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, Micha�~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 Message was sent through the cbm-hackers mailing listReceived on 2017-10-17 05:00:02
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