Status of support for 4KB disk sectors

Gary Palmer gpalmer at
Mon Jul 25 13:24:12 UTC 2011

On Tue, Jul 19, 2011 at 08:48:54PM -0700, Chuck Swiger wrote:
> On Jul 19, 2011, at 8:14 PM, Jeremy Chadwick wrote:
> > On Wed, Jul 20, 2011 at 02:39:28AM -0700, perryh at wrote:
> >> IIRC, Plextor (and maybe some others) had a switch to select 512 or
> >> 2048 as the default transfer size, precisely so that they could be
> >> used as boot devices with systems that supported only 512.
> Come to think of it, I do remember that switch, yes.
> Do you happen to know whether this limitation was part of the Sun hardware,
> or of SunOS?  CMU had a lot of Sun3 machines and NeXT clusters, so I ended
> up mixing NeXT CD-ROM and the Canon? magneto-optical drives with Sun H/W,
> and vice versa.

My memory is a bit fuzzy but I beleive it is at least partly because they
used ufs on the CDs rather than ISO 9660 based filesystems so they could
boot from the CD and have the device nodes there as well as all the other
features a ufs filesystem supports but ISO 9660 doesn't.


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