dpaanlka said:Originally Posted by Mechcozmo
7.6 ran on PowerPC chips, whereas 7.5 ran on 68040 (and earlier) chips.
This statement is false, and doesn't really make any sense either.
System 7.5 would run on 68000 chips, 68020 chips, 68030 chips, 68040 chips, and PowerPC 601, PowerPC 603, and PowerPC 604 chips as well. (Some of the early 603e/603e Macs, even)
System 7.6 (aka MacOS 7.6) would not run on 68000 chips and probably not on 68020 chips either, but ran on at least some Macs that used 68030 chips and all the 68040 Macs could run it. All Macs with PowerPC chips prior to the G3 could run System 7.6, but the G3 Macs required MacOS 8.
There's never been a MacOS version where the new version would not run on the old chip, unless you're counting specific installation-builds (like installing System 7.5 "for this computer only" on a Mac IIci results in a copy of System 7.5 that won't boot on a PowerMac, or the version of OS X 10.4.6 that installs on a MacBook Pro won't boot a PowerBook G4). Every update would run on a few of the older models.
There have been many cases where the prior OS version would not run on the new chip, though. Can't boot a Quadra on System 6, a PowerMac on 7.1, a G5 Mac on 10.2.6, or an Intel Mac on Panther.