smj wrote: Referring to what makes it an "a" versus an "au" - didn't the "au" models always have SCSI, whereas some "a" models were only shipped with IDE?
No, `a' models shipped with SCSI, as opposed to `no suffix' models.
R4000
R4000
R4000
R4400
R4400
R8000
R10000
R4000PC
R4000SC
R4600
R5000SC
R5000
RM7000
2xR10000
R12000
2xR12000
-
2x2xR10000
R16000
4xR16000
among more than 150 machines : Apollo, Data General, Digital, HP, IBM, MIPS before SGI , Motorola, NeXT, SGI, Solbourne, Sun...