Int 21/AX=4405h

COMBI-disk v1.13 - CONTROL COMBI-disk

AX = 4405h
BL = drive number (00h = default, 01h = A:, etc) for RAM disk
CX = number of bytes to write
DS:DX -> buffer containing command packet (see #01539)

Return:
CF clear if successful
AX = number of bytes actually transferred
CF set on error
AX = error code (01h,05h,06h,0Dh) (see #01680 at AH=59h/BX=0000h)

See Also: AX=4404h"COMBI"

(Table 01538) Values for COMBI-disk command code: 80h flush cache 81h change options byte 82h shrink memory 83h expand memory 84h get dirty block information 85h reset write errors 86h reset counters

Format of COMBI-disk command packet: Offset Size Description (Table 01539) 00h WORD version 02h BYTE command code (see #01538) ---command code 80h--- no additional fields ---command code 81h--- 03h BYTE new options byte (see #01540) ---command code 82h--- 03h WORD number of KB to release ---command code 83h--- 03h WORD number of KB to expand ---command code 84h--- 03h DWORD -> buffer for block info (see #01541) ---command code 85h--- 03h DWORD block ID ---command code 86h--- 03h BYTE which counters to reset

bit 0:
Hard disk read counts

bit 1:
Hard disk write counts

bit 2:
RAM disk read/write counts

Note: Multiple commands may be placed in a single packet by stringing together as many command/argument pairs as desired

Bitfields for COMBI-disk options byte: Bit(s) Description (Table 01540) 0 cache off 1 cache frozen 2 write caching enabled 3 delayed writing disabled 5 fix memory allocation (no XMS lending) 6 no 'sector not found' error

Format of COMBI-disk block info: Offset Size Description (Table 01541) 00h DWORD block ID 04h BYTE bitmask of valid sectors in block 05h BYTE bitmask of dirty sectors in block 06h BYTE last error returned by BIOS 07h BYTE number of errors

Category: Disk I/O Enhancements - Int 21h - C

Interrups Categories Contents