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Re: Drives confirmed working with KryoFlux

Posted: Sat Jul 20, 2019 3:41 pm
by brightcaster
As far as I remember IBM inverted some control signals! So it's not done with a simple adapter or twisting some wires...

David

Re: Drives confirmed working with KryoFlux

Posted: Mon Jul 22, 2019 11:15 am
by brightcaster
Once again I have to correct myself! It's not a matter of inverted signals with the IBM PS2 drives but a change in position of pullup resistors. The PS2 floppy drives have some pullup resistors on board which are usually found on the controllers side. So they may work with some modification....

http://www.vcfed.org/forum/showthread.p ... post398805

In my opinion, it's better to sell a working PS2 drive than to use it with the kryoflux, as these drives are nowadays becoming very rare and much more expensive than a well-functioning standard floppy drive!


David

Re: Drives confirmed working with KryoFlux

Posted: Sun Aug 11, 2019 1:39 pm
by curtcool
Old IBM 5,25" drive - Type 0386-001 - Can it work?

A while ago I bought an old 5,25" drive for not too much money, aiming to try it on Kryoflux. It's supposed to be a standard 1.2mb drive but ... Since I haven't been able to locate it on the net anywhere, I can't be sure...

Now, I have been trying out for a bit but when calibrating, I get the message "control command rejected by the drive". The drive spins, but, as they say, no cigar.

Now, I see 4 possible reasons why:

a. The drive doesn't work with Kryoflux¨
b. The jumpers on the drive (I count 7) needs to be set correctly
c. Connection is somehow bad, I'm not expert on 5,25" drives and could have taken a wrong turn connecting the cable
d. It needs the "slow" firmware.bin mentioned in the Kryoflux manual, which can't be found in the archive.

So which is it? Any experts here who could be of help, it would be appreciated.

The 9 jumpers I can find are:
4 pairs of jumpers located near the data plug - named 0,1,2,3 - seems obvious to me that these are used to set the drive ID - I tried with both 0 and 1.

2 more pairs on board, related text seem to be 4, dc and 24

3 pins with text s2, tn, rd

2 pins with text 96, s3

2 pins with text s4, dh

Best regards
Frank / Copenhagen, Denmark

Re: Drives confirmed working with KryoFlux

Posted: Sun Aug 11, 2019 1:50 pm
by ZrX
curtcool wrote:
Sun Aug 11, 2019 1:39 pm
Old IBM 5,25" drive - Type 0386-001 - Can it work?

A while ago I bought an old 5,25" drive for not too much money, aiming to try it on Kryoflux. It's supposed to be a standard 1.2mb drive but ... Since I haven't been able to locate it on the net anywhere, I can't be sure...

Now, I have been trying out for a bit but when calibrating, I get the message "control command rejected by the drive". The drive spins, but, as they say, no cigar.
Try with the drive without power to move the heads towards the spindle, then power on the drive and see if it auto-resets the heads back to track 0. If not try the calibration and it should move the heads to track 0 before doing calibration.

If the heads don't move to track 0 there's something wrong with the drive electronics. If they do it could be the jumpers, or something else.

Re: Drives confirmed working with KryoFlux

Posted: Sun Aug 11, 2019 2:48 pm
by SomeGuy
It sounds like IBM just slapped their own label on the drive. Post some pictures of it an perhaps someone can ID the actual model.

If this was not intended for a PC/AT or compatible then the jumpers very well might need to be changed.

Re: Drives confirmed working with KryoFlux

Posted: Mon Aug 12, 2019 2:46 pm
by curtcool
ZrX: I will try this.

In the mean time, here are some photos of the drive, should anyone be clever enough to ID it :).

Re: Drives confirmed working with KryoFlux

Posted: Mon Aug 12, 2019 2:48 pm
by curtcool
And one more:

Re: Drives confirmed working with KryoFlux

Posted: Mon Aug 12, 2019 7:56 pm
by SomeGuy
Yea, that's what I thought. Goofy mainframe/mini stuff.

The actual IBM part number on that label is 1685550.

Searching turns up: 1685550 · OEM IBM 5364 FLOPPY DRIVE

and pulling up IBM 5364:

http://www.ricomputermuseum.org/Home/eq ... 364-s36-pc

"The IBM model 5364 was called the "System/36 PC" or "Desktop 36" (and also, informally, the "Baby/36" by some - but this name was later attached to a software program produced by California Software Products, Inc.). The 5364 was a June 1985 attempt by IBM to implement a System/36 on PC-sized hardware. Inside, there were IBM chips, but the cabinet size was reminiscent of an IBM PC-AT of the period. The machine had a 1.2 MB 5.25-inch diskette drive, which was incompatible with PCs and with other S/36s. The control panel/system console (connected via an expansion card) was an IBM PC with at least 256KB RAM."

Which tells us this drive is not IBM PC compatible, but does not say what the difference is, who actually manufactured it, or if it can be made IBM PC compatible. (It might involve more than just jumpers)

I'd suggest creating a new thread about this topic either here or on the vcfed.org vintage computing forum. It's likely some IBMer on the vintage computing forum would have more information.

Re: Drives confirmed working with KryoFlux

Posted: Tue Aug 13, 2019 10:48 am
by curtcool
SomeGuy: Major thanks for your help. If nothing else, this will teach me to buy one of the drives already known to be compatible when available here in DK (it happens) - I didn't pay much for this one, and can possibly resell it. But can't help wondering how this ended up here, though ;). I shall try to find more information, but I reckon you are right that more than just changing jumpers is required to make it work with either Kryoflux or a normal (old) PC.

Re: Drives confirmed working with KryoFlux

Posted: Tue Aug 13, 2019 6:49 pm
by SomeGuy
Well, the #1 thing when buying a floppy drive is to know what the model and revision is, and make sure technical documentation is available for that model/revision.

Even a "compatible" drive can appear incompatible or broken if it was jumpered for a non-PC system.

In theory the Kryoflux should work with any "Shugart" style interface, but there can be some odd variations one might not expect. For example, 100tpi drives, drives that spin at different RPM speeds, drives that take power through the card edge connector (poof!), I've read about some double sided 8" drives that can emulate dual single sided units, the large System/36 apparently has some funky auto-loading 8" system.

And even then, there are smaller issues that the drive designers never thought of that affect Kryoflux users such as filtering of GCR signals and different bitrates, amount of write "noise" created when switching off write or splicing, access to extra tracks, or the ability to flippy mod. Honestly, the drives listed in this thread are a little vague about some of these.

Now that you know what the drive is from, who knows, you might even get lucky and sell it for more. Half the battle of selling something is knowing what you have.