PROCESS DISKOX, where X = { A, B, C, ..., J }
                 ------- ------

Parameters, alphabetically:
decimf    exthdr    flinc     fno       fon       format
frange    ftr       lno       lrange    ltr       noinc
ofmt      ontrcs    opath     posaft    renum     retrac
rewind    secs      set       spath     trace0    trinc


Document Date:  17 June 2009
Doc mods: 
   Add RETRAC and RENUM (RENUM is the same as FON).  June 2009
   opath DATE and opath SHOTNO generate file names.  June 2005
   OFMT 0 means OFMT is the same as the input data format.  March 2005
   Add FORMAT BINARY and remove SEGY and SIO,  June 2003
   Add EXTHDR to control writing of Rev 1 records, May 2003
   Add TRACE0 to control writing of trace 0, March 2003
   Change BIG preset to YES, Sept. 2002

Process DISKOX is a set of 10 processes which write SEG-Y disk files.  
The process names are actually DISKOA, DISKOB, DISKOC, ..., DISKOJ, but 
are listed here as a single process since they are virtually identical.  
SIOSEIS permits any process to appear only once in the PROCS list, yet 
the user may wish to save the data at multiple stages.  Processes 
DISKOA, DISKOB etc. permit up to 4 distinct disko output stages.  e.g.
PROCESS INPUT GEOM GATHER DISKOA NMO STACK DISKOB FILTER PLOT END

Each process DISKOX is totally independent of any other process DISKOX.  
The order A, B, C, D does not matter since this is just a way of allowing
four unique processes.  e.g. PROCESS DISKIN STACK DISKOD PLOT END is 
valid.

The shot/rp numbers and trace numbers of the output are the same as the 
input except when FON, NOINC, FTR, or TRINC are given.  The output 
shot/rps always start with trace one and output trace numbers are always
incremented by 1.


PARAMETER DICTIONARY
--------- ----------

OPATH  - The output pathname (filename).
       = DATE or date, the filename will come the SEG-Y trace header in
         the form: dayDDD-HHMMz.segy, where DDD is the day of year and
         HH is the hour, MM is the minute of the SEG-Y time of shot.
       = SHOTNO or shotno, the filename will come the SEG-Y trace header
         in the form: shotSSSSSS.segy, where SSSSSS is the shot number
         (word 3) in the SEG-Y trace header.
         Required. e.g. opath /seis/vel.123

OFMT   - The data word format of the output disk file.
       =0,  Same as the input format.
       =1,  IBM floating point.   ****   OBSOLETE  ***  
       =2,  32 bit 2's complement integer.
       =3,  16 bit integer.
       =5,  IEEE floating point.  (non standard in SEGY rev 0, but
            standard in SEGY rev. 1.)
       THE FOLLOWING IS NOT STANDARD:
       =4,  UTIG 16 bit floating point
         Preset = 5 

FON    - The first output shot/rp number.
RENUM  <0, In conjunction with POSAFT means the last shot/rp + 1.
       =0, Means that the output number will be the same as the input.
       >0, The first shot/rp will be FON.
         (RENUM is the same as FON - added for compatibility with diskin),
         Preset = 0     e.g.   fon 101

RETRAC - Renumber the trace numbers within each shot/rp so that the
         first trace of each shot/rp is RETRAC.
         Preset = none. e.g.     retrac 1

POSAFT - Position after shot/rp or after the last trace in the file.
       <0,  Position after the last trace of the last shot/rp (append).
       =0, No positioning is done.
       >0,  Position after the shot/rp specified (after the last trace
         of the shot/rp).
         Preset = 0.    e.g.  posaft 1234

SET    - Start and end times, in seconds, of the data to be written to
         disk file OPATH.  Data outside of SET will not be included in
         the output file.  DISKOX SET may not be used to pad with
         zeroes; use DISKIN SET for zero padding.  If SET(1) is before
         the deep water delay, the output will be from the delay, not
         SET(1).
         Preset = none  e.g.  set 2 3  

SECS   - The number of seconds of data to write to file OPATH.  Data
         after delay+secs will be omitted.
         Preset = none

DECIMF - The decimation factor to use in writing the output disk file
         OPATH.  No anti-aliasing filter is applied.  The data passed
         to any process after DISKOX will NOT be decimated.
         Preset = 1  e.g. decimf 2  (every other sample is discarded)

SPATH  - The pathname of the "sort" file.  When SPATH is given, process 
         DISKOX outputs the seismic traces in the order specified by
         SPATH rather than the order actually received. This "desorts"
         a dataset sorted by PROCESS SORT and DISKIN.
         Preset = none  e.g. /usr/users/joe/data/sort.line1

FNO    - The first shot/rp number the parameter list applies to.
         Default = the first shot/rp in file OPATH.   e.g.   FNO 101

LNO    - The last shots/rp number the parameter list applies to.
         Default = the last shot/rp in file OPATH.    e.g LNO 101

NOINC  - The shot/rp increment between FNO and LNO.
         Preset = 1.    e.g. noinc 10

FLINC  - The increment between groups of FNO-LNO shots/rps output.
         Both FNO and LNO are incremented by FLINC after LNO has been
         output.  This feature is useful when groups of rps are to
         be saved.  e.g.  If you want to save 10 consecutive rps out
         of every 100 rps, then use       fno 1000 lno 1009 flinc 100.
         rps 1000-1009, 1100-1109, 1200-1209, .....   will be written.

FTR    - The first trace of each shot/rp to write to disk file OPATH.  
         Traces less than FTR will be omitted.
         Preset = 0     e.g.  ftr  11

LTR    - The last trace of each shot/rp to write to disk file OPATH.  
         Traces greater than LTR will be omitted.
         Preset = the last trace of each shot/rp e.g.  ltr 11

TRINC  - The trace increment between FTR and LTR.
         Preset = 1     e.g trinc 2

FRANGE - The first range (the absolute value of the shot-receiver
         distance) to be included in the output disk file.  Traces with
         ranges less than FRANGE will not be written to disk.  The use
         of FRANGE and LRANGE is useful when CDP gathers are being
         written to disk.
         Preset = 0     e.g. frange 2000

LRANGE - The last range (the absolute value of the shot-receiver
         distance) to be included in the output disk file.  Traces with
         ranges greater than LRANGE will not be written to disk. The
         use of FRANGE and LRANGE is useful when CDP gathers are being
         written to disk.
         Preset = 999999     e.g. lrange 2000

FORMAT - The file format of the output file.
       =SU, the Colorado School of Mines Center for Wave Phenomena's
         Seismic Unix file format is written.  The SU format does
         not contain the SEG-Y EBCDIC or binary headers, but does have
         the SEG-Y trace headers.
       =BINARY, no SEG-Y headers at all are written.  Remember that
         the first and last time samples are written (e.g. 1 second
         of 1 mil data has 1001 samples).  The data are written in
         word type OFMT and in big endian (SEGY) byte order.
         Preset = none      e.g. format binary

ONTRCS - The number of traces per output shot/rp.  If FON is not given,
         FON 1 will be used.  If RETRAC is not given, RETRAC 1 will
         be uses.
         Preset = 0 (not given)  e.g.  ontrcs 1

REWIND - A YES/NO switch indicating that the disk file is rewound for
         EVERY SHOT written.  This is an attempt to create a "circular"
         shot file useful during realtime processing.
       =YES,  Create a new file on every trace 1.
       =NO, NO rewind - a normal file.
         Preset = NO,      e.g.  rewind yes    # rewind the file

TRACE0 - A YES/NO switch indicating whether the SEG-D external header
         should be written as a trace numbered 0 and SEG-Y
         trace id (short word 15) 28.  
       =YES, trace 0 will be written.
       =NO, trace 0 will not be written.
         Preset = NO    e.g.    trace0 yes   # a trace 0 will be written

EXTHDR - A YES/NO switch indicating whether to write the SEG-Y Rev. 1
         Textual Extension Records, if present, or not.
       =YES, the records will be written.
       =NO, the records will not be output.
         Preset = YES (to write the records).    e.g.  exthdr no

BIG    - No longer needed.
         A YES/NO switch when set to YES indicates that the output
         file will be larger than 2GB.  SIOSEIS can not tell in
         advance how large the output file will be and some operating
         systems need to know if the file will be > 2GB so that
         64 bit pointers are used.  Sun and HP need this parameter.
         SGI does not need this parameter.
         Preset = YES.    e.g.  big yes


   
Copyright (C) by The Regents of The University of California, 1988
Written by Paul Henkart, Scripps Institution of Oceanography, La Jolla, Ca.
ALL RIGHTS RESERVED.