On Wed, 25 Feb 2009 18:59:48 -0500, Bob Rutledge wrote: >Victor Gil wrote: >> I need to "compress" 16-byte STCKE format TOD into a 12 byte field without >> losing the sysplex-wide uniqueness. >> >> So, I thought I'd keep the first 10 bytes and the last 2 bytes [Programmable >> Field]. >> >> To my surprise STCKE returns non-zeroes in the bytes #13 and #14 - >> >> ???? >> 00C3CD5B F16F38C5 A8000000 01040002 >> >> Could someone explain what are these 2 bytes for? > >The Principles of Operation is pretty clear about it: > >"When the value of a running clock is stored by STORE CLOCK EXTENDED, the value >in bit positions 64-103 of the clock (bit positions 72-111 of the storage >operand) is always nonzero; this ensures that values stored by STORE CLOCK >EXTENDED are always unique when compared with values stored by STORE CLOCK or >STORE CLOCK FAST, extended on the right with zeros." > >> Also, how save is the assumption that the field can be compressed into 12 >> byte without losing its sysplex-wide uniqueness. > >Given the above, not at all. > If you must abbreviate, simply use STCK. I believe it's still supported.
BTW, did you ever hear of / do you still remember the "Y2K Problem"? -- gil ---------------------------------------------------------------------- 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
