Re: VSAM I/O
Let me guess: you want to encrypt something and don't want to have to modify application programs. My question is how you would control who is authorized to use your hook? And, of course, how do you plan to manage the keys and the changing thereof. -Original Message- From: IBM Mainframe Discussion List [mailto:[EMAIL PROTECTED] On Behalf Of Rob Schramm Sent: Sunday, October 05, 2008 4:50 PM To: IBM-MAIN@BAMA.UA.EDU Subject: Re: VSAM I/O Ulrich, I want to modify it before the original caller sees it. Additionally, if they update or write a new record.. I am looking to modify what gets written. I had considered the VSAM special processing exit, but I don't think it will do what I want. I had haven't contacted IBM yet. I thought I would digest suggestions from IBM-Main before continuing down this path. I am not looking for performance or security, just to be able to look at it .. then decide to modify it or not. Thanks, Rob -- 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: VSAM I/O
On Sun, 5 Oct 2008 12:53:34 -0400, Rob Schramm <[EMAIL PROTECTED]> wrote: >I am looking for the simplest way to intercept/modify an i/o for a VSAM >data set without impacting the application. > >All suggestions are welcome. When you say "I/O", do you mean the logical VSAM I/O, or the physical I/O that results? Assuming the former, what is the context? Are you in a position to run code in the same address space as the app, or does this have to be done via some completely external means? If the former, it is quite easy, and not hopelessly inelegant, to modify one or more of the I/O addresses in the ACB after the OPEN and before actual I/O. Whether you want to take on all the responsibility for handling the various errors that can occur during fairly normal processing, along with data and system integrity and such - well... I've done this with good success in a tightly controlled environment with non-VSAM, but I don't see any fundamental reason it shouldn't work for VSAM. If you need to catch the OPEN/CLOSE, there is SVC Screening. Limited in some ways, but not hard to use, assuming you are suitably privileged. Another approach would be to use something like GPSAM, and subsystem processing. This would be particularly good if you need to run the app externally, e.g. from JCL. There are probably better ideas, but you'd need to explain a bit more of what you're trying to do. Tony H. -- 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: VSAM I/O
Ulrich, I want to modify it before the original caller sees it. Additionally, if they update or write a new record.. I am looking to modify what gets written. I had considered the VSAM special processing exit, but I don't think it will do what I want. I had haven't contacted IBM yet. I thought I would digest suggestions from IBM-Main before continuing down this path. I am not looking for performance or security, just to be able to look at it .. then decide to modify it or not. Thanks, Rob -- 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: VSAM I/O
The simplest way is to purchase a product. It depends on what you want to do with the IO. If you want to re-direct it to other DB, you may find VS/2 (Circle) that does that. There are other products that does that, but VS/2 is the common one. Itschak On Sun, Oct 5, 2008 at 6:53 PM, Rob Schramm <[EMAIL PROTECTED]>wrote: > I am looking for the simplest way to intercept/modify an i/o for a VSAM > data set without impacting the application. > > All suggestions are welcome. > > Rob Schramm > > -- > 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: VSAM I/O
On Sun, 5 Oct 2008, Rob Schramm wrote: > I am looking for the simplest way to intercept/modify an i/o for a VSAM > data set without impacting the application. > > All suggestions are welcome. > > Rob Schramm What occurs to me is to "hook" OPEN. If the dataset is one that you want to intercept, then put your own I/O routine address into the ACB. That way the VSAM I/O instructions will go to your routine. Another possibility is something like BLSR. Make your own subsystem. Have the step have two DD statements. The one that they OPEN would you the one with your subsystem allocated to it. The other DD would have the actual DSN. When they OPEN your subsystem DD, you open the associated DD. They do I/O which goes to your subsystem. It can then do whatever processing it wants to against the associated DD for whatever request came in from the program. Hope this makes sense. Look at the doc how how BLSR works. -- Q: What do theoretical physicists drink beer from? A: Ein Stein. Maranatha! John McKown -- 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: VSAM I/O
In a message dated 10/5/2008 11:55:34 A.M. Central Daylight Time, [EMAIL PROTECTED] writes: >I am looking for the simplest way to intercept/modify an i/o for a VSAM data set without impacting the application. I only know of one way to intercept/modify an I/O of any kind, and it is not simple. You must insert a front-end for an IOS module that is involved with the normal processing of an I/O request before it is started with the SSCH instruction. There are several different modules from which you could choose, but in all cases this is an extremely non-trivial task, your code that inserts the front-end must be authorized, and your code that runs when the I/O is intercepted must be bullet-proof with industrial-strength recovery. If you are not faint-hearted and have a sandbox system that you can crash at least 20 times, email me offline for further enlightenment. And intercepting the I/O is an order of magnitude easier than modifying it once intercepted. The reason that modifying it is so hard is because of the vast complexity of DASD channel programs, all possible variations of which your code must support. Bill Fairchild Rocket Software **New MapQuest Local shows what's happening at your destination. Dining, Movies, Events, News & more. Try it out! (http://local.mapquest.com/?ncid=emlcntnew0001) -- 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: VSAM I/O
Rob, What is it that you don't like about this VSAM I/O? Or what is it that you want to do with it? Allow it? Disallow it? Modify it? Add buffers for performance? You're going to have to tell us a little more about your problem, so we can come up with a good answer. Regards, Ulrich Krueger -Original Message- From: IBM Mainframe Discussion List [mailto:[EMAIL PROTECTED] On Behalf Of Rob Schramm Sent: Sunday, October 05, 2008 09:54 To: IBM-MAIN@BAMA.UA.EDU Subject: VSAM I/O I am looking for the simplest way to intercept/modify an i/o for a VSAM data set without impacting the application. All suggestions are welcome. Rob Schramm -- 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
VSAM I/O
I am looking for the simplest way to intercept/modify an i/o for a VSAM data set without impacting the application. All suggestions are welcome. Rob Schramm -- 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
