PMAS Cookbook

DATA STORAGE

This section describes how to save observational data using CAHA 3.5m DAT tapes or PMAS CDROM.

Note 1:

Please make sure you have stored all of your data immediately after completion of an observing night. Your attempt of saving the whole data set of an entire observing run on the day following the last night of your run may be corrupted because of instrument changeover and PMAS no longer being available to you. CAHA staff takes no responsibility for data integrity and availability after your run.

Note 2:

For redundancy/security, it is recommended to use both options of DAT and CDROM in parallel, or to ftp your data directly from ultra1 to your home institute once you have written to DAT.

Note 3:

If you want to make use of an optional archiving service provided by AIP, please contact Petra Böhm.

Note 4:

All of your raw data from observing resides on the PMAS instrument control computer "rike", a SPARC workstation mounted in the electronics rack of the instrument. In order to save data on mass storage devices, you must first transfer these data to computers "ultra1" or "pmas".

DAT tapes (on SPARC "ultra1")
- Make sure you have registered as new observer on "ultra1" when you begin your observing run (use desktop GUI).
  This tool reserves disk space on "ultra1" for your run and provides graphical information about disk usage.
- Immediately after completion of an observing night, ftp your data from "rike" to "ultra1".
- Locate "ultra1" DAT drive in computer room (one floor below telescope control room), insert DAT cassette
- Save your data to DAT tape.

CDROM (on PC "pmas")
- Locate PC "pmas" (in instrument storage room, 2nd floor, R207). The CD/DVD burning device is mounted in this PC, as well as an additional DAT drive. The CD/DVD SCSI device is 0,0,0.
- login to "pmas", user pmas (for password, contact CAHA staff). Remote login is possible via ssh only.
- Create a subdirectory under ~pmas/burni, using naming conventions as used on "rike" (i.e. run??_YYMMDD, where YY stands for year, MM for month, DD for the day when your observing night begins, e.g. run12_031104 for the night beginning on November 04, 2003. The number of your run is provided by CAHA staff).
- Transfer your data from "rike" to subdirectory on "pmas", use scp.
- For operation from a remote computer, type:
```
            export DISPLAY=hostname:0
            
```
- Start burning programme:
```
	    gcombust &
            
```
- Reiter Options :
  supply names and options if necessary
- Reiter Data Files :
  use add directory and/or add pattern to add directories
- Reiter Burn
  There are two ways to burn CDs, Multisession or Single Image.
  Note: IMAGE in this context is not a CCD frame. An IMAGE is a record of several, normally many, files and directories which needs to be assembled on disk prior to the burning process itself.
  1. Multisession-CD: It is possible to add records to an incomplete CD until the point where it is full. Burn an IMAGE and close. Later on, additional IMAGES can be appended.
  2. Single Image CD: burn a CD with a single IMAGE. It is not possible to append further IMAGES later on.
  Error Messages / Warnings :
  
  1. ** WARNING **: You are probably not running cdrecord as root or you have the wrong permissions
  ==> can safely be ignored
  
  2. What to do on error messages:
  1. /usr/local/bin/dvdrecord: Permission denied. Cannot open "image file name" ==> disk is full !
  2. /usr/bin/mkisofs: Success. Read error on old image ==> CD misplaced.
    
    Eject CD, remove CD from tray, put it back carefully
  3. The supplied image name is a directory, please fill in the full path/image name in the image location field.
    ==> close window "Please select file to add"
  - Reiter Verify
    1. under verify against, enter: /misc/cd
    2. click VERIFY
    3. check output
  - Alternative possibility for verification :
    1. mount CDROM using automounter, i.e. just access /misc/cd; CD will be mounted automatically.
    2. Check your files.
    3. After approx. 30 sec idle, the CD is released again. You can open the tray and remove your disk.
      Note: this doesn't work when any programme is acessing the CDROM, or your default directory happens to be in the directory tree of the CD.
  - You are done.
    Terminate programme combust.
- Low Level
  
  It is also possible to write to CD using the command line. The procedure is described below. For writing DVD, substitute the "cdrecord" statements by "dvdrecord".
page adapted from german version of Th. Fechner