Kodak 6.6MB floppy drive

[DimensionDude]

Yes, you read that correctly. I have a Kodak 6.6MB floppy drive, uses special 5.25 inch diskettes (no longer available). I haven't tried it in quite a while, hope it still works.

Worked great with an XT class machine, it would run on a 386-16 with the turbo turned off. One of the few drawbacks is that it has its own controller card that takes the place of the FDC in the machine. A standard 360K floppy is the only other drive it can operate.

Still, I used it quite a bit before I could afford a hard drive. It seems to work like a hard drive in that the floppies are low-level formatted at the factory, there is a format utility for the high-level format.

Has anyone else seen or used one of these? Any ideas on getting additional media? Any help will be appreciated.

[mbbrutman]

Can you post some details about this drive? A link to any docs (or a scanned copy) would be great.

Floppy disk formats and recording techniques are intriguing. With some simple software a standard 1.2MB drive will write 80 tracks to a 360K double density diskette, resulting in a 720K format. If you goose the number of sectors per track you can do even better.

But still, to get to 6+ MB on 5.25 inch is quite an accomplishment - they might not be using MFM for recording.


Mike

[Terry Yager]

I never knew there were 2.4Mb 5.25" drives till I ran across one a couple weeks ago. It was in an IBM Establishment Controller that I sold on eBay last week.

--T

[Unknown_K]

I still have 10+ year old 360K DD floppies formatted to 800K that work fine. All you needed was a TSR utility to modify the bios on the target machine for it to work.

[DimensionDude]

Hi y'all, thanks for the replies. Here's more info on the Kodak drive:

Label on the disks reads
Verbatim -A Kodak Company-
2S/HD
Formatted Minidisk
17 Sectors/384 TPI
The only physical difference that I can see between these disks and a regular 5 1/4 is that the write-protect notch is at the "bottom" instead of the "side."

Label on the drive reads
KODAK 6.6 Flexible 5 1/4 Disk Drive
The spindle is belt driven, there are 2 servos for the head assembly. By watching it operate I assume one is coarse position, other is fine adjustment.
Half-height drive. The ribbon cable is very much like the data cable for an MFM hard drive, in fact, I think that's exactly what it is. Same conductor count.

The box (yep, got the box, too) reads
Verbatim
6.6MB internal subsystem
5.57MB of formatted data storage per diskette
blah, blah, blah
Designer for use with the IBM PC, IBM PC/XT, IBM PC/AT and compatibles

I don't have a website yet, perhaps in the near future. I haven't found any information on the web about this drive, either. Maybe I just didn't use the right keywords.

I was thinking that being able to low level format a diskette would be useful, but after being reminded of the high TPI count, I doubt that it could be done with a standard floppy diskette.

Kent

[Terry Yager]

I still have 10+ year old 360K DD floppies formatted to 800K that work fine. All you needed was a TSR utility to modify the bios on the target machine for it to work.

The Victor 9000, with double-sided drives, writes 1.2Mb on double-density media.

--T

[DimensionDude]

Hi y'all,

Ok, I've set up a website and put some pictures of the Verbatim Kodak 6.6MB floppy drive. Pardon the poor quality of the pix, my camera is a very good video camera with a lousy still picture capability.

Go to http://www.cox-internet.com/dimensiondude to see the pix.

[mbbrutman]

That was an excellent technical description of it.

If it is just 2S/HD media, I think a normal 1.2MB diskette should work. (That is what the HD refers to.)

Looking at the numbers, a normal 360KB diskette is 48 tracks per inch. A 1.2MB diskette uses double the number of tracks, for 96 tracks per inch. This thing uses 384 tracks per inch; do that math and that is 4 times the number of a normal HD disk.

If you just multiplied 1.2MB by 4 you would get 4.8MB. However, the 1.2MB format only uses 15 sectors per track. If you use 18 sectors per track you are up to 5.76MB which is in the ballpark of what the box says.

I'd definitely try to modify normal 1.2MB diskettes. Unlike substituting double density for high density, this should work out fine. You wouldn't actually be changing the media - just the location of the notch.

[DimensionDude]

mbbrutman,

Thanks for the praise, I try to get technical desriptions right. Although, when I said "standard 5 1/4 floppy" I did mean HD.

I tried long ago to use a standard HD disk but the format command included on the utility disk seems to be high level only. I don't have any way of doing the low level format required. However, I'm thinking now that with a later version of DOS (6.22) perhaps it will allow me to specify the parameters. That could be a worthwhile undertaking when I can get around to setting up a machine with that drive in it.

Kent

[mbbrutman]

I'm confused about the formatting problem.

Granted, no machine BIOS in it's right mind is going to know what kind of drive and controller you have connected. It's possible the controller has a BIOS extension like a hard disk would - you've have to go crawling around through memory to find it. Something like Norton Utilities 5.0 will report on BIOS extensions. If there is a BIOS extension, then it's possible there are utility routines in it.

Do you have all of the software that comes with it?

I think it's unlikely that there is a low level and a high level format like on a hard drive. If a low level format really is needed, then it has to be in the BIOS extension and in a device driver or utility program. But most floppy devices don't have separate high level and low level formats.

What is more likely is that there was a special device driver that told DOS how big this drive was.

If you don't have all of the software, experiment with the DOS DRIVER.SYS device driver. I don't have my DOS 3.3 reference handy, but DRIVER.SYS (or maybe DRIVEPRM?) lets you tell DOS the number of tracks & sectors for a device. With some experimentation you could figure out what works on this hardware.

And if you are in the Southern MN area, I'd be happy to look at it with you. This drive is truly an oddball and I wouldn't mind seeing it.

Mike

[mbbrutman]

Nevermind. Your hosed.

:-)

I just did a little Googling and it sounds like the media came from the factory with the low level format already applied, and the drive is not capable of doing it. Which is exactly what you said. The low level formatting is actually an optical system - these drives were 'floppoptical' which means optical for head positioning and magnetic for reading and writing. The diskettes might be the same magnetically has HD disks, but with the special servo tracks they are unique.

[DimensionDude]

Indeed, it sounds like I'll have to be happy with what disks I already have. The last time I checked with Verbatim they were discontinued. Hadn't thought about the floptical, never saw one in person that I know of.

Dug out the manual since I didn't remember how it was set up. There's a driver for it so dos knows what's out there.

Ah well, we gave it a good try. :D

Kent

[carlsson]

Funny. Already from the first message of this thread, I thought floptical, although I have never seen or used one.

The fact that you had to turn off the turbo on a 386 sounds a little like it would be very tight on timing. If so, it could be a reason why it was discontinued. Maybe it cost more to adapt the controller to newer hardware than the profit would cover. Is it dog-slow like a regular 5.25" HD too?

[DimensionDude]

It is slow compared to what's available today. Here are some specs listed in the user guide:

250kbs-used for reading and writing standard 40 track drives attached to the "standard drive" connector of the controller card.

300kbs-used for reading standard 40 track disks in the Kodak 6.6MB drive.

500kbs-used for reading and writing Kodak 6.6MB disks. Also used for reading IBM 1.6MB, 80 track disks in the Kodak drive.

Am I right in assuming that 1.6MB is the unformatted capacity of a 5 1/4 HD floppy?

At the time I was using this drive on a daily basis, I could install a multiple floppy game on one Kodak disk then play the game (mostly the King's Quest series) without having to swap disks. It was rather annoying to be engrossed in the game and get the "Please insert disk x" message.

Kent

[carlsson]

500 kbps is also the highest transfer rate for 1.44 MB 3.5" floppies, if I understand correctly. So basically it would be equal in speed to a fast HD floppy, only larger capacity.

In terms of installing software on these disks, would you encounter the same obstacles as if you install to hard disk? Can you partition the disk into smaller virtual floppies and somehow make the drive read from the next partition when a disk change occurs?

[patscc]

I ran into something like this before. On my gizmo, a low-level format was applied to media at factory, in essence laying down a servo-track. Sounds like you've got something right up that alley. This would mean you can't use a regular 5.25, since there's no pre-formatted servo track.

The 384 TPI figure makes me suspect you have servo-track media. I don't see those two steppers holding to track with out some sort of servo loop to stabalize the whole thing, kinda like what early 3.5 hard drives did, when they were still stepper based, before they switched to voice-coil actuators.

Most modern floppy controllers are at least, in theory, compatible to something that's called a Intel 82078, which uses a byte for end-of-track(EOT) which basically, means you cap out at 256 cylinders.
A 1.44 has 135 tpi, I think, so it just fits.

So a typical clone floppy controller wouldn't be able to access the upper tracks on your 6.6 floppy.

I wonder if the controller board for it actually has a HD controller chip on it, instead of a FD controller chip. Wild gadget. Treat that media with love, since you're probably the only one that has any.

Damn, now I want one too.

patscc

[barryp]

I ran into something like this before. On my gizmo, a low-level format was applied to media at factory, in essence laying down a servo-track.

I think that's what my Syquest drives do. The media can be high-level formatted but I've never seen anything that'll do a LL format on them. (Not that I've looked very hard)

[DimensionDude]

I've watched the "head servos" while a disk was being read, one of them zooms pretty good, the other makes very minute twitches. I agree, there is probably some type of servo track on the disk that I won't be able to replicate. I've googled my fingers to the bone and haven't come up with anything that relates to this setup at all. I may have to remove the cover so I can see the heads, perhaps that'll give me another clue as to how it works.

Too true, these 11 disks that I have are more than likely all I'll ever have. I suppose, though, that I'm gonna have to put the drive in a machine and see if it's still operational.

I got a pretty good scan of the controller card. I haven't really set up a website yet but I have put the picture on the server. It's at www.cox-internet.com/dimensiondude/controller.jpg
All you'll see is the controller, at least I hope you can see it. I can, just using my browser.

Incidentally, the User Guide is for a 3.3MB and 6.6MB drive. It shows 160 tracks for 3.3MB and 320 tracks for 6.6MB.

Well, shoot. Now I'm even more curious as to how this puppy works :)

[patscc]

Hell, that's one of the classic floppy controller chips, a upD765 The ur-FM/MFM controller. Perhaps some logic to externally extend the EOT size from a byte to 2 bytes, or something ?
This demands further snooping.

The minute twitching one would be the servo follower, the zoomer would be the one that jumps from cylinder to cylinder. Brilliant! I wonder how many of them were made ?

Those chips with the lables, they're PAL's of some sort, in essence custom logic chips. The 28-pin socket, smacks of an option EPROM that you can use to boot from the 6.6 drive. Geez, and I thought N* hard-sector disks were hard to find. Where did you pick it up, by the way ?

patscc

[DimensionDude]

I can confirm that the "twitcher" and the "zoomer" are exactly what you said (and what I had assumed). :)

Don't think I can get a good photo of the mechanism, I'll try to describe it. There's a sliding connection between the head seek drive screw and the seek servo like the drive shaft of a car. One end of the drive screw is captive in a lever. The tracking servo screw feeds through one end of the lever, the fulcrum is at the other end. The head seek drive screw is very close to the fulcrum. The whole upshot of the deal is that the head assembly can be moved a very tiny amount once it is at the correct cylinder.

Didn't see anything special about the heads, I'll look in a regular floppy drive for comparison. Each head (upper and lower) has a 4 conductor cable with shield.

The drive has 2 DIP switch packs, one for drive select, other has 4 switches labeled RDY, DCHG, 600, and SKCPT. ReaDY and DiskCHanGe I understand, the other 2, who knows? The User Guide has a picture and says (paraphrasing) "set the DIPs like this."

DIPs on the controller are for selecting I/O ports, I/O address, DMA, IRQ, and drive select of the Kodak drive.

I got this little gem in the early 1990s. A local BBS had Fidonet where there was a For Sale group that I read regularly. I bought it from an individual, don't remember who or where he was. It came with a few disks, I bought more directly from Verbatim soon after the drive arrived. The next time I tried to buy disks, they had been discontinued. If I dig around some, I may find the invoice for the disks :D

The User Guide never mentions the socket on the controller.

After looking at the controller more carefully, I see that the Kodak drive takes a standard floppy cable, 34 pin. Don't know where I got the idea that the cable was something special.

Kent

[DimensionDude]

Here I go, bringing back an old thread. :)

Last week I installed the Verbatim 6.6MB floppy drive in a 386SX-25 to see if the drive still worked and to find out if the data was readable on the disks. Everything worked fine. Ok, really, I have some old Sierra games (King's Quest, Leisure Suit Larry) on those floppies and I wanted to play them again.

I'm thinking that where I ran into a problem before (10 years ago!) was that I simply had the controller in the wrong mode for a 386. Anyhow, I copied the games to a hard drive for future play. It seemed to read the disks without error. I say this because it didn't make the horrible "ratcheting" sound that indicates that the head is "lost" and has to return to track 0. Heard that sound a lot many years ago when had it installed (improperly, apparently) in a 386SX-16. I get a reminder every time it's powered up, though.

Kent