Re: History of disklables

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

On Wed, Dec 28, 2016 at 08:14:36PM +0100, Edgar Fu? wrote:
> > You must be misremembering something.
> Looks like it.
> 
> So disklables are a BSD thing, not a DEC thing?

Ultrix has a disklabel format, and I've moved drives from VAX to MIPS
Ultrix systems, so the answer really is "it depends".  I have also booted
Ultrix kernels on systems installed with plain 4.2BSD, however, and I didn't
lose access to my drives, so I assume (new-enough) Ultrix had both the DEC
disklabel support and the old compiled-in partitioning as a fallback.

For non-boot drives, you can use disktab, right?  In that case I can't
recall how the partition boundary information actually gets to the kernel.

Do our VAX disk drivers for Unibus/Massbus hardware retain the compiled
in partitioning as a fallback?  Without it, it'd be tough to even read
old Unix filesystems without modifying the disk contents (to write either
an Ultrix or 4.4BSD label into place).

-- 
 Thor Lancelot Simon	                                      tls%panix.com@localhost
	
			Ring the bells that still can ring.