How to automatically update time in cics

Question

I have two questions first is the main one. 1. I was able to display date in a cics map but what i need is, i want it to be ticking i.e., it should be display everysecond updated. 2. I have a COBOL-DB2 program which automatically inserts the data from database(DB2) to a file. I want this program to be called on a timestamp basis i.e., every 1hr, 2hr, or every day.

Thank you

Answer 1

This is not possible in standard CICS using maps. The 3270 protocol does not lend itself to continually updating screens. The majority of automatic updating screens such as consoles and monitoring displays use native VTAM methods, building their own data streams.

It might be possible to do this using unformatted data, but I would not recommend it in CICS. Pseudo-conversational CICS does not have a program in control during screen display, and conversational programming is highly discouraged.

Answer 2

You can do this, but you will need to change modify traditional psuedo-conversationl approach. Instead of returning and waiting for a user event, you can start your tran after some number of seconds with your current commarea and quit. If a user event occurs in that time, you can cancel your start request, if it doesn't, you can refresh the screen timestamp and repeat.

It is kinda a pain just to get a timestamp refreshed. Doesn't make much sense to bother with unless you have a really good reason.

The DB2 stuff is plain easy. Start your tran using interval control, the same START AFTER() described above, and you can have it run hourly, or bihourly, or whatever.

Answer 3

I don't think that you need to modify your pseudo-conversational approach to achieve what you need. Just issue a EXEC CICS START command with a one second delay (just do this once) for a small program that just issues a Send Map (or TC Write) to the terminal facility. Ideally reserve a common area on the screen so all transactions can use a common program. At some point, when the updates are no longer required, CANCEL the START request.The way I see it, the timer update transaction will mix in nicely with you user-initiated transaction flow. If a user transaction is active when the start timer pops, the timer update program will just be delayed a little.

While this should work, you need to bear in mind that you might be driving 3,600 transactions per hour for each user. Is this feature really worth all that?

Answer 4

You can't really do this in CICS, which was designed for pseudo-interactive responses at best. It was designed for use on mainframes where your terminal was sent a whole page or screen, the program read the screen as received (which has some fields the user would update and if you didn't change them the terminal did not send the data back) then, the CICS transaction having taken a part of a screen containing changes, sends the response back and quits.

This makes for very efficient data entry and inquiry programs. But realize, when the program has finished processing the screen, it's quit, it's gone, and it's not even in memory any more, all the resources have been reclaimed. This allows the company to run a mainframe with 300 terminals and maybe 10 megabytes of real memory, because when the program is waiting for you to respond, it's not using any resources at all, if there are 200 people running a data entry program, they are running a re-entrant program in which all 200 of them are running the same copy of the same program and the only thing they're using is maybe 1K of writable storage per user for the part that has to read a screen or a file record and do some calculations. Think about that, 200 people are running the same program and all of them, simultaneously, are using one module that uses 20K of memory for the application - and it's the same 20K for every single one of them - and 1K each of actual read/write data.

Think about that for a moment, the first user to start that data entry program uses 20K of memory for the application, plus 1K for the writable data. Each user after that who is being processed on that program uses an additional 1K of memory, that's all. When they're sitting there looking at the terminal, all they might be using is 4 bytes in a table to tell the system there's a terminal connected. No resources are used at all.

To be able to have a screen updated on a regular basis means that something has to keep running, which is not something CICS does very well. CICS is not intended to be used for interactive processing the way a PC does because you're actually running live on the PC.

Answer 5

EXEC CICS ASK TIME END-EXEC to update the timestamp. EXEC CICS SEND MAP DATA ONLY END-EXEC to update the screen.

However, using the suggested EXEC CICS START TRANSID ('name' | namefld) DELAY (time) END-EXEC. is actually the better way.