FITS Tapes and Miriad

Miriad has a single task, fits, to read and write FITS files - both visibility and image data. One significant shortcoming of fits is that it cannot work directly from a tape device - the FITS file must be on disk. The Miriad utility, tpcp, is needed to copy FITS files between disk and tape, whereas the UNIX command mt might been needed to position the tape. See the appropriate Miriad help or UNIX man pages on these commands. However, to copy from tape to disk, one would use

% tpcp device fits-file

Here device is the tape device. Typically it is something like /dev/nrst0. Note that you should always use the ``raw, non-rewinding devices'' - that is devices whose names start with nr. The output is fits-file.

To write a FITS file to tape, use

% tpcp -b 2880 fits-file device

This causes an unblocked FITS file to be written (record length of 2880 bytes).

To move the tape to the end-of-tape, use

% mt -f device eom

To skip forward n files, use

% mt -f device fsf n

and to rewind, use

% mt -f device rewind