Didn't realize the that color was removed when the message was sent
Here are my questions
Thanks in Advance
FRR information is stored off of PSA - not in any task related block.
Statement. As opposed to a SCB Thus the routine FRR can be called by a SRB
or TCB since
PSA is
related to the CPU
Question What if there is a CPU switch in the routine being protected by the
FRR
When DAS came out (MVS/SP1.3) ESTAE could not operate in other than
primary=home=secondary. The only way a PC routine could do recovery was thru
an FRR. Rather than require that these routines get a lock to be protected, a
secondary FRR stack was created and a bit in PSA that indicated that an EUT
FRR stack was active. Then, if there is a task switch, the EUT FRR stack is
saved and restored upon redispatch.
Question I thought PC routines are protected by a ARR
Question Going back to the first comment if EUT FRR are per TASK how does the
Z/OS know
they are
the secondary since all FRR's Are Created by SETFRR
-----Original Message-----
From: IBM Mainframe Discussion List [mailto:[email protected]] On Behalf Of
michealbutz
Sent: Sunday, July 17, 2011 4:48 PM
To: [email protected]
Subject: Re: Explination of EUT/FRR
Questions in RED
-----Original Message-----
From: IBM Mainframe Discussion List [mailto:[email protected]] On Behalf Of
Binyamin
Dissen
Sent: Sunday, July 17, 2011 4:17 PM
To: [email protected]
Subject: Re: Explination of EUT/FRR
On Sun, 17 Jul 2011 15:45:30 -0400 michealbutz <[email protected]>
wrote:
:> 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
Also External.
IOW not subjected to be interrupted by something external.
:> Unlocked means not holding a Lock Holding a Lock means using some Flavor
of the
:>SetLock
:> Task means running in Task Mode as opposed to a SRB
:> When the Term FRR is appended it means this unit of work is protected by a
FRR
More of a historical thing.
FRR information is stored off of PSA - not in any task related block.
As opposed to a SCB Thus the routine FRR can be called by a SRB or TCB since
PSA is
releated to the CPU
What if there is a CPU switch in the routine being protected by the FRR
When DAS came out (MVS/SP1.3) ESTAE could not operate in other than
primary=home=secondary. The only way a PC routine could do recovery was thru
an FRR. Rather than require that these routines get a lock to be protected, a
secondary FRR stack was created and a bit in PSA that indicated that an EUT
FRR stack was active. Then, if there is a task switch, the EUT FRR stack is
saved and restored upon redispatch.
I thought PC routnes are protected by a ARR
Going back to the first comment if EUT FRR are per TASK how does the Z/OS know
they are
the secondary since all FRR's
Are Created by SETFRR
A key zero routine in any environment (TCB/SRB, any address spaces) can define
an EUT FRR. Of course, if the routine was in TASK mode this does add
restrictions (one the EUT FRR is established no SVCs, etc.) but if the routine
does not know how it is being called and does not need the services this is an
easy way to go.
--
Binyamin Dissen <[email protected]>
http://www.dissensoftware.com
Director, Dissen Software, Bar & Grill - Israel
Should you use the mailblocks package and expect a response from me,
you should preauthorize the dissensoftware.com domain.
I very rarely bother responding to challenge/response systems,
especially those from irresponsible companies.
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