HelpPC 2.10 Quick Reference Utility Copyright 1991 David Jurgens

                 INT 21,44 - I/O Control for Devices  (IOCTL)

       Standard Call Format

       AH = 44h
       AL = function value
       BX = file handle
       BL = logical device number (0=default, 1=A:, 2=B:, 3=C:, ...)
       CX = number of bytes to read or write
       DS:DX = data or buffer

       on return:
       AX = error code if CF set
       AX = # of bytes transferred if CF not set

       For more information, see the following topics:

       IOCTL,0   Get Device Information
       IOCTL,1   Set Device Information
       IOCTL,2   Read From Character Device
       IOCTL,3   Write to Character Device
       IOCTL,4   Read From Block Device
       IOCTL,5   Write to Block Device
       IOCTL,6   Get Input Status
       IOCTL,7   Get Output Status
       IOCTL,8   Device Removable Query
       IOCTL,9   Device Local or Remote Query
       IOCTL,A   Handle Local or Remote Query
       IOCTL,B   Set Sharing Retry Count
       IOCTL,C   Generic I/O for Handles
       IOCTL,D   Generic I/O for Block Devices (3.2+)
       IOCTL,E   Get Logical Drive (3.2+)
       IOCTL,F   Set Logical Drive (3.2+)

               DEVICE STATUS
               DEVICE HEADER
               DEVICE ATTRIBUTES

Esc or Alt-X to exit int 21,44 Home/PgUp/PgDn/End ←↑↓→
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