Timeline for Why did CP/M and MS-DOS use the BIOS instead of their own drivers to access hardware?
Current License: CC BY-SA 4.0
7 events
| when toggle format | what | by | license | comment | |
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| Jun 8 at 0:55 | comment | added | Simon Kissane | "but it's still effectively part of the DOS operating system" => I don't think this is correct. IBM started developing their ROM BIOS before they'd decided on the OS, and its API doesn't resemble the CP/M BIOS API. By contrast, the MS-DOS BIOS API (not used by programs, only for MSDOS.SYS to call IO.SYS) is obviously conceptually inspired by the CP/M BIOS API, albeit incompatible with it. Really the ROM BIOS and the DOS / CP/M BIOS are two different things with a common name. | |
| Oct 3, 2020 at 18:51 | history | edited | user3840170 | CC BY-SA 4.0 | edited body |
| Jul 12, 2019 at 12:46 | comment | added | Thorbjørn Ravn Andersen | The CP/M machine I used back then had a boot loader that required sector 0 to be in single density format. Then when CP/M was running the rest of the floppy was in double density format. | |
| Aug 4, 2017 at 19:33 | comment | added | Tommy | I think it wasn't merely ease of booting; the original PC shipped with as little as 16kb and MS-DOS was only one of the operating environments offered: IBM wanted to hit all possible use cases so e.g. Microsoft's ROM BASIC was also right there. It didn't run on MS-DOS or anything else, it's a complete firmware solution. Just like all of the immediate competitors of 1981. So BIOS stuff can be shared only because it's right there in ROM. | |
| Jun 8, 2017 at 8:44 | comment | added | JeremyP | @john_e Good point. It would be better to say all it required was a boot loader in ROM. | |
| Jun 7, 2017 at 9:47 | comment | added | john_e | Saying "CP/M had a bootloader in ROM" isn't meaningful -- CP/M ran on many different machines with widely varying ROMs. There was no single ROM bootloader common to them all. | |
| Jun 6, 2017 at 9:21 | history | answered | JeremyP | CC BY-SA 3.0 |