4.7.1. What are the characteristics of Lisa Xenix?

Lisa Xenix is a Microsoft variant of SCO unix. The last version for the Lisa is 3.0.

It supports multiple users via terminals connected to the built-in serial ports, as well as the Tecmar 4 port serial card.

Two add on packages require installation on a Widget hard drive, or a second ProFile (attached to dual a parallel port card). One is a development environment which includes a C compiler (K&R only, not ANSI) and a text based word processing suite called Lyrix.

Xenix does not support the Lisa's mouse, nor graphics; only text mode operations.

Hard Disk Size vs I/O board ROM version

Some portion of Xenix assumes that the size of the parallel port hard disk connected to the built-in port always corresponds to the type of Lisa. In particular:

if the I/O board ROM is version A8, the hard disk connected to the built-in port must be 5 MB
if the I/O board ROM is version 88, the hard disk connected to the built-in port must be 10 MB

Since 5 MB is too small to install everything in the Xenix distribution, on a Lisa 2 you may want to use an additional ProFile or use a modified I/O board ROM to make Xenix think it has a 10 MB drive. (You cannot just use the 88 EPROM instead, as the 6504 floppy disk controller code differs between them.)

Using an EPROM programmer, you can read the stock EPROM and burn a new one, changing the ID byte (at offset $1141) from A8 to, for example, $89 . This will make Xenix think the machine is a 2/10, and you can use a 10 MB drive on the built-in parallel port.

If you do this, make sure you label the EPROM carefully, as it won't work properly in a 2/10 I/O board. Hence the suggestion to use $89 in order to distinguish it from the real 2/10 ROM. The high 3 bits of the I/O ROM version are what Xenix uses to distinguish a 2/10 from a 2/5.

Note that other software (MacWorks, for instance), may look explicitly for I/O ROM version A8 or 88, and if the wrong ID is found, some parts of the software that depend on particular timing of the 6522 VIA chips may misbehave (eg. sound pitch may change, and AppleTalk may not work).

Thanks to Guido Deiana for assisting with this work-around.

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