That’s what I’m trying I.E overlapped i/o BSAM > On Mar 7, 2021, at 12:40 PM, Clark Morris <[email protected]> wrote: > > [Default] On 7 Mar 2021 07:57:02 -0800, in bit.listserv.ibm-main > [email protected] (Joseph Reichman) wrote: > >> If you read a larger number of bytes into core let’s say above the bar less >> I/o should speed things up no ? >> > If you have a large enough number of buffers, the difference should be > negligible. For QSAM I hope they would be above the line taking > advantage of the 31 bit address space. HavingBSA oddball data sets which > require special handling and maybe even EXCP will probably cost more > time than you save. Playing with BUFNO and NCP are a better > expenditure of time and effort. > > Clark Morris >> >>>> On Mar 7, 2021, at 10:40 AM, Radoslaw Skorupka <[email protected]> >>>> wrote: >>> >>> ?W dniu 06.03.2021 o 16:50, Laddie Hanus pisze: >>>> LBI is available on DASD the largest block that will fit on 1 track, on >>>> the 3390 thats about 56K. Logical record (LRECL) is still limited to >>>> 32760, This is for new datasets being written. Existing datasets will read >>>> one block per i/o and will be no larger than what written. this is for >>>> BSAM read/check. manual DF/DSS Advanced services under the DEVTYPE macro >>>> will has a table of largest blocksize per decice type >>> >>> The problem is I have never seen LBI block on DASD. >>> Can I allocate such dataset using ISPF 3.2 or JCL DD ? >>> Can I copy existing LBI dataset using IEBGENER or IDCAMS? >>> >>> It's more or less like long member names in PDSE. They exist, however I >>> haven't found any. >>> And I think it is not only my observation. >>> >>> From the other hand large blocks on tape are widely used and supported by >>> existing system tools. >>> >>> Last, but not least: author of the thread wants better performance. I would >>> not expect significant performance improvement by changing BLKSIZE =half >>> track to whole track. >>> >>> -- >>> Radoslaw Skorupka >>> (looking for new job) >>> Lodz, Poland >>> >>> ---------------------------------------------------------------------- >>> 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 > > ---------------------------------------------------------------------- > For IBM-MAIN subscribe / signoff / archive access instructions, > send email to [email protected] with the message: INFO IBM-MAIN
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