pvm_xstar is a software tool whicn fosters concurrent execution of the XSTAR command line application on independent sets of parameters, within a Paralle Virtual Machine. XSTAR is a computer program for calculating the physical conditions and emission spectra of photoionized gases (Kallman & Bautista 2001). Copyright (C) 2008-2009 Massachusetts Institute of Technology Author: Michael S. Noble <email@example.com> This software was developed at the MIT Kavli Institute for Astrophysics; it was funded in part by NASA and the Smithsonian Institution, through the AISRP grant NNG05GC23G and Smithsonian Astrophysical Observatory contract SV3-73016. Permission to use, copy, modify, distribute, and sell this software and its documentation for any purpose is hereby granted without fee, provided that the above copyright notice appear in all copies and that both that copyright notice and this permission notice appear in the supporting documentation, and that the name of the Massachusetts Institute of Technology not be used in advertising or publicity pertaining to distribution of the software without specific, written prior permission. The Massachusetts Institute of Technology makes no representations about the suitability of this software for any purpose. It is provided "as is" without express or implied warranty. THE MASSACHUSETTS INSTITUTE OF TECHNOLOGY DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE MASSACHUSETTS INSTITUTE OF TECHNOLOGY BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.