On Sat, 4 Feb 2017 01:49:13 -0500, Jim Mulder wrote: > There are no coding requirements for the application, When you do >a QSAM OPEN for Input, the first read-ahead I/Os are scheduled by OPEN, >and the application program can proceed without waiting after the OPEN at >least to the point of doing the first GET. Subsequent read-ahead I/Os can >overlap with the application program processing. > > Similarly for QSAM output, the application program can be doing PUTs into >buffers while output I/O is in progress for previously filled output buffers. > I suspect that if the programmer upens for Update the access method can't know whether to read-ahead.
> The application program has little control over this, other than some >DCB/DCBE parameters. > Is this still, as Ed recalls, part of a separately-priced SAMe feature? Thanks, gil ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
