Re: Couple more newbie questions.

[PaulMmn <PaulMmn@xxxxxxxxxxxxx>]

John--

I will defer to others concerning the reuse of system addresses.

As far as PFs and deleted records are concerned--  As you have noted, 
the space for a deleted record is merely flagged as 'deleted' at the 
system level.  Programs reading the file don't even know those 
records exist.

This space is reused when the PF is reorganized, or if the file is 
set to REUSEDLT(*YES).

Records flagged as deleted are also dropped by CPYF on the 
destination file.  These records can be included if you select 
COMPRESS(*NO)  (Compress out deleted records).

The deleted records can be recovered since the space is not 
physically deleted (as long as the file is not reorganized).

The hard way:

- SAVOBJ to a SAVF.  This saves the entire object, including deleted records..

- A SAVF can be read by an RPG program (record length 528 bytes).

- Read the SAVF records, and divide up the information retrieved into 
blocks the same length as the original file.  I don't recall if each 
record has any header information attached or not.

- Write the retrieved blocks to a copy of the original file.

- This can be interesting, because the length of the original records 
will not map into 528 except in -very- rare cases!  So you'll need to 
assemble the records to be written into a buffer, fed from either 
multiple SAVF records, or sub-segments of the 528 bytes.

The Easy way:

There are several commercial utilities that will let you read and 
re-activate deleted records.  We are using DBU.

--Paul E Musselman
PaulMmn@xxxxxxxxxxxxxxxxxxxx




At 1:44 PM -0600 1/2/09, McKown, John wrote (in part):
> 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.
>
> John McKown
>
> Systems Engineer IV