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    AST RESEARCH, INC.           TECHNICAL BULLETIN # 0978              9-21-94

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                        PREMMIA LX AND ADVANTAGE! EXP CHECKSUM ERROR

    PROBLEM:        While attempting to install Windows NT V 3.1 on the 540
                    Quantum drive in the Premmia LX or Advantage! EXP systems,
                    when NT checks the disk while booting up, the following error
                    message appears:

                        STOP: C0000221 {Bad image CHKSUM}

                    The system then hangs.  If rebooted, the problem disappears
                    but will reappear after a number of reboots.  After a number
                    of occurrences the system becomes unbootable and the hard
                    drive must be reinstalled.

    CAUSE:          According to Microsoft Windows NT version 3.1 does not
                    support the Logical Block Addressing (LBA) mode and disk
                    drives that are larger than 1024 cylinders.

                    The LBA option in advanced CMOS Setup is only available with
                    BIOS 1.10.

    SYSTEMS
    AFFECTED:           AST
                    PART NUMBER     DESCRIPTION

                    501288-XXX      PREMMIA LX P/60
                    501422-XXX      ADVANTAGE! EXP P/60

    SOLUTION:       When installing Windows NT 3.1 on the Quantum drive, there are
                    two options:

                    1. Use CMOS Setup Autoconfigure; LBA Disabled.  This will
                       result in 1-n partitions, depending on how you instruct NT
                       to divide the disk, with a total useable disk space of 472
                       MB.

                    2. Use CMOS Setup Autoconfigure; LBA enabled.  This will
                       result in 2-n partitions you must have at least 2) with total
                       useable disk space of 515 MB.

                    In order to maximize the Quantum drive space, follow the
                    Windows NT installation procedure (from CD-ROM) listed below:

                    1. Use a new drive.  If not new, set the CMOS to Autoconfigure,
                       LBA Enabled. Boot from a floppy, run FDISK, and remove all
                       existing logical drives and partitions.

                    2. Set CMOS to Autoconfigure, LBA Enabled.

                    3. Begin NT Setup.  Use all the defaults - Express install.

                    4. Create two partitions (at least).  For example, 125 MB for
                       the C: drive and 390 MB for the D: drive.  The smaller the
                       C: drive, the faster the formatting.

                    5. Install and format NT to the C: drive.

                    6. The system will reboot and continue its Setup.

                    7. When Setup is complete, the system will automatically reboot.

                    8. Boot the system from a DOS floppy.

                    9. Copy the ATDISK.SYS driver into C:WINNT\SYSTEM32\DRIVERS.

                   10. Format the D: drive (and others).

                   11. Reboot from the C: drive.

                    The driver, ATDISK.SYS, is available from Microsoft via
                    Compuserve.  This is a self extracting file that contains the
                    driver and a readme file.  In Compuserve, type GO WINNT.
                    Currently, the file is located in the Fixes & Updates Library.
                    Download the file PCIATD.EXE.

                    NOTE: Update to BIOS 1.10.

                    WARNING:  Be sure to back up all data before deleting the
                    partitions and reformatting the hard disk.  AST is not liable
                    for any loss of data.