On 8/3/2023 11:54 AM, Jerome Shidel via Freedos-devel wrote:
On Aug 3, 2023, at 12:37 PM, Bret Johnson via Freedos-devel
<freedos-devel@lists.sourceforge.net> wrote:
Yeah, USB and CD/DVD makes only sense for a 386+ ...
USB, yes. CD/DVD, no. USB requires PCI which in turn requires 386+.
Actually, there were supposedly USB host controllers manufactured for the ISA
bus instead of PCI, but I've never actually seen one. But USB protocols assume
you're using a 32-bit (and in some cases 64-bit) CPU so USB really only makes
sense on 386+, though you could probably make things work on a lesser CPU if
you absolutely had to.
But CD drivers existed back in the early days and they never required anything
special of the CPU. They would sometimes take advantage of special features if
they were available, but it wasn't required. AFAIK, there are no DOS DVD
drivers anyway since I don't think anything has ever supported UDF.
I don’t recall any sub-386 ever shipping with a CD-ROM drive. But, there may
have been a couple very high end machines.
The main problem why I consider a CD/DVD drive is that on pre-386
computers, you rarely have an IDE/ATAPI controller to connect a common
CD-ROM drive. Yeah, theoretically, you could use a SCSI one, but that's
a completely different kettle of fish...
The first time I used CD-ROM drives was at least on a 486 machine. You
could try to use and ATAPI controller on an AT class computer (80286, or
lower), but then you are getting down into a deep dark rabbit hole where
you need to know what you're doing anyway, so trying to adapt FreeDOS
would be a manual option.
Hence, from a general, default installation option POV, I stick with my
assessment that it makes only sense for a 386+ machine...
Ralf
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