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1. 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 - that would be bad for orbit correction for instance, since most magnets in the linac will be SLC control system. Similarly, the SLC-aware-IOC and EPICS BPM acquisition API will allow both an XAL based application, or the SCP, to acquire IOC hosted BPMs, but are there "classical" SLC BPMs that must be acquirable by XAL applications.
   

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   WindowsFilesystem WindowsFilesystem

2. Windows filesystem.
   If we do require native execution on Windows that decision should be made clearly and early, and resources assigned to implement the common executable and configuration file distribution so that Unix and Windows running applications are in sync and see the same configuration files. Java Web Start and Eclipse update site technology may be places to find solutions.
   

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   XAL_nocoupling XAL_nocoupling

3. XAL Plane Coupled modeling.
   The existing XAL probes for calculating R-matrices, run on either the X-plane or Y-plane and returns only a 2x2 matrix for each element. That is, it's uncoupled. This is reflected in the fact that only the Twiss parameters can be stored into an XAL file - it only contains uncoupled optics. It may be that XAL is in fact tracking a plane coupled system, but only returning the X or Y plane block-matrices - need to verify. So, if plane coupled orbit correction is important for us, we need to verify what XAL is doing, add at least 4x4 probe API, also probably also 6x6 tracking.
4. XAL Modelled acceleration and solenoid. XAL does not model acceleration nor solenoid field
5. Archiver. Which one?
6. 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.
7. Scripting. It may be that the requirement for user-level scripting of complex operator procedures is a requirement that should not be minimized.

REQUIRED ADDITIONS TO SLC CONTROL SYSTEM

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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

This section lists outstanding questions. Questions that have been answered are listed below in Answered Questions.

Questions about requirements

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   AnchorverifyAFSclientverifyAFSclient Verify AFS client for Windows is not workable. AnchorbestWindowsX11bestWindowsX11 Find best performing Windows X11 server for JFC/Swing clients.

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   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).

2. 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?
3. Does XAL really not model acceleration? If not how is it useful for SNS?
4. Verify that XAL does not model a plane coupled system.
5. Does XAL offer matrix manipulation, linear algebra and fitting adequate for the LCLS? Ans: yes, uses JAMA.
6. 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.

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   q_numbeamlines q_numbeamlines

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

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R&D

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

Matlab

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1. Are we going to offer user-level scripting for automating complex procedures such as "turning on the Injector" (per Galayda)? see R&D scripting.

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   q_slchist q_slchist

   Will SLC history data be streamed to the EPICS archiver and then turned off? This depends on whether there is an adequate viewer.

Questions about "Systems"

1. Anchor
   verifyAFSclient verifyAFSclient

   Verify AFS client for Windows is not workable. If an AFS client for

2. Anchor
   bestWindowsX11 bestWindowsX11

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

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.

Scripting

Are we going to attempt to provide a scripting interface to the applications themselves? Clearly one can "script" EPICS and AIDA data exchanges, from say matlab, but this kind of scripting does not include canned user-level procedures as offered through the applications' APIs because the applications themselves incldue a lot of code which will not be available through the EPICS/AIDA interfaces. User level GUI scripting may be possible by direct interface to X11

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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.

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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

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1. XAL http://www.sns.gov/APGroup/appProg/xal/xal.htm
2. XML entry in Wikipedia http://en.wikipedia.org/wiki/XML

3. Anchor
   ref_latticefiles ref_latticefiles

   LCLS lattice files http://www-ssrl.slac.stanford.edu/lcls/linac/optics/
4. JAMA http://math.nist.gov/javanumerics/jama/

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   ref_XAL_applications ref_XAL_applications

   http://www.diamond.ac.uk/CMSWeb/Downloads/diamond/Events/EPICS/XAL_Applications_Correlator_Framework.pdf

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ANSWERED QUESTIONS

This section lists questions that have been answered since the birth of this document.

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