joel@gould9.UUCP (Joel West) (03/13/86)
This probably is not in the kosher definition of HFS, but I
would note I tried the following experiment:
Build an HFS 400kb disk (using option-initialize under 'Erase Disk')
Install System 3.1.1, Finder 5.2, HardDisk 20 1.1a (off of the
12/85 software supplement).
Try to boot off of a Mac 512.
The result is Sad Mac code #F0064
It all works if the disk is non-HFS. I presume the "HD20" patches don't
get installed soon enough in the boot process, and that HFS volumes can
be the boot disk only on a machine (e.g. Plus) with HFS in ROM.
--
Joel West (619) 457-9681
CACI, Inc. Federal, 3344 N. Torrey Pines Ct., La Jolla, CA 92037
{cbosgd,ihnp4,pyramid,sdcsvax,ucla-cs}!gould9!joel
gould9!joel@nosc.ARPAephraim@wang.UUCP (pri=8 Ephraim Vishniac x76659 ms1459) (03/17/86)
> Build an HFS 400kb disk (using option-initialize under 'Erase Disk') > > Install System 3.1.1, Finder 5.2, HardDisk 20 1.1a (off of the > 12/85 software supplement). > > Try to boot off of a Mac 512. > > The result is Sad Mac code #F0064 > > It all works if the disk is non-HFS. I presume the "HD20" patches don't > get installed soon enough in the boot process, and that HFS volumes can > be the boot disk only on a machine (e.g. Plus) with HFS in ROM. > -- Exactly right, Joel. The Mac first has to find and load the system file on the startup floppy, then execute the patches (PTCH) resources in it. One of these (PTCH 105) opens the Hard Disk 20 file and executes the patches it finds there (0, 1, and 2). HFS isn't running until all this has happened. Also, the "signature bytes" in an HFS volume header are different, so the 64K roms will think it's a non-Mac diskette immediately.