Yes, I was talking about all references using PLO. I was also assuming this was a "work" queue where "deletion" from the chain was the methodology for claiming ownership of the element. However, any serialization method that performs deletion must also have a method for claiming ownership before an element can be deleted. It doesn't matter whether deletion is an actual release of storage or the placement of the element into a free chain. If any process other than the owning process maintains a reference to an element without claiming it, the problem exists whether you use locks, PLO, CS, whatever. If the reference is nothing more than searching the chain, then PLO Compare and Load can solve that. If the reference is more than that, the problem is not storage overlays or 0c4s. The problem is a missing method for ownership. If this is true for this application, the chain is only serializable with a lock and the lock must be held throughout the period where the element is referenced before the element can be safely deleted.
-----Original Message----- From: IBM Mainframe Discussion List [mailto:[email protected]] On Behalf Of Jon Perryman Sent: Friday, November 08, 2013 1:11 PM To: [email protected] Subject: Re: Serialization without Enque The storage overlay does not pertain to the PLO. It pertains to the entire element not being immediately removed from any type of use. Just because you removed the element from the chain does not mean it's not in use somewhere. You can't even say how long the element may be in use (e.g. task does not get any CPU because of CPU load or swapped out address space in multi-address space serialization). Jon Perryman. >________________________________ > From: Kenneth Wilkerson <[email protected]> > > > >A storage overlay cannot occur in a properly implemented PLO with a >counter as long as the counter is properly maintained with every >process incrementing it by 1. Even in in a free chain implementation, >an improper PLO sequence can result in a circular or broken chain. > >-----Original Message----- >Behalf Of Jon Perryman > >This specific paragraph from Peter is about "FREE QUEUE PROTOCOL". > ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
