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1500 questions
27
votes
2 answers
Apple II: Applesoft BASIC memory management
I am trying to write an Applesoft / floating point BASIC program using high resolution graphics and some assembly language code.
My BASIC program is quite large, and after running the program for a while it crashes for no apparent reason, or my…
Dale Mahalko
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27
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17 answers
How much did the first hard drives for PCs cost?
I would like to know how much early PC hard drives cost but have only been aable to find adjacent or unsourced data.
According to the Centre for Computing History:
The "IBM 5161 Expansion Chassis" came with one 10 MB hard disk and
allowed the…
Ellen Spertus
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27
votes
4 answers
Why did the Atari 8-bit computers make beeping noises while accessing the disk and cassette drives?
If you've ever used an actual Atari 8-bit computer with either a cassette or disk drive, you would have noticed that it made a variety of "beeping" noises while accessing the devices. Specifically, loading a cassette made a "cluuug" sound repeatedly…
bjb
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27
votes
6 answers
Is there still no "digital version of PCBs and ICs" software that all future emulators can use?
It strikes me that, in theory, it would be possible to skip the classic approach of emulation and instead literally build a NES, SNES, Nintendo 64 or any console with digital "components", which are wired together just like the original machines, on…
Jaramy C.
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- 3
27
votes
4 answers
Use of undocumented opcodes
I figure this is fitting for Retrocomputing.SE because CPUs like the 6502 and Z80 and the PDP-8, and probably others, have undocumented instructions and will happily execute them, in contrast with serious and modern CPUs which will trigger some sort…
Omar and Lorraine
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27
votes
5 answers
Did any Amiga 500 games or programs (apart from paint programs) use more than 32 colours?
While the Original Chip Set (OCS) and Enhanced Chip Set (ECS) Amiga computers had the 32 x 2 colour EHB (Extra Half-Brite) and 4096 colour HAM (Hold And Mofify) screen modes, where these ever used outside paint programs, for instance in games?
If…
nsandersen
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27
votes
4 answers
Why was it common to reference memory locations using negative numbers on some BASICs?
If you had an Apple II, it was common in BASIC to reference memory locations above the 32K point by using a negative number. For example, if you wanted to click the speaker you would PEEK/POKE -16336 or if you wanted to enter the Apple II monitor, a…
bjb
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27
votes
4 answers
8080 vs. 8086 - Are 16 Bit CPUs bloaty by nature?
In comments to a parallel question (Why was IBM BASIC so Huge?) one point discussed is code density of 8 vs. 16 bit CPUs. Some assumptions were that 16-bit must be more bloaty due to its need for an address mode byte in each instruction, whereas…
Raffzahn
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27
votes
5 answers
Why was IBM BASIC so Huge?
The early versions of Microsoft BASIC required 4KB of ROM, and many versions existed in the 8KB and 16KB size. But Microsoft's IBM BASIC (known as "Cassette BASIC") for the original IBM PC (Model 5150) required 32KB. This seems odd to me given…
Brian H
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27
votes
1 answer
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 first operating system called DOS?
rwallace
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27
votes
9 answers
What other tricks were there to get more data onto floppy disks?
I remember using a utility back in MS-DOS 3.3 days, called MAXI Disk, that somehow magically managed to get 420K on a 360K 5¼″ disk. I assume it managed it by destroying some redundancy like a backup FAT.
How did it work? Were there other tricks to…
user230910
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27
votes
1 answer
What is a dropfile?
After reading Charles Duffy's comment on Was there a clearly identifiable "first computer" to use or demonstrate the use of virtual memory?:
I had a computer science professor around 1999 or therebouts who still bemoaned that virtual memory had won…
wizzwizz4
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27
votes
4 answers
What was the intention with the Commodore 128?
The Commodore 128 had 2 CPUs, 2 video graphic chips, and 2 I/O systems/chips.
It had 3 modes: Commodore 64 mode, Commodore 128 mode and CP/M. The first shared one of each CPU/chip, the CP/M mode the other.
Was it the original intention to combine…
Michel Keijzers
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27
votes
1 answer
Why were pipes removed from the Lisa?
I was recently looking at some documentation for programming the Apple Lisa: https://lisa.sunder.net/LOS_Reference.pdf and I was surprised how advanced it was for the time. It had a lot of features that didn't make it to the Mac until much later. …
wrosecrans
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27
votes
3 answers
What does a Nintendo Game Boy do when turned on without a game cartridge inserted?
When a Nintendo Game Boy is turned on, it displays a logo read from the cartridge (looking like this) before starting the game. What does it display if there's no cartridge inserted from which to read the logo? And what happens after that?
cjs
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