Subject: Re: Mainframe synchronized with Internet time???
From: Edward Jaffe (edjaffe@phoenixsoftware.com)
Date: Fri Jul 25 2008 - 11:10:07 EDT
McBride, Catherine wrote: > As someone else pointed out, mainframe clocks are very, very precise, accurate to within a small fraction of a second over a 10-year period. > Not in my experience. We've seen noticeable clock "drift" in every generation of mainframe we've ever owned. On the old machines (4341, 4381, etc.) we used to reset the clock with every IPL. These days we leave our mainframes up as long as we can. (We have to. There are about 8 systems that need to come down when we POR.) We installed an OS/2 program to synchronize the SE on our MP3K to NIST every day. That made it painfully obvious how much our TOD was drifting (about a minute every very few months). Our z800 didn't fare much better. And, our current machine -- a z9BC -- seems to lose about a minute every quarter or so. So, we set it a couple of minutes fast each time we POR. If you want a mainframe TOD to be correct, you'll need STP or older clock synchronizing hardware. -- Edward E Jaffe Phoenix Software International, Inc 5200 W Century Blvd, Suite 800 Los Angeles, CA 90045 310-338-0400 x318 edjaffe@phoenixsoftware.com http://www.phoenixsoftware.com/
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