[rescue] looking for SGI Indigo 2 system

[Scott Quinn]

The Indy stored the MAC/serial number (on SGI they're the same thing) in the
NVRAM. The Indigo2 stores it in a small PROM chip that is mounted on the riser
board that also holds the keyboard/mouse/serial/AUI ports. The good news is
that it is the same part for all Indigo2s, so you can replace the mainboard
with an IP22, 26 (not recommended, R8k is touchy), or IP28 R10k and still have
the serial number stay the same.

Further info might be good - if the original machine is an R10k then a R4k
replacement may not work (R10k is MIPS-4 and supports 64-bit binaries under
IRIX, whereas IP22/R4k is MIPS-3 and while the processor is 64-bit the kernel
installed only runs -o32 and -n32 binaries. If the software is old and built
under IRIX 4 you'll need R4k, though, as R10k only runs IRIX 6.2 and later
which do not have support for ECOFF binaries.)