Page History

...

1. Objective
2. Desktop
3. Basic Modelling Environment
4. Architecture
5. Applications
6. Error Handling, Logging and Viewing
7. Tool Summary
8. Red Flags
9. Required Additions to SLC Control System
10. Required Solutions
11. Job List
12. Questions
13. R&D
14. DetailsError Handling, Logging and Viewing
15. Glossary
16. References

...

TOOL SUMMARY

This section summarises utilities that will be used to develop LCLS applications.

Integrated Development Environments

Not a good idea to prescribe these for everyone. Three good open source choices for our technology stack are emacs+jdee, Netbeans (including matisse) and the Eclipse IDE. All three include CVS integration.

...

RED FLAGS

Some important choices or questions.

SLC CAMAC Magnet control and SLC BPM data acquisition by XAL Applications. The SLC CA server does not presently support "set" operations, so there is not presently a way for XAL applications, which use EPICS Ca through JCA, to change the value of CAMAC magents. Possible solutions are to add set to SLC CA, or to change XAL applications to use AIDA, or to accept that XAL applications can not control SLC CAMAC magnets - how bad is that . SLC BPM acquisition through JCA should also be verified, since the SLC BPM acqusition is oriented toward acquisitions of whole beamines.

...

XAL Modelled acceleration and solenoid. XAL does not model acceleration nor solenoid field

Archiver. Which one?

XAL file generation directly from Oracle. Is there a mechanism to flag items in the oracle db for inclusion in the lattice? Danger is people will edit the Oracle db to say move an item to a new z location or include a dummy bpm, and the lattice will change.

...

REQUIRED ADDITIONS TO SLC CONTROL SYSTEM

An LCLS model beamline, associated sectors and db additions in support of it, must be added.

SCP runtime problems on Linux fixed. At time of writing this includes a problem with dialog inputs, data has to be entered twice.

Pulse-id acquisition by Correlation Plots. Presently broken needs to be fixed.

...

REQUIRED SOLUTIONS

This section lists functional components of the LCLS modeling applications architecture which for which we need to decide on a vendor:

1. Numerical Analysis package, for matrix manipulation and linear algebra. Some classes of XAL extend JAMA 4, this may be sufficient.
2. J2EE compliant Application Server. Application Servers include technology for accessing databases (eg oracle) and displaying information to the web. This will be useful for displaying static control data, model information and other slow control configs etc, to the web and to the Integrated Control Program. Suggest Apache Jakarta, plus PHP, Xerces, Xalan, etc.

...

JOB LIST

Lists some jobs that might otherwise be forgotten.

1. SQL script and other munging to get from Oracle db description of geometry and devices to a lattice description in an XAL input file.
2. The XAL tracker. An XAL application which tracks the lattice and produces a 2nd XAL file containing the twiss parameters for each device, plus other per-element parameters.
3. Add acceleration and solenoid elements to XAL.
4. Check XAL's linear algebra support. Done: it uses JAMA -see ref.
5. Create a Skills Matrix for applications, eg, XML and associated technologies (DOM, XSL etc), Oracle and associated technologies (SQL, PHP, persistence).

...

QUESTIONS

...

ERROR HANDLING, LOGGING AND VIEWING

A programmer spends half their time handling errors, so making that as easy as possible is a productivity priority. For LCLS we will use the following technology stack:

Err package (see http://www.slac.stanford.edu/grp/cd/soft/err/^{Image Added}) makes the process of rigorously handling errors easy. It allows a programmer to define an error code in a structured, recorded global way; and to use that code to issue errors and associated diagnostics from or linux, solaris, windows platforms in either java or C/C++, and issue them directly to CMLOG (or some other message logger). It includes support for exception chaining ("caused-by") and exception translation, so the end user can see what systematic thing caused their functional problem (E.g. of a error logged by Err in cmlog might be "UnableToTrackBeamlineException: LCLS ; caused by FileNotFoundException: LCLS.XML when attempting to steer LCLS".

Cmlog. cmlog is a message logger that can be used for error messages. It includes components for receiving messages to log from programs running on the network (either in hosts or IOCs), logging those errors in a database, and a viewer for browsing the logged messages.

jcmlog. jcmlog is a sophisticated error log viewer for CMLOG developed at SLAC recently for LCLS. It is in general much faster and smother than the nominal CMLOG viewer from Jlab and includes facilities for handling the particular requirements of Err (above) such as horizontal scroll for long messages.

TOOL SUMMARY

This section summarises utilities that will be used to develop LCLS applications.

Integrated Development Environments

Not a good idea to prescribe these for everyone. Three good open source choices for our technology stack are emacs+jdee, Netbeans (including matisse) and the Eclipse IDE. All three include CVS integration.

RED FLAGS

Some important choices or questions.

SLC CAMAC Magnet control and SLC BPM data acquisition by XAL Applications. The SLC CA server does not presently support "set" operations, so there is not presently a way for XAL applications, which use EPICS Ca through JCA, to change the value of CAMAC magents. Possible solutions are to add set to SLC CA, or to change XAL applications to use AIDA, or to accept that XAL applications can not control SLC CAMAC magnets - how bad is that . SLC BPM acquisition through JCA should also be verified, since the SLC BPM acqusition is oriented toward acquisitions of whole beamines.

XAL Modelled acceleration and solenoid. XAL does not model acceleration nor solenoid field

Archiver. Which one?

XAL file generation directly from Oracle. Is there a mechanism to flag items in the oracle db for inclusion in the lattice? Danger is people will edit the Oracle db to say move an item to a new z location or include a dummy bpm, and the lattice will change.

REQUIRED ADDITIONS TO SLC CONTROL SYSTEM

An LCLS model beamline, associated sectors and db additions in support of it, must be added.

SCP runtime problems on Linux fixed. At time of writing this includes a problem with dialog inputs, data has to be entered twice.

Pulse-id acquisition by Correlation Plots. Presently broken needs to be fixed.

REQUIRED SOLUTIONS

This section lists functional components of the LCLS modeling applications architecture which for which we need to decide on a vendor:

1. Numerical Analysis package, for matrix manipulation and linear algebra. Some classes of XAL extend JAMA 4, this may be sufficient.
2. J2EE compliant Application Server. Application Servers include technology for accessing databases (eg oracle) and displaying information to the web. This will be useful for displaying static control data, model information and other slow control configs etc, to the web and to the Integrated Control Program. Suggest Apache Jakarta, plus PHP, Xerces, Xalan, etc.

JOB LIST

Lists some jobs that might otherwise be forgotten.

1. SQL script and other munging to get from Oracle db description of geometry and devices to a lattice description in an XAL input file.
2. The XAL tracker. An XAL application which tracks the lattice and produces a 2nd XAL file containing the twiss parameters for each device, plus other per-element parameters.
3. Add acceleration and solenoid elements to XAL.
4. Check XAL's linear algebra support. Done: it uses JAMA -see ref.
5. Create a Skills Matrix for applications, eg, XML and associated technologies (DOM, XSL etc), Oracle and associated technologies (SQL, PHP, persistence).

QUESTIONS

1. Anchor
   verifyAFSclient verifyAFSclient

   Verify AFS client for Windows is not workable.

2. Anchor
   bestWindowsX11 bestWindowsX11

   Find best performing Windows X11 server for JFC/Swing clients.

3. Anchor
   q_dbgeoonly q_dbgeoonly

   How complex is the conversion of Oracle DB to XAL lattice? Does the db contain enough to emit a lattice? Mark Woodley warns that there are probably many things necessary in the XAL lattice which need not be in the DB (marker points), and many things in the DB which should not be in the lattice. This latter class includes things like dummy BPMs, so not simply the case that everything of a given class should be in the lattice. People change the z of things in the DB. May be a good idea to have a "Skeleton" XAL file (maybe processed by xsl/php).

4. Anchor
   kmodtobdes kmodtobdes

   Verify there is no "KMOD to BDES" requirement?
   1. That is, is there a Lattice Diagnostics requirement for online applications, and a need to keep magnet "fudge factors"?
   2. Which XAL applications allow one to update the EPICs magnet k-values after a successful model run?
5. Does XAL really not model acceleration? If not how is it useful for SNS?
6. Verify that XAL does not model a plane coupled system.
7. Does XAL offer matrix manipulation, linear algebra and fitting adequate for the LCLS? Ans: yes, uses JAMA.
8. How long does XAL take to parse an XAL beamline? It has to build a DOM tree, which can't be negligible. Since that is a requirement of every XAL application at initialization its an important performance bottleneck.

9. Anchor
   q_numbeamlines q_numbeamlines

   How many beamline descriptions should there be?
10. What is the canonical list of XAL physics apps?
11. Does LCLS need SVD based orbit minimization? Is there an orbit minimization in XAL?

R&D

This section outlines some constrained R&D we should do to check architecture decisions.

Matlab

Accelerator Toolkit (AT)

See what applications are available in Accelerator Toolkit (AT). Use of matlab for applications depends on desirability of the functionality offered, responsiveness of the application in the context of a large accelerator's operations, and importantly, ability to secure licensing with manageable cost/benefit.

Specifically: Do AT applications appear to offer support for configurations necessary in a large machine (e.g. choosing from available bpms and correctors in an orbit correction package). How does it handle errors? Are bpm statuses communicated to the user interface and graphics?

Matlab Plotting

Can Matlab be used as a general purpose charting engine? This would be very much more desirable than XAL's charting if having charted the data for a plot one could easily "drop into matlab" to further analyse the data just plotted.

Filesystem and distributing software releases

Should the production executables (XAL java jar files etc) and configuration files be on AFS or NFS? Operative points in the question are that both XAL and Eclipse require that the user specify a "workspace" at startup, which defines their particular configuration. This workspace must always be writable, so AFS token expiry after 25 hrs use, can be problematic. Simplest solution is makefile "install" to a mounted NFS directory - but that directory has to be accessible by all head nodes (that is, all linux desktops running the applications).

Eclipse includes two software distribution mechanisms: first requires "pull" (the user initiates the update), 2nd is Java Web Start, which checks for updates at predefined intervals.

DETAILS

This section gives details behind architectural statements made above.

Why so definite about x86 Linux RH with KDE/GTK-2?

To create a high performance user interface we should lock down the desktop hardware. We can support more than one such configuration, such as x86 Windows and x86 Linux with GTK, but for high performance UIs we need to build for specific desktops, so we have to know what they will be a-priori. Eg, when building SWT/Jface apps, one has to target a gives set of desktops so the appropriate libraries can be included in the build

...

1. That is, is there a Lattice Diagnostics requirement for online applications, and a need to keep magnet "fudge factors"?
2. Which XAL applications allow one to update the EPICs magnet k-values after a successful model run?

...

R&D

This section outlines some constrained R&D we should do to check architecture decisions.

Matlab

...

Accelerator Toolkit (AT)

See what applications are available in Accelerator Toolkit (AT). Use of matlab for applications depends on desirability of the functionality offered, responsiveness of the application in the context of a large accelerator's operations, and importantly, ability to secure licensing with manageable cost/benefit.

Specifically: Do AT applications appear to offer support for configurations necessary in a large machine (e.g. choosing from available bpms and correctors in an orbit correction package). How does it handle errors? Are bpm statuses communicated to the user interface and graphics?

Matlab Plotting

Can Matlab be used as a general purpose charting engine? This would be very much more desirable than XAL's charting if having charted the data for a plot one could easily "drop into matlab" to further analyse the data just plotted.

...

Filesystem and distributing software releases

Should the production executables (XAL java jar files etc) and configuration files be on AFS or NFS? Operative points in the question are that both XAL and Eclipse require that the user specify a "workspace" at startup, which defines their particular configuration. This workspace must always be writable, so AFS token expiry after 25 hrs use, can be problematic. Simplest solution is makefile "install" to a mounted NFS directory - but that directory has to be accessible by all head nodes (that is, all linux desktops running the applications).

Eclipse includes two software distribution mechanisms: first requires "pull" (the user initiates the update), 2nd is Java Web Start, which checks for updates at predefined intervals.

...

DETAILS

This section gives details behind architectural statements made above.

...

Why so definite about x86 Linux RH with KDE/GTK-2?

To create a high performance user interface we should lock down the desktop hardware. We can support more than one such configuration, such as x86 Windows and x86 Linux with GTK, but for high performance UIs we need to build for specific desktops, so we have to know what they will be a-priori. Eg, when building SWT/Jface apps, one has to target a gives set of desktops so the appropriate libraries can be included in the build.

...

ERROR HANDLING, LOGGING AND VIEWING

A programmer spends half their time handling errors, so making that as easy as possible is a productivity priority. For LCLS we will use the following technology stack:

Err package (see http://www.slac.stanford.edu/grp/cd/soft/err/^{Image Removed}) makes the process of rigorously handling errors easy. It allows a programmer to define an error code in a structured, recorded global way; and to use that code to issue errors and associated diagnostics from or linux, solaris, windows platforms in either java or C/C++, and issue them directly to CMLOG (or some other message logger). It includes support for exception chaining ("caused-by") and exception translation, so the end user can see what systematic thing caused their functional problem (E.g. of a error logged by Err in cmlog might be "UnableToTrackBeamlineException: LCLS ; caused by FileNotFoundException: LCLS.XML when attempting to steer LCLS".

Cmlog. cmlog is a message logger that can be used for error messages. It includes components for receiving messages to log from programs running on the network (either in hosts or IOCs), logging those errors in a database, and a viewer for browsing the logged messages.

jcmlog. jcmlog is a sophisticated error log viewer for CMLOG developed at SLAC recently for LCLS. It is in general much faster and smother than the nominal CMLOG viewer from Jlab and includes facilities for handling the particular requirements of Err (above) such as horizontal scroll for long messages.

NAMES

Light relief - what are we going to call this system?

...