On Sun, Jul 17, 2011 at 2:45 PM, michealbutz <[email protected]>wrote:
> Hi, > > > I have seen these terms EUT Enabled Unlocked Task /FRR and this my > understanding > I ASSUME Enabled means Enabled for I/O interrupts BIT 6 of Psw the only > way I know how > to set this is with the LPSW inst > No, there's also the external interrupt. Both I/O and external interrupts are masked by the last two bits in the first byte of the PSW. The actual interrupt enablement for the underlying CPU is governed by bits in a control register which get AND-ed with the PSW bits to decide whether the corresponding interrupt will be allowed to occur. There are multiple ways the bits can be turned on or off. You should not try any of them. > Unlocked means not holding a Lock Holding a Lock means using some > Flavor of the > SetLock > Yup. Also includes certain special cases such as when running under control of a disabled interrupt exit (e.g timer DIE). There are no locks actually held, but the system acts as if you're holding the CPU lock. > Task means running in Task Mode as opposed to a SRB Yep. > When the Term FRR is appended it means this unit of work is protected by a > FRR > Yes. But what makes an EUT FRR an "EUT" FRR is that you specified EUT=YES on the SETFRR macro. If you had set an FRR in a condition where you would not normally need one, the system will unceremoniously remove it during the next interrupt. "EUT=YES" tells RTM that you know what you're doing and that the FRR should be left alone. Typical use case is where you're about to get into one of the conditions that would require an FRR and you want to provide the FRR ahead of time, e.g. to perform some post recovery cleanup, release locks etc. All of which is pretty advanced stuff. Not a safe area for tourists. -- This email might be from the artist formerly known as CC (or not) You be the judge. ---------------------------------------------------------------------- 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
