Any memory requirements formula would have to be based on: applications
type/mix,
processor speeds, and number of active processes. IMHO, the formula below
doesn't seem to take any of these into consideration. For example, today
with VT sessions, the average 'user' may be logged on 2 or 3 times. Using '5
Mb per user' translated as sessions would be grossly out of line. Also, many
systems have several 'daemon' type of batch jobs that aren't very active.
These obviously wouldn't require 20 Mb.

I have seen many cases were additional memory will speed up read only batch
processes to the detriment of interactive response times. So one has to
question claims like %50 faster and ask for more specifics based on the type
of performance problem at hand.

A primary concern in adding memory to a multi processor system is the memory
interleave configuration. IMHO, the amount of memory added is a secondary to
the number of interleaves created.

I have a longer list of 6.5 notes. I any one would like a copy please email
me directly.
Also,if any one would like specific assistance feel free to call or email me
directly.
Cordially,

Mike Hornsby
Co-founder/Chief Technical Officer
Beechglen.com
513-922-0509
[log in to unmask]




----- Original Message -----
From: "Bill Lancaster" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Wednesday, March 22, 2000 7:58 PM
Subject: Re: MPE/iX 6.5 memory requirements


> Hi,
>
> The 1gb per processor is dead wrong.  The "right" answer for how much
> memory you should buy is "how much can you afford".  There is currently
> almost no point of diminishing returns on memory (except for some very
> unusual edge cases), although this may change with 6.5 as more memory
> becomes available (up to 16gb).
>
> Many times people have used convoluted rules-of-thumb to answer this
> question.  Largely these are a waste of time, especially since memory is
so
> cheap (ain't competition a wonderful thing???).
>
> Bottom line is buy as much as you can afford and don't spend a lot of time
> trying to justify it, if you can help it.
>
> BTW, additional memory often helps online transaction performance but very
> often dramatically improves read-oriented serial batch performance .
>
> HTH,
>
> Bill Lancaster
> Lancaster Consulting
>
> At 03:32 PM 3/22/00, Sletten Kenneth W KPWA wrote:
> >After Mark asked:
> >
> > > Is it at all possible we're talking 4GB of *LDEV1* here,
> > > instead of 4GB of RAM?
> >
> >Chuck replied with:
> >
> > > Nope, the formula is for RAM.
> > >
> > > OS and network processes - 128 mb
> > > 5 mb per user
> > > 20 mb per batch job limit
> > > ratio of 1% memory to total disk
> > > 1 gb memory per processor
> >
> >The first four sound O.K., but the "1 gb memory per processor"
> >has to be wrong....  I *know* you can run a 9X9 multi-processor
> >box with no problem with a lot less than that....
> >
> > > And adds that a minimum for 6.5 is 4gb
> >
> >I'm still with Mark:  I think that 4GB is for LDEV 1 disc...
> >
> >:-) ,
> >Ken Sletten