On Thu, 27 Dec 2007 12:39:31 -0600 "McKown, John" <[EMAIL PROTECTED]> wrote:
:>I'm curious if anybody knows how z/OS actually processes the OPEN for a :>DUMMY DD statement. I know that basically output is ignored and input :>causes an immediate EOF. But I wondering if OPEN is smart enough that if :>a file is opened for OUTPUT, the address in the DCB is simply to a :>IEFBR14 type module, or is it more complicated that that? Could be. Though I would hope that it would validate RDW's for V(B) files. :> Does it even :>bother to validate the LRECL, BLKSIZE, and RECFM? If so, why? Just to be :>compatible? Does it bother to get I/O buffers? Why? Because the application may not check to determine if it is a dummy file. The application may require the data from the JFCB :>I guess INPUT would be more difficult, but perhaps a dynamically created :>I/O module which invokes the EODAD immediately or goes to an ABEND :>subroutine if there is no EODAD or if the EODAD is to be executed a :>second time. Same question about LRECL, BLKSIZE, RECFM, and I/O buffers. :>Just curious at the end of the year freeze. The same issues. The application using the DD is usually not aware that the file is DUMMY thus all support for QSAM/BSAM I/O must be the same. -- Binyamin Dissen <[EMAIL PROTECTED]> http://www.dissensoftware.com Director, Dissen Software, Bar & Grill - Israel Should you use the mailblocks package and expect a response from me, you should preauthorize the dissensoftware.com domain. I very rarely bother responding to challenge/response systems, especially those from irresponsible companies. ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
