>And you are worried that you are factoring in 12 irrelevant bits that may add up over time.
The 12 bits really are not irrelevant. >bits to the right of the rightmost bit that is incremented are stored as zeros True. But do you know which is the rightmost bit that is incremented? It is not bit 51 of the TOD clock (that has been true for a long time). It is machine-dependent. <snip> That fits with my understanding that those bits to the right are to ensure STCK uniqueness in a multi-CPU system, and STCK doesn't guarantee uniqueness on any system -- two readings may be taken between increments. </snip> STCK values are guaranteed to be unique within an LPAR (whether 1-CPU or multi-CPU). STCKF values are not guaranteed to be unique. You can think of STCK as spinning until the increment occurs. STCKF does not need to spin. That spinning is the (potentially large) difference between the time taken by STCK and that taken by STCKF. Peter Relson z/OS Core Technology Design ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
