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

[Mark Rivers via Tech-talk <tech-talk at aps.anl.gov>]

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