some digital
signals inside, in the sense of saturating transistors and on-off
logic, but the basic mechanisms that moved the ball on the screen
were analog. For an example of the kinds of things that go into
an analog video game, consider the use of current sources and
integrators instead of clocked counters to determine the X and Y
positions of the "ball" on the screen. The decision to illuminate
the dot on the screen then rests on an analog comparitor that
compares the outputs of these integrators with the outputs of
another pair of integrators that effectively track the current
coordinates of the video scan on the display screen. Sure, there
may be one and gate used to determine that both X and Y coordinates
match, but the heart of the computation is analog!
Doug Jones
jo...@cs.uiowa.edu
Charles Lasner
>by corn...@eisner.decus.org:
>>
>> If it's putting dots on the screen (and if it contains TTL!),
>> it's probably not an analog device. I suspect you mean that
>> it does not contain a microprocessor or a semblance thereto.
No, Nein, Nyet! There is nothing in the remotest sense digital about this
device!!!!! There are no gates whatsoever. All is done with analog
comparators including the gating on of the moving dot which unblanks the
video directly at the tracked location which is determined as Doug says,
which itself is an analog comparison.
>
>No, the point is that the Magnavox Odyssey used analog techniques
>to drive the logic of the game. No doubt there were some digital
>signals inside, in the sense of saturating transistors and on-off
>logic, but the basic mechanisms that moved the ball on the screen
>were analog. For an example of the kinds of things that go into
>an analog video game, consider the use of current sources and
>integrators instead of clocked counters to determine the X and Y
>positions of the "ball" on the screen. The decision to illuminate
>the dot on the screen then rests on an analog comparitor that
>compares the outputs of these integrators with the outputs of
>another pair of integrators that effectively track the current
>coordinates of the video scan on the display screen. Sure, there
>may be one and gate used to determine that both X and Y coordinates
>match, but the heart of the computation is analog!
Even that is done by two analog comparators. These people went out of their
way to avoid digital. (I was part of the expert witness consultancy on a case
directly concerned with this aspect. The Odyssey was covered by an overly
broad patent that doesn't distinguish between a digital and an analog
implementation. The case wasn't broken on this ground however, instead we
got 'em on prior art using the PDP-8!)
>
> Doug Jones
> jo...@cs.uiowa.edu
DEC uses an analog comparator to do the select logic on the TU55/TU56
DECtape connected to controllers such as the TC01/TC08.
Every DECtape drive has a connection to a line called SELECT ECHO. It is
driven with a DEC standard relay driver card which has predictable analog
characteristics. When not selected, the driver contributes only a negligible
leakage current, but when selected, the driver transistor is driven only into
the active region. (Normally, this card, with a large output transistor, is
meant to drive some large contactor relay coil or other multi-amp load, but
in this application, it is "loafing" and driving a 1/4W resistor.)
In the TU55, the relay driver module is of course driven by negative logic
signals. In the TU56, the relay driver module is a newer card that is
driven by TTL signals, but is otherwise the same design. (DEC had a habit
of updating certain stock module designs for specific purposes. The TTL
version of the relay module is essentially the original card with a level
converter on the card.) Thus, it is perfectly OK to mix systems where
some drives are TU55 and some are TU56, etc.
So, there are up to 8 possible drives with individual relay drivers connected
to SELECT ECHO. Within each tape controller there is an analog comparator
connected to that line, along with the modest load resistor. When one drive
selects, the resultant voltage is predictably within a narrow tolerance range.
It will be too high if no drives select, and too low if 2-8 drives select.
Thus, the analog comparator's output is used to create the internal signal
called SELECT ERROR.
The same "logic" is used to drive the WRITE ECHO signal. IFF there is not
a SELECT ERROR condition, then another comparator checks the voltage on
WRITE ECHO. Of course that signal could only be in two states, i.e., not
driven or driven by the selected drive (or overdriven by too many drives,
but then SELECT ERROR is set invalidating the WRITE ECHO signal).
Thus, there is a purely analog interface between the drives and the controller
on not only the head data, but also the select and write-protect logic. The
command logic does use logic levels to control motion of the motors. For the
TU55, either the old "relay" levels or negative logic levels are used, and
the construction of the TU55 is all R-series logic, with an optional card to
level convert from relay -> negative if needed in an older system (such as
a 555 DECtape system. The TU55 was originally called the "Solid-State
DECtape Drive".). The TU56 accommodates all of that, and additionally uses
an additional level converter because it can also be driven by TTL levels.
The TTL levels are used in the TD8E and the TC-11. The negative levels are
used in the TC01, TC08, TC12, TC02, TC15, etc. (The last two are the PDP-9
and PDP-15 controllers respectively.)
cjl
Kip Crosby
In article <1993Sep3.1...@news.uiowa.edu>, Douglas W. Jones,201H MLH,3193350740,3193382879 (jones@pyrite) writes:
> [....arcana deleted....]
>The border between computers, calculators and controllers can get fuzzy,
>for example, ENIAC was clearly a programmable calculator, but was it a
>computer? You could reprogram it with a patch panel change, and it was
>powerful enough that someone could have programmed a patch panel to make
>it interpret a stored program, but to my knowledge, nobody did it.
>
von Neumann_ right to hand (chorus of "Why NOT?!",) but I think von
Neumann, Adele Goldstine and Arthur Burks actually _did_ do that.
If I can dig up ch. and verse I'll be back with it.
__________________________________________
Kip Crosby kcr...@crayola.win.net
Computer History Association of California
"History is what you make it...."
Kip Crosby
In article <davidh.13...@harlequin.co.uk>, David Hembrow (dav...@harlequin.co.uk) writes:
>Is this in fact true ? If you know enough about the way in which ENIAC
>was put together, could you provide some details of what it was in fact
>capable of ? I'd be interested in knowing something about the workings
>of some of these early computers ( especially the programmable ones ).
>
>ie.
>
>o Amount of memory
>o Instruction set
>o I/O capabilities
>
core, 304 ditto in a func. table, 96 in the patch panel, and 8 in
mag relays as a single-card cache. There were 97 instructions of 2
decimal digits each, with 5 or 6 instructions per word (there were
some 12-digit words,) and fixed-decimal arithmetic. I/O was by
IBM 80-col card at 125 cards/min I and 100 cards/min O.
All of this and much more is in:
_Historical Dictionary of Data Processing_
James W. Cortada
Greenwood Press, Westport, CT, USA
which is three hardcover volumes, Technology, Biographies, and
Organizations. Invaluable for the historian, fascinating reading,
best for stuff before 1980, and (this is the hard part) about
US$150 the set -- but you can buy the individual volumes.
Cheers,
Kip Crosby
In article <26932j$f...@apakabar.cc.columbia.edu>, Charles Lasner (las...@watsun.cc.columbia.edu) writes:
>I truly believe in the intended cause the CHAC people are attempting, and
>I really hope they succeed, but unfortunately, they seem to be victims of
>their own predictions. In order for such an organization to succeed, it
>must *flawlessly* pursue its subject matter.
>
>Towards that end, I would suggest that groups such as alt.sys.pdp8 act
>as super-proof-readers of such material, i.e., post draft copies here first
>and allow us pedantic pdp-8'ers and other interested hanger-outers to tear
>apart their articles for technical accuracy, all in the interest of upping
>the quality of the product, etc.
We're delighted to have super-proofers -- that's a lot of why we're
on USENET to begin with. Tear away! (Not that people haven't.)
On the other hand, I will concede (being one) that editors are
human, and no less fallible in that capacity than in any other;
flawless pursuit of subject matter is perennially desired and less
often attained. If we publish articles that need no correction,
great. If our articles go out to readers and somebody finds a
bug, then, to publish the article _and_ the correction still does a
service to the community and enriches the public record. When the
October ENGINE appears you'll see that we do publish corrections,
even at a length that will surely satisfy the most pedantic.
>As it stands now, it's a little too revisional for me, although admittedly
>only a little. Forgive me for saying it, but from my vantage point, someone
>who happened upon a 1401 in 1965 ain't a pioneer! This is only marginally
>before my time, and I already knew enough to know the mistakes pointed out
>elsewhere, and I consider myself "second generation", not a true pioneer in
>the industry, etc.
>
I don't quite get the intent of the word 'revisional', but in any
case, certainly "someone who happened upon a 1401 in 1965 ain't a
pioneer." IBM announced the 1401 in October 1959 and, in fact,
projected in an internal report that the end of the useful life of
the series would occur in 1965. But while pioneering work is
important to CHAC, and preserving the record of it is an important
part of our mandate, it ain't the whole story, either. If
somebody can make an interesting, illuminating point about computer
use in California, at the appropriate length, then it doesn't
matter whether they were the first to gain experience with a
system or (as might be equally intriguing) the last.
I wouldn't worry about billg getting _all_ the credit. He was born
in the year that the first IBM 704 was delivered, so vacuum-tube
computing is probably safe from the attribution :-)
Stephen Wolfson
So look up back issues circa '75-76.
Now then where did I put my old TV Typewriter terminal :-)
young a t
|>for a number of other old machines. The next one I'd like to hammer
|>down is the IBM 701, a 1953 gem for which I happen to have the
|>principles of operation book. If you like such things, here's a
Hey -- maybe you're the person to answer my perpetual query about the Q bit!
...
|>Registers: Accumulator -- 37 bits.
|> two extra bits are provided for magnitude overflow.
^^^^^^^^^^^^^^
That sounds like the 704's AC: 35 bits + S,P,Q
|> MQ (multiplier-quotient) -- 38 bits.
??? Really? Not 36? The 704 MQ had 36.
|>Number system: Signed magnitude
|> Arithmetic assumes 35 bits right of the point.
I believe floating-point came in with the 704. People wrote "fixed-point"
arithmetic routines for these machines, assuming the binary point was at
some conventional place (left end, right end, or middle) of the word. Even
wrote square-root routines and trig functions for fixed-point arithmetic.
...
|>Notes on instructions:
...
|> Note the lack of logical operations. The importance of shifting
|> was understood, but if you wanted to mask something, you had to
|> shift one way and then the other, letting bits fall off the ends
|> of the accumulator to clear them, and keeping in mind the extra
|> two magnitude bits on the accumulator.
Yeah. Same problem with shifting the 704 AC. The Q bit would get you
every time.
...
|>Unit record formats:
|>
|> 80 column punched cards were handled as 12 rows of 72 columns, with
|> each column stored in two consecutive memory locations, reading
|> from the bottom of the card to the top. A patch panel determined
|> which columns the printer and punch would handle.
Which is why FORTRAN statements only used the first 72 columns.
|> The printer had 120 columns, with a character set of 48 characters.
|> Output was in card image format, so no more than 72 characters
|> could be printed per line. A patch panel determined which 72.
Yes; but if that was the same printer the 704 used, you could then print the
rest of the 120 columns on a second print cycle. Took a special wiring panel
to read the sense magnets back to the CPU, though.
|> The magnetic tape drives stored data in 6 channels, with a 7th
|> channel added for parity, all on half-inch wide tape with 1400
|> feet of tape per reel. This was the first computer to use this
|> format, a format that lasted through the 1960's.
You left out the density: 200 bpi. There used to be "tape developer fluid"
you could buy that had little black magnetic particles suspended in something.
Dip the tape in, and the bits turned black. After the solvent evaporated, you
could lift them off with Scotch tape and read the bits from a damaged piece of
mag tape.
|> The magnetic drum system stored 2048 words per drum, addressed
|> by even integers as in main memory. Words on drum are randomly
|> accessable (within the limits of latency), with a set-drum-address
|> command used to specify the starting drum address of each transfer,
|> followed by a sequence of copy instructions to move the data.
|>
|> I/O instructions, particularly the copy instruction, were blocking,
|> and would hang the CPU until the transfer was complete.
Sounds just like the 704 in that respect. The Load-button sequence was:
select card reader
copy 9-left word to absolute address 0
copy 9-right word to absolute address 1
transfer control to location 0
Those first 2 words from the loader card had to read in the rest of the card,
which had to read in the rest of the program. We had very thin bootstraps
in those days....
It used to be a game to see if you could write an input-conversion routine fast
enough to convert & store a card's worth of data before the card reader needed
another "select" instruction. If so, you could keep the card reader running at
its full speed of 90 cards/minute. If not, you lost a whole cycle, and the
reader went CHUNK. CHUNK. CHUNK. instead of slurp slurp slurp....
The catch was that cards were punched column-wise, but read row-wise; so you
had to read the *whole* card and rearrange all the bits just to read the 72
characters. Converting characters to binary representation took more time on
top of that.
A big speedup came with the 7090, which used Data Channels for I/O instead of
having to synchronize the program with the rotation of the hardware.
--
A.T.Young a...@mintaka.sdsu.edu
Astronomy Department
San Diego State University
San Diego CA 92182-0540
Kip Crosby
In article <269eib$4...@apakabar.cc.columbia.edu>, Charles Lasner (las...@watsun.cc.columbia.edu) writes:
>In article <CORCORAN.9...@difrel.world>,
>Travis Corcoran <corc...@icd.teradyne.com> wrote:
>
>>My aptmate <mike...@analog.com> is the proud owner of a *WORKING* Pong
>>game.
>
>Stories like this seem to cut down on some of the CHAC story about there
>being only a few of them left?
>
attach to your TV, but about the original arcade version in the
big plywood box. The figure of nine is from a source at the
American Museum of the Moving Image, which owns one.
Kip Crosby
In article <93635081313...@gilly.UUCP>, da...@gilly.UUCP (da...@gilly.UUCP) writes:
>las...@watsun.cc.columbia.edu (Charles Lasner) writes:
>
>>Stories like this seem to cut down on some of the CHAC story about there
>>being only a few of them left?
>>
>>cj "owner of less than 4,000,000 PDP-8's"
>
>Chill out dude, there's a difference between the coin-operated arcade
>games that article was about, and the home version that you can get
>anywhere these days for $15. Arcade games are "upgraded" to new games
>by swapping the guts and putting new stickers on the outside, so most
>of the early one are extremely rare now.
My point exactly. -- kc
Joe Morris
Um...the 1402 had a tube...as in "Neon lamp", also as in "pilot lamp" for
the annunciators. (Great fun, BTW, was to scramble the annunciator jewels
so that the "ready" annunciator for the card *reader* would appear as
"chip box full"...) As far as I recall (from too many years ago) the
1402, like the 1401, was completely transistorized and had no logic
vacuum tubes.
Trivia quiz: the IBM boxes of that era all used plug-in cards, made of
yellow phenolic plastic, with discrete components. What was the three-letter
name used to describe this technology, and what did its letters stand for?
(I can give the 3-letter name but can't recall the definition.)
Oh yes...the neon lamp in the 1402 was used for the dynamic timer.
Joe Morris / MITRE
William Tyler
>>Robert Bernecky said to All:
>
>> RB> Yup. 1401s had disk drives (the mighty 1311). See "IBM 1311 Disk
>> RB> Storage Drive, Form A24-3086".
>
>>Right. We had one o' them, late in the life of our 1401's.
>
Speaking of obsolete technology, the 1311 disk drive had a
*hydraulically* actuated arm. One of the 1311s I used to use would
leak a little hydraulic oil from time to time. I've used 1311s both on
a 1401 and on an IBM 1620 II. As configured for the 1620, the 1311 had
100 cylinders, 10 usable surfaces (6 platters, but the top and bottom
surfaces weren't used for data storage), 100 decimal digits per
sector, and I think 20 sectors per track, though my memory could be
failing somewhat.
Bill
--
Bill Tyler wty...@adobe.com
Alan Greenberg
ma...@antimatr.hou.tx.us (Mark Whetzel) writes:
>In article <jcmorris.747519992@mwunix>, jcmo...@mwunix.mitre.org (Joe Morris) writes:
>> edwar...@his.com (Edward Rice) writes:
> [ 1401 musings and 1311 disk rumbles deleted ]
>
>> Trivia quiz: the IBM boxes of that era all used plug-in cards, made of
>> yellow phenolic plastic, with discrete components. What was the three-letter
>> name used to describe this technology, and what did its letters stand for?
>> (I can give the 3-letter name but can't recall the definition.)
Alan
Mark Whetzel
> edwar...@his.com (Edward Rice) writes:
[ 1401 musings and 1311 disk rumbles deleted ]
> Trivia quiz: the IBM boxes of that era all used plug-in cards, made of
> yellow phenolic plastic, with discrete components. What was the three-letter
> name used to describe this technology, and what did its letters stand for?
> (I can give the 3-letter name but can't recall the definition.)
Woa, do I remember that logic... this is driving me nuts..
Was it ECL? Emitter Coupled Logic?
Been entirly TOO long ago for this.. The 2540 reader/punch nightmare was
full of this logic. Can't remember excttly now at 5AM.
--
AIX..... NOT just another UNIX. (tm)
Mark Whetzel | My own RT system.. My own thoughts..
DOMAIN: ma...@antimatr.hou.tx.us | IBM RT/135 running AIX 2.2.1
UUCP ..!menudo!lobster!antimatr!markw | comp.sys.ibm.pc.rt FAQ maintainer.
Mark Whetzel
> yellow phenolic plastic, with discrete components. What was the three-letter
> name used to describe this technology, and what did its letters stand for?
> (I can give the 3-letter name but can't recall the definition.)
This got me thinking about the 2540 reader/punch that we had for many
years. When I first started working at the company I work for, as a
computer operator, many moons ago, on a IBM System/370 model 165 we
had (2Mb of main memory!) with 3330 disk drives.
It had the most ornery 2540 reader/punch.
It was our primary card reader for the longest time until the 2501 reader
came out... much faster!
Anyway.. we had this jobrun that this guy loved to submit on about 4-5
complete boxes of cards. (heavy!) The reader part worked just fine, and
was good for this job because the loader tray could take an entire box
of cards, plus some. This job would mash about for a few hours
and then HASP would need to punch the output, back ON 2-3 boxes of cards.
Without fail, the first job to be punched would get continual punch
checks, and keep re-punching the first card (the lace card!) and
never proceed.
We could clear the punch checks by pressing stop on the punch unit...
open the chip box door, and SLAM it HARD!
Hit start.. and the entire punch run, including any other waiting
punch jobs would punch just fine, including lace cards.
UNTIL.. it sat idle for too long..
whatever that interval was, we never figured it out.
The CE's kept trying to fix it but NEVER could find the problem with it.
They had at one time or another replaced the ENTIRE set of those yellow cards
and still could not clear the problem... until the day we de-comissioned it.
The account CE we had (Joe Vento and Jim Murphy.. nice guys!)
finally REALLY tore into it for the next couple of days (Pride was at stake
here..) and found the problem.
A combination of a cold solder joint and a shorting wire on the wire-wrap
backplane. Seems the wire was tight up against a square pin and the corner
had cut into the insulation of the wire. Hard to find!!
Later,
markw
Richard H. Miller
|>
|> It was our primary card reader for the longest time until the 2501 reader
|> came out... much faster!
Just as an aside, I don't think the 2501 was faster than the 2540; We used the
2501 as a student CR with the heavy stuff going to the 2540.
[story about wierd failure of a 2540 Card reader]
|>
|> A combination of a cold solder joint and a shorting wire on the wire-wrap
|> backplane. Seems the wire was tight up against a square pin and the corner
|> had cut into the insulation of the wire. Hard to find!!
When we had our KI-10, just after we had replace DEC as the H/W maintenance
group by Tymshare, the KI-10 would suddenly just freeze. We could clear it
up but it would randomly freeze again.Tymshare did their diagnosis and nothing
would clear up the problem. They were finally at a loss and brought in a bright
light, magnifying glass and the listing of the wire wraps. They then proceeded
to start with tracing/verifying each wrap. I think they started up in the
upper right bay and finally the located a drop of solder which had fallen onto
the memeory bus connector (which is at the low left bay). Cleared up the
problem but I had to feel for them looking at each wrap.
We also had a timing problem with the KA-10 which went on for two weeks. We
were screeming bloody muder and finally DEC brought in one of the designers
of the processors who proceeded to diagnose the problem and found a clock
slightly out of spec.
--
Richard H. Miller Email: ri...@bcm.tmc.edu
Asst. Dir. for Technical Support Voice: (713)798-3532
Baylor College of Medicine US Mail: One Baylor Plaza, 302H
Houston, Texas 77030
Joe Morris
Right. Now if someone can figure out what it stood for we'll both know.
Joe Morris
Jim Haynes
IBM's early computers / Charles J. Bashe ... [et al.]. Cambridge, Mass. :
MIT Press, c1986.
--
hay...@cats.ucsc.edu
hay...@cats.bitnet
"Ya can talk all ya wanna, but it's dif'rent than it was!"
"No it aint! But ya gotta know the territory!"
Meredith Willson: "The Music Man"
Alan Bowler
>
>Speaking of obsolete technology, the 1311 disk drive had a
>*hydraulically* actuated arm. One of the 1311s I used to use would
>leak a little hydraulic oil from time to time. I've used 1311s both on
>a 1401 and on an IBM 1620 II. As configured for the 1620, the 1311 had
>100 cylinders, 10 usable surfaces (6 platters, but the top and bottom
>surfaces weren't used for data storage), 100 decimal digits per
>sector, and I think 20 sectors per track, though my memory could be
>failing somewhat.
>
You memory is correct. This gave you a grant total of 2 million digits
or 1 million characters. The 1620 used two decimal digits to express
an character. I never used a 1401.
The 1311 disks were amazingly reliable. One of ors leaked some
hydraulic oil onto the drive belt one day, and you could see that the
disk was spinning much slower than it should. However, everything
still worked just fine. No data loss, no read or write errors.
it dynamically adjusted its read/write clock to compensate for
differences in disk speeds. The CE used to just use a Kimwipe to mop
up the oil.
IBM continued to use hydraulic seek arms for long after the 1311.
As I recall they only switched after Ampex started selling "plug
compatible" drives for /360's that used voice coil seek arms.
Paul Pierce
|> >There was no tube in the 1401 per se, but I think there may have been in the
|> >1402 Card Reader/Punch unit.
|> the annunciators. (Great fun, BTW, was to scramble the annunciator jewels
|> so that the "ready" annunciator for the card *reader* would appear as
|> "chip box full"...)
Great fun, but the lights are all incandescent, not neon.
|> As far as I recall (from too many years ago) the
|> 1402, like the 1401, was completely transistorized and had no logic
|> vacuum tubes.
No transistors in the 1402, except for the power supplies in the bottom
that power the 1401 processor. All the 1402 control logic is small
wire-contact relays and a few larger ones for power control.
|> Oh yes...the neon lamp in the 1402 was used for the dynamic timer.
That's right, one for the reader and one for the punch. But thats not a
vacuum tube, its just a light. There is one tube, I think; the amplifier
for the dynamic timer is a 12AU7. Maybe that's what Edward remembers.
There are no other vacuum tubes in a normal 1401 system. The 1401 is all
transistors, the 1402 card read/punch has all the relays and power
supplies for the processor (left) side of the 1401 (if its a tape
machine it has a right side with its own power) and the 1403 printer has
no logic except for some hydralic valves for the paper feed motor and
maybe a sense amp for chain position. The 729 or 7330 tape drives have
relay or transistor control logic and a transistor data path.
|>
|> Joe Morris / MITRE
--
Paul Pierce p...@ssd.intel.com
Intel
Ethan Dicks
: In article <erd....@kumiss.cmhnet.org>, e...@kumiss.cmhnet.org (Ethan Dicks) writes:
[ Discussion of Odessey deleted ]
: If it's putting dots on the screen (and if it contains TTL!), it's probably not
: an analog device. I suspect you mean that it does not contain a microprocessor
: or a semblance thereto.
I mean what I said! I never said that it contained TTL parts of any kind. I
said that the Odessey is an analog device. TTL is not required to put dots
on the screen. neither is a microprocessor.
If there are any ICs on the main board, they are Linear, not TTL.
-ethan
Edward Rice
> Trivia quiz: the IBM boxes of that era all used plug-in cards, made of
> yellow phenolic plastic, with discrete components. What was the
> three-letter name used to describe this technology, and what did its
> letters stand for? (I can give the 3-letter name but can't recall the
> definition.)
>
> SMS popped into mind, but I don't have old books nearby to verify.
>
JM> Right. Now if someone can figure out what it stood for we'll both
JM> know.
Standardized Module System? (SWAG)
Edward Rice
RH> [story about wierd failure of a 2540 Card reader]
|> A combination of a cold solder joint and a shorting wire on the
|> wire-wrap backplane. Seems the wire was tight up against a square pin
|> and the corner had cut into the insulation of the wire. Hard to find!!
RH> When we had our KI-10, just after we had replace DEC as the H/W
RH> maintenance group by Tymshare, the KI-10 would suddenly just freeze...
A friend of mine at Honeywell, the company's senior software fixer-upper for
their large-scale 6000 systems, got a trouble call from the Army War College.
He got home a week or so later. Furious and amused. The problem appeared to
be software failing under heavy load, but in fact turned out to be a
sporadically failing piece of hardware whose effects were nullified under most
conditions by the condition of a particular register. Unless the top three
bits of the register were <whatever> at exactly the same time that the circuit
blipped, nothing would happen. All conditions met, the system crashed hard,
and never the same way twice.
John West
>That's why I prepared the alt.sys.pdp8 faq (and I'm still working
>on improving it). Eventually, I'd like to see similar faq files
>for a number of other old machines. The next one I'd like to hammer
>down is the IBM 701, a 1953 gem for which I happen to have the
>principles of operation book. If you like such things, here's a
>brief summary:
PDP1, anyone? I've got a heap of manuals and things (from an
emulator/clone project I'm working on). The following is from memory, so it
is incomplete and probably incorrect.
Computer: PDP1
Date: erk. I've forgotten. 1960 is not more than 3 years away.
Technology: Transistors
>Main memory: 4096 words of 18 bits. Ferrite core. Memory extension box
gives 65536 words of 18 bits and changes operation of some
instructions to address it.
>Addressing: words
>Registers: AC: 18 bits
IO: 18 bits
6(?) flag bits
Number system: One's complement. 18 bits
Instruction: 18 bits. Mostly 6 bits of opcode followed by 12 bits of
address. Low bit of opcode is 'indirect' bit - operand is at
location pointed to by the location given in the instruction.
Some instructions use the address field as a micro-code
instruction. Various bits control various operations. Opcode
72(?) is for IO - address specifies what operation to do.
IO instructions depend on what extra boxes you have plugged
in. Most instructions take 10us.
Core memory is inherently RMW, and instruction set takes
advantage of this - you have 'store instruction part' and
'store address part' instructions for self modifying code. No
stack. Subroutine call places old PC into AC.
Wonderful vector displays that put this VGA rubbish to shame. The cheap one
was addressable to 1K*1K. Vector so no jaggies on your lines. You could buy
a character generator box that drew 5*7 characters in one of 4 sizes, and
could cope with 200 or so without flickering.
I'm very impressed at how fast it was. 10us doesn't sound like a
particularly speedy instruction, but if you compare it to things like the
6502 (nearly 20 years later) with an average 4us per instruction, it is
quite good. With the multiplier option, you could multiply 18 bit words in
under 25us.
John West
Andy Rabagliati
across the room (1220 Lab, BAC Bristol), and it failing to power up.
Symptom :- blown fuse.
Time to debug.
Hmmm - put in another one ... fuse blows.
Put in a bigger one - it blows too - small puff of smoke.
Station five people round the box as spotters - put in big fuse again.
Puff of smoke - somewhere at the bottom of the rack.
Again .. Aha ! Near power connector.
Someone had put the power receptacle too close to the steel wheel
castor - which was resting against the live pin of the receptacle.
Replace burned receptacle, turn wheel - back on track again.
Cheers, Andy.
Dave Horsfall
jcmo...@mwunix.mitre.org (Joe Morris) writes:
| Trivia quiz: the IBM boxes of that era all used plug-in cards, made of
| yellow phenolic plastic, with discrete components. What was the three-letter
| name used to describe this technology, and what did its letters stand for?
| (I can give the 3-letter name but can't recall the definition.)
Ummm... I've got heaps of those cards (used to strip 'em for the
diodes and transistors) - DTL == Diode-Transistor Logic?
--
Dave Horsfall (VK2KFU) VK2KFU @ VK2RWI.NSW.AUS.OC PGP 2.3
da...@esi.COM.AU ...munnari!esi.COM.AU!dave available
James Cassidy
I think they were called SMS => Standard Modular System cards. If
I remember correctly, they had cards like a multiple input NAND, or
NOR, etc. Logic functions which RTL/DTL/TTL ICs did on a single chip.
Not all the gates on a SMS card were necessarily used (depending on what
the card was being used for). I can remember a graduate student
searching through the 1620 schematics, looking for unused gates he
could scrounge. Part of his thesis was to add instructions to the
machine.
---
Jim Cassidy / cas...@NeoSoft.com
Chris Marriott
>
>In article <1993Sep3.1...@news.uiowa.edu>, Douglas W. Jones,201H MLH,
>3193350740,3193382879 (jones@pyrite) writes:
>> [....arcana deleted....]
>>The border between computers, calculators and controllers can get fuzzy,
>>for example, ENIAC was clearly a programmable calculator, but was it a
>>computer? You could reprogram it with a patch panel change, and it was
>>powerful enough that someone could have programmed a patch panel to make
>>it interpret a stored program, but to my knowledge, nobody did it.
>>
>I don't have my copy of Goldstine's _The Computer from Pascal to
>von Neumann_ right to hand (chorus of "Why NOT?!",) but I think von
>Neumann, Adele Goldstine and Arthur Burks actually _did_ do that.
>If I can dig up ch. and verse I'll be back with it.
>
On a wall that I used to walk past every day, at Manchester University,
there's a plaque saying "The world's first stored-program digital computer
was operated in a room on this site, 1946" (or words to that effect).
Chris
--
--------------------------------------------------------------------------
| Chris Marriott | ch...@chrism.demon.co.uk |
| Warrington, UK | 10011...@compuserve.com |
| Save the whales. Collect the whole set. | CompuServe: 100113,1140 |
--------------------------------------------------------------------------
Mark Brader
> > > computer? You could reprogram it with a patch panel change, and it
> > > was powerful enough that someone could have programmed a patch panel
> > > to make it interpret a stored program, but to my knowledge, nobody
> > > did it.
> > >
Well, sort of. Here's the latest version of the chronology which I've
posted from time to time. Note the item dated "Sep 1948".
> On a wall that I used to walk past every day, at Manchester University,
> there's a plaque saying "The world's first stored-program digital computer
> was operated in a room on this site, 1946" (or words to that effect).
I hope it says 1948, because that's when it was.
# # # # # # # #
What was the first computer and who built it?
It turns out that this is more a question of definition than a
question of fact. The computer, as we now understand the word,
was very much an evolutionary development rather than a simple
invention. This article traces the sequence of the most important
steps in that development, and in the earlier development of
digital calculators without programmability. It may help you
to decide for yourself whether you think the first computer was
the ABC, the V3 (aka Z3), the ENIAC, the SSEC, the Manchester
Mark I, the EDSAC, or perhaps yet another machine -- and how to
apportion the honor of invention among John Atanasoff, Charles
Babbage, Presper Eckert, John Mauchly, Alan Turing, John von
Neumann, Konrad Zuse, and others.
----------------------------------------------------
This article has evolved from an original version that I drafted
in 1988, and has been posted to various Usenet groups several times.
It has been prepared primarily from two sources:
Bit by Bit: An Illustrated History of Computers
by Stan Augarten
1984, Ticknor and Fields, New York
ISBN 0-89919-268-8, 0-89919-302-1 paperback
A History of Computing Technology
by Michael R. Williams
1985, Prentice-Hall, Englewood Cliffs, NJ
ISBN 0-13-389917-9
Either of these books is well worth a trip to the library to read.
(Unfortunately, finding either one in a bookstore today would be an
unlikely proposition.) Augarten is a journalist; he writes very
readably, but occasionally does not say exactly what he means.
Williams is a computer science professor; his book is superior in
technical depth, and covers additional subject areas including
analog computing and computing in ancient times.
For some material I also consulted the following four books.
The Dream Machine: Exploring the Computer Age
by Jon Palfreman and Doron Swade
BBC Books, London, 1991
ISBN 0-563-36221-9
The book of the TV series of the same title, which changed to "The
Machine that Changed the World" when it was shown in the US on PBS.
I enjoyed the content but found the typographic design so hideously
mannered as to be distracting. This book has less technical detail
than the two mentioned above, and a greater emphasis on the impact of
computers on the modern world; a considerable fraction of its length
is on the uninteresting :-) period after the end of this chronology.
Portraits in Silicon
by Robert Slater
1987, MIT Press, Cambridge, MA
ISBN 0-262-69131-0
Articles about, and interviews with, 34 of the people to whom goes
much of the credit for the computer world being the way it is, from
Charles Babbage to Donald Knuth.
The Computer Comes of Age / Ainsi naquit l'informatique
by R. Moreau, English translation by J. Howlett
1981, translated 1984, MIT Press, Cambridge, MA
ISBN 0-262-36103-2
Concentrating on the period from the mid 1940s to mid 1960s, and
with a noticeably IBMish viewpoint.
Encyclopedia of Computer Science and Engineering, 2nd ed.
editor Anthony Ralston, associate Editor Edwin D. Reilly Jr.
1983, Van Nostrand Reinhold, New York
ISBN 0-442-24496-7
The title is self-explanatory.
Finally, the August 1988 issue of Scientific American contained an
article about the Atanasoff-Berry machines. There is also a book
by Clark Mollenhoff about them, some information from which was
forwarded to me by email. And the February 1993 issue of Scientific
American contained an article about Babbage's difference engines
and the modern-day completion of one of them.
----------------------------------------------------
I've tried to mention in this chronology each machine within the
relevant time period that meets the following criteria. First,
it must do arithmetic digitally; this eliminates, for instance,
the slide rule. Second, it must actually do arithmetic rather
than just assisting the user's memory; I consider this to eliminate
the abacus as well as, say, Napier's Bones. Third, it must do
essentially the whole computation, with little or no assistance
from the user; you could subtract 16 on a 6-digit Pascaline by
adding 999984, but this doesn't mean we should say that a Pascaline
could subtract. Fourth, it must work on user-supplied operands;
in 1364, Giovanni de' Dondi completed a clock that used chains of
various lengths to represent calendar cycles and compute the date
of Easter, but this does not qualify even if the chains advanced
in discrete "digital" steps (I haven't seen a description detailed
enough to say whether they did).
And finally, the machine must have either been technologically
innovative, or else well known and influential. For certain concepts
of special importance, I have also listed the first time they were
*described*, although they were not implemented at that time.
Where I do not describe the size of a machine, it is generally
suitable for desktop use if it has no memory and is unprogrammable
or if it is a small prototype, but would fill a small room if it has
memory or significant programmability.
The term "full-scale" is used, in contrast to "prototype", to refer
to a machine with sufficient capacity to do regular useful work.
For the sorts of machines described toward the end of the chronology,
I generally consider them "completed" when they first run a program,
even though they may be subject to further modifications and debugging.
The names Tuebingen, Wuerttemberg, and Mueller should have an
umlauted "u" in place of the "ue" used in this ASCII text.
----------------------------------------------------
A Chronology of Digital Computing Machines (to 1952)
----------------------------------------------------
1623. Wilhelm Schickard (1592-1635), of Tuebingen, Wuerttemberg
(now in Germany), makes his "Calculating Clock". This is a
6-digit machine that can add and subtract, and indicates overflow
by ringing a bell. Mounted on the machine is a set of Napier's Rods
(or Bones), a memory aid facilitating multiplications. The machine
and plans are lost and forgotten in the war that is going on.
The plans are finally rediscovered in 1935, only to be lost in war
again, and then re-rediscovered in 1956 by the same man! The machine
is reconstructed in 1960, and found to be workable.
(Schickard is a friend of the astronomer Kepler.)
(According to an informal communication, Schickard sometimes used the
device for 7-digit calculations, counting rings of the overflow bell
by putting rings on one of his, uh, personal digits...)
1644-5. Blaise Pascal (1623-1662), of Paris, makes his "Pascaline".
This 5-digit machine uses a different carry mechanism from
Schickard's, with rising and falling weights instead of a direct
gear drive; it can be extended better to support more digits, but
it cannot subtract, and probably is less reliable than Schickard's
simpler method.
Where Schickard's machine is forgotten -- and indeed Pascal is
apparently unaware it ever existed -- Pascal's becomes well known
and establishes the computing machine concept in the intellectual
community. He makes more machines and sells about 10-15 of them,
some supporting as many as 8 digits. (Several survive to the
present day.) Patents being a thing of the future, others also
sell copies of Pascal's machine.
(Pascal is also the inventor of the bus.)
c.1668. Sir Samuel Morland (1625-1695), of England, produces a
non-decimal adding machine, suitable for use with English
money. Instead of a carry mechanism, it registers carries on
auxiliary dials, from which the user must reenter them as addends.
1674. Gottfried Wilhelm von Leibniz (1646-1716), of Leipzig,
designs his "Stepped Reckoner", which is constructed by a
man named Olivier, of Paris. It uses a movable carriage so that it
can multiply, with operands of up to 5 and 12 digits and a product
of up to 16. The user has to turn a crank once for each unit in
each digit in the multiplier; a fluted drum translates the turns
into additions. But the carry mechanism requires user intervention,
and doesn't really work in all cases anyway.
Leibniz's machine doesn't get forgotten, but it does get misplaced
in an attic within a few years -- and stays there until 1879 when
it is noticed by a man working on the leaky roof!
(Leibniz, or Leibnitz, is also the co-inventor of calculus.)
1775. Charles, the third Earl Stanhope, of England, makes a
successful multiplying calculator similar to Leibniz's.
1770-6. Mathieus Hahn, somewhere in what is now Germany, also makes
a successful multiplying calculator.
1786. J. H. Mueller, of the Hessian army, conceives the idea of
what came to be called a "difference engine". That's a
special-purpose calculator for tabulating values of a polynomial,
given the differences between certain values so that the polynomial
is uniquely specified; it's useful for any function that can be
approximated by a polynomial over suitable intervals. Mueller's
attempt to raise funds fails and the project is forgotten.
1820. Charles Xavier Thomas de Colmar (1785-1870), of France,
makes his "Arithmometer", the first mass-produced calculator.
It does multiplication using the same general approach as Leibniz's
calculator; with assistance from the user it can also do division.
It is also the most reliable calculator yet. Machines of this general
design, large enough to occupy most of a desktop, continue to be sold
for about 90 years.
1822. Charles Babbage (1792-1871), of London, having reinvented
the difference engine, begins his (government-funded)
project to build one by constructing a 6-digit calculator using
gear technology similar to that planned for the difference engine.
1832. Babbage and Joseph Clement produce a prototype segment of
his difference engine, which operates on 6-digit numbers
and 2nd-order differences (i.e. can tabulate quadratic polynomials).
The complete engine, which would be room-sized, is planned to be
able to operate both on 6th-order differences with numbers of about
20 digits, and on 3rd-order differences with numbers of 30 digits.
Each addition would be done in two phases, the second one taking
care of any carries generated in the first. The output digits
would be punched into a soft metal plate, from which a plate for a
printing press could be made.
But there are various difficulties, and no more than this prototype
piece is ever assembled.
1834. George Scheutz, of Stockholm, produces a small difference
engine in wood, after reading a brief description of
Babbage's project.
1834. Babbage conceives, and begins to design, his "Analytical
Engine". Whether or not this machine, if built, would
have constituted a computer depends on exactly how "computer" is
being defined. One essential feature of present-day computers
is absent from the design: the "stored-program" concept, which is
necessary for implementing a compiler. The program would have
been in read-only memory, specifically in the form of punch cards.
(In this chronology, such machines will be called "programmable
calculators".)
Babbage continues to work on the design for years, though after
about 1840 the changes are minor. The machine would operate on
40-digit numbers; the "mill" (CPU) would have 2 main accumulators
and some auxiliary ones for specific purposes, while the "store"
(memory) would hold perhaps 100 more numbers. There would be
several punch card readers, for both programs and data; the cards
would be chained and the motion of each chain could be reversed.
The machine would be able to perform conditional jumps. There
would also be a form of microcoding: the meaning of instructions
would depend on the positioning of metal studs in a slotted
barrel, called the "control barrel".
The machine would do an addition in 3 seconds and a multiplication
or division in 2-4 minutes.
1842. Babbage's difference engine project is officially canceled.
(The cost overruns have been considerable, and Babbage is
spending too much time on redesigning the Analytical Engine.)
1843. Scheutz and his son Edvard Scheutz produce a 3rd-order
difference engine with printer, and the Swedish government
agrees to fund their next development.
1847-9. Babbage designs an improved, simpler difference engine,
which will operate on 7th-order differences and 31-digit
numbers, but nobody is interested in paying to have it built.
(In 1989-91, however, a team at London's Science Museum will do
just that. They will use components of modern construction, but
with tolerances no better than Clement could have provided... and,
after a bit of tinkering and detail-debugging, they will find that
the machine does indeed work.)
1853. To Babbage's delight, the Scheutzes complete the first
full-scale difference engine, which they call a Tabul-
ating Machine. It operates on 15-digit numbers and 4th-order
differences, and produces printed output as Babbage's would have.
A second machine is later built to the same design by the firm
of Brian Donkin of London.
1858. The first Tabulating Machine is bought by the Dudley
Observatory in Albany, New York, and the second one by
the British government. The Albany machine is used to produce
a set of astronomical tables; but the observatory's director is
then fired for this extravagant purchase, and the machine is
never seriously used again, eventually ending up in a museum.
The second machine, however, has a long and useful life.
1871. Babbage produces a prototype section of the Analytical
Engine's mill and printer.
1878. Ramon Verea, living in New York City, invents a calculator
with an internal multiplication table; this is much faster
than the shifting carriage or other digital methods. He isn't
interested in putting it into production; he just wants to show that
a Spaniard can invent as well as an American.
1879. A committee investigates the feasibility of completing the
Analytical Engine and concludes that it is impossible now
that Babbage is dead. The project is then largely forgotten and is
unknown to most of the people mentioned in the last part of this
chronology -- though Howard Aiken is an exception.
1885. A multiplying calculator more compact than the Arithmometer
enters mass production. The design is the independent, and
more or less simultaneous, invention of Frank S. Baldwin, of the
United States, and T. Odhner, a Swede living in Russia. The fluted
drums are replaced by a "variable-toothed gear" design: a disk with
radial pegs that can be made to protrude or retract from it.
1886. Dorr E. Felt (1862-1930), of Chicago, makes his "Comptometer".
This is the first calculator where the operands are entered
merely by pressing keys rather than having to be, for example, dialed
in. It is feasible because of Felt's invention of a carry mechanism
fast enough to act while the keys return from being pressed.
1889. Felt invents the first printing desk calculator.
1890. US Census results are tabulated for the first time with sig-
nificant mechanical aid: the punch card tabulators of Herman
Hollerith (1860-1929) of MIT, Cambridge, Mass. This is the start of
the punch card industry. The cost of the census tabulation is 98%
*higher* than the previous one, in part because of the temptation to
use the machines to the fullest and tabulate more data than formerly
possible, but the tabulation is completed in a much shorter time.
Another precedent is that the cards are read electrically.
(Contrary to popular impression and to earlier versions of this
chronology, Hollerith's cards of 1890 are not the same size as
US paper money of the time; they are much smaller. Other sizes of
punch cards will also appear within a few years.)
1892. William S. Burroughs (1857-1898), of St. Louis, invents a
machine similar to Felt's but more robust, and this is the
one that really starts the office calculator industry.
(This machine is still hand powered, but it won't be many years
before electric calculators appear.)
1906. Henry Babbage, Charles's son, with the help of the firm of
R. W. Munro, completes the mill of his father's Analytical
Engine, just to show that it would have worked. It does. The
complete machine is never produced.
1919. W. H. Eccles and F. W. Jordan publish the first flip-flop
circuit design.
1931-2. E. Wynn-Williams, at Cambridge, England, uses thyratron
tubes to construct a binary digital counter for use in
connection with physics experiments.
1935. International Business Machines introduces the "IBM 601",
a punch card machine with an arithmetic unit based on relays
and capable of doing a multiplication in 1 second. The machine
becomes important both in scientific and commercial computation,
and about 1500 of them are eventually made.
1937. George Stibitz (c.1910-) of the Bell Telephone Laboratories
(Bell Labs), New York City, constructs a demonstration 1-bit
binary adder using relays.
1937. Alan M. Turing (1912-1954), of Cambridge University, England,
publishes a paper on "computable numbers". This paper solves
a mathematical problem, but the solution is achieved by reasoning
(as a mathematical device) about the theoretical simplified computer
known today as a Turing machine.
1938. Claude E. Shannon (1916-) publishes a paper on the
implementation of symbolic logic using relays.
1938. Konrad Zuse (1910-) of Berlin, with some assistance from
Helmut Schreyer, completes a prototype mechanical binary
programmable calculator, originally called the "V1" but retroactively
renamed "Z1" after the war. It works with floating point numbers
having a 7-bit exponent, 16-bit mantissa, and a sign bit. The
memory uses sliding metal parts to store 16 such numbers, and works
well; but the arithmetic unit is less successful.
The program is read from punched tape -- not paper tape, but
discarded 35 mm movie film. Data values can be entered from a
numeric keyboard, and outputs are displayed on electric lamps.
Nov 1939. John V. Atanasoff (1903-) and graduate student Clifford
Berry (?-1963), of Iowa State College (now the Iowa State
University), Ames, Iowa, complete a prototype 16-bit adder. This is
the first machine to calculate using vacuum tubes.
1939. Zuse and Schreyer begin work on the "V2" (later "Z2"),
which will marry the Z1's existing mechanical memory unit to
a new arithmetic unit using relay logic. The project is interrupted
for a year when Zuse is drafted.
(Zuse is a friend of Wernher von Braun, who will later develop the
*other* "V2", and after that, play a key role in the US space program.)
1939-40. Schreyer completes a prototype 10-bit adder using vacuum
tubes, and a prototype memory using neon lamps.
Jan 1940. At Bell Labs, Samuel Williams and Stibitz complete a
calculator which can operate on complex numbers, and give
it the imaginative name of the "Complex Number Calculator"; it is
later known as the "Model I Relay Calculator". It uses telephone
switching parts for logic: 450 relays and 10 crossbar switches.
Numbers are represented in "plus 3 BCD"; that is, for each decimal
digit, 0 is represented by binary 0011, 1 by 0100, and so on up to
1100 for 9; this scheme requires fewer relays than straight BCD.
Rather than requiring users to come to the machine to use it, the
calculator is provided with three remote keyboards, at various
places in the building, in the form of teletypes. Only one can be
used at a time, and the output is automatically displayed on the
same one. In September 1940, a teletype is set up at a mathematical
conference in Hanover, New Hampshire, with a connection to New York,
and those attending the conference can use the machine remotely.
1940. Zuse is released from the army and completes the Z2.
It works better than the Z1, but isn't reliable enough.
(Later he is drafted again, and released again.)
Summer 1941. Atanasoff and Berry complete a special-purpose calcu-
lator for solving systems of simultaneous linear equations,
later called the "ABC" ("Atanasoff-Berry Computer"). This has 60
50-bit words of memory in the form of capacitors (with refresh
circuits -- the first regenerative memory) mounted on two revolving
drums. The clock speed is 60 Hz, and an addition takes 1 second.
For secondary memory it uses punch cards, moved around by the user.
The holes are not actually punched in the cards, but burned. The
punch card system's error rate is never reduced beyond 0.001%, and
this isn't really good enough.
(Atanasoff will leave Iowa State after the US enters the war, and
this will end his work on digital computing machines.)
Dec 1941. Now working with limited backing from the DVL (German Aero-
nautical Research Institute), Zuse completes the "V3" (later
"Z3"): the first operational programmable calculator. It works with
floating point numbers having a 7-bit exponent, 14-bit mantissa
(with a "1" bit automatically prefixed unless the number is 0),
and a sign bit. The memory holds 64 of these words and therefore
requires over 1400 relays; there are 1200 more in the arithmetic
and control units.
The program, input, and output are implemented as described above for
the Z1. Conditional jumps are not available. The machine can do 3-4
additions per second, and takes 3-5 seconds for a multiplication.
It is a marginal decision whether to call the Z3 a prototype; with
its small memory it is certainly not very useful on the equation-
solving problems that the DVL was mostly interested in.
Jan 1943. Howard H. Aiken (1900-1973) and his team at Harvard
University, Cambridge, Mass. (with IBM's backing), complete
the "ASCC Mark I" ("Automatic Sequence-Controlled Calculator Mark I"),
also called the "Harvard Mark I". This electromechanical machine is
the first programmable calculator to be widely known: Aiken is to
Zuse as Pascal to Schickard.
The machine is 51 feet long, weighs 5 tons, and incorporates 750,000
parts. It includes 72 accumulators, each incorporating its own arith-
metic unit as well as a mechanical register with a capacity of 23
digits plus sign. (See the ENIAC entry, below, for a more detailed
description of such an architecture.) The arithmetic is fixed-point,
with a plugboard setting determining the number of decimal places.
I/O facilities include card readers, a card punch, paper tape readers,
and typewriters. There are 60 sets of rotary switches, each of which
can be used as a constant register -- sort of a mechanical read-only
memory.
The program is read from one paper tape; data can be read from the
other tapes, or the card readers, or from the constant registers.
Conditional jumps are not available. However, in later years the
machine is modified to support multiple paper tape readers for the
program, with the transfer from one to another being conditional,
sort of like a conditional subroutine call. Another addition allows
the provision of plugboard-wired subroutines callable from the tape.
Apr 1943. Max Newman, Wynn-Williams, and their team at the secret
Government Code and Cypher School, Bletchley Park, Bletchley,
England, complete the "Heath Robinson". This is a specialized machine
for cipher-breaking, not a general-purpose calculator or computer but
some sort of logic device, using a combination of electronics and relay
logic. It reads data optically at 2000 characters per second from
2 closed loops of paper tape, each typically about 1000 characters long.
(Turing was a student of Newman's.)
(The secrecy that surrounded this machine and its successors at
Bletchley Park will still be partially in effect at the time of
writing, hence the vague description. Newman knew Turing from
Cambridge, and had been the first person to see a draft of Turing's
1937 paper. Heath Robinson is the name of a British cartoonist known
for drawings of comical machines, like the American Rube Goldberg.
Two later machines in the series will be named for London stores
with "Robinson" in their names!)
Sep 1943. Williams and Stibitz complete the "Relay Interpolator",
later called the "Model II Relay Calculator". This is a
programmable calculator; again, the program and data are read from
paper tapes. An innovative feature is that, for greater reliability,
numbers are represented in a biquinary format using 7 relays for
each digit, of which exactly 2 should be "on": 01 00001 for 0,
01 00010 for 1, and so on up to 10 10000 for 9.
(Some of the later machines in this series used the biquinary
notation for the digits of floating-point numbers.)
Dec 1943. Tommy Flowers and his team at Bletchley Park complete
the first "Colossus". This successor to the "Robinson"
series machines is entirely electronic, incorporating 2400 vacuum
tubes for logic. It has 5 paper tape loop readers, each working
at 5000 characters per second.
(10 Colossi will eventually be built. Turing also has an important
role at Bletchley Park, but does not work directly on the machines.)
1944-5. Zuse almost completes his first full-scale machine, the "V4"
(later "Z4"), which resembles his earlier designs. Its
memory reverts to the Z1's mechanical design, storing 1000 words of
32 bits in less then a cubic meter; the equivalent in relays would
have filled a large room.
As the war begins to go very badly for Germany, Zuse's work is dis-
rupted several times, and then abandoned for the duration. An air
raid had destroyed the Z3 in 1943, but the incomplete Z4 survives the
war's end in a basement.
1945. Zuse invents a programming language called Plankalkul.
Jun 1945. John von Neumann (1903-1957), having joined the ENIAC
team, drafts a report describing the future computer
eventually built as the "EDVAC" ("Electronic Discrete Variable
Automatic Computer" (!)); this is the first description of the
design of a stored-program computer, and gives rise to the term
"von Neumann computer".
The first draft of the report fails to credit other team members
such as Eckert and Mauchly; when this version becomes widely
circulated, von Neumann gets somewhat too much credit for the
design. The final version corrects the oversight, but too late.
(Von Neumann, also noted for his mental calculating ability, is
the only one of the principal computer pioneers in the US familiar
with Turing's 1937 paper.)
Nov 1945. John W. Mauchly (pronounced Mawkly; 1907-80) and J. Presper
Eckert (1919-) and their team at the Moore School of Electrical
Engineering, of the University of Pennsylvania, Philadelphia, complete
a secret project for the US Army's Ballistics Research Lab: a program-
mable calculator called the "ENIAC" ("Electronic Numerator, Integrator,
Analyzer, and Computer").
The ENIAC's architecture resembles that of the Harvard Mark I, but
its components are entirely electronic, incorporating 17,468 vacuum
tubes. The machine weighs 30 tons, covers about 1000 square feet
of floor, and consumes 130 or 140 kilowatts of electricity.
The machine incorporates 20 accumulators (the original plan was for 4).
The accumulators and other units are all connected by several data
buses, and a set of "program lines" for synchronization. Each accum-
ulator stores a 10-digit number, using 10 bits to represent each digit,
and also incorporates circuits to add a number from a bus to the
stored number, and to transmit the stored number or its complement to
a bus.
A separate unit can perform multiplication (in about 3 milliseconds),
while another does division and square roots; the inputs and outputs
for both these units use the buses. There are constant registers, as
on the Harvard Mark I: 104 12-digit registers forming an array called
the "function table". 100 of these registers are directly addressable
by a 2-digit number from a bus (the others are used for interpolations).
Finally, a card reader is available to input data values, and there
is a card punch for output.
The program is set up on a plugboard -- this is considered reasonable
since the same or similar program would generally be used for weeks
at a time. For example, connecting certain sockets would cause
accumulator 1 to transmit its contents onto data bus 1 when a pulse
arrived on program line 1; meanwhile several accumulators could be
adding the value from that data bus to their stored value, while
others could be working independently. The program lines are pulsed
under the control of a master unit, which can perform iterations.
The ENIAC's clock speed is 100 kHz.
Mauchly and Eckert apply for a patent. The university disputes this
at first, but they settle. The patent is finally granted in 1964,
but is overturned in 1973, in part because of the previous work by
Atanasoff, with which Mauchly was acquainted.
(The BRL wanted the ENIAC to use on the difficult problem of making
aiming tables for use by artillerymen. It isn't ready in time for
the war, and overruns its original budget by 225% -- problems that
will face Eckert and Mauchly again on later projects.)
Feb 1946. The ENIAC is revealed to the public. A panel of lights is
added to help show reporters how fast the machine is and what
it is doing; and apparently Hollywood takes note.
Jul-Aug 1946. The Moore School gives a course on "Theory and Techniques
for Design of Electronic Computers"; lectures are given by
Eckert, Mauchly, Stibitz, von Neumann, and Aiken among others. The
course leads to several projects being started, among them the EDSAC.
Jul 1947. Aiken and his team complete the "Harvard Mark II", a large
programmable calculator using relays both for its 50 floating-
point registers and for the arithmetic unit, 13,000 of them in all.
Sep 1947. A moth (?-1947) makes the mistake of flying into the Harvard
Mark II. A whimsical technician makes the logbook entry "first
actual case of bug being found", and annotates it by taping down the
remains of the moth.
(The term "bug" was of course already in use; that's why it's funny.)
1947. Frederick Viehe (?-1960), of Los Angeles, applies for a patent
on an invention which is to use magnetic core memory.
1947. Aiken predicts that the United States will need a total of six
electronic digital computers.
c.1947. The magnetic drum memory is independently invented by several
people, and the first examples are constructed.
(As noted below, some early machines will use drums as main memory
rather than secondary memory.)
Jan 1948. Wallace Eckert (1902-1971, no relation to Presper Eckert)
of IBM, with his team, completes the "SSEC" ("Selective
Sequence Electronic Calculator"). This technological hybrid has
8 vacuum tube registers, 150 words of relay memory, and 66 paper
tape loops storing a total of 20,000 words. The word size is
20 digits, stored in BCD in the registers.
As with the Harvard Mark I in its later form, the machine can be
switched to read instructions from any of the paper tapes. There
is also some use of plugboards in its programming. But it can
also cache some instructions in memory and read them from there;
thus, in effect, it can operate either as a stored-program computer
(with a very small program memory) or not. Because it can do this,
IBM's point of view is that this is the first computer.
Jun 1948. Newman, Freddie C. Williams, and their team at Manchester
University, Manchester, England, complete a prototype machine,
the "Mark I" (also called the "Manchester Mark I"). This is the
first machine that everyone would call a computer, because it's the
first with a true stored-program capability.
It uses a new type of memory developed by F. C. Williams (possibly
after an original suggestion by Presper Eckert), which uses the
residual charges left on the screen of a CRT after the electron
beam has been fired at it. (The bits are read by firing another
beam through them and reading the voltage at an electrode beyond
the screen.) This is a little unreliable but is fast, and also
relatively cheap because it can use existing CRT designs; and it is
much more compact than any other memory then existing. The Mark I's
main memory of 32 32-bit words occupies a single Williams tube.
(Other CRTs on the machine are less densely used: one contains only
an accumulator.)
The Mark I's programs are initially entered in binary on a keyboard,
and the output is read in binary from another CRT. Later Turing
joins the team (see also the "Pilot ACE", below) and devises a primi-
tive form of assembly language, one of several developed at about the
same time in different places.
Sep 1948. The ENIAC is improved, using ideas from Richard F. Clipper of
the BRL and Nicholas Metropolis of Los Alamos. Each program line
is permanently wired for a different operation, and a new converter
unit allows them to be addressed by a program, the way the function
table can -- thus implementing, in effect, opcodes. With this change,
the program can now be entered via the *function table*.
(This conversion will sometimes be described as making the ENIAC into a
stored-program computer, but the program memory is still read-only.
However, setting up a program now takes a matter of hours, rather than
days as before.)
Fall 1948. IBM introduces the "IBM 604", a programmable calculator
and card punch using vacuum tubes. It can read a card,
perform up to 60 arithmetic operations in 80 milliseconds, and punch
the results on the same card. The programming is by plugboard.
All machines first mentioned in the chronology from here on are
stored-program computers.
1949-51. Jay W. Forrester and his team at MIT construct the
"Whirlwind" for the US Navy's Office of Research and
Inventions. The vague date is because its advance to full-time
operational status is gradual. Its original form has 3300 tubes
and 8900 crystal diodes. It occupies 2500 square feet of floor.
Its 2048 16-bit words of CRT memory use up $32,000 worth of tubes
each month. There is also a graphical I/O device consisting of a
CRT (only one dot can be displayed at a time) and a light pen.
This allows the machine to be used for air traffic control.
The Whirlwind is the first computer designed for real-time work;
it can do 500,000 additions or 50,000 multiplications per second.
Spring 1949. Forrester conceives the idea of magnetic core memory as
it is to become commonly used, with a grid of wires used to
address the cores. The first practical form, in 1952-53, will replace
the Whirlwind's CRT memory and render obsolete all types of main
memory then existing.
April 1949. The Manchester Mark I, its main memory now upgraded to
128 40-bit words (on two CRTs), acquires a secondary memory
in the form of a magnetic drum holding a further 1024 words. Also
at about this time, two index registers are added to the machine.
May 1949. Maurice Wilkes (1913-) and his team at Cambridge Uni-
versity complete the "EDSAC" ("Electronic Delay Storage
Automatic Computer"), which is closely based on the EDVAC design
report from von Neumann's group -- Wilkes had attended the 1946
Moore School course. The project is supported both financially
and with technical personnel from J. Lyons & Co. Ltd., a large
British firm in the food and restaurant business.
This is the first full-scale operational stored-program computer,
and is therefore the final candidate for the title of "the first
computer".
Its main memory is of a type that had existed for some years, but
had not been used for a computing machine: the "ultrasonic delay
line" memory. It had been invented originally by William Shockley
of Bell Labs (also one of the co-inventors of the transistor, in
1948), and Presper Eckert had made an improved version in connection
with radar systems. It works by repeatedly converting from the usual
electrical data pulses to ultrasonic pulses directed along, typical-
ly, the length of a tank of mercury; on arrival at the other end,
the pulses are converted back to electrical form. The memory must
be maintained at a particular temperature, and only the few bits
currently in electrical form are accessible. In the EDSAC, 16 tanks
of mercury give a total of 256 35-bit words (or 512 17-bit words).
The clock speed of the EDSAC is 500 kHz; most instructions take
about 1500 ms to execute. Its I/O is by paper tape, and a set of
constant registers is provided for booting.
The software eventually supports the concept of relocatable proce-
dures with addresses bound at load time.
Aug 1949. Presper Eckert and Mauchly, having formed their own company,
complete the "BINAC" ("Binary Automatic Computer") for the
US Air Force. Designed as a first step to in-flight computers, this
has dual (redundant) processors each with 700 tubes and 512 31-bit
words of memory. Each processor occupies only 4 square feet of floor
space and can do 3500 additions or 1000 multiplications per second.
The designers are thinking mostly of their forthcoming "UNIVAC"
("Universal Automatic Computer") and don't spend much time making
the BINAC as reliable as it should be, but the tandem processors
compensate somewhat.
Sep 1949. Aiken's team completes the "Harvard Mark III". This
computer has separate magnetic drum memories for data and
instructions. Only some of the data drums can be addressed by
the CPU; the others serve as secondary memory. The total memory
capacity is 4000 instructions, 350 16-bit words in the main data
drums, and 4000 words more in the secondary memory. The machine
contains over 5000 vacuum tubes and 2000 relays.
May 1950. A group at the National Physical Laboratory, Teddington,
England, complete the "Pilot ACE" (pilot project for an
"Automatic Computing Engine"). This had been largely designed by
Turing when he was there in 1945-47; he had left and gone to Manches-
ter because the designs were not being implemented. The main memory
of this computer is in the form of 200 separate ultrasonic delay
lines, thus allowing better addressability than other ultrasonic-
based machines. An additional group of short delay lines serve as
registers, each of which performs a particular operation automatic-
ally on a number directed to it. Most operations then consist simply
of routing a number, or a counted stream of numbers, from one delay
line to another. Punch cards are used for input and output; a drum
will be added later for secondary memory.
(A successor to this machine will be named "DEUCE".)
1950. Zuse's Z4 is finally completed and goes into service at
ETH (Federal Polytechical Institute) in Zurich, Switzerland.
The design is modified so that it can do conditional jumps. The
machine also implements a form of intstruction pipelining, with the
program tape being read 2 instructions ahead and various optimiz-
ations performed automatically.
The Z4 remains in use for 5 years at ETH and 5 more in France, and
Zuse soon begins making his machines commercially. He eventually
sells some 300 machines before being bought out by Siemens.
1950. Douglas Hartree (the leading expert in the country on the
specialized computing machines called differential analyzers)
gives his professional opinion to Ferranti Ltd., of Manchester:
as the 3 existing computer projects will suffice to handle all the
calculations that will ever be needed in England, Ferranti would be
well advised to drop the idea of making computers for commercial sale.
Feb 1951. A rather more optimistic Ferranti Ltd. completes the first
commercial computer. This is yet another "Mark I", but is
also known as the "Manchester Mark II", "MUDC", "MUEDC", and "MADAM"!
It has 256 40-bit words of main memory and 16K words of drum, and
includes 8 index registers. An eventual total of 8 of these machines
are sold.
(The index register's contents are added, not to the address taken
from an instruction, but to the entire instruction, thus potentially
changing the opcode! Calling Mel...)
Mar 1951. Presper Eckert and Mauchly, having sold their company to
Remington Rand, complete the first "UNIVAC", which is the
first US commercial computer. (The US census department is the first
customer.) It has 1000 12-digit words of ultrasonic delay line memory
and can do 8333 additions or 555 multiplications per second; it con-
tains 5000 tubes and covers 200 square feet of floor. For secondary
memory it uses magnetic tapes of nickel-coated bronze; these are 1/2
inch wide, and store 128 characters per inch.
Fall 1951. The Lyons company receives its reward for supporting the
EDSAC, as T. Raymond Thompson, John Simmons, and their team
complete the "LEO I" ("Lyons Electronic Office I"), which is modeled
closely after the EDSAC. Its ultrasonic memory is 4 times as large,
and avoids the usual temperature dependency by using one delay line
as a master and synchronizing the others to it instead of to a clock.
The Lyons company wants the LEO I for its own use -- payroll, inven-
tory, and so on; it is the first computer used for commercial calcul-
ations. But other companies now turn out to be interested in the LEO,
and Lyons will soon find itself in the computer manufacturing business
as well.
1951. Grace Murray Hopper (1906-1992), of Remington Rand, invents
the modern concept of the compiler.
1952. The EDVAC is finally completed. It has 4000 tubes, 10,000
crystal diodes, and 1024 44-bit words of ultrasonic memory.
Its clock speed is 1 MHz.
1952. The IBM "Defense Calculator", later renamed the "701", the
first IBM computer unless you count the SSEC, enters
production at Poughkeepsie, New York. (The first one is delivered
in March 1953; 19 are sold altogether. The machine is available
with 2048 or 4096 36-bit words of CRT memory; it does 2200 multipli-
cations per second.)
(IBM stayed out of the computer market for some time because its
president, Thomas Watson Sr., didn't want the company competing
against its own business machines. His son and eventual successor,
Thomas Jr., disagreed, and realized that if it was the US *military*
that wanted to buy a computer, Thomas Sr. would not say no to them.)
1952. Grace Murray Hopper implements the first compiler, the "A-0".
(But as with "first computer", this is a somewhat arbitrary
designation.)
----------------------------------------------------
A few things have happened since then, too, but this margin is too
narrow...
--
Mark Brader, SoftQuad Inc., Toronto, utzoo!sq!msb, m...@sq.com
Nature is often much more interesting than we would like her to be.
However when we finally do understand something, we strike our
foreheads and cry "Of course!", and then marvel at how beautifully
simple it was all the time. -- Leigh Palmer
This article is in the public domain.
Sean Case
> There used to be "tape developer fluid"
>you could buy that had little black magnetic particles suspended in something.
>Dip the tape in, and the bits turned black. After the solvent evaporated, you
>could lift them off with Scotch tape and read the bits from a damaged piece of
>mag tape.
The hardware people where I work still use it... it's one way of checking
the head alignment on the tape. I don't think they've tried recovering
data with it.
The other thing it's good for is demonstrating how tape works to trainees.
Sean Case
--
Sean Case g...@coombs.anu.edu.au
"The day is surely coming when bank robbers will
plead in mitigation that the getaway car had its
hazards on." -- Ben Elton, _Gridlock_
Charles Lasner
>a...@ucssun1.sdsu.edu (young a t) writes:
>
>> There used to be "tape developer fluid"
>>you could buy that had little black magnetic particles suspended in something.
Reeves-Soundcraft "Magnasee" was a brand of the stuff with the ferrite
suspension in it dissolved in Carbon Tet. It evaporates and shows you the
flux pattern, etc.
It was also useful for quarter-track audio tape to see if the height adjustment
was reasonable on the head before azimuth adjustments were made. On some
tape decks, the azimuth adjustment might interact with height, so you had to
check the final alignment with the liquid stuff, etc.
cjl
Paul Repacholi
> a...@ucssun1.sdsu.edu (young a t) writes:
>>could lift them off with Scotch tape and read the bits from a damaged piece of
>>mag tape.
>
> The hardware people where I work still use it... it's one way of checking
> the head alignment on the tape. I don't think they've tried recovering
> data with it.
Where do they get it from? I need some for head alighnments, and can't
find any.
~Paul
DoN. Nichols
Well ... what I have, _Mag View_ I obtained from Saxitone Tape Sales
in the Washington D.C. area a few years ago, but they have gone out of
business.
It is in an aerosol can, labeled "Magnetic Tape Track Developer",
and was manufactured/packaged by Nortronics, the company that makes
replacement tape heads for almost any flavor of audio tape drive. The part
number on the can is QM601, and contains 4 Oz. of TrichloroTrifloroEthane
and Iron Power based on the label. It might be more difficult to get these
days, with the increased concern about chloro-fluoro-carbons. It doesn't
take much, so I have had many years of use from it. (I also don't need to
use it often.)
Good Luck
DoN.
--
Email: <dnic...@d-and-d.com> | ...!uunet!ceilidh!dnichols
<dnic...@ceilidh.beartrack.com>
Donald Nichols (DoN.) | Voice (Days): (703) 704-2280 (Eves): (703) 938-4564
--- Black Holes are where God is dividing by zero ---
Edward Rice
CL> Reeves-Soundcraft "Magnasee" was a brand of the stuff with the ferrite
CL> suspension in it dissolved in Carbon Tet. It evaporates and shows you
CL> the flux pattern, etc.
I thihnk the stuff our field engineers used was called "MagnaFlux."
Jim Haynes
Well you may be on to something there - I remember MagnaFlux or maybe
Magnaflux being a method of parts inspection, especially used in the
aircraft industry. The idea was that if there was an invisible crack
in a steel part you would put the part in a strong magnetic field and
put some kind of fluid on it that would cause the crack to become
visible because of the magnetic field discontinuity caused by the crack.
So if you don't come up with anything through the magnetic tape industry
you could try talking to an aircraft repair shop about MagnaFlux.
Now there was also a gadget, made by 3M as I recall, which had some
magnet fluid sealed in a round viewer. You could shake the cell to
randomize the fluid, and then set it on top of the tape and see the
bit patterns on 1/2" tape.
Rick Smith
>This article has evolved from an original version that I drafted
>in 1988, and has been posted to various Usenet groups several times.
> ...
>For some material I also consulted the following ... books.
> [some omitted...]
> The Computer Comes of Age / Ainsi naquit l'informatique
> by R. Moreau, English translation by J. Howlett
> 1981, translated 1984, MIT Press, Cambridge, MA
> ISBN 0-262-36103-2
>Concentrating on the period from the mid 1940s to mid 1960s, and
>with a noticeably IBMish viewpoint.
Yipes! _Never_ use this book without double checking what it says.
Gordon Bell did a scathing book review of it in Annals of the History
of Computing (don't have the reference, but it should be shortly after
publication). Bell's critique and Moreau's rebuttal should be required
reading for anyone who reads history books.
A basic problem is that Moreau got too much information from
Datamation's "Ten Years Ago" and "Twenty Years Ago" columns instead of
going after the original sources. There's a lesson there.
rick.
sm...@sctc.com roseville, minnesota
Brian Murray
>Well as I recall there was an article in IEEE on constructing a pong game.
>So look up back issues circa '75-76.
>
>Now then where did I put my old TV Typewriter terminal :-)
Around that time some clever sod put the whole pong game on a single
chip and called it the AY-3-8500 (from memory). There were a number of
projects in magazines that used that chip, and it is the basis for the
commercial home TV pong games everyone has in a box in the back of the
cupboard. Perhaps the IEEE article used this chip?
P.S. has anyone got the schematics of the original TTL pong game?
--
------------------------------------------------ Brian Murray ---
bri...@cbme.unsw.edu.au CBX250 Apple//c VAX 11/750 SGI Indigo
-----------------------------------------------------------------
ben...@dstos3.dsto.gov.au
> Reeves-Soundcraft "Magnasee" was a brand of the stuff with the ferrite
> suspension in it dissolved in Carbon Tet. It evaporates and shows you the
Carbon Tet ? I would have expected the tape to dissolve !
We had a little gadget once with the fluid between two plates of glass, less
messy and reusable. It was about the size of a small compass.
Regards,
John Bennett ben...@scm.dsto.gov.au
Head, I.T. Services Development Phone : +61 8 259 5292
Corporate Information Systems FAX : +61 8 259 5537
DEFENCE SCIENCE AND TECHNOLOGY ORGANISATION Postal: Bld 73 Labs Area
AUSTRALIA PO Box 1500 Salisbury
South Australia 5108
AUSTRALIA
David K. Bryant
>In article <74849188...@Clone.his.com> edwar...@his.com (Edward Rice) writes:
>> CL> From: las...@watsun.cc.columbia.edu (Charles Lasner)
>>
>> CL> Reeves-Soundcraft "Magnasee" was a brand of the stuff with the ferrite
>> CL> suspension in it dissolved in Carbon Tet. It evaporates and shows you
>> CL> the flux pattern, etc.
>>
>>I thihnk the stuff our field engineers used was called "MagnaFlux."
>>
>Well you may be on to something there - I remember MagnaFlux or maybe
>Magnaflux being a method of parts inspection, especially used in the
>aircraft industry. The idea was that if there was an invisible crack
>in a steel part you would put the part in a strong magnetic field and
>put some kind of fluid on it that would cause the crack to become
>visible because of the magnetic field discontinuity caused by the crack.
>So if you don't come up with anything through the magnetic tape industry
>you could try talking to an aircraft repair shop about MagnaFlux.
No, no, no. The stuff for seeing the patterns on mag tape is
"Magna See" by 3M. I've got a can of it at work.
>Now there was also a gadget, made by 3M as I recall, which had some
>magnet fluid sealed in a round viewer. You could shake the cell to
>randomize the fluid, and then set it on top of the tape and see the
>bit patterns on 1/2" tape.
That's a neat idea.
John G Dobnick
> hay...@cats.ucsc.edu (Jim Haynes) writes:
>
>>In article <74849188...@Clone.his.com> edwar...@his.com (Edward Rice) writes:
>>> CL> From: las...@watsun.cc.columbia.edu (Charles Lasner)
>>> CL> Reeves-Soundcraft "Magnasee" was a brand of the stuff with the ferrite
>>> CL> suspension in it dissolved in Carbon Tet. It evaporates and shows you
>>> CL> the flux pattern, etc.
>>>
>>>I thihnk the stuff our field engineers used was called "MagnaFlux."
>
> "Magna See" by 3M. I've got a can of it at work.
The stuff I recall seeing here (supplied by our Univac CEs) was in a
small glass bottle. Brand name was "VisiMag" I seem to recall. I was
told that using it on a tape was _not_ non-destructive -- i.e., don't
try to use the tape after VisiMag-ing it. It was also quite messy to
work with.
It _was_ quite useful in a number of cases in tracking down "weird"
tape problems. Little things, like discovering that one tape channel
was completely dead on a real-time data recorder. That didn't make the
researcher very happy, given that his data tape was _created_
completely UN-readable.
--
John G Dobnick "Knowing how things work is the basis
Computing Services Division for appreciation, and is thus a
University of Wisconsin - Milwaukee source of civilized delight."
j...@uwm.edu ATTnet: (414) 229-5727 -- William Safire
Pete Lancashire
>From article <dbryantC...@netcom.com>, by dbr...@netcom.com (David K. Bryant):
>> hay...@cats.ucsc.edu (Jim Haynes) writes:
>>
>>>In article <74849188...@Clone.his.com> edwar...@his.com (Edward Rice) writes:
>>>> CL> From: las...@watsun.cc.columbia.edu (Charles Lasner)
>>>> CL> Reeves-Soundcraft "Magnasee" was a brand of the stuff with the ferrite
>>>> CL> suspension in it dissolved in Carbon Tet. It evaporates and shows you
>>>> CL> the flux pattern, etc.
>>>>
>>>>I thihnk the stuff our field engineers used was called "MagnaFlux."
>>
>> No, no, no. The stuff for seeing the patterns on mag tape is
>> "Magna See" by 3M. I've got a can of it at work.
>The stuff I recall seeing here (supplied by our Univac CEs) was in a
>small glass bottle. Brand name was "VisiMag" I seem to recall. I was
>told that using it on a tape was _not_ non-destructive -- i.e., don't
>try to use the tape after VisiMag-ing it. It was also quite messy to
>work with.
Both Magna See and VisiMag are (were) basically the same thing. It was
mode from a magnetic (iron ?) oxide suspended in an inert fluorocarbon.
The destructive part came from haveing the dry powder get onto the
heads and or the rest of the tape drive.
>It _was_ quite useful in a number of cases in tracking down "weird"
>tape problems. Little things, like discovering that one tape channel
>was completely dead on a real-time data recorder. That didn't make the
>researcher very happy, given that his data tape was _created_
>completely UN-readable.
3M also made a 'viewer', can't remember it's name but is was a disk
about 1-1/2 inches in dia, and had the same or similar stuff in side of
it. You put the disk over the tape and the pattern showed up.
Damn am I feeling old ...
-pete
--------------------------------------------
----- Pete Lancashire pe...@sequent.com ----
-------- Kid in spirit. Big Brother --------
-- Adopt ? ME ? I'm single !, Am I going ---
------------- crazy ? HELP -:) -------------
--------------------------------------------
Hank Oredson
Used one of those viewers long ago to find out why a seven
track, even parity, 200bpi tape could not be read.
(Some problem with blocks of zeros ... heh heh ...)
As I recall, the viewer had "VisiMag" stamped on it.
... Hank
--
Hank Oredson @ Mentor Graphics
Internet : hank_o...@mentorg.com
Amateur Radio: W0...@W0RLI.OR.USA.NA
John Schulien
>
>>It _was_ quite useful in a number of cases in tracking down "weird"
>>tape problems. Little things, like discovering that one tape channel
>>was completely dead on a real-time data recorder. That didn't make the
>>researcher very happy, given that his data tape was _created_
>>completely UN-readable.
I've seen it used on hard disk platters. You can see the entire
track/sector/block structure. Neat!
Anyone know where I can get hold of some of this? Mail order perhaps?
I've got some old IBM 3330 and 3350 platters I'd like to develop.
Jeff Jonas
>>>tape problems. Little things, like discovering that one tape channel
>>>was completely dead on a real-time data recorder. That didn't make the
>>>researcher very happy, given that his data tape was _created_
>>>completely UN-readable.
>
>I've seen it used on hard disk platters. You can see the entire
>track/sector/block structure. Neat!
A fellow in my office relates tales of how a similar product is used
by hard disk manufacturers to "see" bad spots (apparently only for
examining bad disks - not part of the regular Q/A program).
A pet project of mine is to use this technology to read floppy disks
and possibly hard disks OPTICALLY without spinning them.
Just put on this coating that makes the magnetism visible and have
a scanner/robotic microscope read and translate the patterns back into data.
Why do this? How about to recover data from mangled or damaged disks
that can no longer spin or safely float a disk head?
How about reading data from a snapped tape? A disk that was cut?
--
Jeffrey Jonas
je...@panix.com
gle...@mwk.com
> In article <1993Oct4.2...@sequent.com>, pe...@sequent.com (Pete
> Lancashire) says:
>>
>>>It _was_ quite useful in a number of cases in tracking down "weird"
>>>tape problems. Little things, like discovering that one tape channel
>>>was completely dead on a real-time data recorder. That didn't make the
>>>researcher very happy, given that his data tape was _created_
>>>completely UN-readable.
>
that was some of the Magna-See stuff encapsulated between two
pieces of thin plastic - this let you just lay it down on something
you wanted to "Magna-See". Much less messy than the liquid stuff...
Lee K. Gleason N5ZMR
Control-G Consultants
gle...@mwk.com
Crazed Sterno Bum
>
>A pet project of mine is to use this technology to read floppy disks
>and possibly hard disks OPTICALLY without spinning them.
>Just put on this coating that makes the magnetism visible and have
>a scanner/robotic microscope read and translate the patterns back into data.
>
>Why do this? How about to recover data from mangled or damaged disks
>that can no longer spin or safely float a disk head?
>How about reading data from a snapped tape? A disk that was cut?
People in the molecular biology community are working on techniques for
automated reading of DNA sequences using a version of those stylus based
microscopes to read the individual bases on an individual strand of DNA.
God, I really wish I could remember the name of those microscopes. A
whole class of instruments with the only fundamental difference being the
signal being transduced by the stylus. Oh well.
--
____________________________________________________________________________
Erik Speckman espe...@romulus.reed.edu GBDS
"If you can't say something nasty, you shouldn't say anything at all."
_____________________________-The USENET Creed-_____________________________
Crazed Sterno Bum
I recall seeing it in the edmond cientific catalog. I don't know if they
still have it.
da...@gilly.uucp
>I recall seeing it in the edmond cientific catalog. I don't know if they
>still have it.
The magnetic field viewer from ES doesn't seem to be sensitive enough
to see bits on tape or disk.
------------------------ uunet!quack!gilly!dave ------------------------
================= Dave Fischer - Nature's Perfect Food =================
----------------------- dave%gi...@speedway.net ------------------------
Hugh JE Davies
>In article <28tefb$5...@panix.com> je...@panix.com (Jeff Jonas) writes:
>>
>>A pet project of mine is to use this technology to read floppy disks
>>and possibly hard disks OPTICALLY without spinning them.
>>Just put on this coating that makes the magnetism visible and have
>>a scanner/robotic microscope read and translate the patterns back into data.
>>
>>Why do this? How about to recover data from mangled or damaged disks
>>that can no longer spin or safely float a disk head?
>>How about reading data from a snapped tape? A disk that was cut?
>
>People in the molecular biology community are working on techniques for
>automated reading of DNA sequences using a version of those stylus based
>microscopes to read the individual bases on an individual strand of DNA.
>
>God, I really wish I could remember the name of those microscopes. A
>whole class of instruments with the only fundamental difference being the
>signal being transduced by the stylus. Oh well.
Scanning tunneling electron microscope. Works by scanning a stylus over the
surface of an object. The stylus has a voltage applied and the amount of current
that "tunnels" across the gap between the stylus and the object can be used to
determine things about the object, as well as controlling the height of the stylus
above the surface. STEMs can also be used to pick up and deposit single atoms,
as ably demonstrated recently by some researchers at IBM, who spelled out the
name of their employer in individual argon atoms on the surface of a tungsten
crystal.
(Marketing droid: "Couldn't you make the logo a little larger?")
Regards,
Hugh.
------------------------------------------------------------------
Huge...@rx.xerox.com Rank Xerox Technical Centre, WGC, UK.
I don't speak for Xerox, nor they for me.
The road to Paradise is through Intercourse.
David Breneman
:
: Thomson-CSF made a gizmo a little larger than a silver dollar
: that was some of the Magna-See stuff encapsulated between two
: pieces of thin plastic - this let you just lay it down on something
: you wanted to "Magna-See". Much less messy than the liquid stuff...
You're the second poster to mention this. Does anybody know if and
*where* these devices can be obtained? I'm interested in one mainly
as an accessory for my recording studio. It could come in handy
when editing tape.
--
David Breneman Email: da...@jaws.engineering.dgtl.com
System Administrator, Voice: 206 881-7544 Fax: 206 556-8033
Software Engineering Services
Digital Systems International, Inc. Redmond, Washington, U. S. o' A.
Ross Smith
>In article <28tefb$5...@panix.com> je...@panix.com (Jeff Jonas) writes:
>>
>>A pet project of mine is to use this technology to read floppy disks
>>and possibly hard disks OPTICALLY without spinning them.
>>Just put on this coating that makes the magnetism visible and have
>>a scanner/robotic microscope read and translate the patterns back into data.
>>
>>Why do this? How about to recover data from mangled or damaged disks
>>that can no longer spin or safely float a disk head?
>>How about reading data from a snapped tape? A disk that was cut?
>
>People in the molecular biology community are working on techniques for
>automated reading of DNA sequences using a version of those stylus based
>microscopes to read the individual bases on an individual strand of DNA.
>
>God, I really wish I could remember the name of those microscopes. A
>whole class of instruments with the only fundamental difference being the
>signal being transduced by the stylus. Oh well.
Scanning tunnelling microscopes, or STMs. A common subject of discussion
on sci.nanotech.
--
... Ross Smith (Wanganui, New Zealand) ... al...@acheron.amigans.gen.nz ...
"A Real Cat's aim is to get through life peacefully, with as little
interference from human beings as possible. Very much like real humans, in
fact." (Terry Pratchett)
DoN. Nichols
>gle...@mwk.com wrote:
>:
[ ... ]
>: you wanted to "Magna-See". Much less messy than the liquid stuff...
>:
>
>You're the second poster to mention this. Does anybody know if and
>*where* these devices can be obtained? I'm interested in one mainly
>as an accessory for my recording studio. It could come in handy
>when editing tape.
I don't know about sources for the Magna-See, but I have here a can
of "Mag View", which was sold by NOrtronics, a manufacturer of replacement
tape heads, and other accessories for audio recording equipment. You can
probably find a local dealer who carries their stuff, though they may need
to special order the Mag View. (I got mine from Saxitone Tape Sales, Inc,
which has since folded.) Mag View is in an aerosol can, and you spray it on
the tape, allow it to dry (a few seconds), and can see the audio tracks. I
don't think that you will be able to see the audio as individual waves,
because the high-frequency bias will make a solid track that overwhelms all
else. (At least, that is my experience on audio tapes.) In the case of
digital, there is no bias, and the tape is recorded in saturation in one
polarity or the other, making the data easy to see. However, it does make
it easy to judge head vertical position.