Here is an old manual that goes into detail about the CCW's for DASD. http://dforeman.cs.binghamton.edu/~foreman/550pages/VM/z-Arch-DASD-CommandRef.pdf
Chris Blaicher Technical Architect Syncsort, Inc. -----Original Message----- From: IBM Mainframe Discussion List [mailto:[email protected]] On Behalf Of Mike Myers Sent: Sunday, February 9, 2020 5:52 AM To: [email protected] Subject: Re: Startio documentation [ External - This message originated Externally. Use proper judgment and caution with attachments, links, or responses. ] Erik: I took the reference I passed you earlier a bit further. If you look here, you will find a lot more detail on EXCP, EXCPVR and STARTIO. It's been a long time since I did my own channel programming and made use of EXCP, but I think you will find all you need to know here. You will also have to look into the structure of channel programming and CCWs for specific device types to understand more about what is really happening. The Principles of Operation can supply much of this. https://www.ibm.com/support/knowledgecenter/SSLTBW_2.1.0/com.ibm.zos.v2r1.idas300/eyocp.htm Mike Myers On 2/8/20 10:26 PM, Susan Shumway wrote: > Hi Erik, > > I searched the Technical help database for System z ( > https://www14.software.ibm.com/webapp/set2/psearch/search?domain=sysz > ) and got plenty of hits for "startio", but none with the term in the > title. If you haven't looked there yet, give it a try and see if > anything looks helpful. > > There are also a number of hits to the term in the V2R4 KC, though > probably not true nerd brain entertainment fodder like what you're > looking for: > https://www.ibm.com/support/knowledgecenter/search/startio?scope=SSLTB > W_2.4.0 . Since it's just a simple term search, Mike's recommended KC > reading is most likely your better bet. > > -Sue Shumway > > > On 2/8/2020 7:11 PM, Christopher Y. Blaicher wrote: >> Having done all of this, I would suggest that you start with EXCP and >> then progress to EXPC/VR. Even with EXCP you have to know and >> understand the relationship of the CCW's you are going to use. Read >> carefully. Start simple. Build on it slowly. >> >> Going from EXCP to EXCP/VR is a big jump. Everything you have to do >> for EXCP/VR you will have to do for STARTIO, plus more. >> >> Once you have EXCP/VR running, go look at the STARTIO macro in >> SYS1.MODGEN. >> >> EXCP and EXCP/VR have some guard rails built into them, but you can >> still really screw things up at EXCP/VR because you will have to >> supply the REAL addresses for the CCW's. >> >> When, and if, you start playing with EXCP/VR, I strongly suggest >> using a sandbox LPAR. If you ever get to STARTIO that suggestion >> should rise to a requirement. >> >> Chris Blaicher >> Technical Architect >> Syncsort, Inc. >> >> >> -----Original Message----- >> From: IBM Mainframe Discussion List [mailto:[email protected]] >> On Behalf Of Mike Myers >> Sent: Saturday, February 8, 2020 4:07 PM >> To: [email protected] >> Subject: Re: Startio documentation >> >> [ External - This message originated Externally. Use proper judgment >> and caution with attachments, links, or responses. ] >> >> 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? >>> >>> Kind regards, >>> >>> Erik Janssen. >>> PS. I had posted the same question through Google groups, but that >>> doesn't work in a way that the actual list gets the message it seems. >>> >>> -------------------------------------------------------------------- >>> -- For IBM-MAIN subscribe / signoff / archive access instructions, >>> send email to [email protected] with the message: INFO >>> IBM-MAIN >> >> --------------------------------------------------------------------- >> - For IBM-MAIN subscribe / signoff / archive access instructions, >> send email to [email protected] with the message: INFO >> IBM-MAIN >> >> --------------------------------------------------------------------- >> - For IBM-MAIN subscribe / signoff / archive access instructions, >> send email to [email protected] with the message: INFO >> IBM-MAIN >> > ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
