[comp.sys.mac.misc] II->IIfx upgrade

kevin@kosman.UUCP (Kevin O'Gorman) (07/20/90)

Having gotten such an upgrade today, I'm a happy camper.  I did learn
why Apple wants this only done by qualified tech support folks, and
also learned that there are some very odd things going on.

The upgrade itself went just fine, no glitches at all.  However, I had
been foresightful enough to be present, and to have my external hard
disk along.  When we booted up the new system, it wouldn't recognize
the drive (no disk icon on desktop).  I began to worry -- I didn't
have that recent a backup (blush!).

However, the HD Setup SC application DID recognize the drive, and
passed a test.  I was not ready to initialize the disk, however.
BTW, the disk is a Jasmine HD 80.

The solution was to boot an older OS on another Mac, which recognized
my HD just fine, use that OS to run the 6.0.5 installer, and try again.
Now, 6.0.5 could recognize my hard drive.

The tech who was doing this would never have tried all this, so it's
very good that I was there.  It does seem very odd to me -- what is
there that 6.0.5 needed in order to launch my drive?  Why doesn't
apple warn about this?

-- 
Kevin O'Gorman ( kevin@kosman.UUCP, kevin%kosman.uucp@nrc.com )
voice: 805-984-8042 Vital Computer Systems, 5115 Beachcomber, Oxnard, CA  93035
Non-Disclaimer: my boss is me, and he stands behind everything I say.

austing@Apple.COM (Glenn L. Austin) (07/26/90)

kevin@kosman.UUCP (Kevin O'Gorman) writes:

>The tech who was doing this would never have tried all this, so it's
>very good that I was there.  It does seem very odd to me -- what is
>there that 6.0.5 needed in order to launch my drive?  Why doesn't
>apple warn about this?

The SCSI driver in 6.0.4 and previous calculated the partition checksum
incorrectly (and didn't care if it was wrong!).  The 6.0.5 driver calculates
it correctly (according to the engineers) and won't mount a drive with a
bad partition table.  I don't know why nobody said anything, I just work
here.

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lsr@Apple.COM (Larry Rosenstein) (07/27/90)

In article <43345@apple.Apple.COM> austing@Apple.COM (Glenn L. Austin) writes:
>
>The SCSI driver in 6.0.4 and previous calculated the partition checksum
>incorrectly (and didn't care if it was wrong!).  The 6.0.5 driver calculates
>it correctly (according to the engineers) and won't mount a drive with a
>bad partition table.  I don't know why nobody said anything, I just work

See Tech Note 258.  It says that the ROM boot code in early machines (e.g.,
Mac II) failed to compute the checksum at all, but that this bug has been
fixed in later machines (e.g., Mac IIfx).  So drives with bad checksums
would mount on machines with the bug but not on recent machines.

I wouldn't have thought that installing just 6.0.5 would fix this; you would
have to install a newer version of the driver with the correct checksum.

-- 
		 Larry Rosenstein,  Object Specialist
 Apple Computer, Inc.  20525 Mariani Ave, MS 46-B  Cupertino, CA 95014
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kevin@kosman.UUCP (Kevin O'Gorman) (07/28/90)

lsr@Apple.COM (Larry Rosenstein) writes:
>In article <43345@apple.Apple.COM> austing@Apple.COM (Glenn L. Austin) writes:
>>bad partition table.  I don't know why nobody said anything, I just work...
>See Tech Note 258.  It says that the ROM boot code in early machines (e.g...

>I wouldn't have thought that installing just 6.0.5 would fix this; you would
>have to install a newer version of the driver with the correct checksum.

It seems odd that these Apple folk are as surprised as I was.  At least the
end result was benign.  And yes, indeed, I said it right the first time:
although I had to go about it in a roundabout way, installing just 6.0.5
did the fix.  There's a hero in Apple there somewhere, as far as I'm
concerned; I suspect the code is against company policy.
-- 
Kevin O'Gorman ( kevin@kosman.UUCP, kevin%kosman.uucp@nrc.com )
voice: 805-984-8042 Vital Computer Systems, 5115 Beachcomber, Oxnard, CA  93035
Non-Disclaimer: my boss is me, and he stands behind everything I say.