zpl1if44@ztivax.UUCP (Richard Poleschinski) (05/13/91)
May 13, 1991 I have an unusual error, which even the folks at Apple Germany haven't been able to figure out yet. Maybe you wizards in Netland can top the profis. Problem: the Mac thinks it has two more floppy disks that it really has and it thinks they have disks in them that are unreadable --this prevents normal operation of the Mac by causing "Disk is unreadable" dialog boxes to continually appear HW/SW: Mac SE, 4MB, HD 20, Superdrive, System 6.0.4, no Inits/Cdevs, no MultiFinder active History: A buggy program wrote -somewhere- into memory and eventually caused an odd-address error, which TMON caught. I rebooted with the programmer switch. The problem occurred for the first time and has reoccurred with every boot since. Symptoms: After successfully booting, the Finder begins to execute. The frames of open folders appear. Then a dialog box appears: "This disk is unreadable", and I can Eject or Initialize. The icon shows a mac and external disk drive and the arrow points to the external drive. Choose Eject. Dialog disappears, and shortly thereafter, another dialog appears: same text, but this time the dialog has an arrow pointing to the upper floppy drive in the Mac. If I always choose Eject, the two dialogs continually reappear in sequence. --But I have neither an upper nor an external floppy drive-- If I choose Initialize for either dialog box, I get the next dialog of the standard initialization sequence: "This process will erase all info on this disk" -->Erase, next dialog: "Name this disk" -->OK, next dialog: "Formating...", next dialog: "Initialization Failed" -->OK. Probably it is writing to the addresses for those floppy drives but getting no response. If I cycle through the dialogs a number of times (just hitting Return on the dialog selects "Eject"), eventually the Finder finishes drawing all the folders. By hitting several Returns in advance and then using the mouse, I can perform operations like normal--open menus, launch applications, etc. In this way, I've backed up all my data and have been able to perform various tests to localize the problem. Localizing the problem: I have no INITs. The problem occurs regardless of whether I boot from the HD or from floppy. I've booted with four different systems, one dating back to April, 1985. The same error occurs with all systems. I've rewritten the Mac's Parameter RAM (choose Shift-Option-Command and open the Control Panel). No change. I've thrown away and reinstalled the System software on the HD. By chance, I discovered that launching some types of applications causes the problem to DISAPPEAR! For instance, starting Canvas or MS Word causes the dialogs to stop appearing the moment I launch the program. If I quit back to the Finder, the problem doesn't reappear, and I can work normally. By launching other programs, however, I can make the problem REAPPEAR, for instance with Apple's File Converter. The problem seems to have to do with scanning all existing drives for mounted volumes (disks). It finds these two non-existent drives and thinks that they have mounted volumes as well. For instance, when the problem is present and I launch FastFormatter, it gives me its own error dialogs to report that the disk is unreadable. When the problem is not present, it doesn't report any errors. The Standard File Package dialogs also scan all existing drives, as the Finder must as well, because when the problem is present and I start THINK C's Compare application (which compares two text files), it begins with a standard file dialog to select the first file. The "Disk is unreadable" dialogs appear on top of the SF dialog. When I choose Cancel from the SF dialog in between the error dialogs, I return to the menu level of the program. The error dialogs are now not appearing! If I now choose File->Set File 1, the SF dialog appears and no error dialogs! If I quit, the problem has diappeared at the Finder too. It makes sense that these programs (Finder, Std File Pkg, FastFormater, File Converter) scan the drives, because they need to sense and react to the user inserting a new disk at any time. But why should some programs cause the problem to disappear, while others cause it to reappear? This is what makes me suspect the problem isn't a hardware problem but a software problem, but that's only a wild guess. Help: No one seems to have any idea what the problem might be. If you have any ideas, please pass them on, I'm all ears! If the solution turns out to be interesting, I'll post it. Many thanks in advance. Pieter van Zee zpl1if44@ztivax.siemens.com Fax: + (49) 89 636 48224 Mail: ZPL 1 IF 34 Siemens AG Otto-Hahn-Ring 6 D-8000 Munich 83 Germany