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Subject: V4 Database Access
From: Ralph Lange <Ralph.Lange@bessy.de>
To: EPICS Core Talk <core-talk@aps.anl.gov>
Date: Wed, 15 Jun 2005 16:47:12 +0200
Another thing that I recently found missing:

I think we agreed to introduce APIs between the IOC database and the CA server that allow - other (network) servers to register with the database (as listeners being interested in getting events) - other (database kind of) things to register as a new provider of "records" (i.e. named DA property catalogs)

Where's the new thing (module, service, handler?) that provides these interfaces?

Seen from 3.14, this takes over some of the functionality that has been in the database and some from Channel Access. It should handle record name resolution and connection to DA interfaces (to handle requests coming in from servers). It should also work as an event handler (broker?) that software modules (like a server or the Vampire) can subscribe to and the database can post its events to that get distributed to the registered listeners.

I'm not sure about the design as all this definitely sounds like a local cut-down version of channel access. If we introduce client-specified monitor deadbands - should handling these deadbands by client be moved from CAS down into that layer to make it available for other transports/servers?

I'm not trying to impose anything here ... it's just that the Vampire needs to intercept db_post_event() and add more channels to the IOC record namespace, and I don't know at which level that would be done.

Cheers,
Ralph


Replies:
RE: V4 Database Access Jeff Hill
Re: V4 Database Access Ralph Lange

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