How Older GEM Data Files are Stored on the VMS System

GEM runs 1 to 16504 were taken using a VMS computer system and the .RAW datafiles are still stored on the VMS system. To access them you will need a username for the VMS computer system. If you do not already have a username then you can obtain one by sending a completed application form to ISIS computer support. The application form may be obtained either from the computer group's web page or from one of the following links: postscript file, pdf file, Word file.

Location of VMS Data Files 

GEM VMS data files (.RAW, .LOG and .SAV files) which are online are stored on disks on the VMS network.. It is recommended that you use the abbreviation GEM_DATA to refer to the VMS directories in which GEM data may normally be found. Users do not have the privilege to change or delete the files in the GEM data directories and it is standard practice at ISIS that once a raw data file has been created it is never altered or lost.

Summary information for a .RAW file may be obtained by typing head 1234 (for run number 1234).

Restoring VMS Data Files 

Data files at ISIS (.RAW, .LOG and .SAV files) are automatically copied to a permanent archive. A sequence of .RAW VMS data files may be restored from the archive by logging on and using the command RESTISIS as follows:

RESTISIS GEM low_run_number high_run_number

(for example: RESTISIS GEM 5000 5005)

This will restore the files to the directory scratch$disk:[GEMMGR.RESTORE] or, if that does not exist, to scratch$disk:[GEMMGR.DATA]. If you want to restore the files to some other directory then add -d user$disk:[abc01] to the RESTISIS command line (where user$disk:[abc01] is the directory you want the files to go in. (Please remember that GEM .RAW files are very large.)

If you want to restore .LOG files or .SAV files then add -l or -s to the RESTISIS command line. Data files which are more recent will be restored more quickly, whilst older files will take longer to be restored.

The current status of restore progress may be determined by typing the command RSTATUS.

NOTE that this VMS command cannot restore data files for runs after 16504 because these are stored on the PC network. If desired it is possible to FTP .RAW files between the VMS and PC computer systems.

Journal Files 

When a run is ENDed, information about the run is stored in a journal file named GEM_DATA:JOURNAL.TXT . This file contains the run number, the user’s name, the run title, the run start time, and the amount of beam used in units of micro-Amp-Hours. At the end of each ISIS operating cycle, the GEM instrument scientists produce a unique journal file for that cycle, named GEM_DATA:JOUR002.TXT , for example. (Cycles are numbered according to a convention where, for example, cycle 002 is the second cycle in the operating/financial year 2000.) Several commands have been set up to give GEM users easy access to the information in the journal files, as follows:

TJ Type the journal file to the screen. (The default is for the current cycle, for any other cycle you must give the cycle number on the command line, for example TJ 992 .)
EJ Edit the journal file. (The default is for the current cycle, for any other cycle you must give the cycle number on the command line, for example EJ 001 . To edit the journal for other than the default instrument type EJ 944 SLS for example.)
SJ aaa Search the journal file for the characters aaa . (The default is for the current cycle, for any other cycle you must give the cycle number on the command line, for example SJ aaa 994 .)
EC Edit the optical disc archive catalogue. (The default is for the current cycle, for any other cycle you must give the cycle number on the command line, for example EC 002 . To edit the catalogue for other than the default instrument type EC 974 SLS for example.)

Last updated on 15 Dec 2005 by Alex Hannon (a.c.hannon@rl.ac.uk)