Gil, When Expanded Storage was introduced on the 390-200 the way VIO worked was changed. VIO was written to ES and not the page datasets, which meant that unless you had really saturated your ES and pushed the migration age down, VIO rarely went any where near a real disk. In a real sense it became a RAM- drive.
This is why DFSORT stopped spitting up when you allocate VIO for SORTWK, and SMS has a quick and easy way to stick all your small Temp datasets into VIO without changing JCL (you decide what small means). Even if you are storage constrained, I would not consider turning off VIO, but just turning it down. Maxsize of 1MB is a pretty safe number, and will catch most of your 1 track temp datasets. Ron > -----Original Message----- > From: IBM Mainframe Discussion List [mailto:[EMAIL PROTECTED] On > Behalf Of Paul Gilmartin > Sent: Friday, 27 January 2006 7:32 AM > To: [email protected] > Subject: Re: Is VIO mandatory? > > In a recent note, Bruce Black said: > > > Date: Thu, 26 Jan 2006 10:40:50 -0500 > > > > AFAIK VIO is required only if you have JCL using UNIT=VIO (or some other > > UNIT= which equates to VIO devices). At one time some IBM supplied > > PROCs (compiler PROCs and such) used UNIT=VIO for temp datasets so scan > > your PROCLIBs. There still may be user JCL in private JCL libraries > > with UNIT=VIO. > > > It ought to be possible to satisfy that with an esoteric. > Unless the jobs depend on 3350 geometry. > > I wonder about teD's statement that there remains a performance > edge for VIO. I understand the paths for paging are highly > optimized. But with modern buffered and virtual DASD the > difference ought to be shrinking. And there's the offsetting > overhead of emulating CKD protocol in virtual memory. > > -- gil > -- > StorageTek > INFORMATION made POWERFUL > > ---------------------------------------------------------------------- > 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 ---------------------------------------------------------------------- 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
