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Using a 3.5" DD drive in a Commodore PC10/20-III

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Scali

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Hi everyone.
I recently bought a Commodore PC20-III. I already have a Philips P3105, with 2 3.5" DD drives.
The Commodore only has a single 5.25" DD drive. Since none of my other PCs have a working 5.25" drive, transferring software is rather complicated.
So I tried moving one of the 3.5" drives from the P3105 to the PC20-III.
Sadly, I haven't had much luck.
Firstly, I had to create a power cable, since the PSU did not have any 3.5" style connectors. Then I had to find a ribbon cable with both 3.5" and 5.25" connectors, because the included cable only had two 5.25" connectors (and no twist to select drive A or B).
Then when I could finally hook up the 3.5" drive, it still didn't work.
I tested with the same cables on the Philips, and both drives worked there, so the cable and power should be good.
On the PC20-III the drive responds to commands, the motor starts spinning, and the led comes on, but other than that it fails.
I tried with "device = driver.sys /d:1 /f:2" in config.sys, but that didn't seem to work either.

So, does anyone have any ideas? I have seen some pictures of PC10/20-III PCs with 3.5" drives online, so I assume there is a way to make them work. But what does it take exactly? Do I need to set some jumper on the motherboard? Is my BIOS not compatible? Could it be a limitation of the onboard controller, so that I would need a multi-i/o card for it or such (perhaps the machines online have newer revisions of BIOS/motherboard)?

Any info would be welcome.
 
My PC10-II came with a Chinon fz-354 3 1/2 double density drive. This unit has some jumpers in the back to select different signal configurations and it is known for being used in Commodore Amiga computers.

I think these Commodore PCs need Amiga configured 3 1/2 drives to work.
 
The PC10-III that I have does not have a configurable BIOS so I don't know if any of the other 10/20 models would either. The PC10-III can use a 3.5" floppy drive but it is DSDD (720K) like nestor's. I was able to put a 720K Gotek drive in my system without any special configuration. You would probably need to use a floppy controller card to access drives larger than 720K.

Please let us know if you get it working.

Heather
 
Thanks for the info so far.
Someone also pointed out that Commodore has a few specific drive models for these computers:
PC 910 Single 3.5" 360K/720K, Internal for PC10/20-I-II-III.
PC 915 Single 3.5" 1.44M, internal for PC10/20-I,II,III, PC30-III EC
PC 920 Single 5.25" 360K/1.2M, Internal for PC10/20-I-II-III.

He said that the controller may not be a generic controller, so it's a bit picky on which drives it works with.
The drive I tested with is a 720K drive from a Philips P3105 from 1987, so it would be 'periodically correct', but it may not be the right type (or I may need to set some jumpers on it).
The theory that these drives may be Amiga drives is interesting. It's plausible. Commodore also used an Amiga bus mouse. There's a big MOS 5720 chip in there for that: http://www.amiga-stuff.com/hardware/5720-mio.html
And that contains a drive controller as well
I have a few Amigas around with working 3.5" drives, so I could see if that will work.
 
Well, I have tried with two Amiga drives... Same as with the drive from the Philips: the power seems okay, because the drive spins up when you insert a disk.
If you try to read from it however, the light comes on, but the drive does not spin up. I am not sure why the 5.25" works properly, while none of these do.

So well, I don't quite know what more I can do.
I guess I'll just have to stick to 5.25" for now... Which is a problem, since this is the only 5.25" drive I have atm. And I don't have any DOS boot floppies or anything.
In other news though... the HDD seems to have some life in it still. At first it wasn't even being detected by the machine. Now it gets detected, and it even tries to boot.
It doesn't get very far, but it manages to tell me that it has a problem reading config.sys and the command interpreter. So apparently it has read at least SOME data from the disk, to get that far (io.sys has been loaded I presume).

So perhaps I should put the HDD in my Philips instead. Then I can boot into DOS and run some tools on the disk. Perhaps it can be restored to a workable state.
 
Been experimenting a bit more...
The 5.25" DD drive is a Chinon FZ-502, which seems to be quite a peculiar drive as well.
I tried using it in one of my modern PCs, to no avail. It seems to have nonstandard signaling. Googling the drive also revealed that this drive was used in Amigas.
For some reason the drive does work fine in my Philips P3105. So currently I have made that a 3.5" and 5.25" configuration.
I should be able to prepare some HDD recovery tools, and perhaps I can get the PC20-III booting from its HDD again at some point (installing it in the Philips didn't work... it was not detected. Would probably need to low-level format it so that the HDD controller gets initialized. But well, if I need to do a full format of the drive anyway, I might as well do that from the PC20-III itself).

I have also found an old Conner 2MB floppy controller (originally came with a tapestreamer). Sadly it does not seem to be possible to disable the onboard floppy controller in the PC20-III, else the Conner would have been a solution perhaps. The Conner can be configured as a secondary controller though. So perhaps that would be a way to get more drives working in the Commodore.
For now I will concentrate on an IBM 5160 I just got. Also has a 5.25" DD drive. But it also has a working HDD. If I can get that machine set up with Laplink, it would be a good way to transfer software to 5.25" disks.

Plan B is to get an XT-IDE card and CF as a HDD for these old machines.
 
Okay, I have since obtained an IBM 5160 with working HDD. I have learnt from that machine that not being able to boot from a 3.5" floppy disk is not the same as the floppy drive not working.
Since that machine can boot from its HDD, I could get into DOS first, then test the drive. And indeed, although it couldn't boot, it could read and write floppies just fine.
So, it might well be that my PC20-III has the same issue: not able to boot, but the drive may have actually worked.

I have concentrated on the HDD for now though. It seems to have slowly come back to life. When I first got the system, it did not even detect the HDD. After a while, it started detecting it, and even tried to boot. But apparently the data was too corrupt, so it didn't get very far. It did mention a problem with config.sys and the command interpreter though, so I figured it had booted at least SOME of MS-DOS to get that far (the BIOS doesn't know about these files).
So, I have used the IBM 5160 with its HDD and 5.25" drive to create a boot floppy with format.com. At first I wanted to save the data off the HDD, but it seemed so corrupt that I just didn't get anywhere. So I decided to just blindly format it and see if it works at all.

And indeed. It seems that the HDD just got demagnetized over the years. Perhaps because it hasn't been used in ages, or just because it was exposed to a magnetic field or whatever.
The first time I formatted the disk, it took a long time, and it reported about 5 MB of the total 15 MB in bad sectors. But, it worked well enough to boot from now.
I figured I would format it again to see if it would get better. And indeed, the second time went much quicker, and it went down to about 500KB of bad sectors.
Tried it a few times more, and eventually it settled on about 40 KB of bad sectors. So almost as good as new now!
I also have Laplink/Fastlynx running on the machine now, so I can finally get serious with it :)

In other news, a Paradise 8-bit SVGA card is on its way from Ebay, so the machine will be almost the same as the PC10-III I used to have in the late 80s, yay!
 
Scali said:
The first time I formatted the disk, it took a long time, and it reported about 5 MB of the total 15 MB in bad sectors. But, it worked well enough to boot from now. I figured I would format it again to see if it would get better. And indeed, the second time went much quicker, and it went down to about 500KB of bad sectors. Tried it a few times more, and eventually it settled on about 40 KB of bad sectors. So almost as good as new now!
Click to expand...
Maybe :)

Sometimes MFM drives can look OK after a fresh format but then the sector decay sets in again. You'll need to keep an eye on it for a little while just to be sure. Running SpinRite wouldn't hurt, either. SpinRite will dig out and segregate the weak sectors so that there's less chance of actual further disk deterioration in the disk area currently in use. IMO, SpinRite is an MFM drive's best friend, even more now than when the program was introduced roughly 25 years ago when most MFM drives were still strong and healthy.
 
We'll have to see how it holds up then :)
Anyway, it's a WD93028-X drive, so it should be the stock IDE drive that comes in a PC20-III. So it should be from around 1988-1989.
 
Stone said:
Sometimes MFM drives can look OK after a fresh format but then the sector decay sets in again. You'll need to keep an eye on it for a little while just to be sure. Running SpinRite wouldn't hurt, either.
Click to expand...

Yes, I didn't have a copy of Spinrite handy, and the data on the drive was not mine anyway... It's still a bit bleh, so I think I'll try Spinrite on it anyway. Perhaps format was too kind on it. Mind you, even though there are hiccups, the software I put on that drive has worked fine.
 
Uhhhh, when I said SpinRite I was in MFM mode. :) I don't think it can do for an IDE drive what is does for an MFM drive. The version I use (SpinRite II v2.0) wouldn't even know what an IDE is, anyway. :)
 
Stone said:
Uhhhh, when I said SpinRite I was in MFM mode. :) I don't think it can do for an IDE drive what is does for an MFM drive. The version I use (SpinRite II v2.0) wouldn't even know what an IDE is, anyway. :)
Click to expand...


I use Spinrite 6 successfully on IDE drives from time to time. Where Spinrite 6 comes up short is on SATA drives. There's some verbage on the net about needing to put the SATA registers in IDE emulation mode whatever that is. My understanding is that an upgrade to handle SATA drives was in the works at one time but might now be "abandonware".
 
frustrated said:
I use Spinrite 6 successfully on IDE drives from time to time.
Click to expand...

Do these new versions of Spinrite still work on an 8088-machine? Since this is an XT-IDE drive, I can't connect the drive to a modern IDE system. I need to run the software on the PC20-III itself. It's the only machine that supports the drive.
 
Regardless of the version, SpinRite cannot reformat an IDE drive, for obvious reasons. It will, however, perform pattern testing, error scrubbing, defect management and data recovery.
 
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