1. Aida; Accelerator Integrated Data Access
Middleware Continued
Episode 3; Verdi’s Revenge
M. Claussen, R. MacKenzie, R. Sass, H. Shoaee, K. Underwood, G. White
Could be pronounced ADA?
Now that we have an acronym it might start getting real.
May
EPICS Collaboration Meeting - Paul Scherrer Institut

2. The Un-classic not-so-thin client with a JVM & XML
In the Last Episode…
The Un-classic not-so-thin client with a JVM & XML
CDEV CORBA compliant ORB Channel Access
CORBA compliant ORB
Non-IOC
Application
Cloud
CDEV CORBA compliant ORB Channel Access
CDEV CORBA compliant ORB Channel Access
IOC Applications
May
EPICS Collaboration Meeting - Paul Scherrer Institut

3. EPICS Collaboration Meeting - Paul Scherrer Institut
The Current Episode
Support get/set/monitor any data from/to any source
We’re looking at several Corba Telecom services to support monitors and message logging.
Notify Service build on Event service. Can subscribe, filter etc. Not a CA replacement but may allow us to do CA-like monitors. Has a nice GUI that allows you to look at all “Channels” and filters and see what’s happening.
May
EPICS Collaboration Meeting - Paul Scherrer Institut

4. EPICS Collaboration Meeting - Paul Scherrer Institut
Supporting Ideas
Name and schema mapping
Data location discovered at runtime.
CORBA middleware & services
Server resilience (auto reconfigure on server down)
API and OPI
Language and OS independent
Collections, Aliases, Range Names
Have supporting databases that does hierarchical and networked-like name resolution.
Aorba doesn’t have failover built in yet but there’s a spec and a committee. If we wait long enough it may do most everything.
Object Programming I/F. Corba is OO so try to support both.
Static (system) and dynamic named collections are important.
Pick out pieces of arrays
e.g. SECT27:WIRE:[ ].TWISS.MEAS.X..PSI
May
EPICS Collaboration Meeting - Paul Scherrer Institut

5. Name and Schema Mapping
Gere’s a sample logical record and data it can access.
You discover this using the name service which will be hierarchical, collections, regular expressions and a partridge in a pear tree.
Each name.attribute{.attribute}0+ maps to a database query
May
EPICS Collaboration Meeting - Paul Scherrer Institut

6. EPICS Collaboration Meeting - Paul Scherrer Institut
Salient Features
Given a name.attribute, AIDA finds the source and appropriate query
Uses its own name services
Data Location and Query persist/cached (not rediscovered)
C++ & Java Bindings
Can code as API or OPI
As API can have Aida servers that can be used as in a procedural program.
May
EPICS Collaboration Meeting - Paul Scherrer Institut

7. EPICS Collaboration Meeting - Paul Scherrer Institut
Simple OO Example
Class QUAD {
private AIDA d;
QUAD( string name ) { d = new AIDA(name); }
float get( string attribute ) {
return d.get(‘’B_desired’’); }
float[2][6] getTwiss() {
org.omg.CORBA.Any t= d.getAny(‘’Model.Twiss’’);
...
QUAD fred(‘’quad:pr04144’’);
float bfieldwanted = fred.get(‘’B_desired’’);
float twiss[2][6] = fred.getTwiss();
First example is QUAD magnet. The program wants to get both the desired B field of the quad, and its Curant Snyder, or “Twiss” parameters. So first it instantiates a QUAD with its name. The constructor of the QUAD instantiates an AIDA object telling it the name.
The AIDA object constructor [d = new AIDA(name) ] does all of the processing to work out which server and service (if we use services) is responsible for the named QUAD. It does as much processing as it can with the information given.
Then when an attribute of the quad is wanted the application level QUAD class get() uses the AIDA get() to get the “B_desired” attribute. In this example the attribute the application wants is hard coded, but AIDA supports attribute discovery as one of its basic goals. This example is just for simplicity.
The second get shows how we use the CORBA Any system to get an arbitrary type. In this case a 2 dimensional array is requested – the twiss parameters from the example name mapping 2 slides ago).
May
EPICS Collaboration Meeting - Paul Scherrer Institut

8. EPICS Collaboration Meeting - Paul Scherrer Institut
Where We’re At
Have a complete set of requirements.
Accessed EPICS & old SLC data via Corba.
Java Corba -> JDBC -> Oracle
C++ Corba -> ODBC -> Oracle
Sample Name & attribute databases with query mapping to get data
Have a Java Orb on VMS
Testing Notify Service for Monitors
Ready to implement something real
We’re prototyped all the basic paths.
Have a bit more exploring to do and then
Aida vs. CDEV
Arbitrary hierarchical / networked namespace including aliases, collections etc.
Namespace and mapping in Oracle.
VMS Java Orb made me a Java believer
Interfaces all defined in IDL
What’s next?
May
EPICS Collaboration Meeting - Paul Scherrer Institut

9. EPICS Collaboration Meeting - Paul Scherrer Institut
Cosmic CUD
MANAGE
CUD
DISPLAYS
IOC
SLC DB
Alpha
SCP
CUD
DISPLAY
Aida
Fighting Mad CUD disease!!
Control System Migration Challenge
Continuously Updating Displays
Current system is a hodgepodge of Old and a Kludged EPICS interface
Used heavily in the Control Room
OLDs CUDS are hand coded
Need to display data from anywhere in the system
Uses most of the basic pieces; Monitors, get/put multi database access.
CUD
DISPLAY
Oracle CUD
Configuration
May
EPICS Collaboration Meeting - Paul Scherrer Institut