The X-axis lower/upper limit of the plots is fixed to the value
of 0.1/10.0 keV so that the net source and background spectral
shapes can be compared easily.
If a Y-Y value of a spectral point is negative or null,
the point is not plotted.
If the device is /XWINDOW, the plot is displayed until the
carriage return is hit.
The following device types are recognized by the task and need
an output file :
/PS (monochrome landscape mode, long edge of paper
horizontal)
/CPS (color landscape mode, long edge of paper horizontal)
/VPS (monochrome portrait mode, short edge of paper horizontal)
/VCPS (color portrait mode, short edge of paper horizontal)
/GIF (landscape orientation)
/VGIF (portrait orientation)
The following device type is also recognized by the task and
does not need an output file :