number of iocs in a control system

[Emmanuel Mayssat <emmanuel_mayssat@lynceantech.com>]

That is another design question...
Do you have enough IOC in your epics control system?

Well, recently I was asked the question.
So far the number of IOC I have has been a result of location of
equipment to be controlled (cable length), load average, computer
hardware capabilities (number of PCI slots), and cost.

Are they other reasons I should take into consideration to get the
optimal number of IOC? 

In another email, I just described another design ( 1 ioc per controlled
device ) which could enable easy upgrade when hardware is changed or new
devices to control are added.

So are they high level design decisions (such as how easy it is to
upgrade) that should impact the number of IOC I have?

--
Emmanuel