I agree with Mark, you can look up "system managed buffering" (SMB) in the JCL Reference and JCL Users Guide manuals. AFAIK, BLSR documentation indeed has not been updated since somewhere around OS390 times, so the documentation you found is probably the most current.
That said, IMHO BLSR is still a viable I/O saving mechanism that Just Works (tm). There are ISV products that claim to do better than IBM's solutions (BLSR or SMB) but they are not perfect either. One reason I like BLSR is that it puts the amount of storage you want to dedicate to saving I/O under your direct control, via the HBUFNO and HBUFNI parameters. The drawback is that the amount of memory to use is under your control and therefore you are required to maintain / monitor those amounts as your application matures and changes to make sure you are using the most cost-effective amounts. A two-edged sword. Head-to-head measurements of BLSR vs SMB that I performed a long time ago (probably 10 years or more) gave a slight edge to BLSR in terms of saved elapsed time, but not always. It would be smart to try both methods and see which one works best for your applications. Peter -----Original Message----- From: IBM Mainframe Discussion List <IBM-MAIN@LISTSERV.UA.EDU> On Behalf Of Mark Jacobs Sent: Monday, May 16, 2022 10:56 AM To: IBM-MAIN@LISTSERV.UA.EDU Subject: Re: IBM BLSR subsystem Take a look at the AMP=ACCBIAS keyword. It specifies the assigned VSAM System Managed Buffering specification. Mark Jacobs Sent from ProtonMail, Swiss-based encrypted email. GPG Public Key - https://api.protonmail.ch/pks/lookup?op=get&search=markjac...@protonmail.com ------- Original Message ------- On Monday, May 16th, 2022 at 10:36 AM, Pommier, Rex <rpomm...@sfgmembers.com> wrote: > Hi list, > > Is the BLSR subsystem (batch local shared resources) still a viable/valuable > thing or has it been replaced by something bigger/better/faster? I seem to be > stuck in the mid-90s because the most current documentation I can find on it > is from MVS/ESA 5.1 dated 1994. Is there more current documentation on how to > use it and how it works? Has it been replaced and deprecated? I just had a > developer use it last week and experienced a 40+ reduction in I/Os but I > wanted to read up on its limitations - especially around using it on a shared > VSAM dataset. However I can't find anything newer than 25+ years old. I did > multiple internet searches which is where I found the ESA manual. I checked > the knowledge center and my own z/OS 2.2 and 2.4 collections all to no avail. > > Thanks, > > Rex -- This message and any attachments are intended only for the use of the addressee and may contain information that is privileged and confidential. If the reader of the message is not the intended recipient or an authorized representative of the intended recipient, you are hereby notified that any dissemination of this communication is strictly prohibited. If you have received this communication in error, please notify us immediately by e-mail and delete the message and any attachments from your system. ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN
