Mixed Filesystems

[Mike Raffety]

We have had a fair amount of success with a similar situation, taken a
step further.  Here's what we've got:

A Sun-3/260 pedestal, with a disk pedestal with two Fujitsu-M2333 drives
on a Xylogics 451.  There's a Sun-3 SunOS 3.5 root on xy0a, swap on xy0b,
/usr on xy0g, and another (local use) filesystem on xy0d.  Now, on xy1a,
there's a Sun-4 SunOS 4.0 root, with a vmunix set to use xy1a for root and
swap on xy0b (no point in having TWO swap partitions, especially at 50 MB
each, right?) and /usr on xy1g.

When we want to have a Sun-4, we just swap the CPU cards ... the EEPROM on
the Sun-4 is set to boot xy1a, instead of xy0a, so it's very simple and
foolproof.

We've been able to crossmount the filesystems from the different
architectures and different versions of SunOS pretty well, except if we
mount the Sun-4 SunOS 4.0 filesystem under the Sun-3 SunOS 3.5
architecture, attempting to delete a file panics the kernel (oops!).  It
certainly works on a read-only basis.

Also, the machine has 56 MB of main memory ... a standard 32 MB Clearpoint
card, and three Sun 8 MB cards.  If your CPU is a 1206 part, revision
level 10 or higher (look for the first number written with grease pencil
on the external serial number tag), you can plug in 32 MB cards, and get a
total of 128 MB main memory.  Configure the 32 MB cards like you would for
a Sun-4, and away you go.