The Gauge Connection is an archive for lattice QCD. It is a repository of gauge configurations made freely available to the community. Contributors to the archive include the Columbia QCDSP collaboration, the MILC collaboration, and others.
Hardware and sysadmin support have been provided by NERSC. The storage and transfer charges are underwritten by the QCD Grand Challenge allocation at NERSC. The archivists and web-masters are Jim Hetrick and Gregory Kilcup, who can collectively be reached at qcd-archive@nersc.gov.
The software running the NERSC archive was revised in July 2011 and the source code is available here. It was developed in collaboration with Massimo Di Pierro.
To download configurations, you must login using your OpenID, Facebook login or Google OpenID. You download individual configurations from the web site of use the qcdutils to download data in batch and convert them to ILDG and FermiQCD formats.
When you download a configuration, a script fetches the data from NERSC's HPSS tape robot storage system, stages it on a local disk, and then transmits it back out to you. In the best case, the transfer from HPSS will start almost immediately, and proceed at a rate of about 1 MB/sec. So if, for example, you download a 100 MB file, you should expect at least a 2 minute delay between your mouse click and the time you get the first bytes back.
Configurations are stored in QCD archive format, consisting of an ASCII header which defines various parameters, followed by binary data.
The one obligation incurred by downloading data is the responsibility to acknowledge the contributing group in any resulting publications. We would also appreciate Email to qcd-archive@nersc.gov calling our attention to such papers when they hit the preprint archive, so that we can add a link to your paper from the appropriate page.