SEGYWRITE - write an SEG-Y tape                            

 segywrite <stdin tape=                              

 Required parameters:                                      
      tape=       tape device to use (see sudoc segyread)        

 Optional parameter:                                       
      verbose=0   silent operation                   
                  =1 ; echo every 'vblock' traces                
      vblock=50   echo every 'vblock' traces under verbose option
      buff=1            for buffered device (9-track reel tape drive)  
                  =0 possibly useful for 8mm EXABYTE drive 
      conv=1            =0 don't convert to IBM format                 
      hfile=header      ebcdic card image header file            
      bfile=binary      binary header file                       
      trmin=1 first trace to write                         
      trmax=INT_MAX  last trace to write                    
      endian=1    =0 for little-endian machines (PC's, DEC,etc...)
      errmax=0    allowable number of consecutive tape IO errors 
      format=           override value of format in binary header file 

 Note: The header files may be created with  'segyhdrs'.         


 Note: For buff=1 (default) tape is accessed with 'write', for buff=0  
      tape is accessed with fwrite. Try the default setting of buff=1
      for all tape types.                                  
 Caveat: may be slow on an 8mm streaming (EXABYTE) tapedrive           
 Warning: segyread or segywrite to 8mm tape is fragile. Allow time     
         between successive reads and writes.                    
 Precaution: make sure tapedrive is set to read/write variable blocksize
         tapefiles.                                        

 For more information, type:  sudoc <segywrite>            



 Warning: may return the error message "efclose: fclose failed"
       intermittently when segyreading/segywriting to 8mm EXABYTE tape,
       even if actual segyread/segywrite is successful. However, this
       may indicate that your tape drive has been set to a fixed block
       size. Tape drives should be set to variable block size before reading
       or writing tapes in the SEG-Y format.

 Credits:
      SEP: Einar Kjartansson
      CWP: Jack, Brian, Chris
         : John Stockwell (added EXABYTE functionality)
 Notes:
      Brian's subroutine, float_to_ibm, for converting IEEE floating
      point to IBM floating point is NOT portable and must be
      altered for non-IEEE machines.      See the subroutine notes below.

      On machines where shorts are not 2 bytes and/or ints are not
      4 bytes, routines to convert SEGY 16 bit and 32 bit integers
      will be required.

      The program, segyhdrs, can be used to make the ascii and binary
      files required by this code.