Greg, thanks for for your explanations. Something of your comments I
have found out myself last day.
It's not so easy for a beginner. On UNIX it's more simple, to get the
Offset in a file. I shall read the offset of the beginning and end of
Document X in a printfile. There are millions of documents in
printfiles.
On HOST there is some trouble, because it's common to use
concatination. Normally we put this printfile in a big sort (for
example DFSORT, SYNCSORT e.t.c.) and hope the best.
There is some hope that's faster to position to the right document, if
have read the position in a first read and put this
position,(TTR,Offset) in a smaller data set, and then use this
information to jump to the right position in data set X. The next
document is perhaps in another file and so on. I think, this will only
work in some cases. In most case the sort will be faster.
The crux is, our product works on other plattforms, and there we need
a programm which can read the offset. Sort is on other plattforms not
so fast as on HOST. The Modul must have the same functions and
interfaces as on HOST, only it is written in C. On UNIX is no
concatination and FSEEK is what we need. It's easy.
Now, the problem. Excp seems to be adequate to get all information of
the records on HOST.
IBM says: If I use EXCP and switch to another volume, i can use EOV.
To return to a previous volume I must close an reopen the data set.
This is slow.
I have tried to use BDAM with EXCP. BDAM does not support
concatination. I need one BDAM DCB for each DD. So, I search for
another Macro and found RDJFCB. IBM gives an example for doing this on
one volume. If I use EXCP with BDAM the position is TTTR, not TTR,
that's a little difference.
BDAM gives access to all volumes at the same time, and there is no
need of EOV. The position on a volume is MBBCCHHR, M is the extension.
I have try to use EXCP with concatinated data sets. It doesn't work.
My DCB in my last message was not BDAM. Only for information.
Is extension equal volume? I think not. The HH is what TT is meaning,
I think. All this information is only the information of one volume, I
think.
All I need, is the the right position of document X in data set Y
without closing and reopening it in this task.
My try was open all files in the beginning and switch from one to
another in arbitrary order. In my first reading there is no need to
open all files. In the second run, when I write the output files I
need all files to be open. Close and reopen is to slow.
The Unlike Bit, I don't understand what does that buy me?
regards
J?rg
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