Questions tagged [cp-m]
For questions related to the CP/M operating system by Gary Kildall.
75 questions
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IBM would-be purchase of CP/M
It is well-known that on a sunny day in 1980, when the IBM representatives came knocking on the door of Digital Research, Gary Kildall was still in the air on the way back from visiting another ...
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CP/M SKU per CPU only?
The impression I get is that CP/M relied on the BIOS, provided in ROM with the computer, for all the hardware-specific functions. So if you bought CP/M, you didn't have to specify what computer you ...
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Did CP/M provide compatibility for screen-based programs?
I refer here to 'screen-based programs' that are not actually graphical, but take full advantage of the screen as a two-dimensional array of 80x25 characters, as opposed to typical 'command-line ...
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Can a Harlequin ZX Spectrum clone be modifed to run CP/M?
The ZX Spectrum (and therefore the Harlequin) has its ROM from $0000 to $3FFF, while RAM further up to $5AFF is used for the screen (see Memory-Map). As CP/M expects RAM from $0000 upwards the two are ...
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What is the meaning of M in the Z80 statement ADD A,M
Recently I have been trying to compile CP/M 2.2 from source. When I try to assemble, everything works except for the instructions ADD A,M and SBC A,M, which the assembler returns a syntax error. I ...
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What was the most popular CP/M terminal type?
I'm porting CP/M to a new/old machine (the Amstrad NC200 laptop). Running programs on it is no problem, but running interesting programs (i.e. WordStar, Turbo Pascal and Ladder) involves implementing ...
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Purpose of two disk drives on the Osborne 1
I recently discovered the Osborne 1 computer, and I noticed it had two floppy disc drives.
What was the purpose of including two drives?
user11265
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Was parsing or operating systems the first user of dollar sign as end of string/input?
According to the question Why did DOS use dollar-terminated strings? DOS uses dollar-terminated strings, inherited from CP/M which used them because DEC also used dollar as the string terminator.
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How big was WordStar 1.0?
How big was the original CP/M version of WordStar? As in, the size of the program itself? Presumably it was in the low tens of kilobytes (I don't think it's possible to cram a practical word processor ...
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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,...
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What was the retail price of CP/M?
In the early days of the IBM PC, it was offered with a choice of four different operating systems including PC-DOS for $40 or CP/M for $240. Customers looked at what appeared to be essentially ...
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What are the names of the computers, that were used in the CP/M advertisement?
I am reading the article about the CP/M operating system and wonder which computers are displayed in this picture. I have recognized the "IBM PC" only - in the middle.
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Why did CP/M require RAM in the bottom part of the address space?
A Z80 on RESET, starts executing from 0x0000. This is why the ZX machines and so many others have ROM at the bottom of the address space. Presumably an 8080 is the same. But as I recall, a CP/M binary ...
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Is there a way to execute CP/M binaries on a modern Linux computer
I have a few old programs/games which I'd like to run today. As there is Wine for running Windows programs, I wondered if there is a compatibility layer for CP/M. Obviously it would need to implement ...
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CP/M without floppy drive
I remember reading (at the time when it was current) in a hobbyist magazine about a ZX Spectrum modification to map RAM into ROM (not unusual), and implementing CP/M for it. The author ended the ...
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Getting started with CP/M
I have a Commodore 128, but this is a platform-neutral question.
I have a lot of experience with a lot of operating systems (including DOS, Linux, BSD and AmigaOS) but I never used CP/M much back in ...
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Are there any drivers available to use DivMMC on the Spectrum +3e with CP/M plus?
Heading says it all. I have a Spectrum +3 (with +3e ROMs if that makes any difference) with a DivMMC SD card interface.
This works fine in +3e mode, but as I like to use the +3 with CP/M plus (...
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Fastest non-emulated CP/M Z80-based computer ever built?
What were the fastest CP/M computers ever built?
I'll restrict this to the Z80 variant of CP/M, no CP/M-86, CP/M-68k etc.
Z80 compatibles with higher clock frequencies or more instructions/clock or ...
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Why did CP/M and MS-DOS use the BIOS instead of their own drivers to access hardware?
Modern versions of Windows (and other modern operating systems I suppose) have their own drivers to access hardware.
But as I have read, in the old days, if CP/M or MS-DOS wanted to access hardware, ...
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How many CP/M machines ever shipped? [closed]
How many machines for which CP/M was the primary operating system (so not counting the Commodore 128) ever shipped?
I would also be interested in knowing how many S-100 machines ever shipped. I get ...
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Why does the Commodore C128 perform poorly when running CP/M?
I have seen several claims of poor performance of the C128 when running CP/M, and would like to better understand these claims, especially in comparison to other CP/M machines of the early to mid-...
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How did the Apple II forward binary instructions to the Z80 software card with CPM?
Microsoft produced the Z80 Softcard for the Apple II enabling it to run CPM and many Z80 binary programs.
This seems to be an unthinkable achievement. (For a kid who had an Apple IIe but was only a ...
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Where can I find "Nemesis II", the sequel to "Nemesis", an old CP/M game?
In 1981, the "Nemesis" game was released for CP/M-based machines by Super Soft Inc., with the author attribution of Michael A. Pagels and Michael Q Hiller, and artist attribution of Diana J. Bush. ...
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Why did Amstrad choose such bank combinations for its all-RAM mode in +2A and +3 Spectrum computers?
The +2A and the +3 versions of the ZX Spectrum, made by Amstrad, had a new banking mode, called "special". This banking mode is entered by setting bit 0 of port 1FFD. When active, two bits from this ...
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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 ...
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