    AST RESEARCH, INC.         TECHNICAL BULLETIN #0788                  11-17-92

                   AST 486 SYSTEMS WITH IBM'S 5250 EMULATION CARD

    If an IBM 5250 adapter is installed in an AST 80486-based system, errors may
    occur while accessing a high-density floppy drive.  The DOS error generated
    is "FAILURE READING DRIVE X: ABORT, RETRY, IGNORE, FAIL", where "X" is the
    drive to which access is being attempted.

    The problem occurs because the IBM 5250 emulation card, which defaults to
    using IRQ 5, interferes with the operation of the floppy controller (at IRQ
    6), causing DMA overruns.

    To resolve this problem the following change needs to be made to the
    configuration of the PC Support program.

         In the STARTPCS batch file, at the line "E5250AH.COM" add the switch
         "/L7".  The command line should read "E5250AH /L7". A capital "L" must
         be used.

    This effectively changes the IRQ used by the IBM5250 adapter board
    to 7.  Note that no other device in the system should be using this
    interrupt.