Int 21 Fn 4405  - Sfs V1.00 - Driver Control                               [D]

   AX = 4405h
   BL = drive number (00h = default, 01h = A:, etc)
   CX = number of bytes to write
   DS:DX -> data to write (see #1230)

Return: CF clear if successful
       AX = number of bytes actually written
   CF set on error
       AX = error code (01h,05h,06h,0Dh) (see #1366 at AH=59h/BX=0000h)
Program: SFS (Secure FileSystem) is a shareware encrypting disk driver by
     Peter C. Gutmann

See Also: AX=4404h"SFS"

(Table 1229)
Values for SFS control function:
 00h   "PACKET_SET_DISKINFO"    set disk parameters
 01h   "PACKET_SET_KEYINFO"     set keying information
 02h   "PACKET_SET_READONLY"    select read/write or read-only
 03h   "PACKET_SET_DRIVENO"     set drive number to mount
 04h   "PACKET_SET_MOUNTSTATUS" set mount status
 05h   "PACKET_SET_UNMOUNT"     set/clear quick-unmount hotkey
 06h   "PACKET_SET_TIMEOUT"     set/clear auto-unmount timeout

Format of SFS control data packet:
Offset Size    Description (Table 1230)
 00h   WORD    signature 4330h ('C0')
 02h   WORD    function (see #1229)
---function 00h---
 04h   WORD    sector size in bytes
 06h   BYTE    sectors per cluster
 07h   WORD    number of boot sectors
 09h   BYTE    number of copies of FAT
 0Ah   WORD    size of root directory in entries
 0Ch   WORD    number of sectors on disk, 16-bit
 0Eh   BYTE    media descriptor byte
 0Fh   WORD    sectors per FAT
 11h   WORD    sectors per track
 13h   WORD    number of heads
 15h   DWORD   number of hidden sectors
 19h   DWORD   number of sectors on disk, 32-bit
---function 01h---
 04h 20 BYTEs  master IV for encrypted disk
 18h 64 BYTEs  NDC/SHS keying information
---function 02h---
 04h   WORD    read-only state: 00h read-only, 01h read/write
---function 03h---
 04h   WORD    drive number (see #1231)
 06h   DWORD   sector offset of logical volume from start of physical volume
       0 if logical volume = physical volume
---function 04h---
 04h   WORD    mount status (00h unmounted, 01h mounted)
---function 05h---
 04h   WORD    hotkey (high byte = shift state, low byte = scan code or 00h)
       (see #0005)
       0000h to disable hotkey
---function 06h---
 04h   WORD    timeout in minutes before automatic unmount
       0000h to disable auto-unmount

Notes: the data for function 00h corresponds to a DOS BPB (see AH=53h)
   functions 00h, 01h, and 03h automatically unmount the encrypted drive
   unmounting a drive with function 04h also destroys the encryption
     information in the driver and forces all dirty buffers to be flushed

Bitfields for SFS drive number:
Bit(s) Description (Table 1231)
 15-12 drive access mode
   0000 BIOS access
   0001 direct IDE access
   0010 direct SCSI access
---if BIOS access---
 11-8  unused (0)
 7-0   BIOS drive number
---if IDE access---
 11-8  unused (0)
 7-0   IDE drive number
---if SCSI access---
 11-8  SCSI host number
 7-4   SCSI target ID
 3-0   SCSI logical unit number