User`s manual

DIGITAL-LOGIC AG MSLB-P5 Manual V0.3
PRELIMINARY 174
16.6.7 Interrupt 13h–Extended Fixed Disk Services
The following describes the Interrupt 13h Extended Fixed Disk Services, including the PhoenixBIOS
Enhanced Disk Drive (EDD) services:
Int 13h Extended Fixed Disk Services
AH = 41h Check Extensions Present
Entry:
BX 55AAh
DL Drive Number
Exit:
AH Major version number (20h)
AL Internal use only
BX 55AAh = Extensions present
CX Feature support map:
Bit 0: 1 = Extended disk access
Bit 1: 1 = Removable drive control
Bit 2: 1 = Enhanced Disk Drive Extensions
Bits 3-7, Reserved, must be 0
AH = 42h Extended Read
Entry:
DL Drive Number
DS:SI Disk address packet
AH = 43h Extended Write
Entry:
AL Verify Bits:
Bit 0: 0 = Write with verify off
1 = Write with verify on
Bits 1-7 Reserved, set to 0
DL Drive number
DS:SI Disk address packet
AH = 44h Verify Sectors
Entry:
DL Drive number
DS:SI Disk address packet
AH = 47h Extended Seek
Entry:
DL Drive number
DS:SI Disk address packet
AH = 48h Get Drive Parameters
Entry:
DL Drive Number
DS:SI Address of Result Buffer
Exit:
DS:SI Pointer to Result Buffer:
info_size dw 30 ;size of this buffer
flags dw ? ;info flags (See below)
cylinders dd ? ;cylinders on disk
heads dd ? ;heads on disk
sec_per_track dd ? ;sectors per track
sectors dq ? ;sectors on disk
sector_size dw ? ;bytes per sector
extended_table dd? ;extended table ptr
; (See below)
info flags:
Bit 00 = DMA boundary errors possible
1 = DMA errors handled
Bit 10 = CHS info not supplied
1 = CHS info valid
Bit 20 = Drive not removable
1 = Drive removable
Bit 30 = No write with verify
1 = Write with verify
Bit 40 = No change-line support
1 = Change-line support
Bit 50 = Drive not lockable
1 = Drive lockable
Bit 60 = CHS values for installed media
1 = Maximum CHS values for drive