When using driver versions of FacetTerm, the kernel parameter NCLIST may need to be increased because of the load FacetTerm puts on this parameter. The NCLIST parameter is a character list buffering parameter. If this value is not set high enough, some very unusual symptoms can occur. Some examples we have witnessed on user systems is the lp print system not printing anything until all FacetTerm users have logged off, different FacetTerm windows on different terminals mixing together, FacetTerm hanging inexplicably, and applications running very slow. The reason for these varied symptoms is due to what NCLIST is buffering. This parameter buffers the flow of characters to all serial devices. In this case a serial device can be defined as any printer or terminal attached to a serial port along with all windows running on one of these serial terminals. The formula below will help you calculate how high you need to increase your NCLIST parameter:
(P * 9) + (T * 9) + (W * T * 9)
where P is the total number of serial printers
T is the total number of serial terminals
W is the maximum number of windows any
single FacetTerm will be running
The W value can be a little confusing. Here is an example. Say you have all of your
users running 2 - 4 FacetTerm windows. The value of W will be 4 since this is the highest
number any FacetTerm session will be running.
This formula will give you a number to plug into your NCLIST parameter. Like any UNIX kernel parameter, you probably need to increase your calculated number a little bit to insure that you don't overload the parameter. 20% is usually a pretty good value. This is one of the few parameters that seriously over allocating does not cause major system performance problems.
Here is another example actually using the formula. Suppose you have 10 serial terminals with 3 serial printers. Each of your users will use only 3 windows except for yourself and some other advanced users who will be using 5 windows. So,
P will equal 3
T will equal 10
W will equal 5
Plugging these numbers into the equation will give you this result:
(3 * 9) + (10 * 9) + (5 * 10 * 9) = 567