Since April 23, 2010 two versions of Perple_X have been available in this
directory. These are the standard version in Perp07_windows.zip and a version 
contained in Perple_X_v6.5.0.msi, named PerplexPDF, created by Dave Hirsch. 

PerplexPDF differs from the standard version in two important ways:

1) In PerplexPDF the graphics programs (PSSECT, PSVDRAW, PSCONTOR, etc) create 
generic PostScript (or optionally PDF or SVG output), whereas PostScript 
created by the standard version cannot be read by some graphics programs. 

2) PerplexPDF is self-installing and creates an interface that makes running 
Perple_X simpler, but also has the potential to cause problems for unwary users. 
Specifically the PerplexPDF installation script modifies the system path to run 
Perple_X programs from a system directory, this means that by default WINDOWS will 
run the programs in the system directory rather then in a local directory, as 
installed with the standard version. Thus, if PerplexPDF is installed, but you 
wish to use the standard version of Perple_X you must explicitly specify 
the path to the standard version (e.g., as in ./vertex) or uninstall PerplexPDF.