Command completion/transaction processing

["Peregrine M. McGehee" <peregrine@lanl.gov>]

In the spirit of Ron Nelson's recent posting about Java, I'd like to 
mention that during the course of the EPICS meeting there were also 
discussions about the need to add a robust mechanism for command completion 
a.k.a. transaction processing within EPICS Base. This also concerns the 
issue of supporting higher levels of device abstraction within the IOC 
software.

The first step in this direction is to determine how much of this goal can
be achieved using existing components of EPICS (custom records, R3.13 CA 
links) and already planned (new server) developments within the toolkit.

As many of you know, there are multiple attempts at solutions to these 
issues currently in use throughout the community. These were described in 
the survey of automation techniques presentation (converted from Microsoft 
PowerPoint - includes original) - 
 http://www.atdiv.lanl.gov/aot8/epics/meetings/automation/index.htm

I understand the LANSCE-12 is in need of a short-term solution to 
transaction processing - and for some of the subsystems I'm developing here 
for LEDA I'd like to add a "better" command completion interface than the 
familiar CAD/CAR/APPLY.

Those involved in the discussions were:

Ned Arnold 		APS	(nda@aps.anl.gov)
Marty Kraimer 		APS	(mrk@aps.anl.gov)
Tim Mooney 		APS	(mooney@aps.anl.gov)
Kim Gillies 		GEMINI	(gillies@noao.edu)
William Lupton 		KECK	(wlupton@keck.hawaii.edu)
Bob Dalesio 		LANL LANSCE-8	(dalesio@lanl.gov)
Jeff Hill 			LANL LANSCE-8	(johill@lanl.gov)
Peregrine McGehee 	LANL LANSCE-8	(peregrine@lanl.gov)
Ron Nelson 		LANL LANSCE-12	(ron@lanl.gov)
Steve Hunt 		PSI	(hunt@psi.ch)
Andrew Johnson 	RGO	(anj@ast.cam.ac.uk)	
\
A short - and probably incomplete - list of topics that came up in 
discussion
follow:

Transaction processing
	- short term solution for LANL LANSCE-12
	- issue: potential releasing of lock-sets before put_callback completion
due to asynchronous records

Command interface
	- yet another custom record?
	- PCAS application?
	- has to be accessible from within the database as well as across the
network.

Data representation
	- support under new server?
	- new device support layer?
	- conversion (packing/unpacking) between CA formats and traditional DB
formats - special records?

New server
	- CA links between traditional IOC records and process variables managed
by the new server
	- use of new server applications ("server tools") as gateways to other
protocols (ex. CORBA IIOP).

Aloha,
	Peregrine

Peregrine M. McGehee		Project Engineer: LEDA Control System
(505) 667-3273			peregrine@lanl.gov	
LANSCE-8 Controls & Automation	Los Alamos National Laboratory