On Tue, 17 Apr 2001, Martijn van Buul wrote: > Correct me if I'm wrong, but I seem to recall that the PC-20 was an *XT*, > thus having no BIOS whatsoever. It might require some additional > information for it to work (a la BSD disklabel). I don't know much about the PC20 but I do know about the IBM XT (not clones). The XT supports BIOS extension ROMs. The XT hard drive controllor contains an extension ROM which has parameters for 4 hard drives, 2 10 M drives and a 20 M drive. I think the other drive was a 5 M. The drive was selected by 2 jumpers on the drive controller. Third party controllers had their own ROMs to support their own drives. Larger drives were not generally supported by these machines. The ones that I saw required software drivers in order to work. 8 bit controllers and drives are hard to find, try Jameco. The other thing that needs to be considered is the version of IDE supported. Old machines will probably support only the original IDE specification. The older versions of DOS did not support DMA access on hard drives. Later versions of DOS use DMA access for the hard drives. When the change was made, a lot of cheap controllers and drives stopped working. Also, you need at least DOS 4 to address partitions greater than 60 M. - This message was sent through the cbm-hackers mailing list. To unsubscribe: echo unsubscribe | mail cbm-hackers-request@dot.tml.hut.fi.
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