Re: X-memory POST question

2010-12-23 Thread Chris Craddock
On Thu, Dec 23, 2010 at 1:06 PM, Robert A. Rosenberg wrote: > At 12:31 -0500 on 12/23/2010, Tony Harminc wrote about Re: X-memory POST > question: > > On 23 December 2010 09:43, Binyamin Dissen >> wrote: >> >>> On Thu, 23 Dec 2010 08:30

Re: X-memory POST question

2010-12-23 Thread Robert A. Rosenberg
At 12:31 -0500 on 12/23/2010, Tony Harminc wrote about Re: X-memory POST question: On 23 December 2010 09:43, Binyamin Dissen wrote: On Thu, 23 Dec 2010 08:30:25 -0500 Peter Relson wrote: [...] :>This goes to why, in many cases, XM Post is not safe, [...] Are you implying that

Re: X-memory POST question

2010-12-23 Thread Jim Mulder
> :>The "quick post" approach of using CS to set the post bit of a not-waiting > :>ECB is a fully valid, documented approach. > > :>Of course it is extremely important to do it using the right key and to > :>have some reason to believe that the storage you are trying to update has > :>not be

Re: X-memory POST question

2010-12-23 Thread Tony Harminc
On 23 December 2010 09:43, Binyamin Dissen wrote: > On Thu, 23 Dec 2010 08:30:25 -0500 Peter Relson wrote: [...] > :>This goes to why, in many cases, XM Post is not safe, [...] > Are you implying that one should open an APAR against XM POST as an integrity > exposure? It's hard to see how a ser

Re: X-memory POST question

2010-12-23 Thread Shmuel Metz (Seymour J.)
In , on 12/23/2010 at 08:30 AM, Peter Relson said: >Of course it is extremely important to do it using the right key and >to have some reason to believe that the storage you are trying to >update has not been freed (and potentially re-obtained by a >different job) Is there an option in XM P

Re: X-memory POST question

2010-12-23 Thread Binyamin Dissen
On Thu, 23 Dec 2010 08:30:25 -0500 Peter Relson wrote: :>The "quick post" approach of using CS to set the post bit of a not-waiting :>ECB is a fully valid, documented approach. :>Of course it is extremely important to do it using the right key and to :>have some reason to believe that the stor

Re: X-memory POST question

2010-12-23 Thread Peter Relson
The "quick post" approach of using CS to set the post bit of a not-waiting ECB is a fully valid, documented approach. Of course it is extremely important to do it using the right key and to have some reason to believe that the storage you are trying to update has not been freed (and potentially

Re: X-memory POST question

2010-12-21 Thread Gerhard Postpischil
On 12/21/2010 12:31 AM, Robert A. Rosenberg wrote: I assume that this is safe since you can not stop being the running task between the test and your updating the ECB (and there is not another running thread/task on another engine/cpu which could be dispatching Address Space A). The use of CS is

Re: X-memory POST question

2010-12-21 Thread Anne & Lynn Wheeler
hal9...@panix.com (Robert A. Rosenberg) writes: > I assume that this is safe since you can not stop being the running > task between the test and your updating the ECB (and there is not compare & swap was invented by charlie at the science center when he was working on fine-grain locking for cp67

Re: X-memory POST question

2010-12-21 Thread Shmuel Metz (Seymour J.)
In , on 12/21/2010 at 12:31 AM, "Robert A. Rosenberg" said: >I assume that this is safe since you can not stop being the running >task between the test and your updating the ECB There is no between; CS is atomic. -- Shmuel (Seymour J.) Metz, SysProg and JOAT ISO position; see

Re: X-memory POST question

2010-12-21 Thread Binyamin Dissen
On Tue, 21 Dec 2010 00:31:37 -0500 "Robert A. Rosenberg" wrote: :>At 14:28 -0500 on 12/20/2010, Gerhard Postpischil wrote about Re: :>X-memory POST question: :>>On 12/20/2010 11:28 AM, Charles Mills wrote: :>>>A task in address space A issues a WAIT on an ECB

Re: X-memory POST question

2010-12-20 Thread Robert A. Rosenberg
At 14:28 -0500 on 12/20/2010, Gerhard Postpischil wrote about Re: X-memory POST question: On 12/20/2010 11:28 AM, Charles Mills wrote: A task in address space A issues a WAIT on an ECB in CSA (SP 241). A task in address space B wishes to POST that ECB. Must it use an X-memory POST (ASCB=A

Re: X-memory POST question

2010-12-20 Thread Gerhard Postpischil
On 12/20/2010 11:28 AM, Charles Mills wrote: A task in address space A issues a WAIT on an ECB in CSA (SP 241). A task in address space B wishes to POST that ECB. Must it use an X-memory POST (ASCB=A)? I see that you've already gotten a solution, but the strict answer is no. If the ECB is not

Re: X-memory POST question

2010-12-20 Thread Charles Mills
void the POST if possible. Charles -Original Message- From: IBM Mainframe Discussion List [mailto:ibm-m...@bama.ua.edu] On Behalf Of Binyamin Dissen Sent: Monday, December 20, 2010 8:35 AM To: IBM-MAIN@bama.ua.edu Subject: Re: X-memory POST question On Mon, 20 Dec 2010 08:28:06 -0800 Charl

Re: X-memory POST question

2010-12-20 Thread Binyamin Dissen
On Mon, 20 Dec 2010 08:28:06 -0800 Charles Mills wrote: :>A task in address space A issues a WAIT on an ECB in CSA (SP 241). :>A task in address space B wishes to POST that ECB. Must it use an X-memory :>POST (ASCB=A)? If the ECB is waiting. The XM post is required to schedule an SRB to "wake u

X-memory POST question

2010-12-20 Thread Charles Mills
A task in address space A issues a WAIT on an ECB in CSA (SP 241). A task in address space B wishes to POST that ECB. Must it use an X-memory POST (ASCB=A)? Charles -- For IBM-MAIN subscribe / signoff / archive access instructio