Questions tagged [mainframe]

for questions about retrocomputing mainframes or clusters

Filter by
Sorted by
Tagged with
7 votes
1 answer
396 views

Why did IBM skip "System/380" as a mainframe family name?

I've been reading Exhibit 14971 from US vs. IBM (Parts 1, 2, 3) which seems to give a very good overview of the history of the computer industry up to 1980, particularly the way IBM handled its ...
user avatar
4 votes
2 answers
421 views

Why do computer rooms no longer have raised floors? [closed]

As I understand it, computer rooms in the days of mainframes and minicomputers, commonly had raised floors, so that the space under the floor could be used for power cables and cool air. I'm not clear ...
user avatar
  • 49.3k
8 votes
0 answers
390 views

What did the Big Red Button actually do on the IBM 4341?

Wiktionary explains the origin of the term molly guard: Originally a Plexiglas cover improvised for the Big Red Switch on an IBM 4341 mainframe after a programmer's toddler daughter (named Molly) ...
user avatar
  • 13.9k
14 votes
1 answer
2k views

What is a good COBOL specification to target when aiming to support ~75% or more of mainframe and minicomputer software bases?

There are many specifications for COBOL due to its long history. If one wanted to write software that would be acceptable for use in about 75% or more of existing COBOL projects on mainframes or ...
user avatar
  • 279
5 votes
1 answer
373 views

What were the characteristics of the Siemens 8160 and 9750 terminals?

An answer to a recent question https://retrocomputing.stackexchange.com/a/22332/4274 referred to the Siemens 8160 and 9750 terminals, which struck me as interesting enough to ask about separately in ...
user avatar
  • 49.3k
10 votes
2 answers
1k views

Why did IBM want to keep ICL alive?

According to https://en.wikipedia.org/wiki/International_Computers_Limited International Computers Limited (ICL) was a British computer hardware, computer software and computer services company that ...
user avatar
  • 49.3k
5 votes
2 answers
268 views

Did any computer ever signal floating-point overflow purely with a sticky flag?

Every implementer of floating-point arithmetic, needs to think about how to signal overflow. One possible way to do it is by raising an exception, though this creates the problem that 'exception' can ...
user avatar
  • 49.3k
16 votes
3 answers
890 views

Why did instruction sets since the late 1970s seemingly stop including an "execute" instruction?

Many mainframe instruction set architectures (ISAs) in the 1960s included an Execute instruction, which would treat data as an instruction. I haven't found an architecture designed after 1976 which ...
user avatar
10 votes
1 answer
317 views

What sort of intermediate representation did the first Fortran compiler use?

Proebsting's Law asserts that improvements to compiler technology double the performance of typical programs every 18 years, but even granted that this is somewhat tongue-in-cheek, it's not really ...
user avatar
  • 49.3k
10 votes
1 answer
438 views

Was there a cartoon series in the UK computer press called "Computability Brown"?

My dad was a computing professional in Scotland in the 1970s. He received a couple of industry trade magazines every week, such as Computer Weekly and Computing. In one of them, I remember there being ...
user avatar
  • 17.2k
6 votes
2 answers
1k views

Were any vacuum tube computers built with wire wrap?

I'm trying to gain some understanding of how early computers were built; as discussed in What accounted for the cost of ENIAC? the cost of first-generation computers was not necessarily mostly about ...
user avatar
  • 49.3k
7 votes
1 answer
349 views

Did other computer companies need to license Fortran from IBM?

Reading a fascinating online book about the history of computing, I came across this passage on http://ds-wordpress.haverford.edu/bitbybit/bit-by-bit-contents/chapter-seven/7-5-assembly-language-...
user avatar
  • 49.3k
23 votes
4 answers
4k views

What accounted for the cost of ENIAC?

I'm used to the fact that first-generation computers were very expensive, which I had always assumed was because they contained large numbers of vacuum tubes, each of which is a rather complex, high ...
user avatar
  • 49.3k
11 votes
2 answers
391 views

Did any core-memory computers have a read-and-erase instruction?

Magnetic core, the primary form of computer memory from the mid-fifties to the early seventies or thereabouts, had the slightly awkward property that reading it erased it, so every time the CPU ...
user avatar
  • 49.3k
3 votes
2 answers
205 views

Could early computers use existing punch card machines?

In the early decades of the industry, computers used punch cards for data storage and transmission, partly because they were already widely used for pre-computer data processing; indeed, a major ...
user avatar
  • 49.3k
26 votes
1 answer
2k views

Why was IBM's Scientific Subroutine Package superseded?

It is a familiar fact that scientific software tends to do a lot of vector arithmetic and similar, that one does not want to keep rewriting the low-level code for such, so the usual practice is to use ...
user avatar
  • 49.3k
36 votes
13 answers
8k views

Why were programs entered on punch cards instead of paper tapes?

Dale Fisk's Programming With Punched Cards is a fascinating account of programming in the days of punch cards. The fundamental dynamic was that early computers did not yet support timesharing. The ...
user avatar
  • 49.3k
9 votes
1 answer
885 views

How many transistors in the CDC 1604?

The CDC 1604, released in 1960, was Seymour Cray's first supercomputer, and also one of the first computers made of transistors. (The IBM 7090 was released only the previous year.) How many ...
user avatar
  • 49.3k
8 votes
3 answers
593 views

Uh, oh, I've woken up in 1973. Can I get a job in computing? [closed]

I've woken up in 1973. Until I can figure out how to monetize my knowledge of coming political, economic, and social trends, I need to support myself somehow. So... I walk into one of the major ...
user avatar
  • 205
3 votes
2 answers
183 views

Did communication between a PLATO terminal and mainframe use pushes?

I'm trying to learn more about how the PLATO system worked with respect to communications. I've read some of the specs, but coming from a web-background I'm unfamiliar with the underlying way that the ...
user avatar
  • 131
9 votes
6 answers
642 views

Besides the IBM 709 and its descendents, did any other machine have "slightly longer" registers?

This question occurred to me while I was formulating this answer about arithmetic versus logical shifts. The IBM 709, and its descendant the 7090, etc., is a 36-bit mainframe with a classical single-...
user avatar
  • 27.8k
23 votes
7 answers
5k views

What was the last non-monolithic CPU to come to market?

This answer to the question "What was the rationale behind 36 bit computer architectures?" makes the point that early computers were assembled by hand, rather than having central processing ...
user avatar
  • 13.9k
9 votes
6 answers
1k views

What did order processing on a teletype look like?

The earliest business data processing systems were based on batch processing of punchcards. Prepare cards off-line, feed a batch of them through the computer. (Why does one so often hear of payroll, ...
user avatar
  • 49.3k
17 votes
1 answer
1k views

How did SABRE work interactively without screens?

The SABRE airline reservation system went online in 1964, astonishing the world by being among other things the first large-scale interactive computing system. Once the IBM 3270 video terminals were ...
user avatar
  • 49.3k
6 votes
1 answer
203 views

What information was present in line printer printout cover/trailer?

Nowadays, in corporate offices where there are typically several office printers per floor, sending a file to a printer does not result in any additional pages identifying the print job, at least by ...
user avatar
  • 15.8k
6 votes
2 answers
272 views

Documents about timesharing systems, access and resource control and its financials

I delved a bit into the origins of (commercial) timesharing and it seems there have been very interesting computing hardware and software (architectures) which have become relatively unknown but may ...
user avatar
  • 161
4 votes
1 answer
207 views

Has a retargetable disassembler been used successfully for a word-oriented mainframe architecture?

Among many modern disassembly/reverse engineering tools, has any been used to disassemble legacy code for a word-oriented mainframe, preferably with a non-power-of-2 word length, like CDC 6600 (60 bit)...
user avatar
  • 15.8k
1 vote
0 answers
112 views

Record definitions with IBM COBOL and IMS

A common technology stack for line of business applications in the sixties and seventies was IBM COBOL with the IMS database. I'm curious about how the combination handled record definitions. COBOL ...
user avatar
  • 49.3k
20 votes
17 answers
4k views

Were any IBM mainframes ever run multiuser?

Now of course there is a sense in which they were – some mainframe installations supported thousands of users! But there is a distinction. Consider the familiar fixture in so many 80s computer science ...
user avatar
  • 49.3k
22 votes
5 answers
6k views

Why did mainframes have big conspicuous power-off buttons?

Some fascinating stories in this discussion thread. It starts with discussion about computers overheating, but about halfway through the thread, it switches to discussion of mainframe installations in ...
user avatar
  • 49.3k
5 votes
3 answers
1k views

How was it possible to run IBM mainframe software in emulation on HP?

... At least, without getting sued into the ground? According to one of the answers to What was the most critical supporting software for COBOL on IBM mainframes? We installed a new HP replacing an ...
user avatar
  • 49.3k
21 votes
7 answers
4k views

What was the most critical supporting software for COBOL on IBM mainframes?

Over the past half-century, one of the largest trends in the computer industry has been the replacement of mainframes by microcomputers. Not total by any means – there are still many mainframes in ...
user avatar
  • 49.3k
4 votes
2 answers
303 views

What was the first vector supercomputer?

I am trying to understand the trade-offs between scalar and vector machines, the threshold of complexity/transistor count/performance at which vector machines started to make sense. As data points, ...
user avatar
  • 49.3k
2 votes
3 answers
274 views

When/where was datum and limit relocation invented?

I recently "attended" a meeting of the UK Computer Conservation Society on the subject of LEO (Lyons Electronic Office; Lyons was a bakery and cafeteria business that found itself designing ...
user avatar
  • 27.8k
3 votes
2 answers
470 views

How did the NSA use vector supercomputers?

In the 80s, the NSA was a major customer of supercomputers. https://www.nsa.gov/Portals/70/documents/news-features/declassified-documents/cryptologic-quarterly/NSA_and_the_Supercomputer.pdf discusses ...
user avatar
  • 49.3k
6 votes
2 answers
1k views

What specific factor(s) made Thomas Watson, Jr. (of IBM) so enthusiastic about early electronics?

One of my favourite computer history books is Stan Augarten's "Bit by Bit", which has an author-approved scanned copy at http://ds-wordpress.haverford.edu/bitbybit/ In it, the author makes ...
user avatar
3 votes
0 answers
192 views

Why was the IBM 7070 unsuccessful?

In a talk on the IBM 360 and the computers it replaced the speaker at 39:35 describes the 7070 as 'a dog', and elsewhere contrasts it unfavorably with the 1401 (which considerably exceeded ...
user avatar
  • 49.3k
11 votes
4 answers
3k views

Were round punchcard holes mechanically stiffer?

The most common punch card format was the IBM 80 column by 12 row, with narrow rectangular holes. However, there were other possibilities, such as a later IBM format that used round holes. That one ...
user avatar
  • 49.3k
33 votes
9 answers
10k views

What did code on punch cards do with the other six bits per column?

In the fifties and sixties, program source code was typically stored on punch cards, one card per line. The most common card format was the IBM 80 column by 12 row. For source code, this was commonly ...
user avatar
  • 49.3k
5 votes
0 answers
176 views

Why did the Burroughs 205 not use bi-quinary like the IBM 650?

The IBM 650, one of the first general-purpose digital computers, designed in the early fifties, used decimal digits with bi-quinary representation for reasons discussed here: Why did the IBM 650 use ...
user avatar
  • 49.3k
46 votes
10 answers
10k views

Why did 1950s-60s computers have such wide words?

Modern general-purpose computers typically have a 64-bit word size, but looking back in time, we see narrower CPUs. In the early 80s, the 68000 dealt with 32-bit addresses but the ALU was only 16 bits ...
user avatar
  • 49.3k
5 votes
2 answers
424 views

COBOL and processing card files directly

COBOL was the first exercise in design of a programming language by a committee of representatives from competing companies. irrespective of one's opinion of the technical quality of the end result, ...
user avatar
  • 49.3k
4 votes
1 answer
220 views

What was machine-specific about Honeywell FACT?

While COBOL was the first highly successful business-oriented programming language, several business-oriented languages were designed before it in the late fifties, including Honeywell-800 Business ...
user avatar
  • 49.3k
2 votes
0 answers
189 views

Hitting the CMS Limits of Portable Code

I wrote this arbitrary precision arithmetic utility on BSD in my postgraduate days, then after graduating ported it to DOS using TurboC. Was proud that it would do the same thing with 16bit word ...
user avatar
  • 389
9 votes
10 answers
3k views

How did dusty deck Fortran handle overflow?

In Fortran 77, numerical code that ran on IBM, CDC, Cray etc, how was overflow typically handled? Did it raise an exception? (I would expect such an exception to be inexact on vector machines, i.e. to ...
user avatar
  • 49.3k
5 votes
3 answers
500 views

Is this a custom NASA Langley-built computer or is this a commercial system (ca 1970's)?

CNN's NASA will name its headquarters after Mary W. Jackson, the agency's first African American female engineer and NASA news item NASA Names Headquarters After ‘Hidden Figure’ Mary W. Jackson ...
user avatar
  • 2,159
19 votes
1 answer
601 views

Was the IBM S/360 Responsible for Popularizating the 'A'-to-'F' Notation in Hexadecimal Numbers?

In the early history of computing before the mid-1960s, there wasn't an universal, de-facto standard for the written representation of a hexadecimal number, different computer systems used their own ...
user avatar
  • 2,924
12 votes
1 answer
565 views

Why did IBM develop 5250 block mode terminals when 3270 already existed?

IBM introduced the 3270 family of block mode terminals in 1971, for use with IBM mainframes (System/370 and successors). Then, in 1977, IBM introduced the 5250 family of block mode terminals for use ...
user avatar
5 votes
2 answers
450 views

Data length module of 3.2^n confusion in IBM system/360 architecture

I'm currently reading about the IBM system/360 architecture and there's a part that has me very confused: The decision on basic format (which affected character size, word size, instruction field, ...
user avatar
  • 415
6 votes
4 answers
671 views

How was the APL character set represented on IBM mainframes?

The APL language used a unique set of characters, and additionally allowed overstriking of some characters on the terminal to form characters that were used in the language. When an APL workspace was ...
user avatar
  • 1,270