Experimental Physics and
Industrial Control System

Ben Franksen <[email protected]> · Thu, 9 Sep 2010 19:11:01 +0200

On Donnerstag, 9. September 2010, Marty Kraimer wrote:
>   On 09/08/2010 04:09 PM, Ben Franksen wrote:
> > On Mittwoch, 8. September 2010, Eric Norum wrote:
> >> What's the use case for this, anyhow?
> >
> > Yes, I would be interested in that, too.
>
> The following is not for an embeded system but does show a good use
> for on-line add and delete.
>
> Guabao Shen (BNL) is developing a "gather" service. The service uses
> a javaIOC. The javaIOC has gather records. Each gather record
> collects data from a set of caV3 records and provides the result to
> the client as an array.

Cool. This can be done in V3 (I actually did, it's in the 'fun' module), 
but it is awkward since the number of input links must be fixed per 
record type. My latest trick to circumvent this is to auto-generate 
record types with various sizes from a dbd template and in the 
application select the smallest record type that fits.

> The javaIOC also has a createGather record. The client supplies a
> list of channels to the createGather record. When the record
> processes it creates and installs a new gather record. The gather
> record can be temporary or permanent. If the record is temporary than
> after no clients are attached to the record for some fixed period of
> time the gather record is automatically deleted. If it is permanent
> it can be deleted by request.

Extra cool.

> Both on-line add and delete are required in other for this to be a
> robust service.

Cheers
Ben
-- 
"Never confuse what is natural with what is habitual."
                                                 -- Mahatma Gandhi

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System