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53 votes
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Did IBM encourage Bill Gates to retain the rights over PC-DOS?

TL;DR: It was IBM's idea. IBM never intended to buy any of the software they acquired for the PC - and MS never intended to supply any OS beside Xenix. But MS (Paul Allen) soon recognized the ...
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51 votes
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What did code on punch cards do with the other six bits per column?

TL;DR; Punch card code is not binary but a collection of n out of m encodings. Long Story Yes, really a long story, so I'll only cover the main line from Hollerith to EBCDIC. There are many sidelines ...
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46 votes
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Why does an instruction include the address of the next instruction on the IBM 650?

Very simple: Because there was room for an address and it improves performance a lot. Or as the manual puts it: It is important, however, for the programmer to realize that the simplest method of ...
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41 votes
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Why was IBM's Scientific Subroutine Package superseded?

Specifically concerning EISPACK. what happened was that James Hardy "Jim" Wilkinson in the UK (whose career as an applied mathematician started with practical ballistic modelling in WWII, ...
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35 votes
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Were any IBM mainframes ever run multiuser?

Yes. There were CP/CMS and VM/370 - true multiuser operating systems running on the mainframe with individual users logged in. AFAIK it was mainly used for software developers (to develop IBM ...
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34 votes
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What is the function of this strange IBM apparatus?

Classic IBM 224 Dictating Unit using a magnabelt, often called a Dictaphone, although that wasa trademark of a different company. Introduced in 1966 and sold in high volume and worldwide, way into ...
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  • 173k
31 votes

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

Uppercase text only needs six bits per character. The fundamental mistake that you are making is assuming that punch codes were binary numbers. They were not. The encodings were patterns, ...
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31 votes

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

Although you have many correct answers describing the nature of the coding used in punched cards, no one has touched on the mechanical properties of the cards. Regular users of punched cards in the ...
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28 votes
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What date is 74029 on an IBM Mainframe?

TL;DR: DATE=74029 reads as: Year (19)74, Day 029 (Jan 29th), It's an Ordinal Date in truncated form, expressed in terms of 2 digit year and 3 digit day of the year. Does anyone know when was it ...
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27 votes
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How many OS/2 viruses were there?

The cited source from the question is the source for the English Wikipedia page as well, that claims that there are only very few known viruses for that system. But the low amount of viruses seems to ...
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27 votes
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Why wasn't EBCDIC designed with contiguous alphanumeric characters?

There is a clue in the name - BCD stands for "binary-coded decimal", where 4 bits are used to represent 1 decimal digit (0-9). The hexadecimal values A-F are not used in BCD. EBCDIC is an extended ...
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  • 1,388
27 votes

Was there a clearly identifiable "first computer" to use or demonstrate the use of virtual memory?

The History section of the Wikipedia Virtual Memory page seems to have the details of this: The concept of virtual memory was first developed by German physicist Fritz-Rudolf Güntsch at the ...
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26 votes

How many OS/2 viruses were there?

I have not found a reference, but here's a search for OS/2 on Trend Micro's virus encyclopedia. That finds 30 entries, some of which are actual OS/2 viruses, and some of which are interesting OS/2 ...
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  • 7,814
23 votes

Did IBM encourage Bill Gates to retain the rights over PC-DOS?

My wife began work at MSFT in the downtown Bellevue office in late 1981 (approx employee #90-ish) just a couple weeks before the company's move to the highway 520 building next to the Burger King on ...
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21 votes

Were any IBM mainframes ever run multiuser?

IBM mainframes are still around (IBM Z). Linux has been available for IBM Z hardware and its predecessor, System/390, for 20 years, and z/OS is itself a certified UNIX through the z/OS UNIX System ...
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  • 7,854
20 votes

Why wasn't EBCDIC designed with contiguous alphanumeric characters?

As pointed out by Jon Custer, part of the reason is due to the input at the time being punch cards. If holes were close together there was a risk of the card being unreadable or ripping. In addition, ...
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20 votes
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What was the most critical supporting software for COBOL on IBM mainframes?

TL;DR: Which components or facilities were the biggest obstacle to porting typical COBOL applications? Simply that there were not many applications that made sense to be ported to (desktop) micros. ...
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19 votes

How widely used was 0xDEADBEEF?

It can be found in implementations of zfs such as OpenZFS, inherited from the Solaris Kernel Memory C header file: https://github.com/openzfs/openzfs/blob/master/usr/src/uts/common/sys/kmem_impl.h ...
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19 votes

When did IBM start to use ASCII?

IBM started using ASCII before 1970; the 2260 terminal, released in 1964, used the unpublished (but ratified) 1965 version of the ASA X3.4 standard. IBM mainframes still use EBCDIC, so I don’t think ...
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19 votes
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When did IBM start to use ASCII?

TL;DR: ASCII was never intended for processing, just as an interface standard for data exchange (hence the name American Standard Code for Information Interchange) IBM never switched, it still uses ...
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  • 173k
19 votes

Were any IBM mainframes ever run multiuser?

Another one to mention is MTS which was first released in 1967, last release in 1988. It was in use at Rensselaer Polytechnic Institute from 1976 to 1999, of which I took part during the early 80s. In ...
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18 votes
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Which pointing devices were used by early laptop computers?

One alternative to the trackpoint was a trackball, either below the screen (as in the Macintosh Portable), or next to the screen (as in the Compaq LTE Lite). When the trackball was next to the screen ...
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18 votes
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What is the purpose of the yellow wired panels on the IBM 360 Model 20?

What is the purpose of the yellow wired panels It's the backplane, simply the wiring of the machine. on the IBM 360 Model 20? Not just there, but next to every mainframe was made that way. ...
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18 votes
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How can I resolve these intermittent memory issues?

After removing some more components, and getting under the floppy drive with some light for inspection, I found three "Chhsi"-branded capacitors that were bulging. These caps are part of the ...
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17 votes

How much data could be stored on a single punched card?

it says the original 8inch floppy disk from 1971 could store 80kb of data equivalent to that of 3000 punched cards Given, the text is a bit misleading, as it mixes up firsts. While it is true that ...
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  • 173k
17 votes
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How did SABRE work interactively without screens?

Wikipedia, unsurprisingly, gives incomplete information. A number of important new technologies were developed as part of the five-year R&D of SABRE, including a disk drive capable of storing ...
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  • 5,963
16 votes

Did the IBM PC use the 8088's NMI line?

In a 100% compatible PC, NMI is used only to communicate unrecoverable errors — normally a RAM parity failure, but possibly something else, which should reveal itself via one of the system control ...
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16 votes
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IBM vs DEC and business partners

I don't agree with the answer you read on quora. DEC did have a partner relationship with a certain kind of customer, namely engineering and science labs. Ken Olsen and the engineering staff at DEC ...
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  • 4,510
15 votes
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What's the deal with System/360's "USASCII" mode?

I found the explanation in chapters 23 and 20 of Mackenzie, Charles E, Coded Character Sets, History and Development (Addison-Wesley, 1980), which was linked in a footnote to Wikipedia's ASCII article....
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