Thank you I’m doing searches for files so I have over 100 concatenated files does the access matters I mean I assume QSAM reads a block under the covers
> On Mar 1, 2021, at 1:26 PM, Farley, Peter x23353 > <[email protected]> wrote: > > Joseph, > > I believe that LBI is only for tape inputs and outputs. You can speed up > your processing easier by using either the older BLSR buffering subsystem or > better the newer SMB buffering system. See the JCL reference manual for SMB > parameters. > > Allocate as much REGION as your installation will allow (some installations > limit the maximum any job without special authorization may use, even > sometimes production jobs). > > Use BLSR or SMB to allocate as many buffers as will fit in the REGION size > you can allocate. > > I have seen substantial decreases in run time using these techniques with > very large sequential files. > > I would also recommend using at least software compression or better hardware > compression (if your CPU has it) for your large sequential files. The CPU > time used for compression and decompression will sometimes be offset by > decreases in elapsed time due to reduced I/O burdens for the compressed data, > especially if you have hardware compression available. > > HTH > > Peter > > -----Original Message----- > From: IBM Mainframe Discussion List <[email protected]> On Behalf Of > Joseph Reichman > Sent: Monday, March 1, 2021 1:14 PM > To: [email protected] > Subject: Re: Large block interface for VB > > EXTERNAL EMAIL > > Who uses tape > > I went to bsam trying to speed up my application wonder if going to bsam > > Does anything positive for me > >>> On Mar 1, 2021, at 1:10 PM, Paul Gilmartin >>> <[email protected]> wrote: >>> >>> On Mon, 1 Mar 2021 11:24:57 -0500, Joseph Reichman wrote: >>> >>> It disk then documentation says the system only supports tape at this time >>> is That true ? >>> >> Have you any reason to doubt it? >> >> I suspect it's a hardware limitation. >> >>>>> On Mar 1, 2021, at 11:22 AM, Paul Gilmartin wrote: >>>> >>>> On Mon, 1 Mar 2021 09:12:59 -0500, Joseph Reichman wrote: >>>> >>>>> I have 100 files concatenated that are normally processed by qsam >>>>> with a lrecl 31996 and blksize 32000 >>>>> >>>>> Since processing takes a long time I was looking to speed things up >>>>> by specifying a blksize of 320000 in the DCBE >>>>> >>>> What device type? >>>> >>>>> After the first read using bsam read macro I looked at the first 4 >>>>> bytes ( Block descriptor word ) and it was x’7C4A’ which is 31,888 >>>>> which seemed to me that it was still processing blksize of 32,000 >> >> -- gil >> >> ---------------------------------------------------------------------- >> 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 > > 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 [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
