How to tell Apple II 13 vs 16 sector disks

[pcamen]

I'm attempting to archive my old Apple II floppies; I've got quite a lot.

I'm using the FC5025 device with an old PC 360k floppy drive

http://www.deviceside.com/fc5025.html

Yea, it works, I've successfully converted a bunch to .dsk files suitable for use with the Virtual II emulator.

It's been a number of years since I've done this.  I am getting A LOT of failures.  Like, 2/3 of my disks fail for some reason or another.  I've ordered another floppy drive to see if that is part of the problem.

But, I have to wonder about how to tell if the disks are Dos 3.2 13 sector or Dos 3.3 16 sector disks.  Some of them have a 16 stick on them, so they are clear.  The ripping software has a selection for type of disk (everything, TRS-80, etc.) and has one setting for 13 sector, and another for 16 sector.  Perhaps some of my failures are because I have the wrong type selected.

Is there any indication of what format a floppy is in?  Was there any convention for noting this?  Any physical differences of the floppy disks?

 

[Dog Cow]

Is there any indication of what format a floppy is in?  Was there any convention for noting this?  Any physical differences of the floppy disks?

1.) As a famous politician once said, "You have to pass the legislation before we can find out what's inside." Usually you have to boot the disk to find out what its format is. Statistically speaking, any disk that isn't Apple Pascal, and that is dated 1978 or 1979 is probably 13 sector, as 16 sector didn't exist until 1979 with the Pascal Language System.

2.) Not really, except for the Apple 16 sticker. 13 sector disks are really uncommon.

3.) Yes, but not to the unaided eye. You'd need a microscope to examine the magnetic media and maybe you could tell.

 

[Gorgonops]

Yes, but not to the unaided eye. You'd need a microscope to examine the magnetic media and maybe you could tell.

Make that an electron microscope. Perhaps at that level you'd actually be able to view physical changes in the orientation of the molecules within the magnetic domains, but even then I think you'd have to view the whole track and do some statistical analysis since the size of the actual bits would be the same.

(The difference between 13 and 16 sector disks is that Apple changed the GCR encoding schema so instead of being able to cram 32 possible characters into every 8-bits worth of magnetic transitions, IE, "5 and 3", they were able to get 64 possible characters per byte, IE "6 and 2". The actual pulse width is the same but the latter scheme fits the extra 23%-ish more data on the disk at the cost of potentially slightly lower reliability.)

The only "macroscopic" difference you might see, given that DOS 3.3 came out in 1980, is that very, very, very old 5 1/4" media can have a few physical differences from later media; originally 5 1/4" drives were specified as having "35 tracks" instead of the later 40 because of reliability problems as the tracks got shorter towards the hub, and thus some ancient 5 1/4" media envelopes have shorter holes for the read heads. Also, while drive media has always been coated on both sides some old disks weren't polished on both sides, so one side of the disc might look slightly duller than the other. If you find disks that meet either of these criteria than I suppose it's more likely they were written before 1980, but there's also no reason why media like this couldn't be formatted and used by DOS 3.3 so consider it a guideline, not a rule.
 

I've ordered another floppy drive to see if that is part of the problem.

The one thing a PC floppy drive will never be able to do is read oddball Apple II formats that incorporate tricks like half-stepping. (TL;DR, because Apple II's directly control the stepper motors of the drives and it takes multiple stepper pulses to move the head the full width to the next track it's possible to create crazy things like spiral formats that read like an LP record, among other things, and some of these crazy tricks were actually used for write-protected software.) PC floppy drives don't have that level of control. So, theoretically at least, if the disks you're crapping out on are using crazy copy protection that would be a legit reason you can't read them. That does sound like a bit of a long shot though. My guess is, assuming the disks simply aren't failing because of sheer age, that it's a severe alignment issue.

And it definitely could be age. It's unfortunate but depending how they've been stored some of those disks might literally crumble to dust if you try to read them. Check the surfaces of the disks that are failing and see if you see physical marks, and also check the disk read head to see if it's accumulating a coating of dusty gunk.

 

[pcamen]

And it definitely could be age. It's unfortunate but depending how they've been stored some of those disks might literally crumble to dust if you try to read them. Check the surfaces of the disks that are failing and see if you see physical marks, and also check the disk read head to see if it's accumulating a coating of dusty gunk. 

Yes on both counts.

The head is definitely getting dirty from the floppies.  I've been cleaning it isopropyl alcohol and a q-tip.  Some of the floppies show almost grooves like with a vinyl record. 

Is a working floppy disk not supposed to show any groove looking things?

 

[Gorgonops]

Is a working floppy disk not supposed to show any groove looking things?

Not with any depth. A properly polished disk might have a very, very light "concentric circles" pattern on it, but if there are irregular streaks or flecks you definitely have a problem.

Link with more info, also discussing "mold".

To my depressed non-surprise I've found that some of the old-stock disks I bought for my Apple II's are showing issues like this despite having been sealed in plastic for thirty years. I do need to be more diligent about making sure the junk doesn't build up on the heads because a dirty head can make it worse and bulldoze a groove in a disk that might have otherwise been "okay" but... yeah. These things are getting to the end of their natural lives.

 

[pcamen]

To my depressed non-surprise I've found that some of the old-stock disks I bought for my Apple II's are showing issues like this despite having been sealed in plastic for thirty years. I do need to be more diligent about making sure the junk doesn't build up on the heads because a dirty head can make it worse and bulldoze a groove in a disk that might have otherwise been "okay" but... yeah. These things are getting to the end of their natural lives.

So basically, we should be planning for all floppy-less use of our vintage computers at this point.  I've got a lot of new in box floppies of the 5 1/4 and 3 1/2 variety, but makes me wonder if they will also die soon.

However, it appears new disks are still manufactured:

https://www.amazon.com/s?k=double+sided+double+density+floppy+disks+5.25&i=electronics&ref=nb_sb_noss_2

 

[pcamen]

Hmm, after reading RetroTechnology Herb's info on floppy disks, I'm wondering if it is worth trying to read non-data disks at all:

http://www.retrotechnology.com/herbs_stuff/clean_disks.html

Specifically:

If a disk has not been stored in a closed sealed package, then it is likely to have collected dust, or worse yet, mildew from storage in a damp environment. Attempting to read such a disk is likely to leave crud on the disk drive's read/write heads. Not only is this disk unreadable, but any subsequent disk you put in that disk drive may be contaminated, ore even destroyed!

This might explain at least some of my difficulty in reading disks. 

 

[Gorgonops]

However, it appears new disks are still manufactured:

Those all look like old stock to me. Sony was the last company making 3.5" disks and they quit the business in 2011, unless someone can point to reliable evidence that someone has set up shop again to churn them out I'm going to assume that "new" in any listing I see means new old-stock.

(The guy who runs floppydisks.com supposedly bought about a half a million 5 1/4" disks before the lines for those shut down around 2010. They still sell "new" disks that are presumably from that batch.)

 

[pcamen]

Still, 2010 or 2011 vintage will probably work for some years now, no?

 

[Gorgonops]

Hopefully. But I am starting to feel like that as much as I'm loathe to I should figure on starting to move as much as possible to floppy emulators.

(Just this week I flashed my first pair of Goteks with FlashFloppy. Initially got them intending to put one in a TRS-80 Model 4, but I think my recent Tandy 1000 EX acquisition has jumped to the front of the queue. Need to get some ribbon cable and adapters still, though. Feh.)

 

[Dog Cow]

Hmm, after reading RetroTechnology Herb's info on floppy disks, I'm wondering if it is worth trying to read non-data disks at all:

This might explain at least some of my difficulty in reading disks. 

This happens all the time, and it turns out that you can clean the magnetic disk surface with a couple drops of isopropanol. It will cure a lot of I/O errors. This technique works with both 3.5" and 5.25" floppies.

 

[Dog Cow]

Is a working floppy disk not supposed to show any groove looking things?

Definitely not.

That's a scratch on the disk, usually caused by contaminants on the read/write head of the disk drive. And if the scratch is deep enough, there goes your data with it. It's typical to see scratches on track 0. You ideally shouldn't see scratches on a disk, but if you do, it's usually on track 0.

 

[CC_333]

Maybe there's some place in China that can reproduce these floppies in small batches?

They can replicate just about everything else nowadays, so why not?

It would just take some enterprising people who either have enough of their own money to finance it, or some means of acquiring such funds, using something like GoFundMe or some such.

c

 

[Gorgonops]

I have no doubt there are a few pallets of the needful manufacturing equipment sitting in a dark warehouse somewhere that might someday rise like a phoenix from the ashes, but somehow I think the original disks are going to have to get rarer before you find the seed money for that.

 

[CC_333]

@Gorgonops You're probably right. But it's fun to think about!

And it might not be so unwise to start planning now, as with the way these disks die (especially the NOS ones from >= 20 years ago), they'll probably become rare more quickly than we realize. I agree that it'll probably take the supply getting that low before people would be willing to pay enough to justify new boutique batches being made, so maybe I'm trying too hard to find a solution to a presently nonexistent problem....

However, with that in mind, it might not hurt to stock up on any relatively recent stock from the 2000s or so, just to be safe.

c

 

[pcamen]

Hopefully. But I am starting to feel like that as much as I'm loathe to I should figure on starting to move as much as possible to floppy emulators.

(Just this week I flashed my first pair of Goteks with FlashFloppy. Initially got them intending to put one in a TRS-80 Model 4, but I think my recent Tandy 1000 EX acquisition has jumped to the front of the queue. Need to get some ribbon cable and adapters still, though. Feh.)

I'm intrigued.  Will FlashFloppy work on any model of the Gotek?  Which model do you have? 

Gotek's suite just says inquire and doesn't list any prices, but I see quite a few on eBay for not that much, like this one:

https://www.ebay.com/itm/Gotek-SFR1M44-U100-3-5-Inch-1-44MB-USB-SSD-Floppy-Drive-Emulator-New/163653733050

Do they do a pretty good job at emulating the Apple II drives too?

 

[Gorgonops]

Which model do you have?

I just went through my eBay history to see if I could link directly to the listing I got it from; it's expired (I had these things sitting on myself since last year, it's taking me this long to get to them ), but I don't think there's much variation between them for the most part. (The FlashFloppy website does refer to an "Advanced Gotek" that has extra jumper pin locations and solder points on the board for, among other things, driving SD cards directly instead/in addition to the USB port, but I haven't seen any listings for one explicitly.) The ones I bought were almost the cheapest ones I could find, I paid only $28 for two of them from a listing like this:

https://www.ebay.com/itm/3-5-1-44MB-USB-SSD-Floppy-Drive-Emulator-for-YAMAHA-KORG-Elec-keyboard-GOTEK/162527019254

(The particular seller I got mine from isn't listing them anymore, I think it's just one of those many "drop ship from China" presences that essentially sell random items.)
 

At the same time I also bought four of these little guys, two for the floppy emulators and two to play with:

https://www.ebay.com/itm/Blue-IIC-I2C-0-91-128x32-OLED-LCD-Display-DIY-Module-3-3V-5V-For-PIC-Arduino-/332048200050

Getting the headers soldered to them so I can install them is something I'm hoping to squeeze into the weekend, but they're not really necessary. To flash them I went with the "A-A" USB cable method because of sheer laziness. (I just bridged the necessary enable pins by inserting some fat speaker wire bridges into the holes where the header pins would go; most Goteks don't have them factory installed.) The cable cost me something like $5.
 

Do they do a pretty good job at emulating the Apple II drives too?

Unfortunately FlashFloppy only does Shugart (or at least Shugart-like, which covers quite a lot of systems outside, alas, the big three of Apple, 8-bit Commodore, and 8-bit Atari) emulation at the moment. I have wondered if it might be possible to use the Gotek floppy hardware to do Disk II emulation with suitable firmware and cabling changes; the CPU on the Gotek should be fast enough to handle it. But it's definitely a feature that doesn't exist yet.