How to get LIGO frame data onto local disk

Peter Shawhan
Revised February 13, 2004

`getFrames`

The getFrames utility, which is part of the dataflow package, allows you to retrieve data from the observatory sites or from the data archive at Caltech. You specify which data you want (raw, trend, etc.) using a Universal Dataset Name (UDN), time interval, and one or more channel names. A typical request looks like this:

  getFrames -d //ligo/raw/lho/s2 -t 731300000-731300020 -c H2:LSC-AS_Q,H2:LSC-AS_I

As with many of the utilities in LIGOtools, you can get complete syntax information by typing getFrames without any arguments.

The full list of UDNs (which provide RDS and trend data as well as full frame data from various runs) is given on this web page, with links to display the available time intervals and channels for each UDN. Beginning with version 5.2 of the 'dataflow' package, you can also get this information in a Unix shell by using getFrames, which may be more convenient in some cases. To get a list of all UDNs which provide frame data of one sort or another, type:

  getFrames -d

To get a list of time intervals for a given UDN, say //ligo/raw/lho/s2, type:

  getFrames -d //ligo/raw/lho/s2 -t

To get a list of channels (with sampling rates) for this UDN, type:

  getFrames -d //ligo/raw/lho/s2 -c

(Originally, there was a program called "LARS" (for LIGO Archive Retrieval Server) which handled these requests and served out data from the old HPSS data archive. Now, all of these data requests are handled by LDAS, but we still sometimes refer to the UDN scheme as the "LARS protocol".)

Note that you need a valid LDAS username and password to retrieve data, and you need to store them in a special disk file using the "ldaspw" utility. See the FAQ articles entitled "How to get an LDAS username/password" and "How to store your LDAS username and password".

`lidax`

lidax is a graphical user interface which allows you to manipulate LIGO frame data in various ways. In particular, it can retrieve data remotely using the LARS protocol and write it to disk. There is some usage information, including a "Quick Start Guide", in the Documentation section of the web page for the dtt package.

`guild`

You can also retrieve data from the observatory sites, via LDAS, using guild. From the main window, click on the "Frame data..." menubutton and select "Get raw data from sites". This brings up a dialog box, which includes buttons to check the current channel list and the available time range. The UDN scheme of naming datasets is not used within guild.