Ref: 19880017
Title: Coldbooted AST BRAVO PC With EtherLink II Does Not See Network Servers
Date: 04/26/91

Copyright 3Com Corporation, 1991.  All rights reserved.

When the AST BRAVO PC is used with an adapter that is using shared memory,
such as the EtherLink II, it may not be able to see the network servers
after a cold boot (a cold boot is the bootstrap that occurs after the PC
is powered on).  However, when the PC is warmbooted, all servers can be
accessed without a problem.  (A warm boot is a bootstrap resulting from
pressing the Ctrl-Alt-Del keys.)

This problem occurs because of the factory configuration of the VGA PLUS
card shipped with the AST BRAVO, in conjunction with an adapter using
shared memory.

The VGA PLUS card is factory-configured for 16-bit operation, which causes
it to reserve the addresses from C0000 to C7FFF for video graphics and allows
the addresses from C8000 to DFFFF to be used by other 16-bit devices.  (In
contrast, when the VGA PLUS card is configured for 8-bit operation, it still
reserves C0000 to C7FFF for video graphics but does not limit C8000 to DFFFF
to 16-bit devices.)

When the 8-bit EtherLink II adapter (3C503) is configured to use shared
memory, the choices for the starting address of shared memory are C8000,
CC000, D8000, DC000.  All of these addresses fall in the range being reserved
for 16-bit operation by the VGA PLUS card.  Therefore, to solve the problem
you must choose one of the following configurations:

  1.  The workstation can continue to use the VGA PLUS card in the 16-bit
mode (for faster graphics) and the Ethernet adapter can be configured to use
DMA (slower network response) instead of shared memory.

                                  OR

  2.  The workstation can continue to use shared memory (faster network
response) and the VGA PLUS card can be configured for 8-bit operation.

Set switch 2 on the VGA card for 8- or 16-bit operation.  If you have
questions concerning the VGA PLUS card, consult your AST reseller or the
AST factory.

