Getting stuff off very old disks

[Narf the Mouse]

Looks like most or all of my old Amiga floppies are too old to get data from, at least using the floppy drive I have.

Anything else to do, or am I out of luck?

[Photon]

Well, if it's stuff you've made yourself, or rare stuff, I would give it a go. For all else there are plenty of disk images on the net already of pretty much all types of programs that you can get and put on brand spanking new floppies.

I have a habit to always open the flap and check that the disk surfaces are dust-and hair free (if it's not I blow it off) before I put a disk in any floppydrive. That's a good tip even if the disks are supposed to work fine, cos then you get much less dust accumulation inside the drive.

You haven't written what setup you have. If you have an Amiga without an external floppy I would recommend that regardless, and then you could read the disks with that before giving up on them. There are floppy drive cleaning kits on amigakit.com and eBay if you suspect the drive(s).

[Narf the Mouse]

I've got a Catweasel Mk 4 and an internal floppy drive in a PC. I'm not worried about stuff I can download; it's mostly files myself and others made I'm worried about.

I'm getting, at best (in ImageTool), a lot of red sectors, some yellow sectors and a few green sectors.

[Paul_s]

Speak to Prowler on here (no, he doesn't actually prowl for things but he just likes the name), he's like the McGyver of the floppy disk recovery world

Legend has it he entered a bank vault using the shutter on a 3.5" floppy disk once foiling $50 million dollars of security features!

[alexh]

Whenever I've come across disks that appear not to work it has always turned out to be the drive is broken and in some cases the faulty drive has turned out to be responsible for damaging the disks.

Always test your drive is working well with some unimportant known good disks for a while, take a look under the shutter for signs of damage or ware.

[Narf the Mouse]

Originally Posted by alexh

Whenever I've come across disks that appear not to work it has always turned out to be the drive is broken and in some cases the faulty drive has turned out to be responsible for damaging the disks.

Always test your drive is working well with some unimportant known good disks for a while, take a look under the shutter for signs of damage or ware.

I think you may have something. It's not detecting lack of write protection and its ability to detect disk type just took a sharp nose-dive.

You mean the shutter on the floppy? Not sure how to look for wear and tear there.

Guess I try sticking in a different floppy drive?

[Anakirob]

Have you tried using some kind of data recovery software?
I don't know what Windows software you'd use to recover data from Amiga floppies.
But I guess running DiskSalv from within UAE would work.

[Narf the Mouse]

If I'm reading that right, it's for later than Amiga 500? We only owned an A500.

[alexh]

Originally Posted by Narf the Mouse

You mean the shutter on the floppy? Not sure how to look for wear and tear there.

For me I could see strong rings or scratches where a foreign object (the disk drive heads?) had scratched the disk surface as it rotated.

[prowler]

Originally Posted by Anakirob

But I guess running DiskSalv from within UAE would work.

If ImageTool is not reading the Amiga disks in a floppy drive attached to the Catweasel MKIV, then running disk recovery software under WinUAE is not going to work either.

[Narf the Mouse]

Does it (ImageTool) combine or replace sector reads? That is, within a sector, does it take the reliable data from each read and add it to past reads, or does it simple replace a poorer sector read with a better one, for the entire sector?

[prowler]

Originally Posted by Narf the Mouse

Does it (ImageTool) combine or replace sector reads? That is, within a sector, does it take the reliable data from each read and add it to past reads, or does it simple replace a poorer sector read with a better one, for the entire sector?

I think it just reads a sector at a time and overwrites the old data with the new, even if the new data is less reliable than the old.

What you describe as a better alternative (i.e., adding reliable data from each read to past reads) sounds more like very expensive forensic quality disk imaging software!

[Photon]

You might have told us your setup at the start, we're not psychic

I guess known good disks read fine? I.e. write a disk, read it back, compare - or similar. I guess you're reading Amiga disks written on an Amiga and not with the CW? Were they written on DD disks or HD disks? If HD, is the HD-hole still covered?

Just wondering how you have reached the tentative conclusion that all your old disks are duff.

Tell us more.

[chiark]

Originally Posted by alexh

Whenever I've come across disks that appear not to work it has always turned out to be the drive is broken and in some cases the faulty drive has turned out to be responsible for damaging the disks.

Always test your drive is working well with some unimportant known good disks for a while, take a look under the shutter for signs of damage or ware.

^^^^^This +1. +1 again. And then + another 1.

Seems to be worse with PCs, but I have seen this with Amiga, too. Drives fail.

[Narf the Mouse]

Originally Posted by prowler

I think it just reads a sector at a time and overwrites the old data with the new, even if the new data is less reliable than the old.

What you describe as a better alternative (i.e., adding reliable data from each read to past reads) sounds more like very expensive forensic quality disk imaging software!

Not fully, no. I think it does keep some - Green sectors, at least.

Very expensive as in hundreds or as in thousands?

Originally Posted by Photon

You might have told us your setup at the start, we're not psychic

I guess known good disks read fine? I.e. write a disk, read it back, compare - or similar. I guess you're reading Amiga disks written on an Amiga and not with the CW? Were they written on DD disks or HD disks? If HD, is the HD-hole still covered?

Just wondering how you have reached the tentative conclusion that all your old disks are duff.

Tell us more.

I humbly apologize for not being perfect.

I've got no known good disks. Yep; old amiga 500 stuff. They've got one hole on the upper right, so DD, I think. I used to know that stuff...

Went through a bunch quick. Fields of red with patches of yellow, maybe green.

Originally Posted by chiark

^^^^^This +1. +1 again. And then + another 1.

Seems to be worse with PCs, but I have seen this with Amiga, too. Drives fail.

I ran a disk through 99 retries; the drives not faulty. It's not necessarily a good floppy drive, but it's not damaging. I think. There's no scratches, anyway. Just shiny disk.

[prowler]

Originally Posted by Narf the Mouse

Not fully, no. I think it does keep some - Green sectors, at least.

That's good to hear. Although I own Catweasels I, III and IV, I don't have much experience of using them because I think low level operations like disk imaging are best performed on a machine where the disk format is fully supported by the operating system, i.e., Amiga formatted disks on an Amiga, Macintosh formatted disks on a Mac, etc.

Originally Posted by Narf the Mouse

Very expensive as in hundreds or as in thousands?

The kind of software I'm really talking about would be capable of reading data hundreds or thousands of times from flaky sectors, storing the results of individual reads, and making the data available for bit-by-bit analysis for the derivation, on a maximum likelihood basis, of the disk's contents before the bit rot set in.

I guess you could name your price, depending on exactly what features you require. There would not be a huge demand for this kind of software, or the hardware to run it on and the amount of storage required, so it's likely to be in the thousands rather than hundreds I would have thought.

[Narf the Mouse]

My understanding is the only difference is the floppy controller; a Catweasel is a floppy controller.

I was hoping you knew of something like that.

[prowler]

Originally Posted by Narf the Mouse

Catweasel is a floppy controller.

Yes, of course it is.

Originally Posted by Narf the Mouse

I was hoping you knew of something like that.

What is it that you are asking, exactly?

[Narf the Mouse]

Which means there should be no difficulty reading any supported formats. If there is difficulty, that's something I'd like to know about.

I was wondering how effective ImageTool is at retrieving data, so I asked a specific question based on behavior I'd observed.

[prowler]

Originally Posted by Narf the Mouse

Which means there should be no difficulty reading any supported formats. If there is difficulty, that's something I'd like to know about.

I was wondering how effective ImageTool is at retrieving data, so I asked a specific question based on behavior I'd observed.

There are no special advantages to using a Catweasel for data retrieval, other than the fact that it can be programmed to recognize a variety of disk formats.

Provided both that the disks ares readable and the floppy drive is in full working order, then the ImageTool should have no difficulty creating valid images of the disks.

If you haven't found evidence of physical damage to the disks' recording surface, then the most likely reason for the problems you are experiencing is corruption of the actual data caused, for example, by inadvertently exposing them to a magnetic field.