The subsysten initialization module is still in SYS1.LINKLIB for z/OS 2.5. There's an eyecatcher with 17259 and HBB77C0 in it.
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 12:00 PM, allan winston <jaw191...@gmail.com> wrote: > Building upon Mark and Peter's replies... > > Having retired in 2005, I can’t be absolutely certain, but it is highly > likely that it is still supported, as I am finding reference to Batch LSR > when searching z/OS 2.5 manuals. > > > > If you have MXG in your shop, potential candidates for batch LSR can be > found by running the ANALBLSR program, referring to the documentation in > member ADOCBLSR. In effect, this will find candidate jobs where the VSAM > access is random instead of sequential. You do not want to use LSR when > the VSAM file is accessed sequentially. > > > > To some extent, it can be argued that Batch LSR has been superseded by > facilities within DFSMS. > > System Managed Buffering(SMB) will implement LSR if all the DFSMS > constructs are in place and Direct Optimized has been chosen: > > https://www.lascon.co.uk/VSAM-System-Buffers.php > > > > > > > > For the non-DFSMS case, there are also 3rd party software products that can > be used to alter batch programs to use LSR instead of the default NSR > mode. I was in a shop that used the Data Optimizer component of the BMC > Mainview Batch Optimizer for that purpose. Going this route was simpler > than modifying a large number of catalogued procedures. > > > > Note that in the rare case that you are using LSR, rather than the more > modern RLS, within CICS that you can choose specific buffer sizes for the > index and data buffer pools using Resource Definition Online. Do not let > your heavily accessed files default to buffer pool 1, where an inferior > algorithm will be used to choose buffer assignments. > > > > There is a very interesting GTF trace, F61,that can give you additional > insight into the random access pattern of your VSAM file accesses – both > batch and CICS. There was a package from MKTTOOLS called VLBPAA, that was > based on the F61 GTF trace which I used extensively for gaining insight > into optimizing buffer assignments. No one seems to have been able to > obtain this product from IBM for the past 20 years. The results did become > slightly inaccurate with the introduction of extended format datasets which > modified the meaning of one of the fields within the GTF trace. > > > > The use of VLBPAA and the layout of the F61 GTF trace was documented in a > 1995 Redbook, SG24-2557 System/390 MVS Parallel Sysplex Batch Performance. > Additionally, that manual shows an ICETOOL job stream that can perform a > rudimentary analysis. That book has been removed from the Redbooks web > site – fortunately I downloaded a copy before it was removed. I can send > my copy to anyone who would like a copy. > > > > A couple of recommendations from my experience: > > (a) Always use separate pools for the data and index. This becomes > especially important when the index and data components have the same CI > size. For that case, the data buffers are likely to wash out the index > buffers. > > (b) If it is practical to choose enough index buffers to hold the entire > index component, then do so. > > > > Allan > > > On Mon, May 16, 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 > > > > ---------------------------------------------------------------------- > > The information contained in this message is confidential, protected from > > disclosure and may be legally privileged. If the reader of this message is > > not the intended recipient or an employee or agent responsible for > > delivering this message to the intended recipient, you are hereby notified > > that any disclosure, distribution, copying, or any action taken or action > > omitted in reliance on it, is strictly prohibited and may be unlawful. If > > you have received this communication in error, please notify us immediately > > by replying to this message and destroy the material in its entirety, > > whether in electronic or hard copy format. Thank you. > > > > ---------------------------------------------------------------------- > > For IBM-MAIN subscribe / signoff / archive access instructions, > > send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN > > > ---------------------------------------------------------------------- > For IBM-MAIN subscribe / signoff / archive access instructions, > send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN
