Mainframes vs clusters

[Jonathan Hutchins]

> ... but PCs are getting more sophisticated by the day. And
> Linux is being improved with the same kind of code that makes mainframe
OSes
> so reliable. Give it time, Linux WILL become as stable and powerful as any
> mainframe.

Still, whether you're talking about a single machine or a cluster, the IO
capability of PC architecture is very limited, and isn't likely to ever be
even close to what a "mainframe" can handle.  By definition, a PC is
primarily a desktop device, and when used as a server it's usually with
special storage and I/O hardware (from RAID to parallel high-speed
networking).

Given that we're supposedly weighing mainframes against commodity/desktop
PC's running Linux, I don't really see the PC/Linux system replacing a
system that has four rooms full of modem/terminal/network interconnectors
feeding under the floor to the host.

However, I think there's no question that some of those mainframe hosts are
going to be running some form of Unix.  Many already are, and there's the
virtual Linux server running on the mainframe as well.

Yeah, we're seeing a bunch of cluster applications taking over jobs that
were traditionally done by big, special purpose computers, but I can see a
distinct difference between the kinds of mainframe I'm familiar with and the
kind that's being replaced.  I think we're mostly going to see a mix of
Linux clusters and other types of large systems in really big corporate
systems.

I worked for one company that essentially had a cluster of 24 or so quad
390's - actually, more than one.  The starter motors on for the (three)
generators on the backup power supply were 300hp Allison V6 diesels.

Not sure if they're going with Linux clustering or not.

(Actually, I bet they already have Linux clusters in addition to the big
iron.)

(A note on relevance:  the extent to which Linux penetrates the corporate
market is relevant to our ability to use the knowledge we share through this
group in our professions as opposed to merely playing with it as a hobby.)