Re: bad144 - how useful still? Because it's annoyingly ubiquitous.

[Thor Lancelot Simon <tls%panix.com@localhost>]

On Sun, May 31, 2026 at 11:07:13AM -0400, Jason Thorpe wrote:
> 
> > On May 31, 2026, at 10:21???AM, Thor Lancelot Simon <tls%panix.com@localhost> wrote:
> > 
> > Means moving a drive physically from a DEC system to a Sun VME system
> > would have lost the bad block table, right?  I remember seeing exactly
> > that done a few times with CDC drives that went from VAXen with Emulex
> > controllers to Sun replacements which I expect had Xylogics controllers.
> > I guess to do this safely must have required a low-level reformat by
> > something that wrote the bad144 data in the expected byte order.
> 
> Thinking about this a little more..
> 
> ???Of course.???
> 
> Because it???s not like UFS could handle either byte-order back then, either.

Yeah, I was thinking about that.  But having to create new filesystems is a
little different from having to do a full format in ignorance of which blocks
were already marked as bad.

In one of the two instances I remember personally, I believe the controller
on the VAX was emulating an MSCP controller and thus would have had to
internally manage bad blocks anyhow.  I was pretty sure the other one was
Massbus but I don't know what the controller was (I'm assuming some kind
of Emulex, I don't think I ever saw any other generic SMD controller in a
VAX) nor how it worked.

-- 
Thor Lancelot Simon	                                     tls%panix.com@localhost
  "The liberties...lose much of their value whenever those who have greater
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