Errors Attempting To Write Stream Files

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Orkney
Posts: 13
Joined: Wed Oct 23, 2019 2:17 pm

Errors Attempting To Write Stream Files

Post by Orkney » Mon Oct 28, 2019 3:19 pm

Hello all, thanks for letting me post to the forum. I could use some advice on how to write using my Kryoflux device.

Several weeks ago, I had a limited time block to back up / archive some really (at least to me) interesting data, but I had no idea what the format was. These were disks from a 1980s music computer that used 5.25" drives, a PPG Waveterm A.

There are proper tools for working with these disks on the internet, but I knew that I could not set up a system with the proper floppy controller in the limited time window, so I copied them into files using Kryoflux using the "Preservation" settings, hoping that in the future I could set up a system to properly work with the disks, and write whatever I could out to blank floppies and give it a try.

I now have that system set up with the right kind of drive and controller, but when I try to write the files out to disk, I get

Code: Select all

The image is completely unformatted after analysis
message and the program exits without writing anything to disk. I now know these disks are:

77 tracks of 16 sectors of 256 bytes, double side, single density, 500kb/s data rate

Any thoughts on how I might get Kryoflux to try to write these things to disk? Below is a screen shot of the error, as well as a link to an archive of one disk's Kryoflux's stream files. The operating system is Windows XP.

Thanks for any suggestions

Bruce

Kryoflux Stream File Archive
https://www.dropbox.com/transfer/cap_pi ... co69PUSk7c

Error Screen Shot
Image

brightcaster
Posts: 219
Joined: Fri Nov 08, 2013 10:48 pm

Re: Errors Attempting To Write Stream Files

Post by brightcaster » Mon Oct 28, 2019 6:06 pm

Well it looks as if there is almost nothing but noise in the image! It also looks as if the drive the image has been recorded on had not a constant speed!

So the problem was not the writing but the reading...

I would recomend to test the drive with a known good floppy first. If that fails there must be something wrong with the drive. Other wise I would check if the disk is running smooth inside the jacket.

David

ZrX
Posts: 575
Joined: Tue Dec 06, 2011 9:09 pm

Re: Errors Attempting To Write Stream Files

Post by ZrX » Mon Oct 28, 2019 6:55 pm

From the noise I can see very faint sectors marked (the light radial markings, the dark wiggly lines I have no idea what are those).

The disk clearly spins ok with the drive used with KryoFlux. And what drive originally wrote the sectors was also spinning ok. But what has happened in between I have no idea of.
noise.png

Orkney
Posts: 13
Joined: Wed Oct 23, 2019 2:17 pm

Re: Errors Attempting To Write Stream Files

Post by Orkney » Mon Oct 28, 2019 7:33 pm

Wow, nice graphic!

Thanks for the insight. I used this same drive to read a known good DOS 1.2M floppy as a test, and it seemed to work ok. Any hope for these stream files, or are they complete junk?

That test disk, the process to create it.
  • On a really old PC (using an old FD controller), I created an image using a program named ppga.exe, which was created years ago to read / write these floppies. The tools do check their work as they go, it came across as a "good" disk. (77 tracks of 16 sectors of 256 bytes, double side, single density, 500kb/s data rate)
  • Took the disk our of that 5.25" drive, inserted it into the other computer (running dtc), and used the GUI to create a set of stream files.
  • Attempted to used DTC to write the same stream back to a blank disk, noting the error string, taking a screen shot.
  • Uploaded the stream files to Dropbox, went to this forum to beg for help.
For reference, the Waveterm A image that was used to write that disk can be found here: https://www.dropbox.com/transfer/cap_pi ... pBsn32UGQk . But be aware that attempting to write that image to disk using ppga.exe requires a floppy disk controller that can handle the format. I am using one from an Adaptec SCSI card which seems to be able to do just about anything.

Thanks again to forum members for looking into this. I appreciate the help.

Bruce

ZrX
Posts: 575
Joined: Tue Dec 06, 2011 9:09 pm

Re: Errors Attempting To Write Stream Files

Post by ZrX » Mon Oct 28, 2019 8:16 pm

I really have no idea why KryoFlux only gets noise from the disk if it was working earlier with the old PC setup.

Both sides of the disk show noise almost like on unformatted disk.

Orkney
Posts: 13
Joined: Wed Oct 23, 2019 2:17 pm

Re: Errors Attempting To Write Stream Files

Post by Orkney » Mon Oct 28, 2019 8:40 pm

Thanks ZrX, I deeply appreciate the opinion of someone who actually knows what "good" looks like using this tool. My brother used this same Kryoflux rig to rescue dozens of Amiga disks, what a great project putting these tools together!

Bruce

brightcaster
Posts: 219
Joined: Fri Nov 08, 2013 10:48 pm

Re: Errors Attempting To Write Stream Files

Post by brightcaster » Mon Oct 28, 2019 9:02 pm

Oh yes now I can see;-) I missinterpreted the dark lines as some kind of remaining sector gaps, but they are not actually!

But this nice picture leeds me to a weird idea:

Could it be that the disks was exposed to a strong magnetic mains field while spinning? Could either be 50Hz at 300rpm or 60Hz at 360rpm. Both would result in 20 zero crossings per rotation, which is ecactly the number of the dark lines...

I don't think that the dark lines are really on the disk (than the patterns of both disk sides should be exactly the same), but that some kind of mains hum was feed into the reading head. Maybe the disks flux reversals became so weak that the hum is stronger with this old disk in contrary to the much younger 1,2MB disk you tested okay.

I know this is really a crazy idea, but the calculation fits, right?

David




David

Orkney
Posts: 13
Joined: Wed Oct 23, 2019 2:17 pm

Re: Errors Attempting To Write Stream Files

Post by Orkney » Mon Oct 28, 2019 9:27 pm

Wow, interesting idea. The disk that was uploaded as the example was freshly made, and is in fact correct. I have dozens of other stream file sets that may be in questionable shape. But I wanted to try a read / write cycle with a "known good" disk before I started anything a long-shot as reconstituting those other disks.

If it helps, the PPG Waveterm A reads it just fine. So whatever funky stuff they are doing, it seems to be both consistent and usable.

Any further ideas on what I could try would be most welcome.

Anyone have insight why I get "The image is completely unformatted after analysis" once it reads in all of the stream files? I had thought from reading the docs and everything that I could find on these forms that dtc would just do its best to replay the stream files back to the write heads.

Thanks again everyone for helping me learn.

Bruce

brightcaster
Posts: 219
Joined: Fri Nov 08, 2013 10:48 pm

Re: Errors Attempting To Write Stream Files

Post by brightcaster » Mon Oct 28, 2019 10:00 pm

Did you place the drive directly in front of a crt monitor while reading the disk? I know that crt monitors became quiet rare during the last years, but if you have the waveterm on the desktop? I don't know what the framerate of the monitor in the waveterm is, but PAL used 50 Hz and NTSC 60 Hz for example.

I gues there is propper shielding between the floppy drives and the monitor in the waveterm, but if you place the kryflux drive in front of the crt without any shielding between it could be to much to theese old floppies...

Would be also interesting what your mains frequency is. It should be 60Hz as your drive probably runs with 360rpm (you said that you can read 1,2MB foppies with it). If you are living in an area with 50Hz mains we should quickly forget about my theory! (Except your drive runs with 300rpm of cause.)

David

Orkney
Posts: 13
Joined: Wed Oct 23, 2019 2:17 pm

Re: Errors Attempting To Write Stream Files

Post by Orkney » Mon Oct 28, 2019 10:43 pm

Thanks Brightcaster - The PPG Waveterm A is a self contained unit with main board, CRT and 2 5.25" drives. It's also like 35 years old.

The disk in question was written by an old AT class PC using a TEAC 5.25" floppy drive, which seems to read and write standard DOS floppies without problem, but could not write PPG Waveterm disks until I used a better controller that passed the testfdc.exe suite

Ref here: https://retrocmp.de/ctrl/testfdc/testfdc.htm
and here: http://www.classiccmp.org/dunfield/img/index.htm
with a big list here: https://services.theglitchworks.net/ng/testfdc_results

Which led me to switch to using an Adapter AHA-1542CF in this old AT PC. After making that switch, I was able to read and write Waveterm disks without error.

The disk image that was used to burn this floppy came from the PPG archive (its a .WTA extension), and was written successfully by the old PC using the TEAC drive.

The drive itself is in a standard mounting position within the PC case, and the PC is over 10 feet away from the Waveterm.

Would it help for me to make a few more streams and share them? Maybe it was just a bad read? Referring to the original post, I was unable to re-write that stream set back to disk as dtc rejects the attempt.

Let me know if there is anything I can do to help chase this to ground, and thank you (and all others) for helping out.

Oh yes, power here is 60Hz. I am using an old LCD panel on the AT PC that is writing the disks, so no CRT stuff to impart magnetic fields. Data rate to the floppy on write (from the AT pc using ppga.exe) was 500kb/s.

Bruce

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