I have a multi-volume MVS data set A.B.C with parameters PO=PS and RECFM=FS. The code below runs slowly (Java is used for illustration, in C it will be fseeko call) :
ZFile zfile = new ZFile('//'A.B.C'', 'rb,type=record');
file.seek(1000,0);
file.seek(2000,0);
file.seek(4000,0);
Run time for each seek: 1-2 seconds.
However, the same code runs fast for a single volume data set. Run time for each seek: 5-10 milliseconds.
I need Java code that performs fast (comparable to single volume) direct access to a multivolume data.
Acceptable solutions:
Implementation of a Java method, C, or assembler function that efficiently positions (in milliseconds) file pointer to a given record in both multivolume and single volume data set.
For clarity, Java prototype is:
void fastseek (ZFIle file, long recordNumber);
Note: C/Assembler solution should work in 64-bit architecture.
Note: Expected file size up to 20 Gb,
About the recuiterMember since Sep 7, 2017 Ron Icart
from Pennsylvania, United States