obsdata command

This page is part of the ING document INS-DAS-29: Operations manual for UltraDAS


The obsdata command changes the disc on which raw observations are written. There are two forms of the command; the first tells the system to use a specific disc; the second tells the system to choose the best (i.e. emptiest) disc of those available.


    obsdata <disc-name>
tells the system to use the disc disc-name, which must be one of the set of discs which UltraDAS is configured to known and accept. The disc name must be an absolute path.
tells the system to use the emptiest available disc of those configured.


    obsdata /obsdata/intg
selects the disc intg. Data discs are almost always mounted under the /obsdata branch of the file-system, and their names are usually the name of the associated telescope followed by a lower-case letter.

Notes and caveats

The data discs can be set independently for different cameras on the same telescope. A single obsdata command affects only one camera.

It is possible for a disc to be configured and mounted but still unavailable: it may be full or it might be broken; it might even be write-locked! In this case, the system will not select the disc under any circumstances.

The selectable "discs" are technically partitions of discs, and it's possible to configure two partitions on the same physical disc as separate choices. However, this would be a daft way to use the kind of discs that ING normally deploys. In practice, a partition always fills the whole disc.

UltraDAS considers a disc to be full when there is too little available space to fit in two more observations.