What is a N-way central processor?

[Shengli Zhang]

Hi all,
During the reading of IBM manual and share presentations,I have found that sereral articles mentioned N-way CP,what's the meaning of a N-way CP?What advantage can we get from it?
Does a parallel enterprise server like 9672-R15 contain a N-way CP?Do Amdahl 800 serials and 2000 serials global server have N-way central processors?

Victor

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[John McKown]

"N-way" simply means more than 1 physical CPU (symmetric multiprocessing
or SMP is another name). A 9672-R15 only has a single CPU, so it is not
"N-way". Well, it is, but the "N" is 1, so it's not usually called
"N-way". I don't know anything about those particular Amdahl systems, but
they most likely are "N-way" or multiprocessors.

What does it buy you? That's been discussed a lot. Which is better a
single really fast CPU or multiple small CPUs with the same aggregate
power. The answer, as always, is "it depends". If your main processing is
very CPU bound (i.e. one job which "soaks" the CPU), then a single big CPU
is better since that single program will run in less time. An example is
if you have a single, large, CICS region. CICS application code cannot
make use of more than one CPU at a time, so you want a really powerful one
so that response time is acceptable. However, if you are running multiple,
smaller, CICS systems, or a lot of TSO users, or a lot of non-CPU
intensive batch jobs, then I think that multiple CPU are better (others
disagree). The main reason that I think that multiples are better is
because a single job cannot hog the machine when there are multiple CPUs
(normally - a program which uses multitasking could possibly hog the
entire machine, but I'm talking the "usual" single tasking COBOL
application). Another niceity of multiple CPUs is because in the unlikely
case of a CPU failure, you have backup. This is not as likely now as in
the past, but is a comfort to me. Also, IIRC, the more modern systems have
"backup" CPUs which are not normally seen, but which can be activated by
the microcode in the case of a CPU failure.

Well, I hope this helps you some,

John

[Eric Bielefeld]

IBM seems to have rendered this whole argument moot with their z900 processors, which except for the MP3000, I assume will be the only thing you can buy from IBM once they are shipping in quantity. You pay for 1 thru 16 processors, and there are only really 2 models, the big 20 processor one, or the 10? processor one. You only pay for the number of processors you have turned on. Since Amdahl and Hitachi aren't going to make 64 bit processors, IBM's z900 are the only choice if you need 250 mips or more. Obviously you can have more processors than you need, but I doubt if many will want to pay for the extra processors.

Eric Bielefeld
Sr. MVS Systems Programmer
P&H Mining Equipment
Milwaukee, WI
414-671-7849
eb...@hii.com

>>> joa...@SWBELL.NET 11/14/00 02:58AM >>>

What does it buy you? That's been discussed a lot. Which is better a
single really fast CPU or multiple small CPUs with the same aggregate
power. The answer, as always, is "it depends". If your main processing is
very CPU bound (i.e. one job which "soaks" the CPU), then a single big CPU
is better since that single program will run in less time. An example is
if you have a single, large, CICS region. CICS application code cannot
make use of more than one CPU at a time, so you want a really powerful one
so that response time is acceptable. However, if you are running multiple,
smaller, CICS systems, or a lot of TSO users, or a lot of non-CPU
intensive batch jobs, then I think that multiple CPU are better (others
disagree). The main reason that I think that multiples are better is
because a single job cannot hog the machine when there are multiple CPUs
(normally - a program which uses multitasking could possibly hog the
entire machine, but I'm talking the "usual" single tasking COBOL
application). Another niceity of multiple CPUs is because in the unlikely
case of a CPU failure, you have backup. This is not as likely now as in
the past, but is a comfort to me. Also, IIRC, the more modern systems have
"backup" CPUs which are not normally seen, but which can be activated by
the microcode in the case of a CPU failure.

----------------------------------------------------------------------

[Bob Richards]

--- Eric Bielefeld <EB...@HII.COM> wrote:
> Obviously you can have more processors than you need, but I doubt if
> many will want to pay for the extra processors.

Eric,

It is 20 or "16" CPs.

With z/OS and the new "License Manager", you only pay for what you USE.
This, of course, only applies to CICS, IMS, DB2, MQSeries, etc. that
were announced to support the new feature.

What I am wondering....is how many ISVs are embracing this new pricing
methodology. Actually, one ISV in particular! <grin>

Bob

=====
Bob Richards, OS/390 Consultant Internet: richa...@yahoo.com

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[Andy Lankester]

Not sure to which ISV you are referring but BMC Software has certainly agreed to support it.

For more information please see http://www.bmc.com/corporate/nr2000/100500_1.html

Regards

Andy lankester
BMC SoftwareLtd