raf@PRC.Unisys.COM (Ralph A. Foy) (03/20/90)
The Situation: A couple of times now, i've gotten errors while formatting a floppy. since I get disks for 0.49 each, i don't mind tossing them, since it wouldn't be worth the effort to return them for a free replacement. Now the question: is there a way to use disks with an error? M*-DOS is able to mark bad sectors, and was wondering if AmigaDOS would do the same. Further complication: I had to reformat my hard drive, and a bad cylinder was found... I got around it by just doing a "quick" format, but the idea of a bad sector sitting out there has me a little worried... Again, any way to handle this without re-prepping the drive? Now, a testimonial: I encountered a hard disk problem this past weekend, compounded by my ignorance of the Amiga file systemm I panicked. After poring through every manual and book i had, calling upon all my exprerience with computers, and invoking all deities, saints, and demons in the cosmos, i was able to restore just about everything, and now have the drive nicely partitioned and organized (I had inherited the system, so kept the original owner's setup). Once everything was up and running I compared the experience with those I had with my old and dusty PC and realized how much better the Amiga recovery was. If I had controlled my hysteria a little better, it could have been a very straightforward and simple task. Another thing I realized is how much the shareware and other utilities really make the Amiga environment! For a while I had to boot using the plain vanilla dos disk, and cringed in horror at how slow the mouse was! So, folks--spread the word! Sure the Amiga ain't perfect, but it IS a real alternative to M*-DOS and M*CINT*SH systems (btw, they're not perfect either). Ralph
hart@ug.cs.dal.ca (Todd Darrell Raymond Hart) (03/20/90)
> A couple of times now, i've gotten errors while formatting a > floppy. since I get disks for 0.49 each, i don't mind tossing them, > since it wouldn't be worth the effort to return them for a free > replacement. > > Now the question: > is there a way to use disks with an error? M*-DOS is able to mark > bad sectors, and was wondering if AmigaDOS would do the same. > > [REST DELETED...] > > Ralph Well Ralph AmigaDOS does things in a slightly different way...when data is written to the disk, the individual sector is *NOT* overwritten like in MS-DOS. Instead AmigaDOS does things on a track by track basis. The disk head moves to the track the sector is in and writes out the entire track at once, it does not bother to check to see what use to be there. All sectors are written back to the disk at the same time. Therefore after each write to the disk all data is together in one chunk with a single gap, and not necessarily at the same place on the disk. So one write may be fine and the next shows an error. An article in Amiga Transactor (Vol3, Iss1) gives an excellent description of the encoding schemes used by disk drives and how they work. To quote them: When you write to an Amiga floppy, the drive heads are given a track number to which they can write. They then move immediately to the assigned track and begin writing. They do not wait for a sync mark, nor do they look for a particular sector, and they are not likely to write on the same part of the track that was used before. So that makes it kinda hard to mark a sector as bad as they are only a logical representation of the data on the disk, not physical (one like in MS-DOS). As for your question of the Hard Disk, I don't know as I don't have one yet (only a 500 with a single drive, but hopefully not for long though) so I haven't bothered to really look into their inards other than performance. -Todd __ ///--------------------------------------------------------------------- __ /// The AMIGA, not just another pretty face... | \\\/// Todd D R Hart -- hart@ug.cs.dal.cs | \XX/------------------------------------------------------------------------
birjt@cc.nu.oz (03/29/90)
In article <13211@burdvax.PRC.Unisys.COM>, raf@PRC.Unisys.COM (Ralph A. Foy) writes: > The Situation: > A couple of times now, i've gotten errors while formatting a > floppy. since I get disks for 0.49 each, i don't mind tossing them, > since it wouldn't be worth the effort to return them for a free > replacement. > > Now the question: > is there a way to use disks with an error? M*-DOS is able to mark > bad sectors, and was wondering if AmigaDOS would do the same. Hello, I have a utility that I have called BFormat, this is short for Bad Disk Formater, obvious eh, but I can't remember where it came from. When it it used it formats as normal but when it comes to a bad part of the disk it maps out that particular track as being used ie in the disks bitmap. This way when you later use the disk the DOS thinks that the suspect part of the disk is already used so it doesn't try to write to it, therefore no read/write error. I use it to format all my disks and have never had a problem. One last thing, when it is formating it counts all the tracks ie top and bottom so it appears to format up to 158 cylinders. Hope this helps, Russell