Re: Recovering Data

["Al Barsa/Barsa Consulting" <barsa@xxxxxxxxxxxxxxxxxxx>]

I did this many years ago, but that was then there was no USEOPTBLK or
COMPACT.  Then the record length was 32760 bytes, so I could process the
data in a program, and IBM publishes their compression algorithm.  IBM does
not publish their compaction algorithms (to my knowledge), and the default
of USEOPTBLK makes the record length 262144.

What I did was to take the tapes (then reel) to a 370 architecture system,
and overwrite the header with a utility product called DITTO.  Then I was
able to read the data files from the tape, and copy the data portion to a
PF from tape with CPYF and overrides, or CPYFRMTAP if it existed them.  I
don't remember.

Back them the largest file that I could read was 9999, so I created a
physical file with four records:

A    8000
B    8000
C    8000
D    8760

I then created unkeyed logicals of the PF with one field each.  For the
sake or argument, I called the appropriate files:

FILEA
FILEB
FILEC
FILED

I then processed them in RPG III as follows:

FILEA     IP
FILEB     IC
FILEC     IC
FILED     IC

This was a lot of work, and took many hundreds of hours to do, but
otherwise the client was going to go bankrupt.

You could do the same kind of thing today, but I am unsure of what
limitations you would run into.  ILE languages support files up to 32766
bytes, but as to the subtleties of COMPACT, you are on your own.

I apologize if my recollections are vague, but I did this work 16 years
ago.

Al

Al Barsa, Jr.
Barsa Consulting Group, LLC

400>390

914-251-1234
914-251-9406 fax

http://www.barsaconsulting.com
http://www.taatool.com






                    Chris Whisonant
                    <chris.whisonant@comp       To:     midrange-l@midrange.com
                    orium.com>                  cc:
                    Sent by:                    Subject:     Recovering Data
                    midrange-l-admin@midr
                    ange.com


                    04/02/02 07:41 AM
                    Please respond to
                    midrange-l






OK, I've never seen this done and I may just be really hopeful here, but is
there any way to "uninitialize" a tape or retreive the data. The 3590 tape
has been initialized with CLEAR(*NO). Is there ANY way to get back to the
data?

Here's hoping...
Chris

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