Performance Issues Arise Moving from IDMS

[Margaret Sliming]

I worked for two companies that claim to be able to convert IDMS systems to any language and database.

I was the SME at Astadia for a move from IDMS to C# and Oracle.  

Astadia told their customer that the new application would only be three times slower than their IDMS applications.

Depending on the efficiency of the IDMS database design and how tuned application software is, IDMS is ten to fifty times faster than any distributed replacement application.  

The first thing you need to do with your project is a proof of concept with your new architecture to compare how long a process takes in the new environment versus with IDMS.  You may not be able to get all of your processing done within a 24-hour period on a distributed platform.

Tennessee Gas Pipeline (Tenneco) went bankrupt when they moved off of IDMS for this very reason.  They were not able to keep up because the new applications did not complete in a timely manner.

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[John Abell]

I agree with with your comments but we have seen a few instances, emphasis on a few, that did work because of careful and proper planning.  We have yet to see any conversion where the throughput of high volume transaction applications on IDMS can be met off platform.  I assume that, in the 2 cases that you mentioned, the ones that made the original decisions to convert were long gone before the projects failed. 

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[Margaret Sliming]

Sorry, I did not communicate that well.  Only the web screen and Distributed code (presentation layer) is moved off the mainframe.  This is the cause of most of the load on IDMS.  ADSO holds resources while the user is sitting at the screen.  Using Java as the distribution language, it calls an Access Module which has been created from the ADS dialing.  Response processes are made into mapless dialogs.  This way, Online programs are only in IDMS for a fraction of a second instead of minutes. The only difference is the user communicates with a web screen instead of an IDMS map but the dialog works exactly the same as the ADSO.  This came in handy for the customer I created this for because servers were always going down but they could jump over to the mainframe version.  
I have a presentation I will be happy to give you.  In the meantime I will add it to the projects section of my LinkedIn profile.  The other big issue with IDMS performance is retrieval locks.  These were added to Release 12.0 and I was the programmer who discovered them.  I created a work around which is the difference between day and night. I helped the State of Iowa reduce their daily CPU usage by 5% by changing one dialog to use this method.

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[John Abell]

Hi,



Thanks for the note.



We have code being implemented offshore as we speak that uses the real applications with a Web front-end. Simpler than the proposed Broadcom tool and more generic.



My developer is traveling at the moment but maybe we could have a conference call when he is available about this. We have presented this solution to Broadcom and the discussions continue.



Yours truly,


John T. Abell

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