IBM PC CONVERTIBLE Technical Reference page 147

(AH)'8 READ DRIVE PARAMETERS
DL • DRIVE NUMBER (0-3)
OUTPUT PARAMETERS:
IF DRIVE INSTALLED:
ES:DI • POINTER TO DR1VE PARAMETERS TABLE
CH • MAXIMUM TRACK NUMBER / SIDE (LOWER 8 BITS)
CL (BITS 7-6) • TWO MOST SIGNIFICANT BITS OF
10 BIT TRACK NUMBER
CL
(bits
5-0) • MAXIMUM 512 BYTE SECTOR NUMBER
(6 BITS) PER TRACK
DH • MAXIMUM HEAD NUMBER
DL • NUMBER OF DISKETTE DRIVES INSTALLED ON
AX • 0
BH • 0
SYSTEM (1 - 2)
BL • DRIVE TYPE (1 - 360K 40 TRACK DRIVE)
(2 - 1.2 Meg 80 TRACK DRIVE)
(3 - 720K 80 TRACK DRIVE)
DISKETTE_STATUS IS CLEARED, CARRY FLAG IS RESET.
IF DRIVE NOT INSTALLED:
ES ,AX, BX, CX, DH, 01 • 0
DL • NUMBER OF DISKETTE DRIVES INSTALLED
DISKETTE_STATUS' 0
CARRY FLAG IS RESET.
(AH) • 15H CHECK FOR CHANGE LINE SUPPORT (READ DASD)
DL • DRIVE NUMBER (0-3)
OUTPUT PARAMETERS:
AH • 00 - NO DRIVE PRESENT
01 - DSKT DRV WITH NO CHANGE LINE SUPPORT INSTALLED
02 - DSKT DRV WITH CHANGE LINE SUPPORT INSTALLED
03 - FIXED DISK
DISKETTE_STATUS' 0, CARRY FLAG CLEAR
(AH)'16H READ DISKETTE CHANGE LINE STATUS
DL • DRIVE NUMBER (0-3)
OUTPUT PARAMETERS:
IF DRIVE INSTALLED:
• OOH- DISK CHANGE LINE NOT ACTIVE
- CARRY FLAG IS CLEARED
IF DRIVE NOT INSTALLED:
06H- DISK CHANGE LINE ACTIVE
- CARRY FLAG IS SET
- DISKETTE HEAD STEPPED TO
TRACK 1 THEN 0 TO RESET CHANGE LINE
80H- DISK CHANGE LINE ACTIVE AND
CANNOT BE RESET
(NO DISKETTE IN DRIVE)
- CARRY FLAG IS SET
DISKETTE_STATUS' TIMEOUT (80H)
CARRY FLAG IS CLEARED
IF DRIVE DOES NOT SUPPORT CHANGE LINE:
DISKETTLSTATUS • MEDIA CHANGE (06)
CARRY FLAG IS CLEARED
(AH)'17H SET DASD TYPE FOR FORMAT
DL • DRIVE NUMBER (0-3)
AL • FORMAT TYPE
00 • NOT USED
01 • DISKETTE 320/360K IN 360K DRIVE
02 • DISKETTE 360K IN 1. 2MEG DRIVE
03 • DISKETTE 1.2MEG IN 1.2MEG DRIVE
04 • DISKETTE 720K IN 720K DRIVE
OUTPUT PARAMETERS:
AH'DISKETTE_STATUS' 0 CARRY FLAG CLEAR
NO FUNCTION PERFORMED
2-122 ROM BIOS