I just noticed today that the version of `rubywin' that comes with the
latest (1.6.4-2) version of Ruby for Windows has the prefix
"/cygdrive" hard coded.

Unfortunately, this causes problems when running with Cygwin, because
"/cygdrive" is not mandatory with Cygwin.  It's indeed the default,
but it can be changed my means of the "mount -c ..." command within
the Cygwin distribution.  I and many other Cygwin users make use of
this command to change the drive prefix to strings other than
"/cygdrive", and in that case, rubywin fails to find files when it
tries to execute them inside of its buffers.

Cygwin stores the drive prefix in the registry, and I believe that
rubywin should check for this registry entry, and if it exists, use
its contents as the drive prefix.  If the registry entry doesn't
exist, then using "/cygdrive" should be just fine.

I believe that this mount information would be found under this
registry key (or under one of its subkeys):

  HKEY_CURRENT_USER/Software/Cygnus Solutions/Cygwin/mounts

This should be a fairly easy fix for rubywin, and it will greatly help
Cygwin users who change the drive prefix, because at the moment this
renders rubywin almost unusable to them.

-- 
 Lloyd Zusman
 ljz / asfast.com