Experimental Physics and
Industrial Control System

"Hartman, Steven M." <[email protected]> · Thu, 1 Mar 2018 18:32:09 +0000

> On Feb 28, 2018, at 6:52 PM, Andrew Johnson <[email protected]> wrote:
> 
> When we’re developing instrumentation for an experiment that may have a
> 25-year or longer lifetime, we have to be careful to avoid depending on
> software that has a low bus factor. 

Looking back at EPICS history, the yet-another-display-manager interval (YADM_i) is approximately ten years. About once a decade, a new display manager came along that became the de facto standard for the other new facilities that were built in the following period. 

 * edd/dm (LANL), late 1980s
 * medm (APS), late 1990s
 * edm (SNS), 2000s
 * css (initially DESY, then joined by others), 2010s

(Dates are approximate.)

The 10 year interval seems reasonable given changing technology and expectations for user interface software. This interval may be expected to become shorter in coming years with faster technology evolutions. But it is important to note that of those four applications listed above, only edd/dm is no longer widely used. (And I would not be totally surprised if someone responds to say they are still running edd/dm on an old SPARCstation somewhere.)

The effort required to replace a display manager for a large running facility is quite significant. And these facilities have lifetimes measured in decades. I would caution that choosing a display manager, or choosing to build and maintain a new one, is a long term commitment that should not be taken lightly. 

-- 
Steven Hartman
[email protected]

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System