dudek@utai.UUCP (Gregory Dudek) (03/10/86)
Yesterday my wife did some hacking on our Mac+ and accidentally wrote
all over memory. Although the machine could be rebooted fine, it
insisted on trying to boot from the HD20 FIRST instead of trying the
diskette drive first (as it is supposed to, and normally does). Even
powering off the machine didn't make it return to normal. In desperation,
I tried making the HD20 unbootable by moving the System out of the
"blessed" folder and hiding the Finder elsewhere. I thought this
would have made the HD20 seem like a non-booting volume.
Surprise! It still found the System file & started booting from
the HD20, but then failed part way through (ID=26, DRVR screwup). At
this point, if you turned the machine on with the HD20 on, it would still insist
on booting from there & then crash. If you booted with the HD20 *OFF*,
it would come up from diskette fine, but the you could never get it to
"see" the HD20 (turn it on, off, eject internal diskette, reinsert, ...).
At this point, I couldn't even RE-INIT the HD20 since booting from a
floppy made it invisible, and I couldn't boot from it directly.
(I *could* run the HD20 disk test, which found it to be healthy.)
I finally turned the Mac off & removed the battery. After leaving it
off for a while (20 min. or so, a short off period of 2 min. had NO EFFECT!)
and unplugging it, it rebotted correctly from the floppy and I
could fix up the HD20.
It seems to me like there was something in non-volatile RAM that
told it to look to the HD20 port BEFORE the diskette port! Is there such
a bit? Any other explanations? Is there any way to get the Finder/System
to check out the HD20 port if it "wasn't there" when you powered on?
This sort of problem could be a real headache, rendering an HD20
unusable, if one didn't think of removing the battery.
By the way, as noted, I've got a Mac+ with Finder 5.1 & the "new" system
(3.0?).
Any answers to what really happened or an easier way to fix it?
[Also, is there a utility around for recovering a 800K (DS) diskette with
a blown sector or 2 on track 0 & 1? I killed it while trying to fix
the above problem & fiddling with the VIA ports from the debugger build
into Finder 5.1]
Greg Dudek
Dept. of Computer Science (vision group) University of Toronto
Usenet: {linus, ihnp4, allegra, decvax, floyd}!utcsri!dudek
CSNET: dudek@Toronto
ARPA: dudek%Toronto@CSNet-Relay
--
Dept. of Computer Science (vision group) University of Toronto
Usenet: {linus, ihnp4, allegra, decvax, floyd}!utcsri!dudek
CSNET: dudek@Toronto
ARPA: dudek%Toronto@CSNet-Relayjac@osu-eddie.UUCP (James Clausing) (03/14/86)
I have had a similar problem with my 512K Mac and the external disk drive. For some reason it always tries to boot from teh external drive first. Any ideas and/or fixes, this is with old system and finder 4.1. Jim Clausing jac@ohio-state.arpa, etc.
jimb@amdcad.UUCP (Jim Budler) (03/15/86)
In article <1416@utai.UUCP> dudek@utai.UUCP (Gregory Dudek) writes: > > > I finally turned the Mac off & removed the battery. After leaving it >off for a while (20 min. or so, a short off period of 2 min. had NO EFFECT!) >and unplugging it, it rebotted correctly from the floppy and I >could fix up the HD20. > > It seems to me like there was something in non-volatile RAM that >told it to look to the HD20 port BEFORE the diskette port! Is there such >a bit? Any other explanations? Is there any way to get the Finder/System >to check out the HD20 port if it "wasn't there" when you powered on? >This sort of problem could be a real headache, rendering an HD20 >unusable, if one didn't think of removing the battery. > By the way, as noted, I've got a Mac+ with Finder 5.1 & the "new" system >(3.0?). > A while ago a program called PRAM came across the net which both explains this behavior and allows you to fix it. PRAM can examine and change Parameter RAM values. And yes it shows one for boot drive, Internal/External. -- Jim Budler Advanced Micro Devices, Inc. (408) 749-5806 Usenet: {ucbvax,decwrl,ihnp4,allegra,intelca}!amdcad!jimb Compuserve: 72415,1200