EPICS sequencer update

1
EPICS sequencer update

• Greg White / William Lupton
• greg_at_slac.stanford.edu /
• wlupton_at_keck.hawaii.edu
• EPICS 99
• SLAC, May 27, 1999

2
Changes made in the last year

• Various minor bug fixes
• applied in parallel to base and local
  versions
• Local version converted to work with
  makeBaseApp
• in ANL CVS but not yet released to community
• Good progress on conversion to use Marty
  Kraimers OSI (operating system independent)
  layer
• Greg White (SLAC) will be working on syntax
  extensions

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Local version

• In use at Keck for 3 years
• Major change is support for monitor queues
• dont miss events, even when posted in rapid
  succession
• useful for subsystem coordination and command
  completion
• Details at 1997 EPICS collaboration meeting

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makeBaseApp version

• Contains the local version
• NB, question mark over sequencer deletion (may be
  broken in base version too?)
• Includes Andy Kozubals v1.9 manual
• will be updated to describe new features
• Standard version will remain in base for some
  time? (eventually unbundled)
• individual sites will be able to choose version

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Running sequencers under Unix

• Sequencer run-time support code has been
  converted to use Marty Kraimers OSI layer
• OSI has been implemented for POSIX under Solaris
  and Linux
• Can run an EPICS sequence (with multiple
  state-sets) as a single Unix task
• can debug and test using Unix tools
• can deploy in either environment

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Further details

• In sequencer run-time support code,
• taskXxx() calls become OSIthreadXxx() calls
• semXxx() calls become OSIsemXxx() calls (etc.)
• Under Unix, xxx.st becomes executable xxx
• main thread supports command line input (seqShow
  etc.)
• Code contains no ifdef SOLARIS tests

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To be done

• Tidy up loose ends, e.g.
• Unix version of taskwd routines (in OSI?)
• ca_import(), ca_import_cancel()
• remove libCom.a dependence?
• Add CDEV support (c.f. medm and alh)
• Add ability for sequencer to serve its own
  channels?
• larger issue with OSI, entire IOC functionality
  (except hardware access?) can be replaced by a
  single Unix task
• Document and make available to community

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SNL syntax extensions (1)

• Entry and exit actions
• entry action before first when
• exit action after last when

• Option not to reset delay timer on transition to
  same state
• when enabled, delay is always measured from
  initial entry to the state

state fred entry / when clauses
/ exit
state fred option t / affects state
/ / reverts to default /
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SNL syntax extensions (2)

• Subroutines
• if no args, can use macro
• if no PV-assigned names, can use regular C
  routine
• so only interesting case is where there at least
  one argument is a PV-assigned name
• Will require pre-declaration of such routines

• For exampleint xxx( pv, int )
• implies args are PV-assigned name and int
• code for xxx() must reside within same SNL module
• IS THIS WORTH IT?
• IS IT WHAT IS WANTED?

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Other SNL additions (from 1997)

• snc error-reporting improvement
• ca_put_callback() support
• support more of C language (init, locals, ?
  etc.)
• several state-sets to share single task
• permit hierarchical states

• hooks for external C code to set and test event
  flags (from ISRs too)
• comprehensive test suite
• more?