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] (Paul Gilmartin) writes: > This is the Principles of Operation; it is not the Assembler Services > manual. Note carefully the "provided that" clause. It's important. > Is there any explicit guarantee in the Assembler Services manual that > "the supervisor WAIT and POST routines use COMPARE AND SWAP to > manipulate [ECBs]", and that the ECBs are updated only after all > collateral operations are completed? If not, the programmer who > engages in such shenanigans is using unsupported interfaces. re: http://www.garlic.com/~lynn/2008b.html#31 How does ATTACH pass address of ECP to child? you have to remember that this was being written over 35yrs ago ... after the favorite son operating system people in pok claimed that the compare&swap instruction wasn't necessary (for multiprocessor operation); that test&set (carried forward from 360 multiprocessor) was more than satisfactory. http://www.garlic.com/~lynn/subtopic.html#smp the challenge then to the science center http://www.garlic.com/~lynn/subtopic.html#545tech ... in order to get compare&swap justification for inclusion in 370 architecture ... was to come up with other uses ... that weren't multiprocessing specific. the result was some number of examples of its use in multiprogramming/multithreaded operation (that wasn't necessarily multiprocessing). in any case, since then there have been several generations, allowing compare&swap instruction use to widely permeate through the infrastructure. ---------------------------------------------------------------------- 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
