Selects media characteristics for the specified drive.
Call with:
AH = 18H
CH = number of cylinders
CL = sectors per track
DL = drive
00H—7FH floppy disk
Returns:
If function successful
Carry flag = clear
AH = 00H
ES:DI = segment:offset of disk parameter table for media type
If function unsuccessful
Carry flag = set
AH = status (see Int 13H Function 01H)
Notes:
A floppy disk must be present in the drive.
This function should be called prior to formatting a disk with Int 13H Function 05H so that the ROM BIOS can set the correct data rate for the media.
If the change line is active for the specified drive, it is reset.