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<== Date ==> <== Thread ==>

Subject: Re: Where is histogram?
From: "Southern, Tim" <[email protected]>
To: [email protected]
Date: Fri, 9 Feb 2018 11:07:44 -0500
Hi,

I am replying to a rather old tech-talk post: https://epics.anl.gov/tech-talk/2011/msg01310.php

I was attempting to use the histogram record type on epics base R3.14.11. It threw the following errors when building:
- Record "TEST:Histo" is of unknown type "histogram" - Error at or before ")" ...
- Missing device support entry table PV: TEST:Histo histogram: init_record

To be able to use this record type, I had to install the record's dbd in the application src directory.
1) Add histogramRecord.dbd to src/Makefile
   ie. <App>_DBD += histogramRecord.dbd
2) Create a dbd file with following contents saved in src folder. ie. Filename: histogramDeviceSupport.dbd
   device(histogram,CONSTANT,devHistogramSoft,"Soft Channel")
3) Add above dbd to src/Makefile
   ie. <App>_DBD += histogramDeviceSupport.dbd
4) Type 'make' in src directory

This recipe will allow the record type to work on base R3.14.x . The record appears to have been corrected on base R3.15.x without needing to added it to base.dbd.

Cheers,
Tim 


Hi Mark,

On 2011-07-21 Vigder, Mark wrote:
> I started building an IOC using the histogram record and it gave me an
>  "unknown type" error. I checked the source (I'm using EPICS 3.14.12) and
>  even though the record is defined in <EPICSBASE>/src/rec it's not included
>  in <EPICSBASE>/src/misc/base.dbd. In fact it's the only record defined in
>  /src/rec that is not there.
> 
> This leads me to a number of questions:
> 
> -Is this just a bug? Or is histogram an obsolete record?

Interesting; I'm going to guess that you're not necessarily the first person 
to *notice* this, but I think you're the first to point it out on tech-talk.

I don't believe the omission is deliberate, it's just that the histogram 
record type is fairly specialized and is not used much any more.  It it looks 
like the last time anyone made any significant changes to the code (other than 
just updating it to match API and coding style changes elsewhere in Base) was 
in October 1998.

> -Does this mean nobody is actually using the histogram record?

I can answer that for the APS: we have a total of 4 (four) histogram records 
across the whole of our 320-odd IOCs and well over half a million records in 
our accelerator control system.  Any other histogram users out there want to 
speak up?

> -If nobody uses histogram, what do they use? Waveform?

I would guess other people are using subroutine or array subroutine records, 
and for some uses just a calc or calcout record might suffice.

- Andrew






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