Saving your data on an exabyte file
last update: July 31 1997 by ejb

 1. Data (IRAF) file can be saved to exabyte.
    Each tape can contain about 2 Gigabyte of data
 2. There are basically two method to save the bits:
    - save it using IRAF in IRAF format on tape, goto 3
    - save it using TAR (UNIX command) to tape, goto 9


 3. SAVING USING IRAF:
    Type in IRAF window "epar wfits"
   iraf_files = "ejb*.imh"      IRAF images
   fits_files = "mtac"          FITS filename
      exabyte on atlas   (2.7m) is called mtac
      exabyte on miranda (2.1m) is called mtt
      newtape = yes             Blank tape?
      Be really careful with newtape:
      if yes, all data already on the tape will be lost
      if no, the new data will be appended to the old 
             data files on the disk.
       bscale = 1.              FITS bscale
        bzero = 0.              FITS bzero
  (make_image = yes)            Create a FITS image?
 (long_header = no)             Print FITS header cards?
(short_header = yes)            Print short header?
      (bitpix = 0)              FITS bits per pixel
(blocking_fac = 0)              FITS tape blocking factor
       (scale = yes)            Scale data?
   (autoscale = yes)            Auto_scaling?
        (mode = "ql")   
 4. Before running wfits, first allocate the tape.
    Put the tape in the exabyte drive.
    Type in IRAF window "alloc mtac"
 5. Run wfits by typing "wfits"
 6. Check the data on your tape using 
    "rfits mtac 1-999 make- short+ old+ >tapelist.txt"
 7. type "! more tapelist.txt"
    or if you want print the file "lpr -Plaser107 tapelist.txt"
 8. when finished reading or writing type "dealloc mtac"

 9. SAVING USING TAR.
    make a subdirectory called fits "mkdir fits"
10. use wfits in IRAF
    iraf_files = "ejb*.imh" IRAF images
    make sure you use the extension *.imh
   fits_files = "fits/files_" FITS filename
    the files will now be numbered as:
         fits/files_0001
         fits/files_0002
         fits/files_0003
         fits/files_0004
         etc.
      newtape =                 Blank tape?
       bscale = 1.              FITS bscale
        bzero = 0.              FITS bzero
  (make_image = yes)            Create a FITS image?
 (long_header = no)             Print FITS header cards?
(short_header = yes)            Print short header?
      (bitpix = 0)              FITS bits per pixel
(blocking_fac = 0)              FITS tape blocking factor
       (scale = yes)            Scale data?
   (autoscale = yes)            Auto_scaling?
        (mode = "ql")           
11. go out of IRAF and go the the subdirectory fits
    "logout"
    "cd fits"
12. we can now write the files to tape
    tar cvf /dev/rst0 * 
    this will do the trick, but takes quite some time
13. To check the tape 
    tar vf /dev/rst0 > tapelist.txt
    type tapelist.txt
14. When you get back home and want to read the data
    tar xvf /dev/rst0
15. Go to IRAF
16. Use RFITS to read the fits files on disk