STARTIO does not need no stinking DCB. On Sat, 8 Feb 2020 16:06:56 -0500 Mike Myers <[email protected]> wrote:
:>Hey Eric: :>You might want to start your exploration at a higher level than the :>lowest level you can possibly go to understand the internals of z/OS :>I/O. For example you might want to look at EXCP or EXCPVR first, as both :>prepare for entry into IOS, but both do special setup functions to make :>that possible. :>As an example of the setup needed, consider the difference between EXCP :>and EXCPVR. EXCP, among other preliminary things, converts all addresses :>in the channel program CCWs being passed to IOS from virtual to real :>addresses. Ultimately, these areas must be pagefixed so as to remain in :>storage during the actual I/O operation. Since STARTIO comes at the next :>lower level, everything that an access method must do before calling :>EXCP must also be done. This includes creating a DCB, an IOSB, etc. :>I would recommend you start here, if you haven't already. as it covers :>EXCP and EXCPVR. :>https://www.ibm.com/support/knowledgecenter/SSLTBW_2.1.0/com.ibm.zos.v2r1.idas300/eyocp.htm :>Mike Myers :>On 2/8/20 12:48 PM, Erik Janssen wrote: :>> Hello List, :>> Out of curiosity I want to learn a bit more about startio. Don't worry, I won't go and attempt to mess up someones z/os lpar, it is just for pure nerd brain entertainment. Searching through the archives I found that there is a whitepaper that was written by Peter Haas called "The STARTIO Facility of MVS", that there were some examples called startio.txt or startio.ex.txt, that Bill Fairchild gave a SHARE presentation on the subject in March 2009 in Austin and that IBM documented it, partially, in IOS logic manuals; the versions for :>> OS/VS2 R2 through R3.8 were publicly available. :>> My search engines efforts to find any of the mentioned documents have failed so far, so is there anybody on the list that has (some of) the mentioned documents available and is willing to share? -- Binyamin Dissen <[email protected]> http://www.dissensoftware.com Director, Dissen Software, Bar & Grill - Israel Should you use the mailblocks package and expect a response from me, you should preauthorize the dissensoftware.com domain. I very rarely bother responding to challenge/response systems, especially those from irresponsible companies. ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
