Acknowledgements
================

Many people have helped in significant ways to get DiFX adapted for the
VLBA: Craig West for getting me interested in software correlators to
begin with; Adam Deller for writing DiFX and helping adapt it to the
needs of the VLBA; Steve Tingay and Matthew Bailes for
allowing/encouraging Adam to write DiFX and helping support some of my
travel in Australia; Chris Phillips, John Morgan, Helge Rottmann, Mark
Kettenis, Olaf Wucknitz, Mariano Muscas, Geoff Crew, John Spitzak, Roger
Cappallo, Walter Max-Moerbeck and Dmitry Baksheev for contributing code,
bug reports, bug fixes, and ideas; Maria Davis, Roopesh Ojha and Dan
Veillette for performing careful comparisons with geodetic data; Walter
Alef for hosting the first and second DiFX workshops in 2007 and 2008 at
MPIfR, Bonn; Miguel Guerra for helping define the database and XML
structures and his work on the operator interface; Claire Chandler and
Jon Romney/ for project oversight, test planning, advice, and voices of
reason; Steven Durand for acquisition of computer and Mark5 equipment;
David Boboltz, Geoff Bower, Mark Claussen, Vivek Dhawan, Alan Fey,
Vincent Fish, Ed Fomalont, David Gordon, Miller Goss, Yuri Kovalev, Matt
Lister, Enno Middelberg, James Miller-Jones, Amy Mioduszewski, Leonid
Petrov, Mark Reid, Loránt Sjouwerman and Craig Walker for working
directly with or examinating the output of DiFX and providing valuable
feedback; Cormac Reynolds for maintaining the Difx wiki which hosts
valuable information, hosting the third DiFX workshop in Perth, and
providing lots of code; Jan Wagner, Sergei Pogrebenko, Alexander
Neidhardt, Martin Ettl, Jongsoo Kim and Randall Wayth for reporting
bugs; Eric Greisen for making AIPS work well with DiFX output; John
Benson for working with me to get data into the VLBA archive; James
Robnett, Nicole Geiger, David Halstead and Pat van Buskirk for
substantial computer and networking support and useful discussions on
clustering; Mike Titus and Arthur Niell for providing test data; Leonia
Kogan for carefully reviewing the conventions used; Pete Whiteis and
Bill Sahr for contributing to helper programs; Ken Owens and Cindy Gold
at Conduant for helping resolve Mark5 issues; Doug Gerrard, Bob
McGoldrick, Adrian Rascon, K. Scott Rowe, Lothar Dahlmayer, and Jeff
Long for assembling and maintaining the VLBA DiFX correlator; Juan
Cordova, Paul Dyer, Lisa Foley, Heidi Medlin, Ken Hartley, Alan Kerr,
Jim Ogle, Paul Padilla, Peggy Perley, Tony Perreault, Betty Ragan, Meri
Stanley and Anthony Sowinski for providing operations assistance; Chet
Ruszczyk, Dan Smythe, and John Ball for extensive Mark5 support over the
last decade and Emma Goldberg for helping me work around the
idiosyncrasies of LaTeX and convince it to typeset this document. If I
left anyone of this list that should be there, and there are probably
several of you in that category, I apologize — let me know and I’ll make
sure to add you for the next version’s document.

References
================

.. [opsplan] *VLBA-DIFX Operations Plan*, Brisken, W., 2009, VLBA Sensitivity Upgrade Memo 25, http://library.nrao.edu/public/memos/vlba/up/VLBASU_25.pdf
.. [difx] *DiFX: A software correlator for very long baseline interferometry using multi-processor computing environments*, Deller, A. T., Tingay, S. J., Bailes, M. & West, C., 2007, PASP 119, 318, http://xxx.lanl.gov/abs/astro-ph/0702141 
.. [difx2] DiFX2: A more flexible, efficient, robust and powerful software correlator}, A.\ T.\ Deller, W.\ F.\ Brisken, C.\ J.\ Phillips, J.\ Morgan, W.\ Alef, R.\ Cappallo, E.\ Middelberg, J.\ Romney, H.\ Rottmann, S.\ J.\ Tingay, R.\ Wayth, 2011, PASP, 123, 275, \url{http://arxiv.org/abs/1101.0885}
.. [aips102] The FITS Interferometry Data Interchange Format}, Flatters, C., AIPS Memo 102, \url{ftp://ftp.aoc.nrao.edu/pub/software/aips/TEXT/PUBL/AIPSMEMO102.PS}
.. [aips114] The FITS Interferometry Data Interchange Convention}, Greisen, E., AIPS Memo 114r, \url{ftp://ftp.aoc.nrao.edu/pub/software/aips/TEXT/PUBL/AIPSMEM114.PDF}
.. [mark5-81] Specification for enhanced Mark 5 module directory, Whitney, A., et al., \url{http://www.haystack.mit.edu/tech/vlbi/mark5/mark5_memos/081.pdf}
.. [mark5-100] Mark5 User Directory Formats}, Ruszczyk, C.A., Eldering, B.\ \& Verkouter, H., \url{http://www.haystack.mit.edu/tech/vlbi/mark5/mark5_memos/100.pdf}
.. [sci12] Summary of the b-factor for the VLBA FX correlator}, Kogan, L., VLBA Scientific Memo 12, \url{http://library.nrao.edu/public/memos/vlba/sci/VLBAS_12.pdf}
.. [tempo] *Tempo*, \url{http://www.atnf.csiro.au/research/pulsar/tempo/}
.. [jira] *JIRA*, \url{http://bugs.aoc.nrao.edu}
.. [ngas] *NGAS*, \url{http://www.eso.org/projects/dfs/dfs-shared/web/ngas/}
.. [doi] *Difx Operator Interface Users Guide*, Guerra, M., {\bf Coming soon!}
.. [vex] *VEX parameter definitions*, \url{http://www.haystack.mit.edu/tech/vlbi/mark5/vex.html}
.. [wiki] *DiFX Developer Pages*, \url{http://www.atnf.csiro.au/vlbi/dokuwiki/doku.php/difx/start}