Formatting HD 3.5" Floppies on Apple //e's & //c+'s, Every Time

I made a new thread for this topic, as I felt a similar one veered off course. I just wanted to share that it IS possible to use HD 3.5" floppy disks with standard Apple II hardware, using the 800k disk drives. I do this on Apple //e's and Apple //c+'s all the time and I really never have a problem. Apparently there is an issue if you try to format these (typically pre-formatted with IBM DOS format disks), due to the preloaded format.

Here's my technique; Just take a good magnet to these disks, and rub it all over the outer housing. You have now removed the pre-existing format. Slip it into your disk drive and treat it like a SD 800k floppy disk. I format with the Apple issued ProDOS8 System Disk. I never understood why other people haven't done this and keep spreading the meme that you can't use these disks. Sheesh people! They are made out of the same magnetic-ferro-imbedded plastic stuff as a 5.25" disk, just with a finer grain density.

Mutant Pie

http://www.applefritter.com/content/get-rid-errors-your-floppy-disks-fix-them

What about using a TV degaussing ring? Would that work the same as as big magnet?

What about using a TV degaussing ring? Would that work the same as as big magnet?

If you mean "work the same" in terms of the similar scientific explanations of how magnetism works then I would say no. A magnet would *magnetize* and a degausser would *DEmagnetize*. If you mean "work the same" in terms of rendering the floppy disks from a non-working condition to a *working* condition then I would say that it is possible. The only variable being the relative strength of the electro-magnetic field produced by the TV degaussing ring versus the changing of the magnetism of the disk due to the magnet. This is of course provided that the disk is not magnetized by the magnet to such a degree that the floppy drive cannot provide enough magnetism to format the disk for use. If you attempt to use a magnet that is too strong, then I believe that the disk would be rendered useless unless it is demagnetized afterward. Hence, I do not advocate the use of magnets to solve this type of problem since logically, as well as scientifically, (in my opinion) it makes no sense. Every method of repair I have seen and witnessed in my life is accomplished with degaussing. Think about it - a TV degaussing ring can fix the colors on a TV but a magnet can and often will ruin them. I, of course believe that using a tape eraser on floppies is the best bet since it is designed to demagnetize an object of equal size. I have my doubts about using a TV degaussing ring since when it is used on a TV, you can see the colors go absolutely berserk. This might be caused by it degaussing and magnetizing at the same time in such a way that is appropriate to fix the colors of a TV set. But then again... These are all just my opinions and observations. Feel free to experiment. Empirical evidence would be crucial to answering this question conclusively.

I made a new thread for this topic, as I felt a similar one veered off course. I just wanted to share that it IS possible to use HD 3.5" floppy disks with standard Apple II hardware, using the 800k disk drives. I do this on Apple //e's and Apple //c+'s all the time and I really never have a problem. Apparently there is an issue if you try to format these (typically pre-formatted with IBM DOS format disks), due to the preloaded format.

Here's my technique; Just take a good magnet to these disks, and rub it all over the outer housing. You have now removed the pre-existing format. Slip it into your disk drive and treat it like a SD 800k floppy disk. I format with the Apple issued ProDOS8 System Disk. I never understood why other people haven't done this and keep spreading the meme that you can't use these disks. Sheesh people! They are made out of the same magnetic-ferro-imbedded plastic stuff as a 5.25" disk, just with a finer grain density.

Mutant Pie

Ignorance, ignorance... I will quote this as a reply:

Chuck(G)
July 16th, 2009, 07:50 PM
HD 5.25" media differs from 2D substantially in two ways.

The most important is the coercivity of the magnetic material used--the magnetic field strength needed to magnetize a material.

The coercivity of 2D media is 290 oersteds and about 560 for HD. Thus a much stronger write current is needed for HD.

Another aspect is the coating thickness--about 2.5 microns for 2D and about half that for HD. This means that what you manage to write to HD media with a 2D drive will read back with a lower signal level.

The third factor is magnetic particle size--generally smaller for high-density media. Not particularly important, except to high-density recordings.

The fourth factor is loading--the ratio of magnetic material to binder. Generally, HD media has a lower ratio to avoid problems with "bit crowding" on the inner tracks, where a magnetization change can actually push one following further away. (this is the reason for write precompensation circuitry).

In short, don't do it. You won't like it.

I made a new thread for this topic, as I felt a similar one veered off course. I just wanted to share that it IS possible to use HD 3.5" floppy disks with standard Apple II hardware, using the 800k disk drives. I do this on Apple //e's and Apple //c+'s all the time and I really never have a problem. Apparently there is an issue if you try to format these (typically pre-formatted with IBM DOS format disks), due to the preloaded format.

Here's my technique; Just take a good magnet to these disks, and rub it all over the outer housing. You have now removed the pre-existing format. Slip it into your disk drive and treat it like a SD 800k floppy disk. I format with the Apple issued ProDOS8 System Disk. I never understood why other people haven't done this and keep spreading the meme that you can't use these disks. Sheesh people! They are made out of the same magnetic-ferro-imbedded plastic stuff as a 5.25" disk, just with a finer grain density.

Mutant Pie

Ignorance, ignorance... I will quote this as a reply:

Chuck(G)
July 16th, 2009, 07:50 PM
HD 5.25" media differs from 2D substantially in two ways.

The most important is the coercivity of the magnetic material used--the magnetic field strength needed to magnetize a material.

The coercivity of 2D media is 290 oersteds and about 560 for HD. Thus a much stronger write current is needed for HD.

Another aspect is the coating thickness--about 2.5 microns for 2D and about half that for HD. This means that what you manage to write to HD media with a 2D drive will read back with a lower signal level.

The third factor is magnetic particle size--generally smaller for high-density media. Not particularly important, except to high-density recordings.

The fourth factor is loading--the ratio of magnetic material to binder. Generally, HD media has a lower ratio to avoid problems with "bit crowding" on the inner tracks, where a magnetization change can actually push one following further away. (this is the reason for write precompensation circuitry).

In short, don't do it. You won't like it.

And what was his quote about 3.5" media? Don't honestly know if the numbers/ratios/differences apply to ALL disks or just the 5.25" discussed in the quote you posted (as opposed to what the discussion in this thread was about.)
Be interesting to find out.
Zan

Exactly because of the same attitude that the topic starter has the engineers implemented a fool-proof (to some extent) protection on a 3.5" media by marking the media type with presence/absence of a square hole in the diskette's plastic box...And to sense it they added an additional optocoupler sensor with some additional circuitry in the drives...

Yadda, yadda, yadda. This practice works just fine. Has anyone actually experienced any failure with this method?

Yes, i have. In the early 2000s i have used a mix of HD and DD Disks with DD Drive. The HD-disks are mostly unreadable with a lot of bad blocks but the DD disks still are ok. If you don't need to have reliable disks but a cheap alternative to DD Floppies, HD-Floppies are ok. I had a lot of problems with used HD-Floppies in DD-Drives. But since there are a lot of Floppy-emulators available now, i don't use Floppy-disks quite as much anymore. Even though i have 500 5.25" and 300 3.5" DD floppy disks in sealed packages.

Try ED Floppies, they tend to be very reliable in DD-Drives in my experience. But as ED disks are much more uncommon than DD, it might be complicated to get a hold of them.

HD-floppies tend to create more dirt/residue on the r/w head (and the felt of SS drives) of the floppy drive. Maybe the substrate is softer than on DD floppies?

EDIT:
you can try this yourself:
open a HD and a DD disk up and take out the round sheet of brown/black foil. Take a ear-cleaner (the ones with cotton on the ends) and rub it a bit across the surface of each of the sheets. You will notice more scratches on the HD-disk (black) sheet.

-Jonas

I saw a lot of failures. I used to bring our user groups public domain software library to Apple II meetings. Sometimes I’d use the clubs IIgs, sometimes I’d bring my own. Sometimes someone would bring their own HD floppies, sometimes someone would use one of those free AOL floppies. We saw a pretty high failure rate. Never right away but often enough a few hours or a few days later..

I tried to make disks unreadable by using a large magnet to stick them to my fridge. Also stored a couple of disks on top of a speaker. The disks still worked fine a year later. Accidentally putting a disk on my Apple graphic tablet made it unreadable right away.

Yep, I've had problems using HD 3.5s as DD disks. Name brand, cheap brand, take your pick. It's been hit and miss.

Sometimes it works, sometimes it doesn't. I erase the floppies with a bulk tape eraser, designed for cassette tapes which in theory leaves the media properly degaussed.

For me it's handy in a pinch, but I wouldn't store my only save of something really important on one of those disks.

I'll add my voice the the ones that have had trouble using HD media in DD drives, size not withstanding.

The HD media usually work for a short time, but then forget. The length they will store data reliably is about 1 month with my TRS-80 COCOs. I have never used them on any of my Apples as I have no 3.5" drives and tons of 5.25" DD media. In any case I only use them for temporary storage and glean eBay for expensive DD media when I can find it and need it.

Excluding the AOL disk, we still saw a pretty high failure rate.

"sometimes someone would use one of those free AOL floppies. We saw a pretty high failure rate."

Okay, I'll rephrase. Excluding the worst quality, meant to used once and thrown away AOL issue HD floppies, did you experienced failures with this method? I haven't. The disks I'm talking about have been in both occasional and continual use for over a decade. I admit that they were Sony brand, which is tends to make and test their products to a fairly high standard.