Firmware, software that’s intimately involved with hardware at a low level, has changed radically with each of the different processor architectures used in Macs.
↫ Howard Oakley
A quick but still detailed overview of the various approach to Mac firmware Apple has employed over the years, from the original 68k firmware and Mac OS ROMs, to the modern Apple M-specific approach.
I was excited to read about this, since I’m interested in learning more about the early start up and firmware of early macs…
And I know it’s a brief history…
But having only “Classic Macs based on Motorola 68K processors come with their own Macintosh ROM” seems too brief. I do now know enough to write about it, but know enough to be
dangerousannoying. So here’s some suggestions for a bit more of an incomplete history of earlier mac firmware, I guess.– – –
It probably should have reserved a paragraph for 68K, including some statement about how the Macintosh Toolbox in ROM. Since it later goes in weirdly specific deep details about EFI boot, it probably should also include mentions about how the ROM loads the System Folder from the disk.
Then that could have linked nicely into the next paragraph, for PowerPC, where “Old World ROMs” are described as Open Firmware + Macintosh Toolbox (AFAIUI) [I don’t know how it boots the system]. And then contrast this with “New World ROMs”, which AFAIUI mainly is distinguished by the Toolbox not being part of the ROM [citation needed], I’m not aware of the details of how it boots the system either.
I have no idea why Open Firmware is described as “[being] also a security nightmare”. So a citation around that claim would be helpful.