Re: STARTIO macro doc
In a message dated 7/8/2008 6:03:32 P.M. Central Daylight Time, [EMAIL PROTECTED] writes: If you really want to do it yourself, here are a few things to consider before you jump too far in. 1) Modify OPEN/CLOSE/EOV code to intercept the open and close 2) Intercept device allocation 3) What do you do when DASD gets full? Move data to real tape? Delete oldest? 4) If for #3 you move to tape, how about catalog maintenance? 5) The above have not even started to scratch the surface of all the problems and hurtles that you have to overcome. It is not necessarily easier, but it is more fun (in my weird opinion) to intercept the STARTIO request some time before the SSCH happens (there are several different places where you can do this by front-ending different IOS modules), steal the I/O away from IOS [1], scan the tape I/O channel program's CCWs to determine what it is doing and build a DASD channel program to do the same thing (write a block, read a block, etc.) to a DASD file somewhere, do the DASD I/O, copy its ending status into the equivalent ending status for a real tape device, and finally unsteal the I/O back into IOS [1]. This is seriously difficult stuff, and you will crash your test system many, many times before you are done. You really don't want to do this unless you have a lot of time on your hands, a fire in the belly to learn how IOS internals works, and a fat budget for education or development. There is at least one commercial product that does what you want - redirects the I/O to a real DASD device, and it works pretty much the same as in my footnote [1] below. OTOH, modifying O/C/EOV and device allocation is no picnic, either. There were two separate presentations on STARTIO at the August 1987 SHARE in Chicago. I distributed a sample program to read a DASD volume label using STARTIO to all those in attendance, and this document was published in the proceedings if you can find them. Bill Fairchild Rocket Software [1] This means to render the request temporarily unstartable (there are a number of different and easy ways to do this, including never letting the request be put into the queue), pass a pointer to it while POSTing another address space that analyzes the tape channel program, does the equivalent DASD I/O after validating the possibility of doing it at all (file full, etc.), analyzes the result, fills in the original IOSB's status info (you also have to reflect back the tape device's equivalent error status if things go wrong), then invokes the appropriate IOSB exit to post status back to where the original I/O requester can find out that the tape I/O has ended. I did all this once (not for tape, though), and it took a very long time to get it right. I had the time, the fire in the belly, and the budget. A major part of the difficulty is the large variety and complexity involved in scanning a channel program and supporting all the possible ways of chaining CCWs, all the CCW flag bits, all the types of indirect address lists, and so on. You have to write code that emulates a large fraction of five of the Principles of Operations' most incomprehensible and somnifacient chapters (13-17) in addition to a large fraction of the book that describes how a tape device's CCWs work. Oh, yeah, and the DASD book, too, so you can build the correct DASD channel program. **Gas prices getting you down? Search AOL Autos for fuel-efficient used cars. (http://autos.aol.com/used?ncid=aolaut000507) -- 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
Re: STARTIO macro doc
Thanks to everyone for explaining how this is done. If I'm not wrong, the commercial products use their own DASD format. I thought that using the fake tape that Flex (and Hercules) use would be better. As always, my ideas are horribly difficult. I'll try to come up with something within my grasp (at least for the first few). Lindy -Original Message- From: IBM Mainframe Discussion List [mailto:[EMAIL PROTECTED] On Behalf Of (IBM Mainframe Discussion List) Sent: 9. heinäkuuta 2008 15:49 To: IBM-MAIN@BAMA.UA.EDU Subject: Re: STARTIO macro doc You really don't want to do this unless you have a lot of time on your hands, a fire in the belly to learn how IOS internals works, and a fat budget for education or development. There is at least one commercial product that does what you want - redirects the I/O to a real DASD device, and it works pretty much the same as in my footnote [1] below. -- 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
Re: STARTIO macro doc
Hal, you're absolutely correct in what you say. It's quite easy to convert JCL that reads tapes to reading files off of DASD. But for testing and developing things that actually read from tapes it is better if nothing changes. And I like the way Flex and Hercules does it. Of course I've given up on this idea because I'm not ready for something this difficult (yet). And other companies already have such products. I'll have to wait and dream up another idea. -Original Message- From: IBM Mainframe Discussion List [mailto:[EMAIL PROTECTED] On Behalf Of Hal Merritt Sent: 9. heinäkuuta 2008 18:06 To: IBM-MAIN@BAMA.UA.EDU Subject: Re: STARTIO macro doc Still a little confused. What are you trying to do? If all you want to do is read a file, then just do it. Under z/os, the device type is of no particular interest to the application program. Z/os tracks the device type for you and uses appropriate I/O routines automatically. That is, a given file can exist on any flavor of tape, virtual tape, DASD, or whatever. The application program need only specify the file (dataset) name in the JCL or in the dynamic allocation interface. Assuming the file layout is the same, then the application program can read from all of those devices and remain completely unaware and uncaring. If you want to create a file, then just specify the device type you want to use for this specific instance in your JCL. Again, z/os handles all the details for you. Consider that 'tape' actually covers a very large number of possible device types, each with peculiar requirements. Some 'tape' units may actually be DASD under the covers. But, again, typically this is of no concern. HTH -- 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
Re: STARTIO macro doc
snip I want to do like Flex and Hercules do where the tape is really a file on DASD. ---unsnip--- Go out to the CBTTAPE site and look for AWSTAPE info/programs. Sam Golob can help with information there as well. You don't really need STARTIO, or even EXCP, to emulate that format. AFAIK, Sam uses QSAM for the actual I/O; the devil is in the format details. -- 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
STARTIO macro doc
Does anyone have (or know a link to) any documentation on STARTIO? Google gave up a hint that there was a SHARE presentation on it, but no links that I could find. I'm still thinking how one might create a virtual tape on DASD device on z/OS. Maybe STARTIO is the way to do it. Thanks, Lindy -- 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
Re: STARTIO macro doc
Consider device redirection using SMS. That is, when an application calls for tape it is transparently redirected to DASD. AFAIK, 'virtual tape' is still physical tape. It is just a way to put many logical tape volumes on one physical tape volume in a way that is transparent to the application. Or am I not understanding what you want to do? -Original Message- From: IBM Mainframe Discussion List [mailto:[EMAIL PROTECTED] On Behalf Of Lindy Mayfield Sent: Tuesday, July 08, 2008 5:13 PM To: IBM-MAIN@BAMA.UA.EDU Subject: STARTIO macro doc Does anyone have (or know a link to) any documentation on STARTIO? Google gave up a hint that there was a SHARE presentation on it, but no links that I could find. I'm still thinking how one might create a virtual tape on DASD device on z/OS. Maybe STARTIO is the way to do it. Thanks, Lindy -- 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 NOTICE: This electronic mail message and any files transmitted with it are intended exclusively for the individual or entity to which it is addressed. The message, together with any attachment, may contain confidential and/or privileged information. Any unauthorized review, use, printing, saving, copying, disclosure or distribution is strictly prohibited. If you have received this message in error, please immediately advise the sender by reply email and delete all copies. -- 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
Re: STARTIO macro doc
I want to do like Flex and Hercules do where the tape is really a file on DASD. -Original Message- From: IBM Mainframe Discussion List [mailto:[EMAIL PROTECTED] On Behalf Of Hal Merritt Sent: 9. heinäkuuta 2008 1:21 To: IBM-MAIN@BAMA.UA.EDU Subject: Re: STARTIO macro doc Consider device redirection using SMS. That is, when an application calls for tape it is transparently redirected to DASD. AFAIK, 'virtual tape' is still physical tape. It is just a way to put many logical tape volumes on one physical tape volume in a way that is transparent to the application. Or am I not understanding what you want to do? -Original Message- From: IBM Mainframe Discussion List [mailto:[EMAIL PROTECTED] On Behalf Of Lindy Mayfield Sent: Tuesday, July 08, 2008 5:13 PM To: IBM-MAIN@BAMA.UA.EDU Subject: STARTIO macro doc Does anyone have (or know a link to) any documentation on STARTIO? Google gave up a hint that there was a SHARE presentation on it, but no links that I could find. I'm still thinking how one might create a virtual tape on DASD device on z/OS. Maybe STARTIO is the way to do it. Thanks, Lindy -- 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 NOTICE: This electronic mail message and any files transmitted with it are intended exclusively for the individual or entity to which it is addressed. The message, together with any attachment, may contain confidential and/or privileged information. Any unauthorized review, use, printing, saving, copying, disclosure or distribution is strictly prohibited. If you have received this message in error, please immediately advise the sender by reply email and delete all copies. -- 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 -- 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
Re: STARTIO macro doc
Oh that it would be so easy to do what you want with a little re-direction of the STARTIO. There are a number of Virtual Tape Systems available, but the SMS re-direction is the simplest thing to do. If you really want to do it yourself, here are a few things to consider before you jump too far in. 1) Modify OPEN/CLOSE/EOV code to intercept the open and close 2) Intercept device allocation 3) What do you do when DASD gets full? Move data to real tape? Delete oldest? 4) If for #3 you move to tape, how about catalog maintenance? 5) The above have not even started to scratch the surface of all the problems and hurtles that you have to overcome. The Hercules I/O is intercepting the physical I/O and when it runs out of space, you are cooked. I don't think that is what you want happening to your production MVS. As I said, I wish it was so easy. Chris Blaicher -Original Message- From: IBM Mainframe Discussion List [mailto:[EMAIL PROTECTED] On Behalf Of Lindy Mayfield Sent: Tuesday, July 08, 2008 5:31 PM To: IBM-MAIN@BAMA.UA.EDU Subject: Re: STARTIO macro doc I want to do like Flex and Hercules do where the tape is really a file on DASD. -Original Message- From: IBM Mainframe Discussion List [mailto:[EMAIL PROTECTED] On Behalf Of Hal Merritt Sent: 9. heinäkuuta 2008 1:21 To: IBM-MAIN@BAMA.UA.EDU Subject: Re: STARTIO macro doc Consider device redirection using SMS. That is, when an application calls for tape it is transparently redirected to DASD. AFAIK, 'virtual tape' is still physical tape. It is just a way to put many logical tape volumes on one physical tape volume in a way that is transparent to the application. Or am I not understanding what you want to do? -Original Message- From: IBM Mainframe Discussion List [mailto:[EMAIL PROTECTED] On Behalf Of Lindy Mayfield Sent: Tuesday, July 08, 2008 5:13 PM To: IBM-MAIN@BAMA.UA.EDU Subject: STARTIO macro doc Does anyone have (or know a link to) any documentation on STARTIO? Google gave up a hint that there was a SHARE presentation on it, but no links that I could find. I'm still thinking how one might create a virtual tape on DASD device on z/OS. Maybe STARTIO is the way to do it. Thanks, Lindy -- 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 NOTICE: This electronic mail message and any files transmitted with it are intended exclusively for the individual or entity to which it is addressed. The message, together with any attachment, may contain confidential and/or privileged information. Any unauthorized review, use, printing, saving, copying, disclosure or distribution is strictly prohibited. If you have received this message in error, please immediately advise the sender by reply email and delete all copies. -- 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 -- 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 -- 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
Re: STARTIO macro doc
Have you considered an application like Diligent's Virtual Tape Facility for the Mainframe - VTF/M for short. Or you can call us as well since we are a reseller for VTF/M (sorry, I couldn't resist - my apologies to the list in advance) I use and support this product and there is a lot more to consider than just redirecting the I/O request. Consider how you would do the following: 1) how would you select a job for redirection - jobname, stepname, ddname, dataset name, device type request? 2) how would you identify and create a 'virtual tape drive' to recognize for redirection? 3) how would you handle the allocation of a disk data set to contain your virtual tape file? 4) do you have any automated operations software to interface with and process any messages your code might issue? 5) do you have to interface your virtual tape volumes with an existing tape management system? 6) how would you maintain your library of virtual tapes - add, delete, rename, e-vault support? As you can see - just redirecting the I/O by front ending the STARTIO code may be the easy part. What about all the rest? Save yourself a lot of time and grief - go buy VTF/M that already does everything is the list above. Just my $0.02 - and no, I am not on a commission for VTF/M. :-) HITACHI DATA SYSTEMS Raymond E. Noal Senior Technical Engineer Office: (408) 970 - 7978 -Original Message- From: IBM Mainframe Discussion List [mailto:[EMAIL PROTECTED] On Behalf Of Lindy Mayfield Sent: Tuesday, July 08, 2008 3:31 PM To: IBM-MAIN@BAMA.UA.EDU Subject: Re: STARTIO macro doc I want to do like Flex and Hercules do where the tape is really a file on DASD. -Original Message- From: IBM Mainframe Discussion List [mailto:[EMAIL PROTECTED] On Behalf Of Hal Merritt Sent: 9. heinäkuuta 2008 1:21 To: IBM-MAIN@BAMA.UA.EDU Subject: Re: STARTIO macro doc Consider device redirection using SMS. That is, when an application calls for tape it is transparently redirected to DASD. AFAIK, 'virtual tape' is still physical tape. It is just a way to put many logical tape volumes on one physical tape volume in a way that is transparent to the application. Or am I not understanding what you want to do? -Original Message- From: IBM Mainframe Discussion List [mailto:[EMAIL PROTECTED] On Behalf Of Lindy Mayfield Sent: Tuesday, July 08, 2008 5:13 PM To: IBM-MAIN@BAMA.UA.EDU Subject: STARTIO macro doc Does anyone have (or know a link to) any documentation on STARTIO? Google gave up a hint that there was a SHARE presentation on it, but no links that I could find. I'm still thinking how one might create a virtual tape on DASD device on z/OS. Maybe STARTIO is the way to do it. Thanks, Lindy -- 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 NOTICE: This electronic mail message and any files transmitted with it are intended exclusively for the individual or entity to which it is addressed. The message, together with any attachment, may contain confidential and/or privileged information. Any unauthorized review, use, printing, saving, copying, disclosure or distribution is strictly prohibited. If you have received this message in error, please immediately advise the sender by reply email and delete all copies. -- 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 -- 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 -- 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
