On Sat, Apr 07, 2001 at 12:00:56PM +0930, Greg Lehey wrote:
> IBM has recently renamed all their product lines to "xSeries", for
> some value of x.  I'm not sure what the 390 is; I thought I heard

The S/390 machines are still S/390 machines. The new machines are the
64-bit systems, and those are the z/Architecture. The older systems
are still around (ie, the P/390, the Multiprise machines, etc). 

IBM likes to use four-digit numbers with another code suffixed
with a dash, and mainframes are no exception. For example, we have
a Multiprise 3000 at work and it identifies itself as a 7090-H70
(but I'm not sure about the 90 part, it might be 7050 or something
else). I'm sure we don't have the -H30 or -H50 models.

Oh, the P/390 is the box used by many smaller vendors because it sits
on a PCI or MCA (don't recall) in an IBM PC of some fashion. OS/2 runs
on the PC side to interface with the "mainframe" side, giving you a
mainframe on your desk (or rack) at a lowish price. I think one
FreeBSD guy has a P/390 that he runs his business on.

Now, the z/900 boxes are 64-bit and have "Freeway" processors. IBM
has 20 Freeway CPUs on one multi-chip module, but "normally" only
16 are used at a time (the others are for I/O or spares). Failover to
spares happens without OS intervention. Base price for a z/900 box
is .75 to 1 million USD or so. Also you must have 60+ amps at either
220 or 440 volts (details on IBM's site). 

That's a pretty serious machine. Oh, and then there is the sysplex,
which is pretty cool .... did I mention that the Olympics web site
had a number of RS/6000 boxes running databases and the front end
was only 3 mainframes (in a sysplex)?

Mainframes are a different kind of "cool". 
-- 
Kevin P. Neal                                http://www.pobox.com/~kpn/

"It sounded pretty good, but it's hard to tell how it will work out
in practice." -- Dennis Ritchie, ~1977, "Summary of a DEC 32-bit machine"