[TUHS] Porting the SysIII kernel: boot, config & device drivers
Steve Nickolas
usotsuki at buric.co
Sat Dec 31 04:56:35 AEST 2022
On Fri, 30 Dec 2022, Paul Ruizendaal wrote:
> One could argue that one of the drivers of the success of CP/M in the
> 1970’s was due to its clear separation between the boot rom, BIOS and
> BDOS components. As far as I am aware, Unix prior to 1985 did never
> attempt to separate the device drivers from the other kernel code. I am
> not very familiar with early Xenix, it could be that Microsoft had both
> the skill and the interest to separate Xenix in a standard binary (i.e.
> BDOS part) and a device driver binary (i.e. BIOS part). Maybe the
> differences in MMU for the machines of the early 80’s were such that a
> standard binary could not be done anyway and separating out the device
> drivers would serve no purpose. Once the PC became dominant, maybe the
> point became moot for MS.
Certainly Microsoft *did* have an operating system, as early as 1981, that
had the concept of separated BIOS and BDOS, but they didn't write it, they
bought it 🤪
That said, given that it existed in MS-DOS, I can't imagine it wouldn't
have been impossible to also implement in Xenix...
-uso.
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