EPICS V4 Working Group G+ Hangout 2015-04-07


1. Status updates

2. Competing V4 AreaDetector Plugins

Planning for FRIB week:

3. Developer Meeting Topics (Monday, Friday AM)

4. EPICS V4 Introduction session

5. Any Other Business
   Next Hangout: No ANJ on 4/21, so 4/14 or 4/28?


Present: MK, DH, UP, RL

Scribe: AJ

AJ posted the wrong time on the Hangout invitation, apologies if anyone missed it because of that (the email agenda to the list was correct).

Status updates

MK: Editing on developers guide, pvaPy doesn’t have support for unions yet, created a branch to implement that and show to him before agreeing how to complete.

AJ: Question about not using EZ (easy) in names.

MK: Probably too late to change that now.

DH: ADpvAccess uploaded, looking at pvTools, and adding different providers which Greg asked for and MS didn’t have time to do. Was working on docs and normative Types, waiting for input Greg.

RL: Nothing to report.

Competing V4 AreaDetector Plugins

UP: Will be discussing this in the AD group, some NSLS guys will be attending too to discuss (Diego and Bruno). Either solution should be fine, hoping the V4 guys will tell us which is the better solution

DH: Fairly simple code just copying data, but Bruno’s code doesn’t copy the attributes. That’s one of the fairly substantial parts of my code. VAL field can be of any type but Bruno’s encoding uses the size of the data type, doesn’t handle unsigned data types, missing one of the timeStamp fields; Only attribute set is color mode, and that is done wrong. My solution uses zero-copy whereas he does copies.

AJ: Difference between interfaces?

DH: Not really, all have port, address, PV name. Follow standard AD pattern, his names are a bit more generic. Don’t know anyone who’s tried building mine (except me).

MK: Haven’t been keeping up with AD meetings, will try to attend.

Developer Meeting Topics for FRIB

DH: Tentative program shows wrong days…

AJ: I emailed Larry Hoff to try and change that. What subjects do we want to cover on the Monday & Friday AM.

AJ: pvRequest will come up…


EPICS V4 Introduction session

MK: Talks will be based on Developers Guide, we’re working on updating that.

MK: Thurs 2pm to 4:15 we could fill that whole time, maybe with a break.

AJ: Suggest 2 hours if possible, to allow for a close-out talk at the end?

DH: Not very much time to do an API-level introduction. Sent Marty my ideas.

MK: We have to think carefully what we’ll cover, pick parts of the DevGuide.

DH: Need a subset of the guide for what we’ll cover.

MK: Agree what parts to cover, for each section and give simple examples for each.

DH: This is the TOC for the talk, possibly also for the DevGuide.

  1. Overview of V4
  1. V4 Modules
  2. Brief description of modules: pvData and pvAccess. pvDatabase, normativeTypes, pvaSrv, easyPVA, pvaPy
  3. pvData and pvAccess
  4. Data types and Channel Services
  5. Normative Types
  6. EPICS V4 resources and website
  7. Where to find information (getting started guide, developer guide, pvAccess spec, NT spec, downloads, repos)
  1. Building and running EPICS V4
  1. Building from tar
  2. Building from repos
  3. Running examples and pvAccess tools
  1. pvaSrv example
  2. pvAccess tools
  1. pvget
  2. pvput
  3. pvinfo
  4. pvlist
  5. eget
  1. pvDatabase example
  2. Service example
  1. APIs for pvData
  1. pvData
  2. Introspection and data APIs
  1. Field and PVField class hierarchies
  2. Creating simple structures
  3. Scalars and scalar arrays
  4. Nested Structures
  5. Unions
  6. Structure and union arrays
  1. Standard fields
  2. Normative types
  3. Example of one type, e.g. NTScalar
  1. Servers and Clients
  1. Writing a pvDatabase example
  2. Writing an RPC Service example
  3. easyPVA example
  1. [Brief intro to] pvAccess API

DH: What we can cover depends how much time we can get.

AJ: How much time do you want?

DH: Was basing this on a half-day. We can’t do all the above in 90 minutes. We could still do the Monday afternoon, we just don’t get to the V4 meeting.

AJ: Depends

AI on AJ: Andrew to talk to Larry to find out how much time we can get, email group.

Any Other Business

AJ: Next meeting? Can’t do 4/21

MK: MS and I will be at BNL April 27-29.

AJ: Next week then if there’s anything to discuss.