Re: Applications using over 2 gigabytes of addressing

From: Harley (dennis.harleyNoSpam_at_worldnet.att.net)
Date: 11/27/03 

Date: Thu, 27 Nov 2003 14:08:25 GMT

"Michael Mattias" <michael.mattias@gte.net> wrote in message
news:JH2wb.5000$aw2.1494709@newssrv26.news.prodigy.com...
| "Harley" <dennis.harleyNoSpam@worldnet.att.net> wrote in message
| news:Tm2wb.315845$0v4.18414718@bgtnsc04-news.ops.worldnet.att.net...
| >
| > "Clark F. Morris, Jr." <cfmtech@istar.ca> wrote in message
| > news:3F94484C.5BFFD357@istar.ca...
| > | As a z/OS (IBM mainframe) COBOL programmer, I am trying to get a
handle
| > | on the uses for more than 2 gigabytes of addressability for an
| > | application. .....
| >
| > TABLES.
| >
| >
| > The current, production, system relies heavily on VSAM random access,
and
| > has very heavy I/O traffic, some EXCP counts go to 1,000K.
| > The Wall Clock Time is 1.5-2 hours, the CPU utilization is low compared
to
| > the wall.
| > This system is mission critical ,and the JOB completion time is
monitored
| by
| > upper management.
| >
| > I'm looking at replacing some of the random access processes with
| sequential
| > processing, and using internal tables.
| > My GUESS is that I can get the system to run in well under 30 minutes.
|
| Although I haven't done any mainframe work in about two years, I seem to
| recall one of the (then) 'fairly new things' I had wanted to check out
was
| the virtual I-O available thru JCL.

I haven't seen VIO used in this shop, (and it's been around for quite some
time, I wouldn't call it new).
Neither have I seen Hyperspace used.
I don't even know if Hyperspace is still available.

|
| Might using VIO be an alternative to supporting >2 Gb addressability? Or
an
| option to improve performance when I-O is the bottleneck?

VIO wouldn't really fit in to what I'm doing, unless I want to Open and
Close the files a couple of thousand times.

|
| (I'm more asking than suggesting).

There are alternatives that will speed up I/O, but they usually involve
PAPERWORK up the ying-yang.

As far as going over the 2 gig limit, I'm not even close yet, but in the
future it may be a method we all use. It depends on the Compiler Limits.
I can remember when we conserved storage, especially in CICS.
Now I don't think twice about allocating an internal table that is 8 or even
16 meg.