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1500 questions
16
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2 answers
First language with C-like memory management
This is a nerd question but I can’t find anything in google. So, in which programming language did the classical memory management system first be implemented?
I mean the division into value types (ordinary Int, Bool, etc.) and reference types, for…
Matvey Malatsion
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3 answers
What happened to ZIP RAM?
I have several retro machines and add-on cards for the Amiga that use ZIP RAM. This vertically mounted chip design enjoyed a brief popularity in the early 1990s, in between the original DIP DRAM and the rise of the SIMM memory.
The advantage with…
Brian H
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16
votes
3 answers
Finding byte boundaries in floppy disk MFM bitstreams
I'm building myself a floppy disk interface based on a microcontroller. I'm successfully reading the bitstream off the disk and (probably) decoding the MFM bitstream into actual bits, based on the documentation in…
David Given
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16
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1 answer
Who or what is the 'AH' credited on the die of the Atari TIA chip next to Jay Miner?
I noticed that on the die shot of the Atari TIA chip, at the top you can see an Atari logo and at the bottom there are two initials: JM + AH. I assume that JM means Jay Miner, but who is the AH? I would have thought Joe Decuir would have been the…
bjb
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16
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8 answers
Developing an application in the era of cassette tapes (audio-tapes)
My colleague and I have just had a conversation and we were wondering how the process of developing an application was done in the era of cassette tapes.
Today we have HDDs, backup HDDs, FTPs, repositories in the cloud, etc. -- so we don't care: we…
jacek.ciach
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16
votes
1 answer
How did the Commodore PET 80 column display work?
Some variants of the Commodore PET (e.g. the 8000 and 9000 series, as well as some other versions with an aftermarket add-on) produce an 80x25 character display. Their character set is fixed in ROM using an 8 pixel by 8 pixel cell size. At 60Hz,…
Jules
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16
votes
4 answers
Toolchain and workflow to build CP/M
Building my own version of CP/M has always been a fascinating to-do project. Problem is that it seems that the source code is not in regular assembler, but some kind of macro-assembler like language Gary Kildall developed to ease CP/M maintenance,…
mcleod_ideafix
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16
votes
1 answer
Origin/source of "One Line" one-key game
Circa 1985 in our school BBC Micro lab, we wasted much time playing a tiny type-in game that looked a bit like this:
The playfield was filled with a random arrangement of asterisks, and the player controlled a continuously-growing diagonal line…
scruss
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16
votes
1 answer
Why was the audio output of the SID6581 so variable between chips?
Each of the SID6581s I have tested sound different, particularly when it comes to filter cutoffs and distortion. What are the causes of these variances?
rcntxtlztn
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16
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2 answers
Can we express the instructions to the Analytical Engine in terms of assembler or machine code?
On a recent trip to the London Science Museum I saw Babbage’s Analytical Engine.
Apparently this had an ALU (or equivalent). I can build an ALU out of logic gates but I can’t conceptualise how to do it with gears. I’m trying to map across the…
hawkeye
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16
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3 answers
How widespread was the 'test' activation code for Microsoft products?
Inspired by this question, I recall that many of the older Microsoft products from Windows 3.1 through the late 90's / early '00s supported a 'test' activation code of all 1's. I did this a few times out of laziness on Windows 95/98 machines many…
bjb
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16
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5 answers
What specific technical advance(s) allowed PCs to play "Full-screen full-motion" video?
In the early 1990s, the new buzzword for PCs was "Multimedia", and the gold standard for multimedia performance usually talked about was "full-screen full-motion" video playback. Many will remember early digital videos being played in tiny windows…
Brian H
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16
votes
1 answer
How do Amiga "Monitor" drivers work?
A "Monitor" driver for an Amiga is a file which, when placed in DEVS:Monitors, enables additional screenmodes. The standard PAL or NTSC driver, which provides screenmodes compatible with consumer TV frequencies, is built-in to the OS, but by adding…
Richard Downer
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16
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6 answers
Was photographic film ever used for digital data storage?
I was thinking about how Williams Tubes worked and how one could hypothetically "snapshot" (quite literally!) the state of a computer's memory by simply taking a photograph of the phosphor end of a memory-CRT - then feeding the stored state back…
Dai
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16
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4 answers
What determines which architecture an a.out executable runs on?
The ELF file format has an e_machine field in the header, which specifies which ISA the executable expects. And the e_ident structure also has an EI_OSABI field that specifies which ABI the executable is expecting. My guess is, that these fields are…
Omar and Lorraine
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