CBM Flux Studio: Vorpal track alignment

In the video below I show how CBM Flux Studio can be used to realign tracks in a Vorpal disk image in order to allow users to write it back safely to a physical disk, in a way that matches what the mastering tool did back in the 80s.

In fact, the point in each track from where users can safely start writing it to disk is crucial for the success of the write operation. For example, starting the write in the middle of contiguous data is recipe for disaster.

This is probably something that Mr. Laufwerk is likely to comment on 😀

Here’s the whole workflow we used successfully with SLC to write Vorpal disk images to floppy disks:

  1. KryoFlux was used to sample the original California Games disk to raw stream files
  2. DTC was used to convert raw stream files to G64 and confirm there were no data errors
  3. CBM Flux studio was used to read the G64, correct the write splice for track 27 (DTC got it wrong), validate data, and confirm no data errors existed
  4. CBM Flux Studio was used to save the results to a new G64
  5. the new G64 was written to disk with KryoFlux
  6. the written disk was sampled again with KryoFlux to raw stream files
  7. DTC was used to convert raw stream files to G64 and confirm there were no data errors
  8. CBM Flux studio was used to read the G64, validate data, and confirm no data errors existed
  9. we repeated 5-8 multiple times on different disks and each disk loaded successfully on a C64

The catch here is that in all cases we worked with the extended G64 format defined by the SPS team (created by DTC itself when converting raw stream files to G64), which includes write splices (the exact point in each track from where to start writing the track back to a physical disk).
If you try to write a standard G64 for a Vorpal title to a floppy disk with KryoFlux, DTC will probably just write data assuming it is from index to index, which is recipe for disaster, unless the G64 is correctly realigned.

G64 files created from NIB files with nibconv are not adequately realigned when working with Vorpal: They might work in emulators and Ultimate 64, but not when written to a physical disk.

What one should be using to write back to a floppy disk, in absence of more sophisticated options, is either:

  • a G64 with extended info, *correct* write splices for all tracks, and verified data integrity, or
  • a standard G64 realigned by CBM Flux Studio (instead of nibconv) with verified data integrity.

Stay tuned for more.

About Luigi Di Fraia

I am a Senior DevOps Engineer so I get to work with the latest technologies and open-source software. However, in my private time I enjoy retro-computing.
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3 Responses to CBM Flux Studio: Vorpal track alignment

  1. Daryl Bidewell says:

    This is incredible, when shall this be available? I really want to test, I’ve tried slowing the drive and a whole host of other things but cannot get Vorpal to remaster via Zoomfloppy Nibtools and Kyroflux DTC.

    • Hard to tell as I am busy upskilling in my new job still. Vorpal disks can be saved without slowing the drive.

      I don’t know your specific case, but two conditions have to be met if you want to successfully write disk images back to disk:
      – write splices need to be selected properly (most of the time, when creating a G64 from raw streams, DTC does a good job estimating them, but it is known to have issues at times)
      – the data in all sectors needs to be validated

      CBM Flux Studio does both things. Example for the latter: https://youtu.be/2RhU0S2y4x4?t=196

      • Daryl Bidewell says:

        Hi Luigi, many thanks for reply very much appreciated. I have tried to write california games from a nib converted to a g64 from the c64 preservation project using DTC and Nibtools, I’ve a few variations of this game (NTSC, NTSC Patched and a PAL) all load fine via my Ultimate II from file direct, but when mastered and in the case of DTC without any i22a mastering information I am lost!.
        I own 64,64C,128 and 1541,1541ii,1570 and most importantly a 1571, all are perfectly aligned and clean.

        In anticipation of CBM Flux Studio, do you have any guidance on write splice function in DTC?

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