Well, these 4200's seem to be quite good, but let's look at
expansion potential, as we don't want to pull a "PC". If
the 4200 is expected to be a resonable public archietecture
with a future, which it seems to be, then we should use it,
but we should put more into infrastructure. The spec I have
seen of the goal board should imho havve eisa, at least
We've discussed this before :
1. The 4200 is available in a R4000PC compatable 179 pin PGA
package as well as a surface mount package.
If you go with the 179 pin PGA, you have an immediate,
plug-compatable upgrade path to the R4000PC (100Mhz,
8KI, 8KD), or R4400PC (100 or 150Mhz, 16KI, 16KD)
(Note : you have to also change the serially downloaded
boot information determining memory interface speed and
access patterns as well as the clock crystal)
2. There's nothing stopping you from making a daughter card with
the 179pin PGA connector on the bottom - AMD does this to
get their surface mount 386DX chips into normal 386 PGA
sockets, HP did it on some of their 68k workstations to
allow for either 68040 or 68030+68882 boxes, etc.
With a daughter card like this, you can use 4200 surface
mount chips, 4000/4400 MC/SC chips with the 128 bit
interface to second level cache, etc.
3. The IDT Orion should ship some time in a 179 pin PGA package.
In other words : there is no upgrade problem with a 4200.