Talk:CDC 7600

> The 7600 was main processor code compatable to the > 6600, but the 7600 PPs were not compatable to 6600 PPUs.

I have to deal with what I believe to be a fallacy in two different places.

I have no indications that the 7600 was in any way compatible to the 6600, not OS, not compiler, and not instruction set. And this was SOP. My experience was on a 6400 running I think SCOPE (GRC) for a firm (Information Magnetics) which had serious computing problems evaluating getting 7600 time (we never did in the end, using UCLA's 360/91).

So I checked with an ex-officemate who used S/N 1 7600 and the run down he gave me was the lack of availability of parts (memory) which resulted in the 2 stage memory which would vastly make a difference in the instruction set irrespective of the PPUs.

So I need references to convince all of us (include compilers [OS], specific instructions, etc.).

--enm 8/18/2004

The 7600 CPU was 'almost' entirely instruction set compatible with the 6000 series. There were only a few new instructions - like being able to address Extended Memory on a word-by-word basis - rather than block copies. There were a few monitor-mode differences as well. (This is worthy of more information, because Mr. Cray redesigned the I/O in some interesting ways. Sorry, I don't have time today...) But COMPASS (the assembler), the Fortran compilers, and many other pieces of 'normal' CDC software - even COBOL - ran on the 7600 with minor changes. These changes were mostly related to the OS differences - not the CPU instructions themselves.

If you want specific references, please look at any CDC COMPASS or Fortran manual from about 1970 forwards. In fact, the later Cyber-176 system was basically a 7600-style CPU and peripheral processors, combined with a set of 6000-compatible peripheral processors. It could run the normal NOS operating system, in addition to the older 7600-specific versions of SCOPE.

--Wws 6/3/2006

Agreed with Wws. The claims in the main page are completely misleading; no other reference makes the claim that there was no object code compatibility. I propose to weaken the article in line with this discussion and other articles (notably the conflicting information in [CDC_6600] unless somebody posts some good reasons before a get a round tuit. Groogle 08:35, 28 April 2007 (UTC)

ECS word size

ECS word size was 8*60=480 (logical) or 8*61=488 (physical) with one parity bit per each 60-bit CM word.

I can't find 7600 manual online, but there is 6600 manual referenced on the 6600 page. In the ECS section (page D-1) there is a list item:

Memory organized in logically independent banks of 488-bit words (eight 60-bit words plus parity bit for each) with corresponding multiphasing of banks

6*60=360 bit words would require multiply/divide by 6 in the CM vs. ECS address conversion logic.

70.187.140.60 (talk) 03:07, 11 December 2015 (UTC)

"No fixed point arithmentic

Not entirely accurate. Consult and you'll see that, as with the 6600, there was no fixed-point multiply/divide, but there was a separate 60 bit integer "long add" functional unit. Of course, the increment units also did 18-bit add/subtract operations.

Since the multiply units could do unnormalized double-precision operations, the lack of a fixed-point multiply was not a serious issue, since one could still recover a 48 bit integer product with a single floating point multiply operation.

174.22.17.211 (talk) 19:55, 11 May 2016 (UTC)CPG

I changed the text.--agr (talk) 20:18, 11 May 2016 (UTC)

References

No integrated circuits were used!

As written here https://books.google.fr/books?id=sQwE8Gpsj5EC&lpg=PA36&ots=FykNYywUGS&dq=cdc7600%20integrated%20circuits&hl=fr&pg=PA36#v=onepage&q=cdc7600%20integrated%20circuits&f=false

instead high density modules were used, see https://people.cs.clemson.edu/~mark/cdc7600.html

Stephanefr (talk) 04:14, 21 February 2017 (UTC)

External links modified

Hello fellow Wikipedians,

I have just modified one external link on CDC 7600. Please take a moment to review my edit. If you have any questions, or need the bot to ignore the links, or the page altogether, please visit this simple FaQ for additional information. I made the following changes:

• Added archive https://web.archive.org/web/20110720064938/http://www.cisl.ucar.edu/computers/gallery/cdc/7600.jsp to http://www.cisl.ucar.edu/computers/gallery/cdc/7600.jsp

When you have finished reviewing my changes, you may follow the instructions on the template below to fix any issues with the URLs.

This message was posted before February 2018. After February 2018, "External links modified" talk page sections are no longer generated or monitored by InternetArchiveBot. No special action is required regarding these talk page notices, other than regular verification using the archive tool instructions below. Editors have permission to delete these "External links modified" talk page sections if they want to de-clutter talk pages, but see the RfC before doing mass systematic removals. This message is updated dynamically through the template {{source check}} (last update: 5 June 2024).

• If you have discovered URLs which were erroneously considered dead by the bot, you can report them with this tool.
• If you found an error with any archives or the URLs themselves, you can fix them with this tool.

Cheers.—InternetArchiveBot (Report bug) 12:31, 28 July 2017 (UTC)

Acronym LLNL I think needs a definition. Lawrence Livermore National Laboratory. 24.197.209.81 (talk) 14:57, 23 February 2024 (UTC)