> -----Original Message----- > From: IBM Mainframe Discussion List [mailto:IBM-MAIN@LISTSERV.UA.EDU] > On Behalf Of Paul Gilmartin > Sent: Wednesday, December 05, 2012 11:02 AM > To: IBM-MAIN@LISTSERV.UA.EDU > Subject: Re: Historical question regarding the stop command > > On Wed, 5 Dec 2012 08:03:16 -0800, Charles Mills wrote: > > >> How does STOP work? > > > >From a programmer's point of view, it sets a flag and posts an ECB. > > > >> Is MODIFY similar? > > > >Yes, both are quite similar in how they work. Modify is a flag plus > the > >text of the command. AFAIR Stop is just a flag, but I might well be > >wrong and I am too lazy to look it up right now. > > > Same ECB or different ECB? Or does the flag indicate whether the > operation was STOP, MODIFY, or ... (What else?)
Same physical ECB. There is a control block, the CIB, which describes the communication. It has a "verb" for STOP, MODIFY, and START. Each of these reside in a CIB. That's how a program can pick up information from the START command which initiated it (if there is one, that is). Using QEDIT, you tell z/OS how many CIBs can be queued to your address space. The default is 0. The QEDIT macro is also used to get the address of the next CIB, if any, and also to free it. A "one stop" macro. There is only a single ECB involved. It is reset when the number of CIBs is zero. The ECB itself is in system storage. There is special code in WAIT which allows key 8 code (application) to WAIT on the key 0 ECB. > > >z/OS "knows" whether a program has gone through the motions of telling > >z/OS it was prepared to accept console commands. ... > > > May I assume that "telling" includes providing z/OS with the address of > the ECB(s)? No, z/OS tells the code where the ECB exists. > > Thanks, > gil Ref, with example assembler code: http://publibz.boulder.ibm.com/cgi-bin/bookmgr_OS390/BOOKS/iea2a8b0/2.3 Implemented in IBM's z/OS C run time via the __console2 routine. ref: http://publibz.boulder.ibm.com/cgi-bin/bookmgr_OS390/BOOKS/EDCLB1B0/3.138 -- John McKown Systems Engineer IV IT Administrative Services Group HealthMarkets® 9151 Boulevard 26 • N. Richland Hills • TX 76010 (817) 255-3225 phone • john.mck...@healthmarkets.com • www.HealthMarkets.com Confidentiality Notice: This e-mail message may contain confidential or proprietary information. If you are not the intended recipient, please contact the sender by reply e-mail and destroy all copies of the original message. HealthMarkets® is the brand name for products underwritten and issued by the insurance subsidiaries of HealthMarkets, Inc. –The Chesapeake Life Insurance Company®, Mid-West National Life Insurance Company of TennesseeSM and The MEGA Life and Health Insurance Company.SM ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN
