Re: Couple more newbie questions.

A PF can be defined more than one way.

One way is that when a record is no longer needed, to immediately make the
space available for more records. This way can impair performance, since
the system needs to search for an available hole in which to insert a new
record.

Another way is to leave the file "fragmented", with new records added to the
end. The second way makes for better performance, provided the file is
periodically reorganized, so that the physical sequence is consistent with
most logical way of accessing.

There's a 3rd party tool out there, which I am sure someone will tell you
how to get at it, permitting access to deleted records.

Also, a lot of software applications do not "really" delete records, they
just change some flag to indicate "inactive" record, or ready to delete.
Then you use the reorganization software that comes with the application, to
physically remove the deleted records. You can use system functions to view
what is in those records.

When you have files that fluctuate wildly in size, you need to be aware of
wasted disk space. Most files grab more disk space as needed, but unless
your reorganization is structured to take file size down to actual space
needed, you will have files that today have tiny volume records, but are
eating disk space equal to when they were at their largest.

I am now wrapping up on EOM PHYSICAL EOY COST-replacement.
I worked average of 10 hours, every frigging day Dec-26 thru Jan-3
and I have put the company on notice that next week I will be working short
days until I regain my stamina ... I am exhausted

so far our data is good ... our 2008 sales $ were approx 15% larger than
2007, although another question is customers paying bills ... one of our
biggest just went bankrupt due to the economy
The inventory $ value increased about 15%, but approx 10$ of inventory is
unused

On Fri, 2 Jan 2009 13:44:38 -0600, McKown, John wrote

Just to be sure that I understand about the "single level store".
When an object is created, it gets an address. The MI uses this address
(which I think of as a virtual storage address) to access the object.
When that object is destroyed, the address is never reused. From my
reading, the address still points to the destroyed object. The
storage for the contents of the object is released, but the "header"
now has something that says "this object is invalid". If the object
was a permanent object, that specific address is never reused unless
the entire system is dumped and restored. If the object was a temporary
object, the address might be reused after an IPL. True? This is what
I gathered from reading Dr. Soltis' books.

Also, in a PF, when a record is deleted, the space for that record is
not used for a new record. New records are always added at the end
of a physical file. Space can only be reclaimed when the PF is re-

organized.

Now for my question. Is there any way to read that deleted record? I
ask because there was an old access method on MVS called ISAM. It
did not delete records either. It simply marked the record as
deleted with an indicator in the record. But a person could use a
special option which would allow a program to read the deleted
record. So I was curious if it is possible to read a "deleted" record.

Hope everybody is having a good year, so far.

John McKown

Systems Engineer IV

IT

Administrative Services Group

HealthMarkets(r)

Administrative Services Group

9151 Boulevard 26 * N. Richland Hills * TX 76010

(817) 255-3225 phone * (817)-961-6183 cell

john.mckown@xxxxxxxxxxxxxxxxx * www.HealthMarkets.com

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