SLAC ESD Software Engineering Group
Stanford Linear Accelerator Center

The History of CHADS
The Porting of CHADS to dpTestHist under the
GrenAIDA-newLabour AIDA Release.


This page presents the history of CHADS and also
the work that was done to port CHADS to run under the lastest release of AIDA.

What's this project all about?

In the beginning, I created a program called CHADS (Channel Archiver Data Source). Chads was without form, and void; and darkness was upon the face of the deep. Then I said, let me port Chads to dpTestHist under the lastest release of AIDA.

The porting of Chads to dpTestHist provided a c++ server to replace the java server which George/Greg wrote. That new c++ server is called and runs under the GrenAIDA-newLabour AIDA Release.

This new DpTestHistServer optionally calls the EPICS Channel Archiver to return real history data instead of just returning static hard-coded test data like does.

The next phase of this project is to provide the actual History Server called It will also run under the GrenAIDA-newLabour AIDA Release.

Here's what George/Greg wrote about returning history data through GrenAIDA newLabour:
With the latest release of AIDA, it is now possible for AIDA data providers to choose to return a "raw" Any, for instance, one that has been populated by streaming data into an Any from a IDL defined struct via the insert() Helper routine of that struct. An example case is if the Data Provider is returning data that is already available through CORBA as struct. Another example (as right now) is when the c++ implementation of DaValue is not yet available, so the utility routines for populating it, and for converting it to an Any (toAny) are not yet available, but we still need to return a structure.

For these reasons this Aida Data Provider ( has been written to test the raw CORBA any handling of Aida, and illustrates the use of an IDL defined structure, histData.

(the comments above are from George/Greg's file $AIDA/idl/dpTestHist.idl). is here: $AIDA/edu/stanford/slac/aida/dp/dpTestHist

The History of Chads

The dpTestHist Release

What was done initially for the dpTestHist Server release? This list is in no particular order.

What were the final steps for the dpTestHist server release? This list is in no particular order.

Performance Issues:

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Author: Ron MacKenzie 08-Jan-2003
Modified by: