[comp.arch] RISC vs mainframe

reiter@endor.harvard.edu (Ehud Reiter) (10/27/88)

In article <468@oracle.UUCP> csimmons@oracle.UUCP (Charles Simmons) writes:
>John Mashey brings up a point that I've never had a satisfactory
>answer to.  If we assume that RISC-based manufacturers can build
>machines that outperform mainframes, where will companies like Amdahl
>make their money?

[Chuck points out that mainframes have lots of fast memory, lots of
I/O bandwidth, and lots of reliability/servicability features, and that
incoporating these into any machine would make it expensive, even if
the basic MIPS were cheap]

To this, I would add that most mainframe applications require $$$$ of
peripherals (10's of GB of disk, 1000's of terminals, etc) and software,
and even more $$$$ in support staff (10's of people, each at $100K/yr
including overhead).

The point, then, is that MIP's are one of the cheapest components of a
mainframe computer system *in any case* (even before RISC).  Replacing
a $1,000,000 IBM with a $10,000 RISC box won't help much if you still need
$4,000,000 of memory, peripherals, and software; and have an operations
staff budget of $1,000,000/yr to boot!

As long as MIPS remain an insignificant portion of total SYSTEM cost,
mainframe users will have no incentive to abandon their current machines
and switch to RISC.

					Ehud Reiter
					reiter@harvard	(ARPA,BITNET,UUCP)
					reiter@harvard.harvard.EDU  (new ARPA)