On Thu, 20 May 2021, Christian Groessler via cctalk wrote:
IIRC I had burned the Ultrix CD "normally"
(means without fiddling with block
size, so not 512), but changed the block size to 512 for booting it. IIRC #2,
burning was done on another drive, not the Plextor.
CD-ROM medium format has been standardised and what I guess the 512-byte
sector size jumper only does is logical translation of sector addressing
to fulfil weird OS requirements. So that will not affect burning (unless
you burn on a weird OS, which I guess does not support it anyway).
ISTR upstreaming some fixes to Linux UFS support 20+ years ago to address
this very problem (IIRC OSF/1 or Digital Unix CD-ROMs were also UFS, and I
had a need to access them under Linux for some reason) and with them in
place I thought the loop device hack was not needed anymore.
Perhaps my memory tricks me or something has since regressed though, e.g.
due to changes in the block layer, so I'll try to remember to see what's
happened here when I get to my Ultrix CDs when I'm in my remote lab next
time. It's not a feature that's used on a regular basis after all, so any
regression can be long-lived.