23 Feb
2023
23 Feb
'23
7:44 a.m.
On 02/21/2023 10:48 PM CST Eric Smith via cctalk
<cctalk(a)classiccmp.org> wrote:
Profile trivia:
The firmware _inside_ the Profile is strange in that it doesn't actually
KNOW the size of the Profile it's installed into. At power up, when the
drive reads the home block, the drive size is stored there. That's done
when the drive is formatted. There is different formatter firmware for 5MB
and 10MB drives.
I think that was rather common with early SASI/SCSI controller boards that were separate
from the drive. My Ampro Little Board Plus docs talk about certain controllers that saved
the drive parameters in a reserved sector and some that did not. I believe it
couldn't boot from ones that did not. My guess would be that Apple used separate
controller boards and drives in the Profile. But that's simply a guess.
Will