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How to identify format of 5.25" disk

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krebizfan

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I received a group of 5.25" disks all supposedly created on the same computer. I have been able to read some but others are not showing up as valid disks. Is there any simple way to determine if the unreadable disks have an unconventional format as opposed to alignment issues or disk damage?

The disks I have read all show up as 360kB MS-DOS floppies. The other disks are labeled as 48TPI DS but that means little.
 
Look for a copy of AnaDisk. Use a 1.2MB drive on an older system running DOS. Run SCAN on each floppy. It will not only identify the type, but also tell you about errors.
 
I'd like to add the extremely important piece of information that having bought many bulk unlabelled floppies .... the 360K floppy media coating is lighter in colour (color) than the 1.2MB diskettes.

regards marcus
 
Something like this?
disketter.jpg
 
But that's not reliable (if you want, I can take a photo of some samples). I've got DD media with darker coating than some of my HD media.

What is fairly definitive is the presence or absence of a reinforcement strip around the hub hole. DD (except for very old media) has it; HD (almost universally) does not. I even know why...
 
Well, I've never found colour or even the reinforcement ring to be a reliable density indicator.

What does seem to be pretty consistent though is the transparency; if you hold the diskette in front of a strong light the HD disk will be semi-transparent whereas the DD disk is essentially opaque.

Of course none of this tells you anything about the format on the diskette; that's what programs like Anadisk are for.
 
Just as an update: Anadisk did manage to recognize the disks as quad density 720kB and also managed to dump files that seemed to have some actual content that matched what was anticipated on the disk. The FAT on all 3 disks had been overwritten with the same unusual message which puzzles me. Still being able to recover data off 20 year old disks with a format my systems do not read by default results in a happy feeling.
 
Chuck(G) said:
Do you have a clue what these were from? Can you dump just the first track if not? I can probably ID them from that.
Click to expand...

As I understand it, the disks were created on a Sanyo MBC. Not sure I can forward the first track to you since the disks belong to someone else. My suspicion is that these effects are from some oddball virus because all 3 disks have the same initial contents involving a bible quote. But if I can contact the disk's owner, I will try and see if I can forward the first track or have him contact you directly to more accurately process the disks.
 
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