Den 2026-05-27 kl. 14:00, skrev Jason Thorpe:
So, let’s focus on DEC STD 144, a.k.a. bad144, a.k.a. dkbad. It’s a 1970s-era
bad sector remapping scheme that was already mostly obsolete by the mid-80s
(ever since SCSI drives were able to maintain their own bad sector remapping
information). It is totally and completely useless on any drive made since the
1990s. And yet, its tendrils infest many a NetBSD port’s BSD disklabel
handling because, as far as I can tell, cargo-cultism.
I figure there are a handful of legit use cases for bad144 in NetBSD still:
- The vax port, obviously, but only with the really old drives. (VAX peeps
please help me out here - is bad144 useful drives behind an MSCP-compliant
controller?)
bad144 is not used by NetBSD/vax.
- MSCP drives have their own bad block replacement scheme.
- On RP drives there is a need for BAD144 in the disk driver, but I have
never written that support - no RP drives I have used have had any bad
blocks so I haven't cared :-)
I'm quite unsure if there will ever be a need for BAD144 on any VAX drives.
People using NetBSD/vax on RP07 with bad blocks are probably very close
to NIL :-)
-- R
