HP Vectra Technical Reference Manual page 266

On Exit: AH
=
Return Status
DL
=
#
of drives in system
DH
=
Maximum head address (Total heads - 1)
CH
=
Maximum cylinder address (Total cyls - 1)
CL
=
Maximum sector address (Total sectors/track)
high two bits of CL are the MSB of the cylinder number in CH, making a 10 bit
value
Registers Altered: AH, CX, DX
F13~LT_RESET
(AH
=
ODH)
This command issues a reset command to the hard disc controller. It is essentially the same as
function OH, F13_RESET_DISC, except that a reset is not issued to the flexible disc units.
On Entry: AH
=
F13--ALT_RESET (ODH)
DL
=
device number (>
=
80H)
On Exit: AH
=
Return Status
Registers Altered: AH
This function returns the Direct Access Standard Device (DASD) type code for the attached
device. It also returns the total number of sectors for the entire drive if it is a hard disc.
On Entry: AH
=~
F13_GET_DASD (15H)
DL
=
device number
On Exit: AH
=
DASD type (if Carry Flag not set)
o
=
No drive present
1
=
Flexible disc, no disc change line available
2
=
Flexible disc, disc change line is available
3
=
Hard disc
When AH
=
3 the following registers are valid:
CX
=
Most significant word for total number of sectors on medium
DX
=
Least significant word for total number of sectors on medium
Registers Altered: AH, CX, DX
Disc 257