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AST RESEARCH, INC.         TECHNICAL BULLETIN # 1231                6-21-95

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DISK DRIVES DROP OFF-LINE DURING POST


PROBLEM

During POST, a physical disk drive can drop off-line.  The following text
message is displayed on the system console when this symptom occurs:

Warning:  1 SCSI device is critical
Warning:  The following SCSI device is dead:
		Chn x, Tgt y

NOTES

1.  "x" is the channel on the DAC960 and "y" is the identification
    number of the SCSI disk drive.

2.  This problem is very intermittent and does not occur very often.


CAUSE

The Attention button (ATTN) is pressed during POST.  Pressing the button 
forces a shortened POST memory test which can aggravate the DAC960 
controller when it is in the process of initializing the disk drives.


SYSTEMS AFFECTED
AST PART NUMBER AND DESCRIPTION

520092-XXX      MANHATTAN SMP 486DX/50
520155-XXX      MANHATTAN SMP PENTIUM/60

PARTS AFFECTED
AST PART NUMBER AND DESCRIPTION

230355-XXX     CONTROLLER DAC 5-CHANNEL
221134-001     FRU DAC5 HD CTRL


SOLUTION

Do not press the "ATTN" button during POST.


ADDITIONAL NOTES

1.  If the disk sub-system is configured as a redundant RAID (RAID levels 
one, five or six) and the text message is displayed during POST, the disk 
drive can be rebuilt after booting into the operating system.  See the user's 
documentation to review the procedure.

2. If the symptom continues to occur even when the "ATTN" button is not 
pressed, contact AST's Technical Support at (800) 727-1278 for 
troubleshooting assistance.