rcbaem@rwb.urc.tue.nl (pooh 'Ernst' Mulder) (04/11/91)
Can anyone explain what happened??? Two weeks ago I got a memory upgrade. My Mac Plus has 4 Mb now, which I thougt I needed to be ready for System 7.0. Then, after a couple of days, strange things started to happen. This article describes those things. For those with weaker nerves, there is a solution to the problems at the end of this article. And a question too. For those wondering, the problems were only indirectly connected to the memory upgrade, and had nothing to do with virusses or inits. Mac Plus 4 Mb of memory 20Mb Rhodime hard disk System 6.0.5 Suddenly, after a couple of days of perfectly correct behaviour, I got a couple of errors. Programs started to complain "IO Error, Internal File System (-128)" and the Finder started to complain in the lines of "This file can't be removed because the file doesn't exist"... Allright, I had been programming a little, so I might have messed up the file system a bit. Things like that happen. I made an extra backup of my hard disk, for the last one was a day old. The backup program complained about my hard disk's directory, but backed up anyway. Then I took a disk repair utility, and it told me there was something wrong with my B-tree, and that certain directory extentions were bad. Okay, I reformatted the hard disk. I restored the contents of my hard disk, and during the first minutes everything seemed well. Only not for long, the errors started to come back. Disinfectant revealed nothing at all, when it was a virus it would be a brand new one. Anyway, after I rebooted once again, I took a look in the system folder. What??? The System file was gone, and so were half my inits! I had booted and was running a system without a System file! Whatever utility I used, the System fole was gone. It wasn't invisible or so, just gone. The weird thing was that the Mac still booted. The System file was there somewere, maybe in some unexisting folder or something? I reformatted once again. To be on the very safe side, I took the unchanged, always-locked-disks, of the System software (6.0.5) and started to install a Clean Fresh system on my freshly formatted hard disk. It seemed fine. And it was, until the Installer crashed. Rebooting revealed a hard disk with a 8Mb large system file!!! This even prooved to be reproducable! I reformatted once more. Using SCSI test program I tested my drive thoroughly. All was well. After two evenings of puzzles and 3 hours of hard disk tests I was completely out of options. What could it be? Was there something I configured differently, and _System_Wide_?? There was. The Control Panel's cache... Installed System Wide in the parameter ram... With 4Mb of memory I thought a 128K cache would be a fortune! When I turned the cache off, all problems were solved. The Installer worked again, I was able to restore the hard disk, and even now I'm using my Mac without problems. And I didn't lose any data :) Is this a known bug in the Control Panel's ram cache? Coule it be a bug in my hard disk's SCSI driver? Sould I use 6.0.7 instead of 6.0.5? I'm puzzled. If anyone has _any_ clue on why I can't use the ram cache provided by the General Control Panel, please inform me. All the facts are in the text above. pooh -- /********************************************************************* * Everything stated above is absolutely true. * Only the facts have been changed to protect the people involved. ***/
rcbaem@rw6.urc.tue.nl (pooh 'Ernst' Mulder) (04/17/91)
Summary:
There's nothing wrong with the Control Panel cache.
Hello world,
First I would like to thank everyone who repied. I have found the
source of the problems. I've got a third party SCSI port (You know? The
ones you plug in the ROM sockets of a Mac 512 to have a SCSI port. My
Mac once was a Mac 512, and now it's a Mac 512 with 4Mb and SCSI :) to
which I traced back the problem. I wrote a small RAM test program and
my RAM is OK. So is my Hard Disk. After some research the SCSI port was
the only thing left that could be wrong.
I called the manufacurer and explained my problem. They immediately
recognized it and said I probably had an older model SCSI port which
had a bug in one of its PALs. They replaced the PAL with a new one and
all problems were gone! (so far :)
The bug in the PAL would only have effect after certain sequences on
the address bus. Apparently these occur in the Control Panel cache code
and when copying files in MultiFinder.
Well, I'm rather glad this problem is solved. I'm just a bit ashamed to
have posted a long article claiming the Control Panel cache didn't work
(which is probably not true :) but a erratic PAL wasn't one of the
first things I could think of.
Well, all's well that ends well.
Thanks!
pooh
--
/*********************************************************************
* Everything stated above is absolutely true.
* Only the facts have been changed to protect the people involved.
***/