We are trying to change to channels and containers from DFHCOMMAREA. Most of our existing code is AMODE(24). will it work, if we simply change the existing link and xctl commands to use channels to pass data. If yes, is there any performance considerations related to AMODE(24) programs to use channels?
Right now, we plan to change it as (single channel / multiple containers for a trans) as a replacement for COMMAREA.
Or is it wise to use multiple channels ie. channels for each functionality within a transaction?
I have looked at the best practices for the migration. But need to know if we should expect any issues during migration? anyone performed such activity before, plz let me know if factors to be considered?
Joined: 08 May 2006 Posts: 1099 Location: Dublin, Ireland
Most of our existing code is AMODE(24). will it work, if we simply change the existing link and xctl commands to use channels to pass data.
Is there a reason why, when you recompile your programs to make this change, that the programs will remain AMODE(24)? These days, most languages will compile to AMODE(31) and linkedit/bind as RMODE(ANY).
The choice of whether to use single channel/single container or single channel/multiple container would depend on application design.
Joined: 14 Jan 2008 Posts: 2504 Location: Atlanta, Georgia, USA
A heads-up for you regarding Channels/Containers. Since CICS/TS 3.2, they are stored "above the bar" in 64-Bit storage defined to the MEMLIMIT during Startup. Keep in mind that although they're stored in 64-Bit storage, when an application requires access, the Channel/Container is processed in your 31-Bit EUDSA (ask your CICS SYSPROG), so ensure that they're not too big. In fact, IBM warns customers about large Channels/Containers and region degradation, with SOS possibilities. Your CICS SYSPROG will probably have to increase the EDSALIMIT in the SIT.