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Conversion between FITS and internal format
The FITS conversion commands INTAPE and OUTTAPE can both
access FITS files on disk or directly on tape devices. Thus, it is in
principle possible to use general system utilities to transfer the
FITS files between disk and tape. When using operating system
utilities special care must be taken to ensure that the files on the
tape conform to FITS blocking specification - it is by no means
obvious!
The syntax of FITS conversion commands is as follows:
INTAPE file_list id device [flag]
OUTTAPE cat[,list] device [flag] [dens,block] [type]
These are described in more detail in the following sections.
In order to save disk space, it may be desirable to compress the
files. For this purpose, operating system utilities may be used (e.g. compress for UNIX). The steps to achieve this are as
follows:
- Use OUTTAPE to write file to disk in FITS format.
- Compress FITS file on disk e.g. compress.
- Use system utility to save compressed file on tape e.g. tar.
To retrieve files execute the above process in reverse order.
Next: Devices
Up: Data Exchange Format
Previous: Restrictions
Petra Nass
1999-06-09