Ref: 20570001
Title: 8088 Processor Causes Local Drive Problem on 3+Open Network
date: 7/1/90

Copyright 3Com Corporation, 1991.  All rights reserved.

SYMPTOM:  A customer was experiencing intermittent read and write
faults on the local floppy drive in his PC when it was connected to a
multivendor network with 3+Open.  The PC contained an EtherLink (3C501)
adapter with a Start PROM.

The faults were first detected when the customer attempted to locally
format his floppy disk.  When the PC was connected to a busy network, the
problem increased in frequency.  When the PC was disconnected from the
network problem, the problem disappeared.

SOLUTION:  The 8088 processor spent so much time handling DMA from the
network that it could not handle the foreground read and write processes
on the floppy drive before a read or write fault was detected.

The problem was solved by changing the type of DMA handling from the
default of BURST MODE to BYTE MODE.  This parameter must be added in the
PROTOCOL.INI file.

