After reading the story of Compare and Swap for, lo, all these many years, I
am sorry but I must ask.

Charlie who?

-----Original Message-----
From: IBM Mainframe Discussion List [mailto:IBM-MAIN@LISTSERV.UA.EDU] On
Behalf Of Anne & Lynn Wheeler
Sent: Saturday, July 02, 2016 12:08 PM
To: IBM-MAIN@LISTSERV.UA.EDU
Subject: Re: Multithreaded output to stderr and stdout

0000000433f07816-dmarc-requ...@listserv.ua.edu (Paul Gilmartin) writes:
> I'm trying to envision how to use WAIT/POST to do that since no more 
> than one task can be WAITing on a given ECB.  I vaguely recall long 
> ago writing code that used a variant of a CS example in PoOps to 
> manage a queue of ECBs.

charlie had invented compare-and-swap when he was doing fine-grain
multiprocessing locking for cp67 at the science center ... some past posts
http://www.garlic.com/~lynn/subtopic.html#545tech
and
http://www.garlic.com/~lynn/subtopic.html#smp

initial attempts to get it included as part of 370 were repulsed, the
370 architecture owners said that the POK favorite son operating system
people (os/360 and descendants) were saying that TS (test&set) was more than
sufficient for multiprocessor support (they had been coming from a single
global system spin-lock that was obtained by first-level interupt handlers).

thus was born the science center examples how multi-threaded applications
(not necessarily running on multiprocessor) could use compare-and-swap ...
that still appear in princples of operation.

early application uptake of compare-and-swap were the large multi-threaded
DBMS and transaction processing. In the 80s, you start seeing other hardware
platforms implementing instructions with comapre-and-swap semantics
(especially those selling into transaction and DBMS markets).

--
virtualization experience starting Jan1968, online at home since Mar1970

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