Experimental Physics and
Industrial Control System

Tom Pelaia <[email protected]> · Tue, 24 Mar 2009 13:21:49 -0400

Hi,

At SNS we use JCA/JNI for production and use JCA/CAJ for testing

through the gateway outside the controls network. JCA/CAJ is more

convenient for external use since it doesn't require the EPICS

libraries and JNI plugin to be present on the client machine. However,

we encountered serious issues with earlier versions of CAJ, so it

isn't accepted for use inside of our controls network. In particular,

there was an issue with IOC crashes being correlated with CAJ clients.

That may have since been fixed. Another issue which may have also been

fixed is that channels would sometimes fail to reconnect

automatically. We also encountered connection issues when attempting

to connect thousands of channels using CAJ.

Basically, JCA/JNI tends to be more acceptable for production since it

uses the native CA libraries that are supported in the EPICS

community. JCA/CAJ is a very good, convenient, pure Java attempt at

implementing the same CA client protocol, but since it isn't the

"official" CA implementation it isn't as well accepted. More testing

will be needed to provide confidence in JCA/CAJ for use inside the

controls network.

best regards,
tom

On Mar 24, 2009, at 12:19 PM, GaryCarr wrote:

Here at LANL/AOT-IC we are just starting to replace JCA1 with JCA2

in our Java applications. Since moving between JCA2 and CAJ is just

a one line code change, I have run my applications with both, and

don't see any real differences between the two. A couple of questions.

How many people are using JCA2?

how many people are using CAJ?

Is there any reason to choose one over the other?