Control characters
Mark Brader
Now that the origin of ^ for exponentiation is apparently cleared up...
what is the origin of the practice of writing Control-A as ^A?
I presume this comes from a particular system or program, but which?
And a more basic question: what is the origin of the notion that the
characters SOH, STX, ETX, etc. should always be inputtable by using the
A, B, C, etc. keys in conjunction with a second shift key called Control?
On this point, I am aware of this notion being used only in ASCII and
its internationalized derivatives. Now, the ASCII standard defines
"control character" and identifies certain characters as being control
characters, but as far as I know it does not require there to be a
pairing between the control characters and certain graphic characters.
The pairing is implicit in the choices of bit patterns, though. Did
the Control key appear with the first ASCII terminals, or did it predate
ASCII in connection with some older, now obscure character code, or is
it a widely copied later innovation, or what?
--
Mark Brader "This is just the result of someone sitting down
SoftQuad Inc., Toronto before a computer and carefully removing his
utzoo!sq!msb head first. It's a phenomenon which is becoming
m...@sq.com more and more common." -- Leonard Wibberley
This article is in the public domain.
Dik T. Winter
>
> Now that the origin of ^ for exponentiation is apparently cleared up...
> what is the origin of the practice of writing Control-A as ^A?
> I presume this comes from a particular system or program, but which?
>
>
> And a more basic question: what is the origin of the notion that the
> characters SOH, STX, ETX, etc. should always be inputtable by using the
> A, B, C, etc. keys in conjunction with a second shift key called Control?
>
CNTRL-. to get a NUL, and more of these aberrations where the normal sequence
would also require a SHIFT. (This is true on the newer ANSI standard keyboard
were @, ^ and _ are all uppercase; on the older keyboards they were all
lowercase.)
> On this point, I am aware of this notion being used only in ASCII and
> its internationalized derivatives.
This is getting it backward. ASCII is a nationalization of ISO 646 (as are
the others).
> Now, the ASCII standard defines
> "control character" and identifies certain characters as being control
> characters, but as far as I know it does not require there to be a
> pairing between the control characters and certain graphic characters.
> The pairing is implicit in the choices of bit patterns, though. Did
> the Control key appear with the first ASCII terminals, or did it predate
> ASCII in connection with some older, now obscure character code, or is
> it a widely copied later innovation, or what?
It certainly does not predate ASCII. Look in (e.g.) R.W.Bemer, Survey of
Coded Character Representation in CACM (no date on copy, but I would say
late 1960 or 1961) pages 639-642. (This ought to be sufficient to track it
down.) There is also the article: R.W.Bemer, H.J.Smith, Jr., F.A.Williams, Jr.,
Transmission/Data Processing Code, also in CACM (also no date, probably late
1961, or 1962) pages 212-217 etc. The latter article is clearly a forerunner
of the later ANSI (then ASA)/ISO standard; it still has a very limited set of
control codes. Only when ASCII/ISO came about in approx. 1963 there was a
character code with more than a handful of control codes. Note however that
the first standard also included a 6-bit standard code with only four or five
control codes (this was later abandoned). Early equipment that used the ASCII
standard nearly fully complied with their keyboard layout:
! " # $ % & ' ( ) = ~ |
1 2 3 4 5 6 7 8 9 0 - ^ \
Q W E R T Y U I O P ` {
q w e r t y u i o p @ [
A S D F G H J K L + * }
a s d f g h j k l ; : ]
Z X C V B N M < > ?
z x c v b n m , . /
This was for the HP 2640; other equipment had similar layout (except of course
the national versions for some European languages that had many layout
differences). There was a clear pairing between shifted and unshifted
character; only a single bit had to be toggled (although the bit depended on
the key). It was then very natural to introduce the CNTRL key which also would
toggle some bits. Hence the pairing. Of course, early teletypes were a bit
special, in that they had only single case letters and used SHIFT-K, SHIFT-L,
SHIFT-M etc. for some of the characters [, \ and ], etc.; but this also was
pairing based on similarity in bit pattern. The reason is a simple mechanical
one, which does not really hold for electronic equipment.
This paring was destroyed with the newer keyboard layouts (which was dictated
by the secretaries who wanted ( and ) above 9 and 0 resp., just as on their
typewriter). And now people forget and I get questions as: why do you not
use CNTRL-. for that function?
OK, now the base question, where derives the use of ^A etc. My first exposure
to this usage was in the seventies when I aquired access to our Unix system.
And checking through the manuals I have here at home (quite a lot) I find
that *none* of them make use of the circumflex to mark a control character!
But then, I do not need Unix manuals :-). The range is from DEC-10 to
Cray. So I suppose it derives either from Unix or its predecessor (MULTICS),
or perhaps from BCPL (but I suppose not the last). Was it already in version
6 of Unix?
--
dik t. winter, cwi, amsterdam, nederland
d...@cwi.nl
Mark Crispin
>OK, now the base question, where derives the use of ^A etc. My first exposure
>to this usage was in the seventies when I aquired access to our Unix system.
>And checking through the manuals I have here at home (quite a lot) I find
>that *none* of them make use of the circumflex to mark a control character!
>But then, I do not need Unix manuals :-). The range is from DEC-10 to
>Cray. So I suppose it derives either from Unix or its predecessor (MULTICS),
>or perhaps from BCPL (but I suppose not the last). Was it already in version
>6 of Unix?
The first DEC operating systems for the PDP-6 (the predecessor to the
PDP-10 and the DEC-20) used uparrow (the predecessor of circumflex) to
mark control. This is in 1964 documentation.
I don't think Multics used this convention at all. For a while,
anyway, IBM 2741s were used as Multics terminals.
I don't know if any PDP-5, PDP-4, or PDP-1 software used this
convention. I doubt anything on the PDP-5 ever did. I don't think
DEC ever wrote an OS for the PDP-1, but they may have for the PDP-4.
But the ^x convention is certainly at least 6 years older than Unix
(1970).
_____ | ____ ___|___ /__ Mark ("Gaijin") Crispin "Gaijin! Gaijin!"
_|_|_ -|- || __|__ / / R90/6 pilot, DoD #0105 "Gaijin ha doko?"
|_|_|_| |\-++- |===| / / Atheist & Proud "Niichan ha gaijin."
--|-- /| |||| |___| /\ (206) 842-2385/543-5762 "Chigau. Omae ha gaijin."
/|\ | |/\| _______ / \ FAX: (206) 543-3909 "Iie, boku ha nihonjin."
/ | \ | |__| / \ / \M...@CAC.Washington.EDU "Souka. Yappari gaijin!"
Hee, dakedo UNIX nanka wo tsukatte, umaku ikanaku temo shiranai yo.
William R. Ward
my question is how did keyboard (typewriter, then computer) layouts go
from:
(from article <27...@charon.cwi.nl> by d...@cwi.nl (Dik T. Winter))
! " # $ % & ' ( )
1 2 3 4 5 6 7 8 9 0
to:
! @ # $ % ^ & * ( )
1 2 3 4 5 6 7 8 9 0
?
Originally, when QWERTY typewriters became common, the former (often
without the 1/! key) was popular. But as electric typewriters became
common, the latter arragement was used. Early terminals and PCs used
the former layout, which was then replaced by the second (along with a
few other major changes mentioned in Mr. Winter's article).
What was the reasoning behind moving the parentheses and ampersand over
one digit (instead of moving the * to 0, for example)? It makes some
sense to have ' and " together as they are now, but to be replaced by ^,
@, and *? Why those characters? And if * was put on typewriter
keyboards, why not the dagger and double-dagger? (of ccourse, many
fancy typewriters have them, but that's beside the point.)
--
------------------------------------------------------------------------
William R. Ward | UC Santa Cruz, CIS | [backbone]!ucbvax!
(408) 426-7267 | her...@ucscf.UCSC.EDU | ucscc!ucscf!hermit
UCSC-Cowell-787 +--------------------------------------------------
Santa Cruz, CA 95064 | Disclaimer: Nobody reads this anyway.
------------------------------------------------------------------------
Bernie Cosell
}In article <27...@charon.cwi.nl> d...@cwi.nl (Dik T. Winter) writes:
}>OK, now the base question, where derives the use of ^A etc...
}The first DEC operating systems for the PDP-6 (the predecessor to the
}PDP-10 and the DEC-20) used uparrow (the predecessor of circumflex) to
}mark control. This is in 1964 documentation.
...
}I don't know if any PDP-5, PDP-4, or PDP-1 software used this
}convention.
We did on our PDP-1d in '64. I suspect that earlier PDP-1s did not,
because ours was about the first with a real TTY scanner on it. Before
that, PDP-1s mostly used the console SOROBAN which used FIO-DEC and
didn't really have the notion of "control chars" [on the other hand, it
did have red and black shifts! :-)].
/Bernie\
Joe Morris
>my question is how did keyboard (typewriter, then computer) layouts go
>from:
>(from article <27...@charon.cwi.nl> by d...@cwi.nl (Dik T. Winter))
> ! " # $ % & ' ( )
> 1 2 3 4 5 6 7 8 9 0
>to:
> ! @ # $ % ^ & * ( )
> 1 2 3 4 5 6 7 8 9 0
>?
>Originally, when QWERTY typewriters became common, the former (often
>without the 1/! key) was popular. But as electric typewriters became
>common, the latter arragement was used. Early terminals and PCs used
>the former layout, which was then replaced by the second (along with a
>few other major changes mentioned in Mr. Winter's article).
>What was the reasoning behind moving the parentheses and ampersand over
>one digit (instead of moving the * to 0, for example)? It makes some
I can't speak for the real early days of typewriters (I started typing
around 1950) but I don't think I ever saw a normal (non-computer) typewriter
keyboard with the parenthises as shifted 8/9. Although there have been a
few keys added to the "standard" office keyboard layout in the past 40 years
(primarily 1/! and =/_, with an abortive attempt in the '60s to add an
interrobang), the basic layout has been a constant which wasn't changed
when electric typewriters became popular.
To the best of my knowledge the first layout shown above originated with
the Teletype 33 keyboard. The TTY was a mechanical device (that's for
the newer members of the audience...nobody who used the #$%^& thing needs
to be reminded of the fact) so the only way to generate the codes was by
some physical linkage...no PLA's allowed. The design of the 33 assigned
each character key a basic pattern which could be modified by flipping
bits if the SHIFT or CTRL key were pressed. This meant that in order to
avoid making the thing more of a Rube Goldberg kludge than it already was
the design had to group on one keytop characters which shared the same
basic bit pattern.
Looking at the ASCII chart, we find:
b7b6b5 b4b3b2b1 --- (in decimal)
0 1 2 3 4 5 6 7 8 9
0 1 0 sp ! " # $ % & ' ( )
0 1 1 0 1 2 3 4 5 6 7 8 9
Look familiar? that's why the shifted decimal digits on a Teletype are
arranged that way. (OK, the zero is on the right on a keyboard. Picky.)
When electronic terminals became popular there was no agreement in the
industry over how the keyboards should be laid out. Some vendors opted
to continue to emulate the Teletype keyboard, while others used the
flexibility of electronic circuitry to make their product look like an
office typewriter. Although the terms aren't heard much any more because
vendors now all use the typewriter layout, these choices became known as
"bit-paired" and "typewriter-paired" keyboards.
The end of the bit-paired keyboard was the massive introduction of the
computer terminal into the normal office environment where non-tekkie
types, frequently techno-phobic, were expected to use the equipment. Since
the standard office typewriter is what most people were used to (please,
this isn't the place to argue QWERTY vs. Dvorak), its keyboard layout
became the standard.
Joe Morris
Joel B Levin
|m...@Tomobiki-Cho.CAC.Washington.EDU (Mark Crispin) writes:
|}I don't know if any PDP-5, PDP-4, or PDP-1 software used this
|}convention.
|We did on our PDP-1d in '64. I suspect that earlier PDP-1s did not,
But we used control characters very little -- didn't we use SIXBIT
representation internally (no lower case on the '33s, 18-bit words and
the six bit byte instructions on the -1d)? In fact, in the one place
I do remember using control characters a lot, the DDT we used as
monitor and user interface, a control-X was echoed as "X", not as ^X.
Of course you were using the thing up to six years before I got there,
so some older software and documentation may have used the up-arrow
notation.
/JBL
=
Nets: le...@bbn.com | "There were sweetheart roses on Yancey Wilmerding's
or {...}!bbn!levin | bureau that morning. Wide-eyed and distraught, she
POTS: (617)873-3463 | stood with all her faculties rooted to the floor."
Steve Savitzky
my question is how did keyboard (typewriter, then computer) layouts go
from:
(from article <27...@charon.cwi.nl> by d...@cwi.nl (Dik T. Winter))
! " # $ % & ' ( )
1 2 3 4 5 6 7 8 9 0
to:
! @ # $ % ^ & * ( )
1 2 3 4 5 6 7 8 9 0
?
A quick glance at the ASCII character set should tell you why early
terminals (like the TTY) used the former layout: shift just changes a
bit in the code.
The latter layout is that of the de-facto standard IBM selectric.
--
\ --Steve Savitzky-- \ ADVANsoft Research Corp \ REAL hackers use an AXE! \
\ st...@advansoft.COM \ 4301 Great America Pkwy \ #include<disclaimer.h> \
\ arc!st...@apple.COM \ Santa Clara, CA 95954 \ 408-727-3357 \
\__ st...@arc.UUCP _________________________________________________________
Steve Savitzky
my question is how did keyboard (typewriter, then computer) layouts go
from:
(from article <27...@charon.cwi.nl> by d...@cwi.nl (Dik T. Winter))
! " # $ % & ' ( )
1 2 3 4 5 6 7 8 9 0
to:
! @ # $ % ^ & * ( )
1 2 3 4 5 6 7 8 9 0
?
When I wrote my previous posting on the obvious correspondence between
the TTY layout and the ASCII code set, I was under the impression that
the TTY had a layout different from most manual typewriters.
Certainly most manuals did not have a 1 or a 0 key, using l and O
instead. I seem to recall some differences in symbol layout between
different brands of manual, too, but it's been a long time and I may
be wrong about that.
It seems likely that when IBM designed the selectric they did some
studies suggesting that the quotes would be easier to type if they
were on the home row, which in turn suggested moving the parens over
so they were still at the end of the numbers, since they were
re-arranging that row anyway. I do know that most people came to
prefer the selectric layout over the traditional one.
The Unknown User
In article <STEVE.91J...@pluto.Advansoft.COM> st...@Advansoft.COM (Steve Savitzky) writes:
>Certainly most manuals did not have a 1 or a 0 key, using l and O
>instead.
Do other computers' manuals and/or sample programs explicitly
tell users about this distinction?!
On the "Tour of the Apple II" (something like that) disk we got with
our computer, it actually said something to the effect of "You can't use
the l in place of a 1.. To the computer they're different".. Having used
computers for a few years, my intelligence was insulted, but I guess for
new users (especially frequent typewriter users) have to know that..
By the way, you ay most manuals... I think electric typewriters
have "1"s more often than manual typewriters.. Why is that? Because so
people with computer experience won't be k0nfuzed? (I doubt it)
Repeating myself, I was just curious if other people have seen
warnings like that.
--
/Apple II(GS) Forever! unk...@ucscb.ucsc.edu MAIL ME FOR INFO ABOUT CHEAP CDs\
\WRITE TO ORIGIN ABOUT ULTIMA VI //e and IIGS! Mail me for addresses, & info. /
William R. Ward
In article <10...@darkstar.ucsc.edu> unk...@ucscb.UCSC.EDU (The Unknown User) writes:
|
|In article <STEVE.91J...@pluto.Advansoft.COM> st...@Advansoft.COM (Steve Savitzky) writes:
|>Certainly most manuals did not have a 1 or a 0 key, using l and O
|>instead.
|our computer, it actually said something to the effect of "You can't use
|the l in place of a 1.. To the computer they're different".. Having used
|computers for a few years, my intelligence was insulted, but I guess for
|new users (especially frequent typewriter users) have to know that..
Apple is known for stuff like this. In the LaserWriter manual, for
example, it says "WARNING: Do not put your LaserWriter near open flame"
or some such. I don't think I've seen that warning on any other brand
of computer.
| By the way, you ay most manuals... I think electric typewriters
|have "1"s more often than manual typewriters.. Why is that? Because so
|people with computer experience won't be k0nfuzed? (I doubt it)
it's because with manual typewriters, the fewer keys you have, the
easier it is to make (from a mechanical perspective). Electric
typewriters the overhead is not as great, so it's easier (and more
logical) to have 1 and 0 keys. Also, it's a Royal Pain to type an
exclamation mark on an old manual (you have to type an apostrophe,
backspace, period.)
Sam Bassett RCS
Out of curiosity, I went and looked at my dear departed Dad's
194x Remington portable typewriter, and found the key layout as follows:
BS " # $ % _ & ' ( ) *
2 3 4 5 6 7 8 9 0 -
Q P 1/4
q p 1/2
A : @
a ; (cents)
Obviously, this pre-dates ASCII by quite a bit, and it looks to
me like the coding of the ASCII "special characters" was taken from a
keyboard that somebody had in the office . . .
Sam'l Bassett, Sterling Software @ NASA Ames Research Center,
Moffett Field CA 94035 Work: (415) 604-4792; Home: (415) 969-2644
sa...@well.sf.ca.us sa...@ames.arc.nasa.gov
<Disclaimer> := 'Sterling doesn't _have_ opinions -- much less NASA!'
Steve Lamont
>exclamation mark on an old manual (you have to type an apostrophe,
>backspace, period.)
... as opposed to an Underwood Pain? :-)
(Ghod, don't I have *anything* useful to do today?)
spl (the p stands for
pain, I seem to be
into that today,
however...)
--
Steve Lamont, SciViGuy -- (408) 646-2572 -- a guest at network.ucsd.edu --
NPS Confuser Center / Code 51 / Naval Postgraduate School / Monterey, CA 93943
"... most programmers don't even bother going to the metal on machines where
the metal is painful and there's no light to see by..." -J. Eric Townsend
Don Stokes
> Apple is known for stuff like this. In the LaserWriter manual, for
> example, it says "WARNING: Do not put your LaserWriter near open flame"
> or some such. I don't think I've seen that warning on any other brand
> of computer.
The glossary in one of the apple ][ manuals (I forget which one, it was
quite a long time ago) had an entry that went something like:
defenestration: The act of throwing something out of a window.
Doing this with your Apple computer is not recommended.
(Eric, is this note worth adding to the <defenestration> entry in the
jargon file?)
Don Stokes, ZL2TNM / / d...@zl2tnm.gp.co.nz (home)
Systems Programmer /GP/ GP PRINT LIMITED Wellington, d...@gp.co.nz (work)
__________________/ / ---------------- New_Zealand__________________________
Sam Bassett RCS
Not to beat a dead horse ( :-) but what Steve meant by "manual"
was a non-motorized typewriter (your finger powered it) -- not 'manual'
as in 'book of instructions'.
The reason most manual typewriters did not have "1" keys was mostly
economic -- it cost extra money to hang another key and mechanical
linkage in the typebasket, and the things were price-sensitive (it was
definitely an extravagance for my Dad to buy one on a Marine captain's
salary during WWII when he had me, my mom, and HIS mom to support out of
it . . .)
The Unknown User
In <m5ZcV...@zl2tnm.gp.co.nz> d...@zl2tnm.gp.co.nz (Don Stokes) writes:
>The glossary in one of the apple ][ manuals (I forget which one, it was
>quite a long time ago) had an entry that went something like:
>
> defenestration: The act of throwing something out of a window.
> Doing this with your Apple computer is not recommended.
I don't remember which Apple manual this was in, but it was the
first word of the main text of the manual, I -think-..
"On a clear disk you can seek forever..."
Classic.. But now Apple's getting bluer every year and IBM seems
to be getting more "multicolored".. (The latter only because they REALIZE
a home market exists and are actively pursuing it)
Don Stokes
> In <m5ZcV...@zl2tnm.gp.co.nz> d...@zl2tnm.gp.co.nz (Don Stokes) writes:
> >The glossary in one of the apple ][ manuals (I forget which one, it was
> >quite a long time ago) had an entry that went something like:
> >
> > defenestration: The act of throwing something out of a window.
> > Doing this with your Apple computer is not recommended.
>
> I don't remember which Apple manual this was in, but it was the
> first word of the main text of the manual, I -think-..
>
>
> "On a clear disk you can seek forever..."
Or the section entitled:
"Lo, what light from yonder window breaks!"
or, the Text Window.
(Ghod, I still remember this stuff! I haven't touched an apple ][ manual
since '85. I actually used to do Real Work on apple//es, splitting 200K
data files across two diskettes etc, writing own keyboard drivers/input
routines etc -- Great fun!)
Richard Flamsholt S0rensen
From the manual to the Oric Atmos:
"This functions as an on-line visual display unit (VDU) output
device, but we'll just call it the TV!"
-Richard
--
/Richard Flamsholt
ric...@iesd.auc.dk
Ken Yap
a motorbike manual that said:
Warning: Do not drink the battery acid. It doesn't taste good and will
hurt you. Also do not bite the tyres, especially while the bike is
moving. Our lawyers made us put these warnings in.
Maybe it was a good story, but anything is possible in litigation-crazy
US. Are there any other funny excerpts from manuals, computer or
otherwise?
Kevin Hammond
>Apple is known for stuff like this. In the LaserWriter manual, for
>example, it says "WARNING: Do not put your LaserWriter near open flame"
>or some such. I don't think I've seen that warning on any other brand
>of computer.
Isn't this warning there because the laserwriter generates (flammable?) ozone
when printing.
Kevin
--
This Signature Intentionally Left Blank. E-mail: k...@cs.glasgow.ac.uk
Timo Kiravuo
>|
>|In article <STEVE.91J...@pluto.Advansoft.COM> st...@Advansoft.COM (Steve Savitzky) writes:
>| On the "Tour of the Apple II" (something like that) disk we got with
>|our computer, it actually said something to the effect of "You can't use
>|the l in place of a 1.. To the computer they're different".. Having used
>Apple is known for stuff like this. In the LaserWriter manual, for
Apple II and Lazerwriter are way apart. I am not going to bet out
of bed at this hour of night, but I still have somewhere my Apple
II manual which tells you things roughly like "diskettes are
enclosed in plastic, sorry no leather models available" and
"Apple n. a fruit of a tree ... also a make of a home computer"
The 0 and 1 vs. O and I problem is still very alive. Just last
autumn I (Not 1) witnessed our freshmen having problems with
their passwords. After that the password generetion algorithm was
changed to produce passwords without characters 10IO.
And the keyboeard I am typing this on has:
!"#$%&/()=?'
1234567890+'
But of fourse this is the Finnish layout.
--
Timo Kiravuo, kir...@hut.fi
Helsinki University of Technology, Computer Center, Finland
Simon Cocking
Nuke To destroy, demolish, obliterate, wipe out, mung, hash into little
bits, waste, screw up, or make FUBAR, by means of atomic weapons
or with a computer.
and this...
16-inch rotary debugger
A highly effective tool for locating problems
in computer software. Available for delivery in most major
metropolitan areas. Anchovies contribute to poor coding style.
and finally...
:-) A standard smiley. Used to indicate satire or humour.
Who says programmers have no sense of :-) ?
--
/// ^^^^^
__ /// (o o) Didn't 25 years of Doctor
\\\/// Simon Cocking, ^ Who teach you not to trust
\XX/ vac...@monu6.cc.monash.edu.au `-' names like Intel & Zilog?
Richard Wexelblat
Here's the short form of a true story from a jury I was on once. Guy
wanted to see the liquid level in his car battery. Opened the cells and
lit a match to look in. H2 + O2 +fire = BOOM!!! Sued Chrysler with the
following claim: since the owner's manual warned about the explosion
hazard and said not to do that, they knowingly established a hazardous
situation and were criminally liable. Judge threw it out.
--
--Dick Wexelblat (r...@ida.org) 703 845 6601
My computer always does exactly what I tell it to do
but sometimes I have trouble finding out what it was
that I told it to do.
Winston Edmond
>OK, now the base question, where derives the use of ^A etc. My first exposure
>to this usage was in the seventies when I aquired access to our Unix system.
>And checking through the manuals I have here at home (quite a lot) I find
>that *none* of them make use of the circumflex to mark a control character!
>But then, I do not need Unix manuals :-). The range is from DEC-10 to
>Cray. So I suppose it derives either from Unix or its predecessor (MULTICS),
>or perhaps from BCPL (but I suppose not the last). Was it already in version
>6 of Unix?
In article <13...@milton.u.washington.edu> Mark Crispin writes:
>The first DEC operating systems for the PDP-6 (the predecessor to the
>PDP-10 and the DEC-20) used uparrow (the predecessor of circumflex) to
>mark control. This is in 1964 documentation.
>
>I don't know if any PDP-5, PDP-4, or PDP-1 software used this
>convention. I doubt anything on the PDP-5 ever did. I don't think
>DEC ever wrote an OS for the PDP-1, but they may have for the PDP-4.
The PDP-1 used FLEXO code, a six-bit character set in which up-shift and
down-shift were characters (like old 5-bit teletypes), and no, I didn't see
^X in any documentation or program for it.
"Control" characters existed in many character sets, including Flexo, but I
only recall seeing them described as ^X in connection with ASCII, which had
carefully arranged things so that all the character codes were used for
something. Other character sets did not have the regularity in structure
that would make such a convention useful.
My recollection is that an earlier version of representing control characters
was to write the capital letter with a circumflex over it. There was no
circumflex in ASCII at the time, so "<up-arrow><character>" was used as the
closest, convenient ASCII representation. Up-arrow was later replaced by
circumflex (^), which helped, but it was both clearer and easier to write two
characters, ^X, than to bother doing the backspace and overstrike, so the old
convention stuck. There were also other conventions used to indicate control
characters, such as enclosing the character in a circle, each of which used
typesetting tricks to distinguish control-whatever from whatever, but all of
these conventions lost favor because they couldn't be represented in ASCII
documentation.
-WBE
Daniel Briggs
The primary data analysis package here at the NRAO is called AIPS,
(Astronomical Image Processing System). The whole 'motif' of the
package (if that isn't an oxymoron) is based around gorillas and
monkeys. The main reference source of documentation about the package
is called the AIPS Cookbook. (There is a more detailed reference manual
which is almost never used.) In the cookbook, the blank space between
end of the chapter and the end of the leaf it is printed on is filled
with banana recipies!
--
This is a shared guest account, please send replies to
dbr...@nrao.edu (Internet) ["Life's a Beech, and then you Dive."]
Dan Briggs / NRAO / P.O. Box O / Socorro, NM / 87801 (U.S. Snail)
Jonathan Stott
>Also from the Amiga ROM Kernal manuals... (this from the glossary):
>
"If you reply to a message after closing the IDCMP, you will put your
amiga into FIREWORKS_DISPLAY mode"!
-Jonathan
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= Jonathan Stott (jst...@wpi.edu) =
= "Five is RIGHT OUT!" =
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Amanda Walker
OSI: See RSN.
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Amanda Walker
Visix Software Inc.