During a Cold Start (see Section 
) initialisation sequence one
of the tests done by the operating system is to determine the amount of free
space on the EGLE disc. Normally there should be several 100000 blocks
available, but on occasion the disc may be nearly full. Ask your Support
Astronomer to delete files (if any) from expired accounts.
Within the ADAM data acquisition software environment one can check how much disc space is left with the commands CCDSPACE or DSPACE; use these commands occasionally to keep track of the available disc space. If you do run out of space then ADAM will write the next image (observation) into file R0 (normally used for GLANCEs) and will display a warning that it has done so, and why. Thus, if you are low on disc space be on the lookout for such a message.
Inside ADAM you can create more space by purging some of your files that you have already written to the D-tape. Use the PURGE command, answer SYS to the first prompt, and take it from there. If you try to PURGE a file that has not been written to tape previously, you will get an error message to the effect:
`FILE PROTECTED, ARE YOU SURE YOU WANT TO DELETE Y/N'
Reflect on this question, before answering! Pessimists don't purge before their files have been copied to 1600BPI D-Tape and then recopied to 6250BPI C-Tape. The copying program alerts the operator to possibly corrupted files on the D-Tape. Therefore, it is a good idea to use the verify option of the FITSOUT programme when saving data files on the D-Tape. Writing a file to D-Tape unprotects the disc file.
As an alternative to PURGE you can use the DELETE command to delete files m to n:
DELETE Rm-Rn
The DELETE command will ignore protected files (and not prompt for a decision). If you are very sure, you can unprotect a data file with:
REPROTECT/WKEY=0,189 Rm-Rn
Finally, if the cleanup of disc space was prompted by ADAM writing an observation into R0, don't forget to KEEP that data file!