>> Great overview, but is the note above still true with modern DS8000 boxes? >> It's just hard for me to imagine 3390 emulation logic holding that 23K >> hostage.
Tom, As other have mentioned on z/OS it is still valid. Run this JCL and look at the allocation . I used the example of LRECL=500 and optimal blocksize =27500 and max blocksize could be 32500 //STEP0100 EXEC PGM=SORT //SYSOUT DD SYSOUT=* //SORTIN DD * ABC //B27500 DD DSN=&SYSUID..CREATE.BLKSIZE.OF27500, // DISP=(NEW,CATLG,DELETE), // SPACE=(CYL,(7,2),RLSE) //B32500 DD DSN=&SYSUID..CREATE.BLKSIZE.OF32500, // DISP=(NEW,CATLG,DELETE), // SPACE=(CYL,(7,2),RLSE),BLKSIZE=32500 //SYSIN DD * OPTION COPY OUTFIL FNAMES=B27500,REPEAT=10000,BUILD=(500C'A') OUTFIL FNAMES=B32500,REPEAT=10000,BUILD=(500C'B') /* The result is ------------------------------------------------------------------------------- Command - Enter "/" to select action Tracks %Used XT ------------------------------------------------------------------------------- KOLUSU.CREATE.BLKSIZE.OF27500 105 86 1 KOLUSU.CREATE.BLKSIZE.OF32500 165 93 3 Thanks, Kolusu ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN