Difference between a mainframe and an OpenVMS server

[Wim Van den Wyngaert]

No problem to solve, just asking opinions (staffed by statistics if possible).

What is nowadays the difference between a mainframe and an OpenVMS server a la GS1280 or a Sun 15K ?

Are they more relieable ? More IO thruput ?

Wim

[Robert Gezelter]

Wim,

IMHO, for a long time, the terms mainframe, supermini, mini, and micro have lost all reasonable meaning and become sales/marketing buzzwords.

Realistically, if your organization bets its business on a system, you had better run it using the rules for a "mainframe". If you are a nuclear physicist running simulations, even a CRAY or other supercomputer is really a personal computer.

Since it is not uncommon for the processors in different scale systems today to be virtually identical, the discriminator is normally IO bandwidth. Thus a GS-class box might as well be a mainframe for most intents and purposes.

- Bob Gezelter, http://www.rlgsc.com

[Travis Craig]

Wim,

I looked into this question recently and I think the systems are pretty close now. The number of processors is similar. I assume the Alpha processors have fallen off the curve of "Moore's Law" now, and will be too slow pretty soon, but other processors continue to progress. The GS1280 has a mainframe-class number of processors and supports partitioning, multiple operating systems, and (quoted) mainframe-class I/O throughput. I don't know whether it measures MTBF in decades or supports thousands of instances of Linux running on one server, though.

I agree with Bob that a supercomputer is a different animal. It focuses on tasks that need lots of complex computation and run mostly in physical memory, while the mainframe's tasks tend to do simple computation on massive amounts of data, so I/O speed is more important than CPU speed.

--Travis Craig