Filling data from VLA archive format

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Filling data from VLA archive format

VLA data in on-line archive format are read into AIPS++ from disk or tape using the vlafiller tool. Tape drives can be located on the local system or on a remote system accessible on the network. Use of a remote tape drive requires knowledge of the network host name (e.g. gibbon.cv.nrao.edu, or gibbon), and the tape device name (e.g. /dev/rmt/0ln). This can often be determined from the physical drive itself, or by logging on to the remote host and using a UNIX utility such as sysinfo or the UNIX command ls -lut /dev/r[ms]t* to list the device name.

Remote tapes need not be explicitly mounted from AIPS++ as the vlafiller itself will be run on the remote system directly. If you encounter problems in using the filler on a remote host, make sure that the AIPS++ initialization command source /aips++/release/aipsinit.csh is included in your .cshrc file (or the sh equivalent).

The vlafiller tool allows selection on frequency band, calibrator name, frequency range, project, time, subarray, and source, and supports concatenation to an existing uv-data set. To run the vlafiller using a local tape drive, you can use the vlafillerfromtape global function, e.g.:

vlafillerfromtape(msname='cals00feb.ms',       # Load project TESTT from tape to 
                  device='/dev/rmt/0ln',       # MeasurementSet cals00feb.ms
                  files=[2,3],                 # Read only files 2 and 3 on tape
                  project='TESTT');            # in current directory

Note: the first file on a VLA archive tape is always a house keeping file. Thus, if you try to read it, the AIPS++ filler will report that it is not in the appropriate format.

To fill data into AIPS++ using a remote tape drive, set the host name, e.g.:

vlafillerfromtape(msname='/home/cals00feb.ms',   # Load project TESTT from remote 
                  device='/dev/rmt/0ln',         # tape on host 'gibbon' to MS
                  files=[2,3],                   # Read files 2 and 3 on tape
                  project='TESTT',               # cals00feb.ms in /home directory
                  host='gibbon');                # on remote host

Note that it is necessary to specify a full path name (recognizable by the remote host) for the output file when filling from a remote tape drive.

Alternatively, you can use the vlafiller tool (rather than the global function) to set up the filler inputs separately and then run the filler from the Glish command line:

include 'vlafiller.g';
vfill:=vlafiller();
vfill.tapeinput(device="/dev/rmt/0ln" , files=[2,3] );
vfill.output(msname='cals00feb.ms', overwrite=F);
vfill.selectproject(project='TESTT');
vfill.fill(verbose=F, async=F);
vfill.done();

To obtain a summary of the dataset's properties after filling, construct an ms tool, and run the ms.summary function:

mset:=ms(filename='cals00feb.ms');      # Construct the ms tool for the data 
mset.summary(verbose=T);                # Write a summary to the logger window
mset.done();                            # Finish ms tool

Copy the summary information into a file for later use (source or FIELD_ID numbers and the times different sources are observed are particularly useful).

Next: Data examination and inspection Up: Filling VLA data into AIPS++ Previous: Spectral-line case Contents