OS8 abandoned older MFS (Macintosh Filing System) formatting capability for HFS (Hierarchical Filing System). Essentially this means that HFS floppy won't work pre-MacPlus and then only if OS7 or later installed. Conversely, MFS won't work on OS8+. Or, some early Mac commercial software floppies would only open when used as the start-up disk. Try a Command, Option, Shift, Delete Startup while you quickly slip the floppy in.
Don On Feb 15, 8:25 am, chrisA <[email protected]> wrote: > > Another member here recently described the issue in detail (maybe you missed > > it?), but starting with some sub-version of Mac OS8, it stopped supporting > > the 800K format. So, I'm guessing that if you're using OS8.1 or later, the > > Operating System doesn't have the ability to read 800K disks > > Not true. I'm running OS 9.1 and can read/write 800k floppies fine. > Maybe it's the 400k floppies that lost support? > > The OP said: > > > I keep all my vintage stuff really > > clean, including internal components, such a disk drives. > > There's a detailed article about cleaning floppy drives here: > > http://chrislawson.net/writing/macdaniel/2k0314.shtml > > Many, many years ago someone on UseNet posted about this problem and I > clipped the text. Here it is: > > =================== > SUPERDRIVE WON'T RECOGNISE 800k DISKS > > QUESTION: My SE with Superdrive tries to read an 800k disk as a high- > density 1.4MB disk -- which means it thinks the 800k disk needs to be > intialized as a high-density one. > > ANSWER: Some of the early Superdrives in the late-model SEs have > problems. Losing the ability to recognize 800k disks is not uncommon > -- I've seen it myself. The floppies themselves are probably fine; > it's the drive that's screwed up. The sensor that is supposed to feel > whether the disk has the extra hole (that indicates HD) fails to come > into full contact with the disk and so it doesn't work. Sometimes if > you repeatedly insert the disk you'll get lucky and it will read it. > Also you can try to stick your finger in the drive to apply downward > pressure on the disk just after it is inserted. The pressure helps the > sensor detect that the disk does not have the HD hole -- I think it's > like a button that needs to get pressed. If you can get the disk > mounted then the drive should have no more trouble reading it, until > it gets ejected and you try to mount it again. > =================== > > But none of this really explains why *all* your floppy drives bar one > have this same problem. > > Good luck, > Chris. --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Vintage Macs group. The list FAQ is at http://lowendmac.com/lists/vintagemacs.shtml and our netiquette guide is at http://www.lowendmac.com/lists/netiquette.shtml To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/vintage-macs?hl=en Low End Mac RSS feed at feed://lowendmac.com/feed.xml -~----------~----~----~----~------~----~------~--~---
