Questions tagged [mainframe]

for questions about retrocomputing mainframes or clusters

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5
votes
2answers
948 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 ...
6
votes
1answer
300 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-...
23
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4answers
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 ...
10
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2answers
276 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 ...
3
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2answers
162 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 ...
25
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1answer
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Why was IBM's Scientific Subroutine Package superseded?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 ...
36
votes
13answers
7k 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 ...
8
votes
1answer
845 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 ...
8
votes
3answers
530 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 ...
3
votes
2answers
161 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 ...
4
votes
1answer
216 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-...
22
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7answers
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 ...
9
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6answers
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, ...
17
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1answer
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 ...
6
votes
1answer
194 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 ...
6
votes
2answers
265 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 ...
4
votes
1answer
192 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)...
1
vote
0answers
89 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 ...
20
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17answers
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 ...
20
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5answers
5k 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 ...
5
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3answers
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 ...
20
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7answers
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 ...
4
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2answers
259 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, ...
2
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3answers
246 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 ...
3
votes
2answers
433 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 ...
6
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2answers
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 ...
3
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0answers
174 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 ...
11
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4answers
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 ...
32
votes
9answers
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 ...
5
votes
0answers
155 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 ...
45
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10answers
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 ...
4
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1answer
297 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, ...
4
votes
1answer
204 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 ...
2
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0answers
172 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 ...
9
votes
10answers
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 ...
5
votes
3answers
384 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 ...
19
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1answer
543 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 ...
11
votes
1answer
406 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 ...
5
votes
2answers
434 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, ...
4
votes
4answers
447 views

IBM Mainframe APL internals?

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 ...
1
vote
1answer
97 views

Overstriking for APL on 3270s?

This question addressed the question of APL overstrikes on printing terminals. However, IBM also had 3270 video display terminals that supported APL, as well, and those, too, handled overstriking. How?...
4
votes
1answer
112 views

Version list for TOPS-10?

So, does anybody have a list of TOPS-10 versions? I haven't been able to find any information aside from versions 7.03, and 7.04. are these lost to time? To clarify, I'm not asking for the software, ...
6
votes
2answers
404 views

Why did the CDC 6600 expand the word size to 60 bits?

According to http://www.quadibloc.com/comp/cp0201.htm The CDC 1604 used 48-bit floating point with 11 bits exponent and 36 bits mantissa. There was also a double precision format (which I believe was ...
6
votes
1answer
416 views

How many hours of labor did it take to assemble a minicomputer?

A minicomputer like the PDP-8 contained several thousand discrete transistors and other components, all of which had to be soldered by hand, and that was among the simplest computers on the market; ...
24
votes
1answer
6k views

What was the first operating system called DOS?

MS-DOS a.k.a. PC-DOS nee QDOS, was commonly just referred to as DOS. But 'disk operating system' is a very obvious acronym; there must have been previous operating systems so called. What was the ...
11
votes
2answers
1k views

Did any 360-compatible machine implement registers in core?

In the early days of transistors, when they cost on the order of a dollar each, it was possible to implement CPU registers with magnetic cores (the technology used for main memory at the time) instead ...
3
votes
1answer
152 views

What was the first company to sell an IBM compatible punchcard reader?

Punchcards were the primary way to get information into computers up through the sixties. The familiar eighty column format was designed by IBM, and was a factor in the later de facto standard eighty ...
15
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2answers
1k views

IBM mainframe classic executable file formats

Most modern platforms have pretty well-defined file formats; e.g. Windows uses PE, Linux and BSD - ELF (previously a.out), macOS - Mach-O, AIX - XCOFF and so on. What were (are?) common executable ...
13
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2answers
2k views

What is the purpose of the yellow wired panels on the IBM 360 Model 20?

I just finished reading a story about an IBM 360 Model 20 rescue, and some of the pictures caught my eye. Specifically this one: Searching online, led me to several more pictures, all with ...
4
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2answers
390 views

Was sneakernet a job description?

'Sneakernet' is a colloquial term for moving data by walking back and forth with a removable digital medium such as a floppy disk or tape in your hand. In 'IBM's 360 and Early 370 Systems', page 533, ...