I often image disks with Kryoflux that I get from various collectors. The disks are mostly from the C64.
I usually convert the raw streams to G64 with mastering information (-i22a) that I can checkout the content with DirMaster/Style or Vice.
For quite a few G64 images I noticed that there appear issues in various programs. A typical issue in Vice is that the directory preview shows garbage while doing a LOAD"$",8 works fine.
Also DirMaster shows garbage for the directory on some disks and C64-Archive rejects G64s stating they are invalid.
I contacted the authors with some example G64 files. The question came up, if there is some documentation of the G64 with mastering information format available?
It also seems that most programs are tested against Peter Rittwages (C64 Preservation Project) G64 archive. But there seem to be no general G64 image test suite that includes images with certain pecularities to consider.
I would like to suggest to collect such images for a test suite. My hope is that this would help to improve the G64 support in the software.
I have attached three G64 images that are problematic.
- (317.02 KiB) Downloaded 66 times
- directory third disk
- third.png (3.62 KiB) Viewed 1429 times
- directory second disk
- second.png (3.63 KiB) Viewed 1429 times
- directory first disk
- first.png (2.6 KiB) Viewed 1429 times
So this is not G64 related! It happens on the original machine with the original disk! It was intended to behave this way I gues!
However if you take a step back and look at common tools:
Vice 3.3. r35896 (also in earlier Versions) Directory Preview and Dirmaster 3.1.1. for e.g. disk_0001.
And C64-Archive says it is an invalid G64 file on import.
So while the G64s work the applications have problem with them. That is also why I was proposing some kind of G64 image test suite.
So theese weird directories are designed that way and not faulty! Kernels like dolphindos and speedos ignore them (as a feature) while listing a directory. Since the disk samples you uploaded are not copyprotected you may re-read them as d64-images and expirience the same behavoir.
The fileviewer in vice emulates this correctly as its emulating the original look and feel!
So this is nothing to worry about. This is happening with the original disk and machine, as it was designed to behave this way!
C64 Preservation Project
Edit: The first obvious finding is that none of the attached G64 disk images are index aligned.