> It hasn't been tested on one and I do not have access to such a system.

there's the power bill to consider ;) i've abandoned more than a couple of
these systems for just that reason.

> 4d/30 and 4d/35 are both IP12, although 4d/30 is also known as IP14.
> They may also be known as VIP12. V for VME, perhaps.

4D/30 and 4D/35 differ only by clock speed (30MHz, 36MHz respectively).
i believe the indigo chipset is the 4D/3x respun onto a set of ASICs, so
the design "should" be logically similar, though the 4D/3x have a 6U VME
expansion slot and the indigoR3K uses GIO-32.

the VIP12 is the 4D/30 implemented as a 6U VME card that can be embedded
into custom target systems. i have only seen pictures.

IRIX 5.3 was supported on "all" systems of its day; 6.2 was the first "all
>=R4K" (including IP17/IP17B) release, and 6.5 requires an IP19 or higher.
IRIX 5.3XFS requires an IP12 or higher because older systems didn't have
powerful enough SCSI controllers.