Makes sense. Thank you! Frank
>________________________________ > From: Jim Mulder <[email protected]> >To: [email protected] >Sent: Monday, December 30, 2013 4:47 PM >Subject: Re: BLSR > > > >> This is just a curious question about how the JCL DD SUBSYS paramater >works. >> With BLSR you allocate a file to use BLSR with something like this: >> >> //INETACC DD SUBSYS=(BLSR,'DDNAME=INETACC@ MSG=I', >> // 'RMODE31=ALL BUFND=256 BUFNI=64 DEFERW=YES') >> //INETACC@ DD DSN=&DSNENV..INET.INETACC, >> // DISP=SHR >> >> Is there a specific reason why its not the more obvious (to me!) waylike >this? >> >> //INETACC DD DSN=&DSNENV..INET.INETACC,DISP=SHR, >> // SUBSYS=(BLSR,'MSG=IRMODE31=ALL BUFND=256 BUFNI=64 >DEFERW=YES') > > BLSR was originally written at Washington Systems Center as >an assembler language subsystem, which was going to be included >with the book "The Subsystem Interface in MVS/SP Version 3 >GC66-3131-00 August 1989" as a sample >program, and named PHPD after the authors (Penny Heming, Paul Dorn). >That was done without the involvement of >MVS or DFP development, so there was no opportunity to >modify operating system code. > > That code ended up being rewritten in PL/AS, renamed as >Batch LSR, and shipped as a PTF on top of MVS SP 3.1.3. > > With the syntax, you are proposing, >an OPEN for INETACC would be treated as a subsystem OPEN, >and control would be routed to the BLSR subsystem. But there >would be no DDNAME for which BLSR could subsequently do a >VSAM OPEN. Now, maybe it would have been possible for BLSR to >retrieve the necessary information and do a dynamic allocation >to create its own DDNAME for the VSAM data set. I don't know >if the original PHPD authors ever considered that possibility. >It would have been considerably more complex, and probably >beyond the scope of what they were trying to accomplish. > >Jim Mulder z/OS System Test IBM Corp. Poughkeepsie, NY > >---------------------------------------------------------------------- >For IBM-MAIN subscribe / signoff / archive access instructions, >send email to [email protected] with the message: INFO IBM-MAIN > > > > ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
