Ref: 09580001
Title: 3DISK386 and CMOS Configuration on 3S/40x and 3S/5xx Servers
Date: 4/20/90

Copyright 3Com Corporation, 1991.  All rights reserved.

During the boot process in 3S/40x or 3S/5xx servers, a message such as
"Error loading boot sector" may be displayed on the LCD after replacement
of the motherboard.  This will happen if the server has a base drive other
than 150 MB (such as 320 MB or 630 MB).  This message may also be displayed
when replacing the bootable base drive with one other than 150 MB in 3S/40x
or 3S/5xx servers.

It is not the motherboard or drive that causes this error message; rather,
it is caused when the drive's boot records are configured improperly in the
CMOS.

All 3S/40x and 3S/5xx server motherboards are tested and configured for
150 MB drives at the factory.  However, different-sized drives have
different numbers of cylinders and heads, and it is possible to misconfigure
the CMOS when using a drive other than 150 MB.

To eliminate the "Error loading boot sector" messages, 3DISK386 must be
run and the bootable drive must be chosen for the right drive size in the
configuration table.  Follow these steps to redefine the boot drive:

1.  Establish a console connection and run 3DISK386 from the System
Software Disk #1 (P/N 3382-08 or higher).

2.  Select option 2 (Configuration).

3.  Select option A (Display Configuration) and look at the last
selection that CMOS has for the bootable drive.

4.  Select option D (Choose Boot Disk).

5.  Select the appropriate drive and controller combination that you
have in the base unit.

6.  Press ESC twice to quit 3DISK386.

7.  Reset the server.

Now the server knows what kind of drive it has and where the boot sector
resides.

When replacing hard drives, make sure you use the controller that
came with the drive.  The ROM on the Adaptec 4525 controller has several
revisions.  If you have a controller with a rev B ROM, it will only support
a 150 MB drive.  A Rev C ROM will support both 150 MB and 320 MB drives.
To support all drives and the latest 3+ and 3+Open software (630 MB drive,
3+ 1.5.2 and 3+Open 1.0 and higher), a Rev D ROM is required.  If you are
using an older revision of software or a drive smaller than 630 MB, then
the need for a Rev D ROM is not critical.  All of the ROMs are downward
compatible so the Rev D ROM can support either the 630 MB, 320 MB, or 150
MB drive.
