SYSIEFSD Q4 (and its cousins CHNGDEV and VARYDEVS) are used by MVS ALLOCATION to serialize state changes made to devices during allocation processing. Unless things have changed since I was there, these ENQs are never propagated (SCOPE=SYSTEM). I don't know what is meant by "IOS involvement," but ALLOCATION will invoke various services that definitely cause I/O while holding these resources.
Steve Jones did a very nice job describing the problems associated with these resources in '06 at Share in Seattle. Have a look at: http://proceedings.share.org/client_files/SHARE_in_Seattle/S2848SJ112434.pdf Scott Fagen Chief Architect - Mainframe CA Technologies ---------------------------------------------------------------------- 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
