README:

 This is the README for the FIRE DX subset tapes on 8mm tape. 
 The subset region for FIRE-I-CI ranges in longitude by 257.5 to 280 degrees 
 and in latitude by 37.5 to 47.5 degrees. 

 The 8mm tape was written using the unix tar command. The physical block size
  is 30720 bytes. The tar logical block size is 60*512 bytes with 60 being 
  the blocking factor.

 The first archive on every tape will be DXREAD.f which is a FORTRAN program
  to demostrate how to read the data once the files have been extracted 
  from the 8mm tape. The FORTRAN code will be followed by a variable number 
  of archives of the DX SUBSET data. The number of archives is decided by 
  how many satellites covered the subset region.

 Each data archive contains a month of data for a particular satellite. 
 (31 days, 8 gmts, all types)

 The satellite types are :
   0 : geostationary
   S : polar orbiter's South Pole
   N : polar orbiter's North Pole
   A : polar orbiter's Ascending orbit
   D : polar orbiter's Descending orbit 
 NOTE : It is possible for data files to be missing. 

 The following are the commands I use to read the tape on a IBM AIX system.

 To change the tape devices blocksize to match the blocksize when dumped.
      chdev -l rmt0 -a "block_size=30720" 
 Note : substitute the name of your tape device for rmt0

 To move around on the tape.
   tctl rewind   (rewinds tape)
   tctl fsf #    (to skip # number of archives) 
   
 To extract the currently pointed to archive :
   tar -xvf/dev/rmt0 -N 60 -b 60 * 
 Note : rmt0.1 will tell device not to rewind tape when done command.
        This sets the tape up to be able to read next archive without 
        having to do a tctl fsf #.

 To get a listing of what is in a archive : 
   tar -tvf/dev/rmt0 -N 60 -b 60

 If your tar does not have the options -N or -b then the unix command dd
 can be used with tar to duplicate the lost options.
 For example, the following will list the contents of the current archive.
      dd if-/dev/rmt0 bs=30720 | tar -tvf - 
 Note: You still have to do the chdev command.

  
 If there are any questions regarding the tape or the data, feel free to 
 contact : Diane Beuschel
           Goddard Institute of Space Studies
           2880 Broadway 
           New York, NY 10025

           diane@haboob.giss.nasa.gov (internet)           
           (212) 678-5513 (phone)
           (212) 678-5552 (fax)