On Thu, August 15 1996, "Allen Briggs" wrote to "Henry B. Hotz, davagatw@mars.utm.edu, port-mac68k@NetBSD.ORG" saying:

> > I would love to be able to re-use my MacOS Swap partition (which is full of
> > a single VM file) as a BSD swap partition.
> 
> This would be cool, and might be theoretically possible if that file is
> one unbroken range of blocks.  The challenge is then describing that
> swap space to the kernel.  Currently, the kernel expects swap to take
> up an entire device...  Hmmm...  I think that gives us a couple of
> options...

Alternately, I know that on the PC side of things (at least under Linux),
some people worked out some scheme (a fairly gross hack, but hey) to dd off
and gzip to a file the beginning of a Windows swap partition, swap directly
to the partition, and then on shutdown (after swapoff) restore the contents
of the file.  Is this possible on MacBSD?  How much of a partition would you
need to retain to keep all the HFS data structures intact?  (Do they even
all live at the beginning of the partition?)

A scheme like this, if it can be made to work, has of course the great
advantage of not needing kernel support -- it should, I think, be doable
entirely in userspace, provided there's some good way to figure out which of
your BSD partitions holds the HFS filesystem in question.

-- 
Jonathan Lennox
lennox@cs.columbia.edu