The following message is a courtesy copy of an article that has been posted to bit.listserv.ibm-main,alt.folklore.computers as well.
[EMAIL PROTECTED] (Peter Relson) writes: > You can be certain that POST will always support the CS quick-post protocol > and the LOCAL LOCK. re: http://www.garlic.com/~lynn/2008b.html#50 How does ATTACH pass address of ECB to child? as stated in the above post ... the principles of operation wording is from over 35yrs ago ... charlie had invented the compare&swap instruction at the science center while doing fine-grain lock for cp67 ... and the pok favorite son operating system people had rejected it ... i.e. the test&set was more than adequate for the global kernel spin-lock multiprocessor support from 360 ... mention of global spin-lock http://www.garlic.com/~lynn/2008b.html#58 How does ATTACH pass address of ECB to child? the challenge given the science center http://www.garlic.com/~lynn/subtopic.html#545tech was come up with example uses for compare&swap instruction ... other than (multiprocessor) locking operation ... some discussion http://www.garlic.com/~lynn/2008b.html#58 How does ATTACH pass address of ECB to child? i.e. the compare&swap instruction can be used for atomic updates for whole class of operations w/o requiring "locking" operation (which would typically also require supervisor call into the kernel to have uninterruptable operation ... as a means of simulating atomic update). as mentioned in the above analogy with dbms financial transaction and optimistic operation ... that avoids lock ... if certain original conditions continue to hold when the transaction changes are actually made permanent. so the wording in the principles of operation was from the stand-point that the pok favorite son operating system people still had to understand the implications of how compare&swap instruction could be used ... and then actually have the changes permeate their implementation. my familiarity with cp67 dates back to when 3 people from the science center http://www.garlic.com/~lynn/subtopic.html#545tech came out to install cp67 at the univ the last week of jan68 (40yrs ago this week) one might claim that maybe that its time to update that 35+yr old perspective in the principles of operation compare&swap writeup. A.6 Multiprogramming and Multiprocessing Examples http://publibz.boulder.ibm.com/cgi-bin/bookmgr_OS390/BOOKS/DZ9ZR003/A.6?SHELF=DZ9ZBK03&DT=20040504121320 other posts in this thread: http://www.garlic.com/~lynn/2008b.html#31 How does ATTACH pass address of ECB to child? http://www.garlic.com/~lynn/2008b.html#47 How does ATTACH pass address of ECB to child? http://www.garlic.com/~lynn/2008b.html#48 How does ATTACH pass address of ECB to child? http://www.garlic.com/~lynn/2008b.html#51 How does ATTACH pass address of ECB to child? http://www.garlic.com/~lynn/2008b.html#60 How does ATTACH pass address of ECB to child? for some topic drift ... related to dbms operation ... misc. posts about the original relational/sql project http://www.garlic.com/~lynn/subtopic.html#systemr and transcriptions of '95 SQL reunion http://www.mcjones.org/System_R/SQL_Reunion_95/index.html there is mention of compare&swap in the discussion about use for "locking" http://www.mcjones.org/System_R/SQL_Reunion_95/sqlr95-Shoot-ou.html#Index311 in this session: http://www.mcjones.org/System_R/SQL_Reunion_95/sqlr95-Shoot-ou.html however, the speculation about the origin of compare&swap instruction was wrong (i.e. compare&swap was chosen because CAS are charlie's initials). ---------------------------------------------------------------------- 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
