Int 21 Fn 4404  - Dubldisk.sys V2.6 - Get Info                             [d]

   AX = 4404h
   BL = drive number of DoubleDisk drive (00h = default, 01h = A:, etc.)
   CX = number of bytes (000Ah-0014h, call ignored otherwise)
   DS:DX -> data record (see below)

Return: CF clear if successful
       AX = number of bytes read
   CF set on error
       AX = error code (01h,05h,06h,0Dh) (see AH=59h)
Program: DUBLDISK.SYS is the device driver portion of DoubleDisk, a disk
     expander by Vertisoft Systems, Inc.

Note:  the installation check consists of scanning memory for the signature
     "FAT 2.6  byte:", which is immediately followed by a data table

See Also: AX=440Dh
Index: installation check;DUBLDISK.SYS

Format of data record:
Offset Size    Description
 00h   WORD    (call) signature 4444h
 02h   BYTE    (call) function
           00h ???
           01h ???
---function 00h---
 02h   BYTE    (return) ???
 03h   BYTE    (return) ???
---function 01h---
 02h   WORD    (return) 4444h
 04h   WORD    allocation unit size???
 06h   WORD    ???
 08h   WORD    ???
 0Ah   BYTE    ???

Format of signature data table:
Offset Size    Description
 00h  5 BYTEs  ???
 05h   BYTE    first drive number
 06h   BYTE    number of drives
 07h   ???