Re: CP/M-86 Hard Disk Capabilities
- From: John Elliott <jce@xxxxxxxxxxxxxxxxxx>
- Date: Tue, 14 Feb 2006 00:21:41 +0000
Allison-nospam@xxxxxxxxxxxxxxxxxxxxxx wrote:
: CP/M-86 used 512byte sectors like CP/M3 (aka plus) and the math was
: 65535* 512=32mb .
Not in the IBM version it doesn't; the BIOS in CP/M-86 for the IBM uses
128-byte sectors. At 0051:2C08 is the code that translates a sector number
to an offset in the currently loaded track, and that very definitely uses
128-byte sectors:
mov cl,7
shl ax,cl ;Sector number * 128 gives address in buffer
mov word ptr 3A68h,ax
mov cx,64 ;64 words = 128 bytes
ret
PCP/M-86 and DOS Plus do use 512-byte sectors, being based on CCP/M.
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