Looping schemes

There are a number of different ways of dealing with the data detection loop in ORAC-DR. If the system is being used `off-line', the data are all present in the input directory and the pipeline assumes that no new data will appear. In this case the list and inf detection loops are supplied which stop processing when data files can no longer be found. These are the default loops whenever observation numbers are specified with list being used in conjunction with the -list and -from/-to options and inf being used in conjunction with the -from option.

At the telescope new data are continually arriving so a different detection loop is required. The wait loop is used

Occasionally observation numbers are skipped (e.g. when an observation is aborted and not copied to the Sun). In this case the -skip option should be used. Without this option the data detection loop aborts when an observation can not be found (or it continues to wait for a file even though an observation with a higher number now exists). It is probably a good idea to always use the -skip option when processing SCUBA data.