Epson Equity III Product Support Bulletin page 8

Subject: Western Digital XT - GEN Hard Disk Controller Anomalies
8/10/89
Date:
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Recent reports from the field have revealed certain anomalous behavior when
the Western Digital XT- GEN hard disk controller is used in the Equity II +,
Ill + or 386/20 computers.
The XT - GEN controller is an 8 - bit, XT- type "generic" controller. As such,
there would be an immediate loss of performance if it were installed in a 16 -
bit, AT- type ISA bus system. However, the poor performance is not the only
issue. The XT- GEN can produce addressing conflicts that do not directly point
to the controller as the cause. For example:
An Equity II + was equipped with a Seagate ST- 225 hard drive and the XT-
GEN controller. It was also configured with the IBM 5250 terminal emulation
card and software and was connected to an IBM System/36 host. Additionally,
IBM's PC Support/36 software was correctly installed on both the II+ and
System/36. This utility enables file and folder sharing as well as up- and
download capability. The 5250 terminal emulation works perfectly; the PC
Support/36 utility does not. This pointed to an "obvious" incompatibility.
As part of the troubleshooting procedure, a Western Digital WD1003V- MM1
16 - bit controller was substituted for the XT- GEN. With this one change, the
PC Support/36 functions started operating correctly. Other similar examples
have been reported.
Our recommendation is that 8- bit controllers in general should not be used
because of performance losses. The XT- GEN controller should not be used at
all.
Product Support Bulletin
PSB No: S-0089
Originator: