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

[bob dalesio via Tech-talk <tech-talk at aps.anl.gov>]

IOC Core does a lot of robust, high performance, low latency coding while making a flexible process control system. The code has many millions of hours in operation. Making a pvxs needs to recreate this. It is a competent programmer that decides to toss that aside and recreate their own - in python. Understand that this pvxs server comes with the same warnings as newly written drivers.

Making something that works is pretty straight forward. Making something that fails properly is a much more difficult endeavor..

Take care,

Bob

On Mon, Feb 16, 2026 at 3:04 PM Kasemir, Kay via Tech-talk <tech-talk at aps.anl.gov> wrote:

> every database record of every IOC gets exposed as a PV.

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

 

It’s a loosely​​ coupled setup, just like the internet.

On the internet, I can add a file “hello.html” to the web server, and now  http://that.host/hello.html is accessible.

Similarly, you add a record to an IOC and now you have new potential PVs.

If I don’t tell anybody about “hello.html”, nobody will make a network connection to read it.

Same with the PVs. Having 30000 records on an IOC doesn’t mean everybody is continually looking at all of them.

You basically control what’s visible by linking to the web pages from a top-level index.html, or for the IOC example you have some top-level display for the subsystem that shows the key PVs.

The internet has so far been doing well by allowing anybody to get a free IP address, register a DNS name, and then they can create all the web pages they want. Similar with records on IOC.