4. Learning MacOS

Having fitted the MMU to the Macintosh without blowing it up I tried to get MacOS to run with virtual memory. This is supposed to be simple. You click on the memory tool and select 32bit, virtual memory on. Oh no, my memory control didn't have a 32bit option let alone a virtual memory one. I stared a bit, checked on a more modern mac downstairs to be sure I had the right screen. The other Mac which was running the same MacOS version had the required option, I didn't.

This is when I first learned the horrors of the Mac. While Unix says 'Im sorry you can't do that', MacOS has two error messages. It either goes 'eep?' or the box you wanted to set but couldn't is simply not there on you computer until you've installed the other 12 unidenfied items and filled in 3 apparently unrelated dialog boxes. This was an error of the latter category.

It turns out that Apple shipped the MacII with the ability to upgrade to include an MMU chip. Therefore they sensibly shipped it with a system ROM that wasn't capable of of running with the MMU enabled. Brilliant, just don't design anything mission criticial please. Fortunately Apple had concealed on their web site a small tool which patches the ROM entry points so that it can run in 32bit mode.

Ok so all you do is download the tool, install it and off you go. Not so simple. To get the program onto the machine I needed to get the ethernet to work. I ended up using kermit to transfer 700K of ethernet installer onto the Macintosh. About 4 hours of fighting with the completely alien Macintosh archiver tools I had the machine talking appletalk shares to a Linux box using netatalk and an insight into why Mac people meeting a PC for the first time look like they just discovered alien life forms.

About an hour after that I had figured out how to unpack Macbin files and the Macintosh was in 32bit mode and admitted the MMU was present and functional.