On Wed, 27 Mar 1996 19:36:17 -0800 
 Jonathan Stone <jonathan@DSG.Stanford.EDU> wrote:

 > The miniroots were put together using the VND driver.  For
 > reasons I don't understand at _all_,  doing a newfs on a filesystem
 > under a VND driver, on a pmax, appears to reserve space for
 > bootblocks.  (this is, as far as I can tell, the source of the
 > "extra" 16 sectors that has confused many would-be installers.)

I think this is an FFS-ism, not a pmax or vmd-ism.  That 8k of "space" is 
to keep the filesystem from trashing, e.g. bootblocks and disklabels.  If 
it weren't there, you wouldn't be able to newfs the `c' partition on most 
ports.  (For example, the disklabel is offset 2 sectors from the 
beginning of the disk on the hp300).

 > *However*, and this is the point, I can't find any way to write
 > a bootblock (or disklabel) to those 16 sectors.  Is this deliberate
 > or a bug?  If it's deliberate, why are things set up that way?

What I would to is dd the disklabel and bootblocks to a file (in 
whichever order, and with proper spacing), have dd pad that out to 
512-bytes, then dd if=/dev/zero of=file skip=n where n the the number of 
blocks that the other pieces took up...the disklabel should have 
partition a at offset 0 ... then newfs the vnd, and it Should Work.

This would all be much easier if the vnd supported disklabels itself...I 
have a version that does, but I never committed it because it was 
buggy...I guess I'll bubble it up my TODO list...

Ciao.

--------------------------------------------------------------------------
Jason R. Thorpe                                       thorpej@nas.nasa.gov
NASA Ames Research Center                               Home: 408.866.1912
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