Useless Disks?

Today I got 30 used DD floppies from eBay. I tried loading them all up, but only 6 disks worked (2 Fire and Ice and 4 Streetfighter 2). There are also other disks that are fine but won't boot by themselves and need Workbench, like Prowrite. What I am finding annoying is that the disks load up no problems, but when I go to Format them (I don't want Prowrite anyway and there were 3 copies) I get Bad Sector error messages and the disks are rendered useless.
How can a disk be working then get bad sectors during format. Does this make the disks officially useless or is there another way of formatting them that can get rid of the bad sectors? I had half a 720 Kb PC disk taken up with bad sectors but I repeatedly formatted it till I was only losing 70kb. Does the same work for the Amiga? Is this a common problem or could there be something wrong with my drive, or did the person I got them off just look after them poorly?
I haven't tried formatting any of the duff games yet but will probably post again when I have.

[Dizzy]

Try check if the disk is dirty. I bought some disk wich had some dirt on the surface, so I clean them with alchohol (78%), that solved the problem.

I havent repaired floppys for a while, but there was an old
prog called fixdisk or somthing, a bit like writing a band aid
over the bad blocks, either way i used something like that
a while ago and it worked.
if theres no joy here i`ll do some research for ya.

[Amiga1992]

Originally posted by Dizzy
I bought some disk wich had some durt on the surface, so I clean them with alchohol (78%), that solved the problem.

!!! Wouldn't alcohol kill the surface? I am surprised!

[Dizzy]

Originally posted by Akira
!!! Wouldn't alcohol kill the surface? I am surprised!

not the alcohol we use at the hospital (don't know the english word for this), it's clean. I use it to clean my vcr, cd-player and disc-drive etc.

[Frog]

i drink it

I just had a disk come up with bad sector errors after doing 52 of the 79 cylinders. I was determined this disk was going to work so I formatted it again. It got a little bit further, to about 57. After about 10 formats I had managed to get over all the bad sectors! This proves disks can be salvagable, altough one disk has taken me 6 formats already and I've only gained three or four cylinders. In other words: It takes a long time.

Oh and Dizzy, what do you mean by clean the surface, surely you don't mean physically open the disk up and clean the 'floppy' inside?

[Pfloyd]

Why not? Use some isopropanol (don't drink it) and wipe the fingerprints off the floppy disk. Be sure not to scratch the surface; if you do or if there are already scratches, the disk is very likely unusable. In this case I would suggest you to throw the scratched disk away because it could damage your drive.

Don't worry about the magnetic coat. If it isn't already seriously damaged it will survive the cleaning procedure.

I successfully cleaned several floppy disks of different size and for different computer systems. Even the data "under" the dirt was readable again.

If you use dirty disks in your drive, the drive r/w heads will collect all the dirt until it can't read any disks at all. So remember to clean the disks first (if there is any visible dirt on them), then the r/w heads in your drive(s).

=
You do anything at your own risk. I'm not responsible for whatever may happen.

[Fissuras]

just because you have managed to format those bad sectors it does not mean they are good now. Chances are they get bad again in the blink of an eye and you will loose any info recorded.

too bad about the ebay deal though,

best of luck in the future,

why not try some car boot sales for dd disks?.

actualy i think i`ll hunt the charity shops for ami mags
this weekend, i feel lucky.

[Twistin'Ghost]

Originally posted by Fissuras
just because you have managed to format those bad sectors it does not mean they are good now. Chances are they get bad again in the blink of an eye and you will loose any info recorded.

This is true. Back in the day, I was going through so many disks that I kept all of my bad disks in case there was some way to salvage them. A friend of mine bought some util that would make disk copies, plus would format disks even with bad sectors (using some sort of brute force mode, as opposed to mapping out bad sectors). It worked pretty good on most disks, however the errors returned later down the road. The bad thing about that was that it gave me the false sense of security that the disks were safe to write on. Of course the data was not safe and unreplaceable files were only a memory in the Amiga history books.

I never tried degenerated alcohol, but it seems reasonable that it would help. It's what I used to manually remove oxide drop-out particles from videotapes that end up in the portals of the drum of video tape heads. Works a treat and the remaining fluid evaporates!

[DrBong]

@NytroX86
For a software solution I suggest you try Bad Format to try and salvage those disks with soft or hard errors. It is available on Aminet:

http://ftp.uni-paderborn.de/aminetbin/find?bformat

There are other programs like this on Aminet like AllowBad.......just do a search for them if you're not happy with Bad Format.

Bear in mind that if a disk has too many hard errors that it probably will develop problems again not too far down the track if you are able to salvage it. Tis the nature of the beast that errors tend to be cancerous on wonky media.

So you just rip your amiga open and clean the drive heads with some metho?

[Paul]

So you just rip your amiga open and clean the drive heads with some metho?

I used to have a disk with material in the middle, which you put cleaning liquid on.

For a software solution I suggest you try Bad Format to try and salvage those disks with soft or hard errors.

Sounds ideal. Unfortunately I have version 2.05 of Workbench. No CrossDos . There is something called PCD on the disk but that doesn't seem to do anything. So basically I cannot read PC disks at the moment, and thus cannot transfer files between me meega and pc. I'm gonna get a PC to Amiga link pack that comes with all the leads and software for both machines, when I've got a tenner spare.
And for Fissuras and Twistin' Ghost: Damn. I have created a new policy not to try to salvage any disk which have errors that take several formats to get over, or if they start reading bad sectors early on (like the first 40 cylinders). I'm only gonna use the disks for 'backups' of games and Workbench, but I'll use the backups and not the originals so I can run off another copy if they cack.
As for nearly everyone else on this thread: Together you have confused me . I'm not sure you are all talking about cleaning the same part of the disks/drive. Do you mean taking the actual floppy magnetic media out of each floppy disk (which would surely break the disk casing?) and cleaning it or opening up the A600 internal floppy disk drive and attempting to clean the read/write heads and possibly other areas.
Anyway thank you everyone for your ideas

[Dizzy]

The metal flap on the disc can be pushed, then you can claen the surface of the disc. Not breaking the disc.
About the drive, you use a cleaning disc as Paul says

Ahhhh. Thats quite easy then, I knew that you could pull back the metal on the disk (I actually have a bad habit of fiddling with the metal, I've had to snap it off on many PC disks), but for some reason I assumed this method wouldn't work.

[Unknown_K]

How would the 3.5" disks get dirty anyway unless a liquid was spilled on them (since they are fully enclosed).

If I find a disk thats unreadable or has bad sectors I just junk it. Thank god I found good deals on new floppies.

500 5.25" dsdd were $20+ shipping on ebay (perfect for c64 etc)
500 3.5" dsdd were $20 on meritline.com (they are $40 now i think)
300 3.5" hd were $40 from ebay (those suckers cost alot still)

[Dizzy]

many disc wasn't complet closed, little cracks on the side of the discs, or the metal is bend a little etc.
The disc I cleaned was stored in a cellar (i think, I bought them used).

So far I have found 10 of the 30 disks to be working, 2 have formatted first time with no problems and 1 was salvaged with 10 or so formats and now being used as a copy of Workbench to format the others. About 5 have early or stubborn errors, and about 3 I deem too risky to use(they look physically damaged, and some made unhealthy noisess when I tried to use them).
If I really need more disks I might buy 20 HDs for a fiver down the local Currys store, and do the tape over a hole trick. The only problem is they are pre-formatted PC disks which may cause problems.