In general, the Principle Of Operations only describes the "logical" results that facilities are to produce. This allows different models to use different methods to obtain the same "logical" results. IMO, where possible, IBM tries to hide the actual method that the hardware uses to obtain those results just to keep them secret from potential competitors.
I would hope that the TOD clock facility is still fault tolerant. There may still be multiple physical TOD clocks (perhaps not one per CPU or LPAR, etc.), but a reasonable number for redundancy. However, from the view point of each processor there might be only one "logical" TOD facility. To know for sure, I think you need to bluntly ask IBM if the TOD clock facility is redundant. > -----Original Message----- > From: IBM Mainframe Discussion List [mailto:ibm-m...@bama.ua.edu] On > Behalf Of Paul Gilmartin > Sent: Monday, September 06, 2010 9:33 PM > To: IBM-MAIN@bama.ua.edu > Subject: Re: The new POO (Props / ProP ) is available > > On Fri, 3 Sep 2010 16:47:20 -0600, Steve Comstock wrote: > > >http://www- > 01.ibm.com/support/docview.wss?uid=isg2b9de5f05a9d57819852571c500428f9a > > > In which I read: > > In a multiprocessing configuration, a single TOD clock is > shared by all CPUs. Each CPU has its own clock comparator, > CPU timer, and TOD programma- ble register. > > I thought I was told in the past that each CPU had its own TOD clock, > for fault tolerance. Was I misinformed, or did IBM decide subsequently > that the complexity of synchronizing several dozen clocks outweighs > the risk of a single point of failure? > > -- gil > > ---------------------------------------------------------------------- > For IBM-MAIN subscribe / signoff / archive access instructions, > send email to lists...@bama.ua.edu 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 lists...@bama.ua.edu with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
