x, the system path is still an important setting in
Windows Vista. It can be helpful as well as detrimental, depending on
how it??™s used.
The system path is simply a list of folder names kept in memory during
an entire Windows session. If a folder name is listed in your system
path, you??™ll be able to run a program contained in that folder
without having to specify its location. The path is one of several environment
variables that are kept in memory from Windows startup
until you shut down. In early versions of Windows, the path was set
with a line in the now-obsolete Autoexec.bat file; now, all environment
variables are set by going to Control Panel ??? System ???
Advanced System Settings ??? Environment Variables.
By default, the Path system variable (shown in the lower box), contains
the following folders:
%SystemRoot%
%SystemRoot%\system32
%SystemRoot%\system32\Wbem
The %SystemRoot% element represents the Windows folder (usually C:\
Windows); see the discussion of expanded string variables in Chapter 3
for details.
One of the consequences of this design is that if two different versions
of the same executable file (any .exe, .dll, or .ocx file, for instance) are
placed in two different folders in the path, only one of the available
versions of the file??”and not necessarily the most recent one??”may be
in use at any given time.
How do you escape this trap? First, remove any unnecessary directories
from your path variable.
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