Int 21 Fn 4405  - Combi-disk V1.13 - Control Combi-disk                    [d]

   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 #1226)

Return: CF clear if successful
       AX = number of bytes actually transferred
   CF set on error
       AX = error code (01h,05h,06h,0Dh) (see #1366 at AH=59h/BX=0000h)

See Also: AX=4404h"COMBI"

(Table 1225)
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 1226)
 00h   WORD    version
 02h   BYTE    command code (see #1225)
---command code 80h---
 no additional fields
---command code 81h---
 03h   BYTE    new options byte (see #1227)
---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 #1228)
---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 1227)
 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 1228)
 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