Re: Apple Profile low level formatting on an Apple III

From: Ray Arachelian <ray_at_email.domain.hidden>
Date: Fri, 22 Feb 2008 12:15:29 -0500

alker wrote:
> Hi guys,
> thank you very much for your support! Yesterday I finally made it.. I
> changed the cable, changed the slot for the profile interface card
> again and now it works!

Congrats! Any chance you can give us some details as how it worked? I want to collect this info so that I can update LisaFAQ with it. I did see someone previously had success also, but want to make sure I capture the experience of a few folks so that the information is as accurate as possible.
> The low level format took only some minutes; all tests passed. Then I
> put the disk onto my Lisa and initialized and installed MacWorks..
> when copying system files onto the disk there were errors.. hm, also
> the drive does not sound so good. Booting up from the drive ended with
> an error. This surprises me a little bit, because during low level
> formatting and testing all seemed ok....
> Is it possbile with some re-low level formatting to get over this
> troubles? or is the drive simply dead?

You could do it again, but it sounds the media itself is not very stable. If it failed during the installed, it means it wrote some pattern during the install all over the disk and then attempted to re-read this and couldn't, so those are bad sectors. If you power the Lisa down and turn on the Profile by itself, during the first 5 minutes or so, it'll attempt to read all of the disk and "spare" the bad blocks by replacing them with spare blocks. When the light shows "ready" for a few minutes, I'd power it off again, wait a few more minutes and repeat this.

I'd then attempt to install again.

Remember that low level formatting will no repair drives with actual bad media. All it will do is replace the sync marks, the sector/track ID headers for each sector. This is data that is normally never written to again, even when you install an OS. So if there was a sector whose sector ID information was bad because it got demagnetized, the low level format would fix this, but if the physical media is bad, there's nothing you can do to repair it, you can at best hope that the Profile will notice them and replace them by the sparing process.

I think there's a limit of 32 spare blocks, if you have more than a certain number that are bad (might be 32, might be less), you may find some OS's such as Lisa Office System will refuse to install since the drive isn't reliable.

Here's a stupid question, because I've never done it myself: When you did the low level format, was there any option anywhere that said how many spare sectors to allocate as spares? I ask because I don't know if this hard wired into the drive's ROM or if there's any control over the number. I know there's a hard limit in the special block 0xffffe, but not sure if there's a way to raise that limit. (Even if you could LOS I think asks for the actual number and if it's over some fixed number, it'll refuse to install)


Indeed the above link is one of the other sources of info I was collecting for the FAQ and was using the Babelfish translator to understand it. :-) Received on 2008-02-22 12:15:30

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