Re: Software for MS-DOS 1.25

From: William Levak <wlevak_at_SDF.ORG>
Date: Tue, 17 Oct 2017 04:53:24 +0000 (UTC)
Message-ID: <Pine.NEB.4.64.1710170447340.19017@sdf.lonestar.org>
In the XT there is a drive parameter table in the BIOS ROM. Jumpers 
somewhere in the XT (I forget where) tell the system which entry in the 
table to use.

Adding a hard drive to the original PC was done by adding a controller 
card with a BIOS extension ROM.  This ROM contained the routines necessary 
to operate the hard drive.


On Sun, 15 Oct 2017, MichaĆ~B Pleban wrote:

> Hello!
>
> Baltissen, GJPAA (Ruud) wrote:
>
>> I only can tell you this: the XT BIOSes I am familiar with, including IBM, only support up to AH = 5 (to be honest, I only just found out). This means that 6 and higher HAVE to be added by DOS.
>
> That leaves us with a fundamental question - how exactly does MS-DOS
> know what kind of disk drives are attached to the system? We need to
> replicate  this so that DOS uses correct geometry when accessing floppies.
>
> Regards,
> Michau.
>
>
>       Message was sent through the cbm-hackers mailing list
>

wlevak@sdf.lonestar.org
SDF Public Access UNIX System - http://sdf.lonestar.org

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Received on 2017-10-17 05:00:02

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