On 28.06.2013 15:56, Hunkeler, Peter (TLSG 4) wrote:
The application is opening a large number of input files with the C/C++
fopen convention as fopen("//DD:INPUT(member)","r") .
Is this read only data? if so, would it be an option to copy the PDS members
into a TFS file system (one of your own), say after an IPL and leave them there
for your application? TFS access is memory only and should be fast.
It is read only data.
I see that the TFS would increase the performance, as the application is
running by our customers, the goal would be
minimal or no change in the application , JCL etc etc .
The application can run, even currently, under USS, but till now I have
never seen a customer, convert an
application to run under USS , from batch JCL for performance reasons.
Never made any comparison, but I have the feeling
even the ZFS would out-perform the conventional MVS dataset access.
I just think about convert the original input PDS(E) file into a memory
files according this syntax.
You mean naming the files //DD:INPUT(member)? The //DD: is triggering
MVS OPEN in C/C++ instead of file system open. I suspect this will not work.
If I understand the book correctly, this kind of memory file open would
work, the memory file name is
DD:INPUT ... in this case
--
Peter Hunkeler
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