Yes, I definitely agree.

But the discussion was centered (I think) on 3390-3 Shark vs 3390-9
Shark.

If you want better thruput, get ficon (100 MBs over Escon 17 MBs) on
the Shark

I'm on a DS6800 with Ficon2 adapters (200 MBs transfer).  About 90
seconds to do a CMS Format of a 3390-3.  It blows the Shark out of the
water.

Tom Duerbusch
THD Consulting

>>> [EMAIL PROTECTED] 10/18/05 2:09 PM >>>
Something that hasn't been mentioned in this thread is that SHARK dasd
is 
significantly faster than real 3390 spinning disks.  When we replaced
RAMAC 
dasd with SHARK, the clock time to do something was several times less

under the SHARK than the RAMAC.  I never replaced real 3390's with a
RAMAC, 
but I suspect that the RAMAC was faster and probably by quite a bit.

This is all in line with the observations that Lynn Wheeler makes and
has 
made about the lag in the increase in DASD speed vs. CPU speed, but the

SHARK is still extremely fast compared to a real 3390.  The fact of the

matter is that 3390-3 sizes have become the mainframe industry standard
but 
the only thing that is the same between SHARK and real 3390's is the
size 
and (perceived) disk architecture.  I'll bet that you could get more
I/O's 
per second out of a SHARK 3390-27 address than 9 3390-3 addresses.

Bill, how about an "it depends" explanation or clarification.

Jim

At 02:19 PM 10/18/2005, you wrote:
>There isn't much of a problem per say...
>
>If you have a mod-3, you can do xxx amount of I/Os per second before
>hitting a performance problem.
>
>If you have 3 mod-3, you can do 3*xxx amount of I/Os per second.
>
>However a mod-9 can only do about xxx amount of I/Os per second.

Jim Bohnsack
Cornell Univ.
(607) 255-1760

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