INT 13h,  0Ch (12)       Seek to Cylinder                          fixed disk

Positions the read/write heads over a specified cylinder for a fixed
disk. This service can be performed on fixed disks only.

On entry:      AH         0Ch
CH         Cylinder number (10-bit value; upper 2 bits
in CL)
DH         Head number
DL         Drive number (Bit 7 must be set)

Returns:       AH         Status of operation (See Service 01h)
CF         Set if error, else cleared
                                                                          

Notes:         The cylinder number is a ten-bit quantity (0 through
1023). Its most significant two bits are in bits 7
and 6 of CL; the remaining eight bits are in CH. The
starting sector number fits in the low-order portion
(lower 6 bits) of CL.

If an error is encountered, use Service 0h to reset
the drive and retry the operation.

Even though the head value is not needed, you must
supply a legal value--or else the seek will not be
performed and an error will be returned.

For the AT, XT-286, and PC Convertible, the BIOS
executes INT 15h, Service 90h (Device Busy), for the
diskette (Type = 01h) and the fixed disk (Type =
00h) prior to waiting for the interrupt. INT 15h,
Service 91h (Interrupt Complete), is executed upon
completion.

See also: INT 13h, 01h

INT 13h, 0Ch (12) Seek to Cylinder fixed disk