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1500 questions
19
votes
7 answers
Why were closed tape loops never a popular storage medium (or were they)?
Tape storage is, in some sense, the most successful technology across all of IT, being first used in the 1950s and AFAIK still unbeaten today in its niche. Though the success is mostly because tape can be wound up so compactly, it also seems to be…
leftaroundabout
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19
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What is the history of the PDP-11 MARK instruction?
The PDP-11 MARK instruction was intended to be used as part of the standard PDP-11 subroutine return convention. MARK facilitated the stack clean up procedures involved in subroutine exit.
To use it, the caller would put the MARK instruction on the…
Leo B.
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19
votes
3 answers
How do CGA emulators for Hercules graphics work?
HGC cards on IBM PCs used to be able to run CGA software by using a CGA emulator. How exactly did those programs work? What were the limitations?
Arne
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19
votes
8 answers
CP/M in fewer than 80 columns
The standard for business computing in the seventies and eighties was 80 columns, and CP/M was primarily for business computing, so it's unsurprising that CP/M typically ran in 80 columns. For example, the Commodore 128 was nominally capable of…
rwallace
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19
votes
4 answers
Why is the Z80's supply pin in the middle of the data pins?
I recently came across this question, Why are IC pinouts often so illogical?, which asks:
Another example - the Z80's data bus:
I mean, that one just makes no sense to me whatsoever. Not only are then in some seemingly random order, but you…
Greenonline
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19
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6 answers
What are my options for multitasking in MS-DOS 5.0 on an 80186 with EMS?
I've got an HP 200LX, which runs DOS 5.0 from ROM, and I'm using EMM200 to provide some EMS from the C: RAM disk (it uses the memory controller to directly map the "disk" blocks into memory, and thus doesn't rely on disk I/O for swapping).
What…
db2
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19
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10 answers
What caused the demise of BASIC/BASICA in the late 1980's?
While not strictly adhered to, this is somewhat of a generalization of computer listings found in the more popular magazines of the time - BYTE, Kilobaud, PC Computing, etc. This explains the exclusion of other versions of Basic, Pascal, C, Turtle…
jwzumwalt
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19
votes
1 answer
How did the Atari 2600's 6507 handle zero page and stack with only 128 bytes of RAM?
The Atari 2600 used a cut-down version of the 6502 called the 6507. The 6507 was cost reduced by not supporting interrupts and (more importantly) having fewer address lines resulting in that it only supported 8KB. While this had its limitations, it…
bjb
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19
votes
2 answers
How do high-resolution graphics work on the ZX81?
The ZX81 has a display file which is treated rather like a serial file. And the CPU generates addresses which the ULA uses to look up the characters' bitmaps from the ROM (Yes, I know the actual explanation is rather more complicated than this). I…
Omar and Lorraine
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19
votes
1 answer
What kind of software was used to develop Nintendo 64 titles?
There seems to be a lot of discussion online about the development hardware used to create Nintendo 64 titles: SGI Indy "pizza box" workstations, SGI's custom Ultra 64 development boards (aka "DEVELOPMNET" boards), and testing using a modified Sega…
JAL
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19
votes
2 answers
When did README files start showing up in software?
Everyone knows how important documentation is -- for a project to grow past a certain point, it's a must-have. However, almost every software project of any size nowadays comes with at least a README file.
When did including a README file…
tonysdg
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19
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2 answers
First commercial DOS game?
What was the first commercial game sold for use on IBM/MS/PC DOS after the IBM August 12, 1981 release.
jwzumwalt
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19
votes
7 answers
What video connections were common in Europe?
What video connections were common on European TVs and monitors during the "retro" era?
In the USA, first there were none on TVs (RF screw terminals only) and monitors had composite (yellow RCA, CVBS) or nonstandard connectors specific to the…
snips-n-snails
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19
votes
3 answers
Who coined the nickname "Trash-80" and what was the source of their animosity?
In the U.S. in the early 1980's (1980-1982, roughly), the TRS-80 Model I/III computers were commonly referred to by teens and youngsters as the "Trash-80". The best reason I can attribute to this widespread "trash talk" is that the TRS-80…
Brian H
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19
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5 answers
Uptime in ZX BASIC
How can I obtain the uptime of a Sinclair ZX Spectrum machine (ZX48, ZX128, or Pentagon clone) via their BASIC interpreter? Specifically, the same value used by RANDOMIZE 0 to seed its PRNG. I would assume that this uptime would be the number of…
forest
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