Mounting CDs as volumes?

[kouta-kun]

Hi all!
I'm looking for a way to mount Apple-extended ISOs or DMGs as volumes on Netatalk? I tried just mounting them and sharing the folders but the resource forks don't seem to be picked up (mounting ISO9660 with Apple extensions on Linux just ignores the resource forks, as expected).

[rdmark]

I assume this has to do with your maciso-extract program? it would be handy to know exactly what you tried so far, and how we can replicate your setup so that we can inspect exactly the resulting AppleDouble sidecar layout.

there is some discussion on this topic in this forum thread: https://68kmla.org/bb/threads/maciso-extract.52672/

[kouta-kun]

Hi @rdmark ! Actually I vibecoded maciso-extract as a workaround for this after I posted the discussion, but I would rather have some sort of built-in support for ISO/IMG/DMGs, as that approach has some caveats.
As far as what I've tried, my attempts were along the lines of downloading an ISO (either ISO9660 or HFS), mounting it (using Linux obviously) and configuring the mount path as a volume in Netatalk. This of course has the mentioned issue that both the ISO9660 and HFS drivers in Linux don't provide the resource forks and as such the volume is unusable from a real Mac with OS 9 (e.g. executables are not detected as such). I've of course tried both with ea = ad and with ea = sys, but I suspect this is not a viable path without improvements to said drivers.

The easy way to replicate it is to get an ISO, and do the following:

$ mount HereticII.iso /mnt/iso
$ cat >>/etc/afp.conf <<EOF
[HereticII]
path = /mnt/iso
volume name = Heretic II
ea = ad
EOF
$ systemctl restart netatalk

This, at least in my setup and with a variety of options tried (ea = sys, read only = yes, etc) never resulted in a volume that could be used correctly.

[rdmark]

could you point me to an ISO CD-ROM image with AppleDouble on the file system to test this with?

as has been called out elsewhere, Netatalk logic assumes that the file system is writable for metadata, which is why we automatically fall back to "None" when detecting a read-only volume

if you can file a feature request issue ticket here in GitLab we can look into adding a new branch for read-only mode that treats metadata as read-only as well, but it will require some coding

[kouta-kun]

@rdmark, that particularly is the issue. No CDs (at least of importance to OS 9 era users) shipped with specifically AppleDouble on the filesystem. Instead one of two approaches was used:

1. ISO9660 extensions for representing resource forks, as described in Technical Note FL36 by Apple
2. HFS(+) on the CD with a hybrid partition table that allowed Mac's to read the HFS partition and PCs to read a (generally empty) ISO9660 partition

So trying to mount an ISO and read AppleDouble off of it will not work. And (at least as far as I've found, outside my application maciso-extract) no system allows for mounting either of these two approaches in a way that results on AppleDouble representations of the resource forks.

[kouta-kun]

That said if you still want references for both filesystems, I'm not sure how good of an idea it is to add piracy links here but Heretic II off of Macintosh Garden is an example of an HFS filesystem while American McGee's Alice off of the same site is ISO9660 with extensions.