INT 13h,  18h (24)       Set Media Type for Format                       many

This service returns a Diskette Drive Parameter Table (DDPT) for a
specified diskette drive. This service can be performed on diskettes

On entry:      AH         18h
CH         Number of tracks (10-bit value; upper 2 bits
in CL)
CL         Sectors per track
DL         Drive number (Bit 7 must be clear)

Returns:       CF         Set if error, else cleared
AH         Status of operation (See Service 01h)
ES:DI      Pointer to 11-byte Diskette Drive Parameter

Notes:         This service is not available for PCs, PCjrs, XTs
dated before 1/10/86, and ATs dated before 11/15/85.

Machines that support this service call it before
calling Service 05h (Format a Track).

For each supported media type, there is one Diskette
Drive Parameter Table (DDPT).

In the event that the Change Status line is active
(i.e., that a disk change has occurred), this
service first attempts to deactivate the Change
Status line (by properly recognizing the new
diskette). If unable to do so, the service returns
an error. Therefore, if no diskette is present in
the drive, 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) prior to waiting for the
interrupt. INT 15h, Service 91h (Interrupt
Complete), is executed upon completion. Diskette
operations that require the diskette motor to be on
will call INT 15h, Service 90 (Device Busy), with
the type equal to "Diskette Drive Motor Start" (Type
= FDh). This allows the system to perform another
task while the drive motor is waiting to get up to

See also: INT 13h, 01h
See also: INT 13h, 16h
See also: INT 13h, 17h

INT 13h, 18h (24) Set Media Type for Format many