ROM BIOS Drive Parameter Table (INT 13H Service 08H)

ID Number: Q51666

3.00 3.10 3.20 3.21 3.22 3.30 3.30a 4.00 4.01

MS-DOS

Summary:

Interrupt 13H Service 08H returns a pointer to a floppy disk drive

parameter table in ES:DI if it is successful. Interrupt 1EH uses this

parameter table. Information on this table can be found in the

following publications:

1. Page 197 of "The Peter Norton Programmer's Guide to the IBM PC,"

Peter Norton, Microsoft Press, ISBN #0-914845-46-2

2. Page 210 of "The New Peter Norton Programmer's Guide to the IBM PC

and PS/2," Peter Norton and Richard Wilton, Microsoft Press, ISBN

#1-55615-131-4

3. Page 3-23 of the "IBM PS/2 and PC BIOS Interface Technical

Reference," IBM, part number 68X2260 [available from IBM by calling

(800) IBM-PCTB]

More Information:

The parameter table is 11 bytes long and is composed of the following

fields:

Offset Description

------ -----------

00 Specify byte 1: step-rate time, head-unload time

01 Specify byte 2: head-load time, DMA mode

02 Wait time until motor turned off (in clock ticks)

03 Bytes per sector: 0=128, 1=256, 2=512, 3=1024

04 Sector number of last sector on track

05 Gap length between sectors for read/write

06 Data transfer length, used when sector length unspecified

07 Gap length between sectors for format

08 Data value stored in formatted sectors

09 Head-settle time

0A Motor start-up time