=

AST RESEARCH, INC.          TECHNICAL BULLETIN # 0987               9-26-94

=


         BRAVO LC 4/100T AND ADVANCED OPERATING SYSTEM INSTALLATION ON
                                 QUANTUM DRIVES

PROBLEM:        The Bravo LC 4/100T system hangs during advanced operating
                system installation, including SCO UNIX 3.2.4.2, if drive type
                AUTO is selected on Quantum LPS AT540MB drives in the CMOS
                SETUP.  The system hangs when Advanced Operating Systems try
                to initialize the drive partition.

CAUSE:          When AST's system BIOS attempts to AUTOSENSE drives that are
                larger than 1024 cylinders, a problem occurs.  The advanced
                operating system can not access the drive because the physical
                hard disk controller does not offer a drive configuration of
                less than 1024 cylinders.

SYSTEMS
AFFECTED:           AST
                PART NUMBER       DESCRIPTION

                501381-007      BRAVO LC 4-100T


SOLUTION:       On Quantum LPS 540AT drives (firmware TB54A01A revision 04-c),
                select USER DEFINED drive type with 16=heads, 59=sectors, and
                1024=cylinders. With these settings the system does not hang
                and SCO UNIX proceeds with the installation normally.

                NOTE: This information also applies to other operating system
                and software such as Novell version 3.12, Windows NT version
                3.1, and OS/2 version 2.1.