This program simulates the way a process computer works.
The main window of this programme is a picture representing the most important parts of 
the process computer:

	-main board
	- 8 I/O cards. Each card can be used as:
		analogic input card(AI-124) - 24 inputs
		digital	input card (DI_124) - 24 inputs
	- count card- to count impulses (FI-116)- 16 count units
	- digital output card (DO-124) (24 outputs)
	- analogic output card(A-106) (6 outputs) 	
		
The programme simulates the way each one of this cards works. For instance:
every time an AI-124 card gets some data a light turns on and the data is displayed.
This programme is a variant of a real application that runs on a  386/40 MHz process computer
designed by ICE Felix SA Bucharest. This computer has a QNX 4.2 operating system 
and the application's interface is built to "work with" Photon 1.0.
The only one difference between the real application and this programme is the way data
is received: the first one gets data directly from the 8 cards already mentioned
and the second generates data at random.

	When initialising the application a 'setup' function is called. This function enables the user to
specify a type for every attached card. The simulator does not provide a setup sequence -
the configuration is static: 2 AI cards,2 DO cards,2 AO cards,1 F1 card and 1 DI card.
	Each card is served by a special process (depending on card's type) as it follows(this processes
are launched when setup is completed):
		proc_ai works with the AI-124 card
		proc_di works with the DI-124 card
		proc_fi works with the FI-116 card
		proc_ao works with the AO-106 card
		proc_do works with the DO-124 card

	Processes running with the real application communicate with card drivers.
For instance proc_di is blocked waiting for one input to change state. Every time a change of state 
occurs, the proc_di process in awakened.

	In our case,these processes generate input data at random. Data is sent to the 'usp' process
by means of QNX message passing procedure.
	Every time 'usp' receives a message, it calls the 'handler' function that displays data and
also turns on a light to specify which card is active.
	The DO-124 marks the state of each output by turning a light on (light on means 1 logical);
The same works with the DI-124 card for each input. 
	The AI-124 displays 4 values (in V) - one value corresponding to a certain input channel.
One can switch the 4 displayed channels by "clicking" the button related to this card.
	The FI-116 displays the number of impulses received by this card - displayed channels can be 
switched the same way as for the AI-124.
 
	Some more information:
	Each one of the AI,DO,AO cars has "on top" a button labelled 'AI_124','DO_124' and 'AO-124'.
When clicking this button a new window is displayed on the screen. This window shows some more
information on data received from the related card:
	1.The AI-124 window displays 6 graphs - one graph shows data received from one of the 24 
input channels. To switch between graphs you have to click the "NEXT" button.
	2.The DO-124 window displays 24 ON/OFF buttons - each one shows the state of one output.
Clicking the "AUTO" button stops the 'proc_do' from generating data. This way
one can control the  DO-124 card by means of these 24 buttons (in this case
data is sent from 'usp' process to 'proc_do' process).;
	3.The AO-124 has 6 related sliders. Clicking the "AUTO" button one can control the outputs by
means of these sliders (in this case data is sent from 'usp' process to 'proc_ao' process.
