XEN-LS II and Adaptec 154* SCSI cards

As an ISA compatible machine it may be desirable to install an Adaptec 154* series card in the XEN-LS II. This should present no problems on the 25MHz or 33MHz derivative but on the 66MHz machine the Adaptec software driver may fail as the CPU is too fast.

To eliminate this problem on SCO UNIX 3.2v4.[01] you should use the Maintenance Supplement to upgrade to 3.2v4.2 when it becomes available at the end of May. In the interim it may be necessary to reduce the speed of the machine via CPU board switches. SCO did produce an interim patch UNX365 but this has been withdrawn in anticipation of the Maintenance Supplement which fully fixes the problem.

SCO Xenix 2.3.[24] can also be affected by this problem. An adb/_fst patch will rectify the problem. If the problem impacts on an installation the XEN-LS II should be switched to a slower speed whilst the installation is done and switched back only after the patch is installed.

The following shell script will patch the Xenix kernel

:
echo "Patching Adaptec 154x driver in /xenix for fast CPU..."
_fst -w /xenix - < < EOF
adpresent+9?W 100000
ad_sndcmd+9?W 100000
$q
EOF

This script could also be appended to the hdinstall script in /usr/sys/conf