Some Notes about X-ray Data Collection





Data should not remain on xenon (the raxisIV computer) for very long once it has been collected. It should be processed as soon as possible and written to exabyte tape. Do not leave images on the raxisIV disk that you have any interest in saving. Unlike the unix systems in the computer room, any user can delete your files off the raxisIV disk. Also, this disk is not backed up. It is your responsiblity to back up your images on tape.




If you are collecting data, it is a good idea to know how much space is left. Use the command 'df' and look for the line that has the name xenon in it. On lithium, it looks like this: 

Filesystem                    Type  blocks     use     avail  %use Mounted on

xenon:/usr/people/raxisIV     nfs 13900928  8542064  5358864  62  /raxis4/data
If you see the %use number over 80, you will need to free up some space.




Well, you could just start deleting other people's images, but this is probably not a good idea if you like to stay on good terms with your fellow labmates. Try finding out who has the most images on the disk, and when they were collected. A good way to do this is to 'cd' to the /raxis4/data directory on a unix system in the computer room and type 'ddu'. You should see something like this:

helium 3% cd /raxis4/data
helium 4% ddu
nsmail: Permission denied
0       nsmail
1       Desktop
1       andyh
1       anstrom
1       corinne
1       dan
1       doug
1       dumpster
1       karen
1       martin
1       mike
1       rebekka
1       todd
1       wendy
2       license.dat
97      write_here
9090    ssh-2.4.0.tar
33208   RAXIS43
52753   ryter
140676  rob
369268  gjo
2444195 blaine

You can easily see who has images on the disk. To see how old those images are, 'cd' to a users directory, and use the 'ls -l' command:

helium 5% cd rob
helium 6% ls -l
total 281344
-rw-r--r--    1 20376    user      18006000 Oct  8 16:56  dinG1001.osc
-rw-r--r--    1 20376    user      18006000 Oct  8 17:36 dinG1003.osc
-rw-r--r--    1 20376    user      18006000 Oct  8 21:19 ld_test001.osc
-rw-r--r--    1 20376    user      18006000 Oct  8 21:40 ld_test002.osc
-rw-r--r--    1 20376    user      18006000 Oct  9 00:13 ld_test003.osc
-rw-r--r--    1 20376    user      18006000 Oct  9 02:14 ld_test004.osc
-rw-r--r--    1 20376    user      18006000 Oct  9 04:16 ld_test005.osc
-rw-r--r--    1 20376    user      18006000 Oct  9 06:17 ld_test006.osc

If you need disk space, it is the best policy to try to contact those people with images so that they may decide if they want to back them up and then remove them.

However, take the worst case scenerio: it's the weekend, you have a crystal on the raxis which is dying in the beam and you are running out of disk space. You can try to contact the user by e-mail or use the phone list to call her/him at home. Or, if you're feeling really nice, you can write their images to an exabyte tape (and risk wasting lab supplies if they don't want the images). But, if you really need the space, you can delete somebody's old images. Of course, the converse of this is true. If you leave images on the raxis disk, somebody can delete them. So do not to leave any data on the disk.

Also, please don't leave your old images on the disk, thinking that somebody else will eventually remove them. It is a pain to have to chase people down asking them to remove their files. Please take care of your own data.