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 below)

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

See Also: AX=4404h"COMBI"

Format of command packet:
Offset Size    Description
 00h   WORD    version
 02h   BYTE    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
---command code 81h---
 03h   BYTE    new options byte (see below)
---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 below)
---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 options byte:
 bit 0 cache off
 bit 1 cache frozen
 bit 2 write caching enabled
 bit 3 delayed writing disabled
 bit 5 fix memory allocation (no XMS lending)
 bit 6 no 'sector not found' error

Format of block info:
Offset Size    Description
 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