Before ending a period of data reduction with , you should back up those data files which you wish to keep,
delete all of your disk data files, tidy up your work area, and then issue the KLEENEX (to stop the TV, Tek, and
message servers too) or EXIT (to leave the servers running) command to the AIPS program. Of course, if the
computer and disks are part of your very own workstation in your office, you may ignore all this advice. The tape
back-ups are a very good idea in any case. Disk files are easily deleted due to software or user malfunction, or lost
due to disk hardware malfunction.
While processing and particularly just before exiting from , please delete as many of your own data sets as
possible. Images and uv data may be backed up on tape in FITS format using the task FITTP. This task can write
more than one file on tape in a single execution. For example, to backup all sorted uv files (class UVSRT),
type
> CLRNAME C R | to allow any name, class sequence number and disk. |
> INTYP ’UV’ C R | to restrict to uv files. |
> INP C R | to check the inputs. |
> GO C R | to write the tape. |
Then, for example, to write all 3C123 files on disk 2 after the sorted uv data files, type:
to have AIPS wait for the FITTP execution started above to finish and then to run FITTP with the new inputs. |
Note that this sequence will write two copies of any 3C123 UVSRT files to be found on disk 2.
Task FITAB also writes FITS tapes. For uv data it has the advantage of being able to write the data in compressed
form, saving disk or tape, and of writing the data in multiple “pieces” for increased reliability. Unfortunately, the
table form of data used may not be read by older versions and is not understood by other software systems.
FITAB was revised in October 2007 and subsequent output can only be read by versions of UVLOD and FITLD revised
in a corresponding manner. Note that FITAB is used for processed uv data by the NRAO archive — it will matter to
many users to update to a modern release. FITAB may apply a quantization to images on output that allow
the FITS files to be compressed very much more efficiently. If the quantization level is set below 1/4
of the image noise, then the noise in the output image will only be 1–2% larger than in the input
image.
Please delete redundant images and data as soon as possible to preserve disk space for yourself and other users. It is tempting to work on many sets of data at the same time, but this generally takes a lot of disk space and users should limit the amount of data resident on disk to that which will be processed during the session. A data set and all extension files can be deleted by:
> IND n ; GETN ctn C R | where n and ctn select the disk and catalog numbers of the data set to be deleted. |
> ZAP C R | to do the deletion. |
To delete data in contiguous slots from n to m in a catalog, set the INDISK and use the loop:
For massive deletions — the kind we hope you will use when you leave an NRAO site — use:
And to compress your message file, after using PRTMSG to print any you want to keep, use:
> CLRMSG C R | to do the clear and compress. |
DO NOT DELETE OTHER USERS’ DATA OR MESSAGES WITHOUT THE EXPLICIT PERMISSION EITHER OF THE OTHER USER OR OF THE AIPS MANAGER.
To exit from AIPS type:
> EXIT C R | to leave TV, message, and graphics servers running, or |
> KLEENEX C R | to kill server processes as well as AIPS. |
Please clean up any papers, tapes, etc. in the area around your terminal before you go.