Re: [EXTERNAL] Does every DB record need to produce a PV?

["Kasemir, Kay via Tech-talk" <tech-talk at aps.anl.gov>]

Your roadmap oversimplifies a complex integration task and may give the false impression that AI-assisted coding can seamlessly replace deep domain knowledge and careful system integration. Here are some concerns:

1. Although a 50‐page manual with around 200 parameters might be amenable to some degree of automation, using GitHub Copilot in this context risks missing important nuances. The detector’s configuration, timing requirements, or error handling strategies may not be fully captured by merely templating from the epicsdev module.

2. Code generation tools like Copilot, while helpful, often produce boilerplate or even misleading code snippets without understanding the hardware-specific quirks of a detector. The approach appears to rely too much on automated suggestions without a robust review to account for hardware-specific requirements.

3. The roadmap assumes that the programming task is essentially a matter of translating parameters into Python “PVs” with a one-to-one mapping. In practice, integrating with complex hardware typically involves dedicated communication protocols, real-time constraints, and error recovery which require careful design and testing—not just a pull request review cycle.

4. While debugging with the real device might be simpler in Python than in C/C++, this assumes that the abstraction layer introduced is both stable and performant enough for production use. Handling detector data with separate PVAccess servers further complicates the system integration, and the approach does not address how to manage inter-module communication or reliability issues.

5. Relying on a link to the manual in the prompt expects that Copilot (or similar tools) will effectively parse 50 pages of domain-specific information and map it to correct code. This level of semantic understanding is optimistic, and manual intervention will likely be required to ensure accuracy.

In summary, while the proposed approach is a creative starting point, it underestimates the challenges of translating hardware specifications into robust, high-performance software. A more effective strategy would involve a detailed analysis of the manual, collaboration with domain experts, and incrementally prototyping the system with comprehensive tests that simulate the behavior of the real device.

From: Tech-talk <tech-talk-bounces at aps.anl.gov> on behalf of Sukhanov, Andrei via Tech-talk <tech-talk at aps.anl.gov>
Date: Tuesday, February 17, 2026 at 4:18 PM
To: Hartman, Steven <hartmansm at ornl.gov>, David Bracey <dbracey at fnal.gov>, Sukhanov, Andrei <sukhanov at bnl.gov>
Cc: tech-talk at aps.anl.gov <tech-talk at aps.anl.gov>
Subject: Re: [EXTERNAL] Does every DB record need to produce a PV?

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Mark, concerning your reply:

>To provide another counter-example I just checked the IOC for a >Dectris Eiger detector....

The Dectris Eiger Programming Manual is about 50 pages long and describes ~200 real parameters. I would approach support for the Dectris Eiger detector in Python using the following roadmap:

1. Create a new GitHub repository.
2. Use GitHub Copilot to generate Python support for the Dectris Eiger detector, using the epicsdev module as a template and providing a link to the Programming Manual. A well-structured and detailed prompt would improve the results.
3. Copilot generates an initial pull request.
4. Review the code and request modifications or improvements as needed (this may require several iterations).
5. Perform a final review and merge the pull request.

As a result, you would obtain a ready-to-run Python module serving ~200 PVs.

Final tuning with the real device may take several days. Debugging with the real hardware is significantly simpler in Python than in C/C++.

Processing detector data would be better handled by separate PVAccess servers.

Regards, Andrey

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From: Tech-talk <tech-talk-bounces at aps.anl.gov> on behalf of Sukhanov, Andrei via Tech-talk <tech-talk at aps.anl.gov>
Sent: Tuesday, February 17, 2026 2:18 PM
To: Hartman, Steven <hartmansm at ornl.gov>; David Bracey <dbracey at fnal.gov>
Cc: tech-talk at aps.anl.gov <tech-talk at aps.anl.gov>
Subject: Re: [EXTERNAL] Does every DB record need to produce a PV?

 

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From my perspective, an EPICS IOC with ~2000 PVs lacking descriptions, for a device without a Programmer’s Manual, is unmanageable.

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From: Hartman, Steven <hartmansm at ornl.gov>
Sent: Tuesday, February 17, 2026 12:58 PM
To: Sukhanov, Andrei <sukhanov at bnl.gov>; David Bracey <dbracey at fnal.gov>
Cc: tech-talk at aps.anl.gov <tech-talk at aps.anl.gov>
Subject: Re: [EXTERNAL] Does every DB record need to produce a PV?

 

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What makes you think this is unmanageable? There are plenty of counter examples of existing facilities where this works.

-- 

Steven Hartman

hartmansm at ornl.gov

On Feb 17, 2026, at 12:12 PM, Sukhanov, Andrei via Tech-talk <tech-talk at aps.anl.gov> wrote:

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Mark, Kai,
The multitude of the PVs, not related to real device parameters, may pose real trouble for end users. For example, we were provided with an EPICS-driven PSC (power supply controller). The controller itself has ~200 of control parameters. But the IOC hosts ~2000 of PVS. This is just not manageable without tight support from original designers.

/Andrey Sukhanov,

Collider-Accelerator Department, BNL.

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From: Tech-talk <tech-talk-bounces at aps.anl.gov> on behalf of Mark Rivers via Tech-talk <tech-talk at aps.anl.gov>
Sent: Tuesday, February 17, 2026 11:54 AM
To: tech-talk at aps.anl.gov <tech-talk at aps.anl.gov>; David Bracey <dbracey at fnal.gov>
Subject: Re: Does every DB record need to produce a PV?

 

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Hi Dave,

• A naïve user of EPICS would think that every database record of every IOC gets exposed as a PV.

Note that there is not a 1:1 relationship between records and PVs.  Even simple records like "bi" expose many record fields as PVs, not just the .VAL field.  For example, the .SCAN, .ZNAM, .ONAM, .SDIS, .DESC, and many more.  More complex records like the "motor" record have dozens of PVs, like .VELO, .ACCL, .STOP, .DVAL, .RVAL, etc.

Mark

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From: Tech-talk <tech-talk-bounces at aps.anl.gov> on behalf of David Bracey via Tech-talk <tech-talk at aps.anl.gov>
Sent: Monday, February 16, 2026 10:15 AM
To: tech-talk at aps.anl.gov <tech-talk at aps.anl.gov>
Subject: Does every DB record need to produce a PV?

 

A naïve user of EPICS would think that every database record of every IOC gets exposed as a PV.

 

Is this truly the case?  If so, has any mechanism for hiding the “internal” records ever been discussed?

 

The PV-space of an EPICS deployment seems very crowded.

 

Dave Bracey

AD Controls

Fermi National Accelerator Laboratory