Int 21 Fn 4403  - Smartdrv.sys V3.x Only - Ioctl - Cache Control           [c]

   AX = 4403h
   BX = handle for device "SMARTAAR"
   CX = number of bytes to write
   DS:DX -> SMARTDRV control block (see below)

Return: CF clear if successful
       AX = number of bytes actually written
          = 0000h if control block too small for given command
   CF set on error
       AX = error code (01h,05h,06h,0Dh) (see AH=59h)

See Also: AX=4402h"SMARTDRV",INT 2F/AX=4A10h/BX=0000h

Format of SMARTDRV control block:
Offset Size    Description
 00h   BYTE    function code
       00h flush cache
       01h flush and discard cache
       02h disable caching (flushes and discards cache first)
       03h enable caching
       04h control write caching
       05h set flushing tick count
       06h lock cache contents
       07h unlock cache contents
       08h set flush-on-reboot flag
       09h unused
       0Ah control full-track caching
       0Bh reduce cache size
       0Ch increase cache size
       0Dh set INT 13 chain address
---function 04h---
 01h   BYTE    write caching control action
       00h turn off write-through
       01h turn on write-through
       02h turn off write buffering (also flushes cache)
       03h turn on write buffering (also flushes cache)
---function 05h---
 01h   WORD    number of timer ticks between cache flushes
---function 08h---
 01h   BYTE    new flush-on-reboot flag (00h off, 01h on)
---function 0Ah---
 01h   BYTE    full-track writes are
       00h not cached
       01h cached
---functions 0Bh,0Ch---
 01h   WORD    number of 16K pages by which to increase/reduce cache size
---function 0Dh---
 01h   DWORD   new address to which to chain on INT 13

Note:  the previous address is not preserved