5.25" floppy disks with bad sectors - any solutions?

[kishy]

I just took an old Mackintosh 3.5" disk which, of course, wouldn't read on a DOS system. Then I formatted it to 1.7M and wrote a file to it and ran chkdsk. All was fine. Then I formatted it to 1.4M and wrote a file to it and ran chdsk. All is still fine! It is indeed possible to format to 1.7 and then go back to 1.44. This was all done in the drive and I did not need to remove the disk to wipe it.

The program I used was FreeForm v2.31. I tried reformatting with FreeDos Format v1.0 and it appeared to work but upon writing a file or running chkdsk it complained. So, it looks like it all depends upon the formatting program.

I have heard people complaining about inadequacies of the MS format program, but I am surprised that the FreeDos program has the same bug. However, I am not completely sure that the FreeDos program would not be able do it if given the correct parameters. It has several ways of using it. FreeForm is just a no-brainer that's why I used that.

I suspect there's more to it than the program...it's probably much more drive and media dependent. I used WinImage for the ones I did.

 

[Chuck(G)]

There's no basis that I can think of for 1.7M not formatting to 1.44M again. Heck, I reformat disks to all sorts of weird layouts all of the time with no problem.

On the other hand, most new 1.44M media is pretty terrible--and the way drives are mounted in cases nowadays also makes them dust magnets, leading to reading/writing problems.

 

[kishy]

There's no basis that I can think of for 1.7M not formatting to 1.44M again. Heck, I reformat disks to all sorts of weird layouts all of the time with no problem.

On the other hand, most new 1.44M media is pretty terrible--and the way drives are mounted in cases nowadays also makes them dust magnets, leading to reading/writing problems.

It's not that it didn't format back...it did. It just didn't actually hold any of the data anymore (which would suggest the process of 1.44 -> 1.7 -> 1.44 physically stressed the media to the max). They were pretty much brand new disks (less than a year old, a couple of them used briefly and reliably) in a brand new drive at the time.

 

[Chuck(G)]

It's not that it didn't format back...it did. It just didn't actually hold any of the data anymore (which would suggest the process of 1.44 -> 1.7 -> 1.44 physically stressed the media to the max). They were pretty much brand new disks (less than a year old, a couple of them used briefly and reliably) in a brand new drive at the time.

I think you have a mistaken idea of how media is formatted and written. When you format a diskette, every bit on the track is written, used or not. The differences in formats are primarily the placement of the address marks. Anything not used on a track is filled with "filler" bytes. So, there's really nothing different happening when you format a DMF or XDF floppy, other than the address marks (which are data patterns that are missing one or two "clock" bits are in a different spot.

As a roughly analogous situation, this is like saying that once you record "I am Curious (yellow)" on a VHS cart, the tape refuses to hold a copy of "Rebecca of Sunnybrook Farm". It may be, but there's no good technical reason for it.

 

[Ole Juul]

physically stressed the media to the max

What does that actually mean? With all due respect, that sounds like some newfangled physics to me.

If there is some kind of drive problem like Chuck(G) hinted at then there's nothing you can do about that. If there is residual magnetization on the media it can be completely removed by wiping the disk. By wiping the disk, I mean using a demagnetizer such as used for tape. This is usually done in the audio world because you cannot record on previously used tape without having higher background noise than on fresh tape. That is easily solved with a demagnetizer (ie wiping it) and the media is then pretty much as good as new. The erase head, you see, is not very good even in the expensive heavy duty 16 track machines. The same problem exists for floppys but digital recording is much less critical. Where problems come in (apart from dirt and physical damage) is the possible inaccuracy of tracking. That can cause intermittent problems when the signal induced is borderline. In any case, wipe the disk and you're magnetically back to new again.

PS: Tape demagnetizers have been discussed here before and there are lots of cheap ones around. Radio shack sells them.

 

[kishy]

I am very easily and quite likely not understanding something with regards to this, but using a floppy drive (and no other tools, besides of course the software to use said drive) it is not possible to get one of those disks to come back.

I am of course referring to my own experiences with my own disks.
From my perspective, those disks became damaged because they were no longer able to be recovered using "just" a floppy drive.

Much like how a CRT TV with no degauss function (which has been discoloured by a magnet) will be "broken" until someone uses one of those degausser tools on it.

 

[Chuck(G)]

Okay, two items of clarification.

First, are these "factory" DMF diskettes? In other words, are they ones you formatted yourself or ones that someone else (e.g. Microsoft) formatted? The reason I ask is that it was the practice of some duplication houses to crank the write current way up, making it more difficult to reuse disks without degaussing.

Second, are you re-formatting them under DOS and not Windows? Windows formatting involves a check of an existing format before laying down a "hard" format.

Otherwise (I just tried it), I have no problems formatting and then reformatting DMF disks with a standard DOS 80x2x18x512 format.

 

[per]

I am very easily and quite likely not understanding something with regards to this, but using a floppy drive (and no other tools, besides of course the software to use said drive) it is not possible to get one of those disks to come back.

I am of course referring to my own experiences with my own disks.
From my perspective, those disks became damaged because they were no longer able to be recovered using "just" a floppy drive.

Much like how a CRT TV with no degauss function (which has been discoloured by a magnet) will be "broken" until someone uses one of those degausser tools on it.

AT LEAST try an unconditional format (/U parameter) with the /F:360 parameter included. If that doesn't work, you need a bulk ereaser.

 

[kishy]

Okay, two items of clarification.

First, are these "factory" DMF diskettes? In other words, are they ones you formatted yourself or ones that someone else (e.g. Microsoft) formatted? The reason I ask is that it was the practice of some duplication houses to crank the write current way up, making it more difficult to reuse disks without degaussing.

Second, are you re-formatting them under DOS and not Windows? Windows formatting involves a check of an existing format before laying down a "hard" format.

Otherwise (I just tried it), I have no problems formatting and then reformatting DMF disks with a standard DOS 80x2x18x512 format.

I'm pretty sure I specified they were "factory" 1.44MB disks, not DMF. I formatted them TO dmf then used them for the win95 install, then formatted back to 1.44 and had issues.

I formatted "under" Windows (XP) but, as I said, using WinImage. Given that similar operations of 1.44 -> 720 -> 1.44 go over with no issue (assuming of course I tape off the second hole), I'd say the issue is the media I used just doesn't stand up to it. Anything involving a tool outside of my computer would be classed as "repair" to me, meaning the disks were in fact "broken" after the "1.44 to DMF then back to 1.44" thing.

AT LEAST try an unconditional format (/U parameter) with the /F:360 parameter included. If that doesn't work, you need a bulk ereaser.

per, I believe you may be confused (as would happen EASILY in this thread).
We are now on the topic of 3.5" 1.44MB media being formatted to and from DMF (1.7MB)

About those 5.25" disks, all of them are now performing exactly like they should (as 360k disks) except for that one...the "96tpi DSDD" disk. I'll give the unconditional format a try...right....NOW (powering on the "TV tray computer")

 

[kishy]

Well per, it appears /u wins. (see what I did there?)

the "96tpi dsdd" disk took the 360k format like a champ, with no unusual noises or pauses, and there are now apparently zero bad sectors (the more I mess with this stuff, the more it looks like bad sectors simply represent an incorrect format)

 

[per]

per, I believe you may be confused (as would happen EASILY in this thread).
We are now on the topic of 3.5" 1.44MB media being formatted to and from DMF (1.7MB)

About those 5.25" disks, all of them are now performing exactly like they should (as 360k disks) except for that one...the "96tpi DSDD" disk. I'll give the unconditional format a try...right....NOW (powering on the "TV tray computer")

Ok. I just didn't see when the topic changed.

You may try to use the following parameters instead of the /F: x parameter:

(/1 for one-sided media, skip it for two-sided media)
/T:tracks_per_side
/N:sectors_per_track

The Standard 1.44MB format of 3.5" disks uses 80 tracks/side and 18 sectors/track.
The Microsoft 1.68MB format (DMF) of 3.5" disks uses 80 tracks/side and 21 sectors/track.
For IBM XDF format, I have no idea. It may even be a non-standard layout, making it unable to format with the satnadard format program.

 

[Chuck(G)]

For IBM XDF format, I have no idea. It may even be a non-standard layout, making it unable to format with the satnadard format program.

XDF is very different, using differently-sized sectors on each track; something that requires a little "trickery" to do with the standard PC controller.

IBM supplied a utility called, I think, XDFCopy to handle making duplicates.

 

[Ole Juul]

kishi: Anything involving a tool outside of my computer would be classed as "repair" to me, meaning the disks were in fact "broken" after the "1.44 to DMF then back to 1.44" thing.

You can think that way if you like, though I would think that it is the computer which is "broken" in that case. To me it is not reasonable to expect computers to do everything. That could just be a generational thing though. lol I have to rewrite the labels on my floppies when I want them to say something else, even though there is no reason that a floppy drive couldn't print too. It's just more practical to make drives with limited functionality and then do some things independently. Demagnetizing magnetic media is just one of those "outside" things which practitioners of magnetic recording have been doing for a long time - even if you haven't. Please don't take offense - I'm just pointing out that peripherals are an acceptable thing to many people.

I also don't wish to deny what has obviously been your experience. You could have a quality problem with your drive, or drives. "Broken" software is another avenue to explore. Not being familiar with MS-Windows, I can't comment directly on Winimage, but it is distinctly possible that it has some limitations. Not to put down MS, but they have been known to make some programming choices which may limit the users options.

 

[kishy]

You can think that way if you like, though I would think that it is the computer which is "broken" in that case. To me it is not reasonable to expect computers to do everything. That could just be a generational thing though. lol I have to rewrite the labels on my floppies when I want them to say something else, even though there is no reason that a floppy drive couldn't print too. It's just more practical to make drives with limited functionality and then do some things independently. Demagnetizing magnetic media is just one of those "outside" things which practitioners of magnetic recording have been doing for a long time - even if you haven't. Please don't take offense - I'm just pointing out that peripherals are an acceptable thing to many people.

I also don't wish to deny what has obviously been your experience. You could have a quality problem with your drive, or drives. "Broken" software is another avenue to explore. Not being familiar with MS-Windows, I can't comment directly on Winimage, but it is distinctly possible that it has some limitations. Not to put down MS, but they have been known to make some programming choices which may limit the users options.

It just occurred to me that you PM'd me the other day and I forgot to reply...in essence, you're welcome

Very true about not expecting the computer to do everything, but a lot of this does come back to perspective. In my 'generation' of computing (which is, realistically speaking, 486-current), a lot of this "do it yourself" attitude was diminishing and automation was expected. One (of my perspective) would consider a floppy disk (or removable media in general) a zero-maintenance device, one which you use until it stops working easily/normally and then consider nonfunctional. That's not to say it actually isn't...in that case it is my perspective that is flawed.

Quality issues are quite likely, the one I was using at the time was brand new so understandably...it will be of significantly lower quality than a precision designed and built drive of, say, the early 1990s. I wouldn't put it past the media either though, again it was pretty much brand new and as has been stated in this thread they aren't made like they used to be.

WinImage is, in case you're not aware (it could go either way based on your reply) actually third party software which has - by far - better and more capabilities than the built in Microsoft (or whatever company they stole it from) formatting tools. That of course isn't to say MS drivers don't hamper operation of the drive (which I think is what you were hinting at).