Macintosh

Varies with the machine. Which 68k processor (68000, 020, 030, 040), 32 bit clean? The best place to find out what the last supported OS is, is check the apple spec database. Down at the bottom of each mac's listing is a list of supported OS versions. Supported is a key term here, some can use versions that are not supported, but you use them at your own risk. And don't assume similar machines will always support the same OSes. For instance, the Centris/Quadra 610 lists 8.0 as the last supported OS, but other 040 machines like the Quadra 605 (a machine that is actually a step down from the 610), can support 8.1. I can tell you from experience, the 610 will accept an 8.1 install, and will even run for some time... but you will eventually find that the finder will drag to a halt (even scrolling a window will cause the watch to spin longer and longer, finally topping out at about 5 minutes of spinning). And it will eventually corrupt the hard drive. So for the 610, stop at 8.0, but the 605 can go to 8.1 safely. You really need to check the spec database on a machine by machine basis. And even then, it might pay to think about it, ie: my Classic II can support 7.6.1, but it runs faster and smoother, and uses less RAM if I stop at 7.5.5. A general rule of thumb is, 6.0.8 for < 1mb Mac's, 7.5.5 for all other 68000, 7.6.1 for 020's and 030's, and 8.1 for 040's. But there are the flukes in there like the Centris/Quadra 610, so just check before you install. As for getting them, System 6.0.8 (the last pre 7 version) is available on Apple's web site for free. So is System 7.5.5. Anything newer you will need to find used somewhere (many mac resellers have old OS CDs for sale cheap... or just ask a friend that has a version to dupe it for you, short of OS 9 and X, Apple probably won't care... but you do that at your own risk, they might care, who knows). Older OS versions (pre 6) used to be available on Apple's FTP site if you dug around, but I am not sure they are still there. And as a silly aside... has anyone ever tried running OS 7.0.1P on a 128k Mac? According to Apple's Spec database, that is the last supported version for the 128k... I have always wondered if it is a typo, or if it really can run System 7 (someday maybe I will try it with mine) -chris <http://www.mythtech.net>