Running wc3270, s3270, b3270 and pr3287 without installing them
---------------------------------------------------------------

It is possible to run wc3270, s3270, b3270 and pr3287 without installing
them. This allows running them from a USB flash drive or from a directory
copied from another machine.

This is facilitated in two ways. First are the no-install ZIP files, which
are an alternate way the code is distributed. They contain only the minimum
set of files needed. You can simply unzip one of the no-install ZIP files
and run each emulator directly from where you extracted it.

The second helper is is Portable Mode. In Portable Mode, the emulators will
not directly access the Windows Registry, nor (with two exceptions)
will they automatically touch any file outside of the directory where the
executable files reside.

For example, in Portable Mode, trace files are written by default to the
directory where the executable files reside rather than to the current
directory, and wc3270 profiles are written there as well.

The first exception to the Portable Mode 'sandbox' is that the wc3270 Session
Wizard always allows a shortcut to be created on the user's Desktop. The
second exception is anywhere a file path can be explicitly specified, e.g.,
if -tracedir is specified, the emulator will write traces to that directory
regardless of Portable Mode.

Portable Mode is triggered by the presence of the file PORTABLE.txt in the
directory where the executable files reside, directory, or explicitly via
the -portable command-line option. PORTABLE.txt is included in the
no-install ZIP images, but is not created by the installer.

PORTABLE.txt does not need to have any specific contents -- it just needs to
exist in order to trigger Portable Mode.

You can turn off Portable Mode by removing PORTABLE.txt or by specifying the
-noportable command-line option.
