With a small amount of trepidation (but inviting stomping from anybody wh o feels that I'm off-base here) can I remind folk that, on IBM mainframe
hardware, MIPS aren't the whole story. There's channels too - and in an I/O-related situation their power needs to be ADDED to the CPU power to come up with a realistic, "comparative MIPS" figure. It's a very long time since I saw anything that indicated how much MIPpag e is offloaded into the channels by a typical, "mainframe" workload but please remember that, unless you understand how channels are implemented when comparing two different solutions, you can quickly mislead yourself regarding the genuine value of the, "MIPS" comparison. (I have a similar problem regarding, "channel bandwidth" - each individua l channel on a mainframe might be, "slow" but potentially I can have severa l hundred running in parallel - in the right circumstances doesn't this giv e me greater capacity to work with than a single but much faster I/O portal ? Do I want a firehose or do I want the Mississippi? As a man to whom I would happily defer when it comes to performance issues has occasionally been heard to comment, I think, "It depends ...") Regards Jeff Gribbin (Speaking only for himself.)
