68000 Memory Managment (Bechtolsheim patent) (SUID Patent)
Mark Campbell
Protection of data file contents.
Abstract:
An improved arrangment for controlling access to data files by computer users.
Access permission bits are used in the prior art to separately indicate
permissions for the file owner and nonowners to read, write and execute the file
contents. An additional access control bit is added to each executable file.
When this bit is set to one, the identification of the current user is changed
to that of the owner of the executable file. THe program in the executable file
then has access to all data files woned by the same owner. This change is
temporary, the proper identification being restored when the program is
terminated.
--
Mark Campbell Phone: (803)-791-6697 E-Mail: !ncsu!ncrcae!sauron!campbell
Jason Zions
> I used TOPS-10 in 1969 or so; at the time it was already at Version 5 or
> thereabouts. JACCT was already there; I don't know exactly when it was
> introduced. TOPS-10 itself descended from earlier OS's for the PDP-15 (?),
> which, for all I know, already had JACCT or some analogue.
TOPS-10 didn't really descend from any OS; it was sort of written from
scratch with an interesting set of constraints. Someone from DEC wrote a book
discussing the design of the early versions of TOPS-10; fascinating reading.
If TOPS-10 were to descend from any DEC OS, it would be the one that ran on
the PDP-6, the predecessor to the PDP-10 (well, predecessor to the KA-10).
If memory serves, the PDP-15 was a pair of -11's hooked up in tandem (in the
same way a PDP-12 was a pair of PDP-8's in tandem). Exactly what the PDP-15
and PDP-12 were used for, I couldn't tell you.
(Here I am, correcting a correction. If someone corrects me, we may set a
record for levels of digression. This is net.arch, not net.ancient.history! )
--
This is not an official statement of Hewlett-Packard Corp., and does not
necessarily reflect the views of HP. It is provided completely without warranty
of any kind. Lawyers take 3d10 damage and roll a saving throw vs. ego attack.
Jason Zions Hewlett-Packard
Colorado Networks Division 3404 E. Harmony Road
Mail Stop 102 Ft. Collins, CO 80525
{ihnp4,seismo,hplabs,gatech}!hpfcdc!hpcnoe!jason
Steven Deller
> Jerry Leichter says:
>
> > I used TOPS-10 in 1969 or so; at the time it was already at Version 5 or
> > thereabouts. JACCT was already there; I don't know exactly when it was
> > introduced. TOPS-10 itself descended from earlier OS's for the PDP-15 (?),
> > which, for all I know, already had JACCT or some analogue.
>
> TOPS-10 didn't really descend from any OS; it was sort of written from
> scratch with an interesting set of constraints. Someone from DEC wrote a book
> discussing the design of the early versions of TOPS-10; fascinating reading.
>
> If TOPS-10 were to descend from any DEC OS, it would be the one that ran on
> the PDP-6, the predecessor to the PDP-10 (well, predecessor to the KA-10).
> If memory serves, the PDP-15 was a pair of -11's hooked up in tandem (in the
> same way a PDP-12 was a pair of PDP-8's in tandem). Exactly what the PDP-15
> and PDP-12 were used for, I couldn't tell you.
>
> (Here I am, correcting a correction. If someone corrects me, we may set a
> record for levels of digression. This is net.arch, not net.ancient.history! )
Sorry to correct you, but your information is so far off base that it requires
correcting. The PDP-15 and PDP-12 were not at all how you describe them.
The PDP-15 was an 18-bit computer, derived from the 18-bit PDP-9, which
derived from the 18-bit PDP-7 (one of the original UNIX base machines), which
had a common ancestor with the 36-bit PDP-6 in the PDP-4. The PDP-15
primarily added 8 index registers and slight modifications to the instruction
set to handle them, plus some better I/O controls. The PDP-15 was the base
machine for RSX-15 (later RSX-15PLUS or just RSX-PLUS), which was the operating
system predecessor to RSX-11D (later IAS). Hank Krejci (Hank are you out
there?) was one of the primary developers. I programmed an Electrocardiogram
over-the-phone analysis system using it (including dialback to doctor's offices
and the like -- heady stuff for 1972). The PDP-9 instruction set was a
glorified PDP-8 instruction set, i.e. hardly any instructions -- the first
RISC archtecture :-).
The PDP-12 was a 12-bit computer derived from the LINC-8. The LINC-8 was a
join of the Laboratory INteractive Computer developed at MIT (I believe) and
the PDP-8. The LINC instruction set had a number of innovative instructions,
particularly the "add two 12-bit integers plus the overflow carry" which
provided an easy method for efficient multiple-precision arithmetic. It also
included a single instruction to read a tape block with or without wait
(can you say Linctape -- identical to DECtape except that DECtape wound from
the left reel to the right -- clever way around a patent :-) ), and several
single instructions for efficient CRT displaying of data. I firmly believe the
LINC was one of the earliest innovators of application-relative CISC.
The LINC-8 ran LINC code when decoding instructions in the 2nd of the eight 1K
banks. The PDP-12 allowed running either LINC or PDP-8 instructions anywhere;
each instruction set had one additional instruction that switched to the other
instruction decode mode. Anyone in their right mind used the CISCish LINC set
for all real work. The PDP-8 was only used for I/O and "preexisting" code.
This ability to switch the instruction mode anytime led to the (trivial)
pursuit of trying to write machine code that did something useful when
executed in PDP-8 mode, and something else useful when executed as LINC mode.
This was not always so trivial; the base machine only had 8K 12-bit words.
(Yea, we all KNEW there would be MB of memory to burn one day, but at the time
8K of 12-bit words and a 32K word disk -- not 32M word -- was all you could
afford for $20,000!!). This trivial pursuit is, not suprisingly, very similar
to the trivial pursuit seen in another news group of trying to write high-level
code that means "useful" things to two different languages; history always
repeats itself.
We had an multitasking system running on the PDP-12 that did real-time patient
monitoring of 4 patients for ECG, cardiac output, blood pressure, temperature,
plus several background jobs, including doing listings on the ASR-33. Yes, it
was a true multitasking system, and included an aggregate 2K A/D samples per
second (with only 8K you had to process and dispose of the raw data real fast),
real-time annotated displays (it really helped algorithm development to see the
ECG waveform with cursor marks and numeric values, and to be able to freeze the
display any time), and "human-friendly" interactive diagnosis. See the 1971
Proceedings of the ACM Conference, p 682, if you really care (it doesn't hurt
to do a little looking at history, just to give yourself some perspective).
Anyway, I always thought designers of instruction sets could learn something
from the PDP-12 (the PDP-11 instruction set seems to have learned some of its
instruction set there). For the RISC proponents, there was a very nice
instruction set architecture proposed at U of Washington around that same time,
that provided for dropping into and out of (similar to PDP-8/LINC) a very
effiecient, minimal instruction set, that was "optimum" for computation of
expressions -- always thought that CISC and RISC might do better co-existing
than either does alone -- particularly an appliction-related CISC and
expression evaluation RISC.
Finally, for those of you not wise enough to have hit "n" before now :-), the
TOPS-10 system was derived from the PDP-6 OS with substantial influence from
Project MAC. It in NO way derived from the PDP-15, which was released 2 years
after TOPS-10 had reached release 5. The PDP-15 had DOS-15 (derived from
DOS/BATCH-9 and KMS-9) and RSX-15 as mentioned before.
I am also on shaky ground about the exact derivation of TOPS-10 - I just dug
up a copy of DECSystem10 User's Handbook (yes, I'm a hell of a pack rat), but
could not find any proper reference for the OS derivation. However, it is
true that the PDP-6 was the PDP-10 predecessor (both were 36-bit), and as said
earlier, the PDP-4 was the predecessor to the PDP-6 (and the PDP-7).
Just in case you wonder about the other PDP numbers:
PDP-1 was an 18-bit architecture that could be said to be the
predecessor of the PDP-4. It used real old discrete logic B-series
10MHz boards. Hmmm -- 10MHz clock rate in 1962, and now we have, wonder
of wonders, 16.67Mhz "high-speed" micros -- haven't come as far as some
may think in 25 years.
PDP-2 and PDP-3 were aborted -- never finalized.
PDP-5 was Edson DeCastro's first design -- it preceeded the PDP-8. Edson
went on to found Data General when his version of the "new instruction
set architecture" lost out to Gordon Bell's PDP-11. Sorry if I am
slighting other designers -- they are the best known.
PDP-13 was never born -- the number was excluded.
PDP-14 was a non-computer, methodology for building discrete logic
systems from R and S series flip-chips (DTL logic).
After the PDP-15, came VAX.
Sorry to be so long typed (as in long winded, nothing to do with 32-bit
integers), but I hate to see drastically incorrect information on the net.
And anyway, this has far more content and utility than either the discussion
on very large memory (as least the trivial digression on the number of
electrons in the universe), and the one on what average to use for benchmarks
(if you cannot resist averaging benchmarks with no basis for weighting, only
the geomtric mean is defensible -- we did not really need 20 articles stating
this simple fact :-) ).
Good night.
--
{verdix,seismo,umcp-cs}!vrdxhq!deller
George Robbins
>In article <610...@hpcnoe.UUCP>, ja...@hpcnoe.UUCP (Jason Zions) writes:
>> Jerry Leichter says:
>>
>>
>> If memory serves, the PDP-15 was a pair of -11's hooked up in tandem (in the
>> same way a PDP-12 was a pair of PDP-8's in tandem). Exactly what the PDP-15
>> and PDP-12 were used for, I couldn't tell you.
>>
>correcting. The PDP-15 and PDP-12 were not at all how you describe them.
>
>The PDP-15 was an 18-bit computer, derived from the 18-bit PDP-9, which
>derived from the 18-bit PDP-7 (one of the original UNIX base machines), which
>had a common ancestor with the 36-bit PDP-6 in the PDP-4. The PDP-15
>primarily added 8 index registers and slight modifications to the instruction
>set to handle them, plus some better I/O controls.
Perhaps this person was confused by the PDP-15/76, which was a PDP-15 with a
small PDP-11 (/05?) built in as an I/O processor. The PDP-11 was somewhat
modified so the parity bits in its memory and data paths could be used to
pass the 18 bit data used by the PDP-15.
> PDP-14 was a non-computer, methodology for building discrete logic
> systems from R and S series flip-chips (DTL logic).
Noooo, the PDP-14 was a 'programmable' industrial controller. The PDP-16 was
the do-it-yourself 'computer' using register transfer modules. I'd never
seen something so intersting with such completely confusing documentation.
They were M series (DTL and/or TTL) modules, please. The R and S were DCD
(diode-capacitor-diode) logic used in the original PDP-8 and other products
in that timeframe.
Now to leave something correctable: (-8
My old PDP-10 manuals leave the operating system almost nameless, alluding to
things like Timesharing Monitors 10/40 and 10/15 which had been rechristened as
'The Multiprogramming Disk Monitor' and 'Swapping Monitor'. These had derived
from the PDP-6 monitor programs. My PDP-6 manuals are buried too far down to
see what they called it. Now was TOPS-10 a new products, or just a marketing
name for the older monitor program, along with the revisionistic DECsystem-10
name?
--
George Robbins - now working for, uucp: {ihnp4|seismo|caip}!cbmvax!grr
but no way officially representing arpa: cbmvax!g...@seismo.css.GOV
Commodore, Engineering Department fone: 215-431-9255 (only by moonlite)
Rob Warnock
writes:
> ... Now was TOPS-10 a new products, or just a marketing
> name for the older monitor program, along with the revisionistic DECsystem-10
> name?
Well... a little of both. The "Monitor" (as it was known in those days) had
stabilized (?!?!) at version 4S72 (major version 4, "S"wapping support, minor
rev 72), and was getting patched to death with bug fixes. (I think the last
4-series we ran at Emory Univ. was 4S72AJ, where "AJ" means the 26+10th patch;
they got up to 4S72BN or something finally... yeah, 52+14 patches!.) At that
point there was a *massive* rewrite/enhancement/extension, and the major
version bumped to "5". At the same time, "Monitor" became "TOPS-10", and
"PDP-10" became "DECsystem-10".
We're talking about an entirely new TTY driver ["line discipline" to Unix
folk], file system (and disk format... worse than the 4.1 ==> 4.2 move),
and new batch system, spoolers, etc., so maybe the name change wasn't all
that bogus (...but the old hands still called it "the monitor".) It was like
jumping from Unix v.6 to Berkeley 4bsd.
The new system eventually became rock-solid, but the first releases were
murder (worse than 4.2 with no bug fixes!). The 5.01 release wouldn't
stay up very long; 5.02C was sort of o.k. for a handful of users, if you
didn't try to run the batch system or spoolers ("you did WHAT!?!? (*crash*)
(*tinkle*) (*tinkle*)"); 5.02D would survive running with the line printer
spooler active; and by 5.03C the system would take a pretty good beating
from batch & users and keep on going. As I recall, 5.04 was flakey again,
but 5.04A fixed that. 6.01 added paging (in addition to swapping), but had
so many "improvements" it took 'til 6.02A to settle down. (Also, 6.02A was
the last version that was supported in the non-paging KA-10 processor.)
Incidently, even old 4Snn ("10/50 monitor") had the "JACCT" bit ("setuid root")
in the late 1960's, but remember that unlike Unix, the list of JACCT programs
was compiled into the kernel! (And because TOPS-10 was a "job"-oriented system
rather than "process"-structured, the kernel had to really worry about making
sure the JACCT bit got turned off no matter how a JACCT program died, to keep
the user from inheriting the priviledge.) Let's see, the JACCT programs were
LOGIN, LOGOUT, SYSTAT ("ps"), QUEUE ("lpr/lpd"), DAEMON ("init"), and so on.
Rob Warnock
Consultant
{amdcad,sun,fortune}!redwood!rpw3
Roy Smith
> version bumped to "5". At the same time, "Monitor" became "TOPS-10", and
> "PDP-10" became "DECsystem-10".
>
> new batch system, spoolers, etc. [...] It was like jumping from Unix
> v.6 to Berkeley 4bsd.
Well, it couldn't have been that bad then. Up until a few years
ago, we were still running v6 on an 11/34. Then we got a vax and switched
directly to 4.2BSD. Everyone adjusted without much trouble, programmers
and secretaries alike. Problem is, everybody also "adjusted" pretty
quickly to the fact that we had 450 Mbytes of disk instead of 10 :-)
--
Roy Smith, {allegra,philabs}!phri!roy
System Administrator, Public Health Research Institute
455 First Avenue, New York, NY 10016