I sort of think I remember that the IOVT was added after OCO was in effect. I can't find any mention of the IOVT in my 1980s-vintage IOS logic manuals. One other possible source would be TMON/MVS. It has a control block storage display function that displays storage contents under control of a DSECT that maps the storage it is displaying. TMON/MVS may have an internal DSECT for the IOVT, but, if so, it would probably not be complete or up-to-date. If there is such a DSECT in TMON/MVS, I would probably be the person who created it from other sources and guesswork. One example is that we know that the IOVT + offset 24 points to the CDA, whatever that is, as was mentioned in another post in this thread. If enough clues like that could be garnered, a rudimentary DSECT mapping of the IOVT could have been built up. I just don't remember now whether I did that or not 22+ years ago.
Bill Fairchild -----Original Message----- From: IBM Mainframe Discussion List [mailto:IBM-MAIN@bama.ua.edu] On Behalf Of Steve Horein Sent: Saturday, November 12, 2011 12:22 AM To: IBM-MAIN@bama.ua.edu Subject: Re: Data Areas? Thanks for the tip! I did pass along the IPCS command LISTEDT DETAIL to the DASD guy the other day, but I'm not sure if that was a usable solution. On Nov 11, 2011 9:41 PM, "Tony Harminc" <t...@harminc.net> wrote: On 11 November 2011 19:56, Steve Horein <steve.hor...@gmail.com> wrote: > I see. So while not imposs... It can be so, but it can also be educational and even at times, fun. Ordinarily it is unwise to build anything that matters on a base of undocumented and unsupported control blocks, but there are times when you just really need to know. One popular source (heh) for otherwise undocumented control block information is the mappings supplied for use by IPCS. These are in SYS1.MIGLIB (and possibly other places for some products), and the format is described in the IPCS Customization book. Well, there are at least two kinds of things in this dataset: executable routines of various sorts, and control block models defined using the BLS... macros described in the book. While I don't suggest trying to reverse-engineer any programs you may find, you can use IPCS itself to invoke the control block models using the CBF command. Many of these are invoked for you when you run component analysis (option 2.6), or the supplied VERBEXIT commands, and even the output from these analyses often provides useful information. In many cases you can use CBF to format an area of storage that is not the "real thing", e.g. is just a piece of your own private area, using a formatting module with a name suggested by the component prefix you are interested in. Obviously the content of the output will be largely meaningless, but the field names may be useful to know. Need I repeat the warning to avoid relying on anything you may discover for any sort of production use, or indeed anything beyond satisfying your own curiosity? Tony H. ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@bama.ua.edu w... ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@bama.ua.edu with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@bama.ua.edu with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
