THis is my perl program which generates modelines based on four
pieces of input : hsync, vsync, resolution, and dotclock. 
The user only has to choose the vsync, the program makes suggestions 
beyond that point (new in 0.1.0) , or alternatively, they can specify
the vsync on the command line in which case the program works
non-interactively. 

It essentially follows the way of thinking in the XFree86 Video
timings HOWTO. It was inspired by persistent failure of configuration
programs I've used. 

It works on essentially the following logic: 
(note that though these numbers are given, they are all defined in the
top of the program and can be easily changed) 

(a)	The horizontal sync pulse should ideally be 10% of the
horizontal frame length. 

(b)	The horizontal blackout time should be 25% of the active (ie
"drawing-on-the-screen") time

(c)	The vertical blackout time should be about 5%  of the active
time 	

(d) 	THe minimum acceptable horizontal  and vertical front and back
porches are defined by constants (see first few lines of the program
for details) 

(e) 	The sync pulses are placed somewhere between the minimal
acceptable porches. The placement of the sync pulse is determined by
a initial constants  


-- DOnovan