                            HOW TO READ DUBCAT FILES



     The DUBCAT files are the result of an attempt to merge and correlate the
dub files and the corresponding catalog files.  An "old" dub file shows the
expected values for the start time, dub duration, and tape i.d. (A,B,C,D,E) for
the dubs on the dubbed tape.  An old dub file generally contains all the dubs
from the A-daily tape followed by the B-dubs, the C-dubs, etc.; after the com-
plete set of these daily tapes were dubbed, the next set of daily tapes were
dubbed onto the next portion of the dubbed tape, and so on.  A "new" dub file
contains the same information as an old dub file plus the expected hex footage
locations for the dubs.  A new dub file generally contains all the dubs (ie.,
A-dub followed by B-dub followed by C-dub, etc.) for a particular event fol-
lowed by all the dubs for the next event, and so on.  The dubbing for these new
dub tapes ("scatter" dubbing) began near the end of 1977 for CNET and in the
middle of 1978 for HNET and CTEC.  (The old and new dub files are distinguished
by their names.  The name of an old dub file has 7 characters: 4 characters for
the net [CNET, CTEC, HNET] plus a 3-digit number.  The name of a a new dub file
has 10 characters: 4 characters for the net [CNET, CTEC, HNET, ANET, ENET] plus
6 additional characters).  A catalog is generated after the dubbing is done, and
it shows the actual values of the start and stop times and the corresponding hex
footages for the dubs on the dubbed tape. (The catalog start times are up to
about 10 seconds late for IRIG-E and up to about 1 minute late for IRIG-C, due
to the time necessary for the time code translator to read.  The hex footages
are referenced from a foil marker which is placed on the tape generally about
100 hex feet from the beginning of the tape; the foil marker is placed on the
tape above the bottom guide roller on the playback machine, at which point the
hex footage is set to 8000). 


     The names given to the DUBCAT files are at least 6 characters long.  The
first 4 characters are the net (CNET, CTEC, HNET, ANET, ENET) and  the next 2
characters are the year.  The optional next character is a letter (A,B,C,D) that
represents the quarter of the year.  The optional character after the "." is a
hexadecimal number (1-C) that represents the month of the year.  (At the end of
a year or quarter, some of the dubs may have stop times that go into the next
month, quarter, or year.) 


     The DUBCAT files are organized chronologically (based on a line by line
alphanumeric sort), and each line consists of a maximum of 132 characters.  The
columns in each line are organized as follows: 
  col. 1-14: start time
       col. 1-2: year
       col. 3-4: month
       col. 5-6: day
       col. 7: (blank)
       col. 8-9: hour
       col. 10-11: minute
       col. 12: (blank)
       col. 13-14: second
  col. 15: (blank)
  col. 16-21: hex footage at start time
       col. 16: "("
       col. 17-20: hex footage
       col. 21: ")"
  col. 22: (blank)
  col. 23: "-"
  col. 24: (blank)
  col. 25-37: stop time
       col. 25-26: year
       col. 27-28: month
       col. 29-30: day
       col. 31: (blank)
       col. 32-33: hour
       col. 34-35: minute
       col. 36: (blank)
       col. 37-38: second
  col. 39: (blank)
  col. 40-45: hex footage at start time
       col. 40: "("
       col. 41-44: hex footage
       col. 45: ")"
  col. 46: ":"
  col. 47-49: numbers of dropouts
  col. 50: source
           I: start time fixed
           F: stop time fixed
           X: dub file entry without corresponding catalog entry
           Y: catalog entry without corresponding dub file entry
  col. 51: input tape letter (A,B,C,D,E)
  col. 52: status
           O: old tapes
           number from 1-8: new tapes
                           --generally, a lower number means better time code;
                             4 usually means hand dub for CNET, ANET, or ENET;
                             8 usually means hand dub for CTEC or HNET;
                             7 usually means dub stopped early.
  col. 53-55: time code used in cataloging
       col. 53: type of time code
                E: IRIG-E
                C: IRIG-C
       col. 54: track on tape (hexadecimal number from 1-E)
       col. 55: discriminator
                1: 3500Hz
                2: 3950Hz
                3: 1020Hz
                4: 1360Hz
  col. 56-62: name of dubbed tape
       col. 56: net
                C: CNET
                S: CTEC
                H: HNET
                A: ANET
                E: ENET
       col. 57-62: last 6 characters of tape name
  col. 63-132: optional
       col. 63-67: box number stored in Bldg.3A
            col. 63: "-"
            col. 64-67: box number
       col. 68: (blank)
       col. 69-81: start time and corresponding hex footage correction
            col. 69: "["
            col. 70-74: time correction (in seconds)
            col. 75: "("
            col. 76-79: hex footage correction
            col. 80: ")"
            col. 81: "]"
       col. 82-94: stop time and corresponding hex footage correction
            col. 82: "["
            col. 83-87: time correction (in seconds)
            col. 88: "("
            col. 89-92: hex footage correction
            col. 93: ")"
            col. 94: "]"
       col. 95: (blank)
       col. 96-x: remark (with x<133)
            col. 96: "'"
            col. 97-(x minus 1): remark
            col. x: "'"


     The start and stop times (and corresponding hex footages) are generally
derived initially from the values in the catalog.  An "I" in col. 50 means that
the start time was fixed, due to an obvious time code error (this problem was
very rare, ocurring only about 1-2 times).  Most of the time, the start time was
initially assumed to be correct.  If the ratio of the difference in times to the
difference in hex footages was significantly different than 2.048 (ie., such
that the time difference was more than 2-3 seconds from the expected value), the
stop time was fixed ("F" in col. 50).  If there was no catalog entry for a par-
ticular dub file entry, the time and hex footage values were derived from the
dub file ("X" in col. 50).  If there was no dub file entry for a particular cat-
alog entry ("Y" in col. 50), the catalog values of time and hex footage were
used but the validity of these values is uncertain. 


     If, after comparing a dub file entry and a catalog entry, the start time
was found to be late, a time correction (col. 70-74) and a corresponding hex
footage correction (col. 76-79) were subtracted from the start time values to
bring them up to the ideal.  Likewise, if the stop time was found to be early, a
time correction (col. 83-87) and a hex footage correction (col. 89-92) were
added to the stop time values.  In some cases (such as noisy time code), these
corrections are valid, and in some cases (such as actual data loss), these cor-
rections are invalid; however, the corrections were made whether valid or not in
order to minimize the possibility of incompleteness. 


     The number of dropouts (col. 47-49) refers to the number of times the time
code translator put an additional entry in the catalog for a single dub. These
dropouts are caused by such things as noisy time code, dirty heads on playback
machine, and actual data loss. 


     The time code used in cataloging (col. 53-55) is not necessarily the best
or the only time code available.  A different combination of type of time code,
track, and discriminator may give a cleaner time code.


     Any remarks were kept very brief.  A remark generally has the form of a
prefix (which refers to the type or source of a problem) followed by a more
detailed explanation in parentheses.  Some prefixes are as follows:
  INP = input daily tape
  TC = time code
  JD = julian date
Some remarks are as follows:
  INP(MISALL.;ADJ) = the input tape was mistracking when it was originally
                     recorded; at the time of dubbing, the guide roller on the
                     playback machine was adjusted to (hopefully) duplicate
                     the original recording conditions; it is possible this
                     adjustment was made in the wrong direction , causing the
                     tracks to be out of place or missing.
  TC(NO IRIG-E) = IRIG-E time code is unavailable for this dub; IRIG-C or WWVB
                  may be available.
  TC(CD4) = there is IRIG-C time code on track 13 at 1360Hz.
  JD(366) = in the catalog, the julian date read 366; it was corrected to be
            the right date in the DUBCAT file; this is generally caused by the
            IRIG clock not being set on time at the end of a year.
  CF(860121 1614 20 C) = compare this entry with the entry in parentheses (it
                         is uncertain which entry is correct).


     Following are some examples to illustrate the organization and meaning of
the lines in the DUBCAT files: 

800405 1636 00 (C189) - 800405 1653 01 (C37C):  2 B3E71S800016-0620
  (The start time for the above dub is April 5, 1980, at 1636:00 at a hex foot-
  age of C189.  The stop time is on the same day at 1653:01 at a hex footage of
  C37C.  There were 2 dropouts in the catalog [which means there were 3 catalog
  line entries].  The input daily tape was a B-tape.  The status in the dub
  file was a "3", which means the computer had a little trouble reading the
  time code at the time of dubbing [a "2" or even a "1" would have been bet-
  ter]; so the time code may have been a little noisy, and it may have been
  better if a different type of time code or a different track had been used in 
  dubbing.  The type of time code used in cataloging was IRIG-E on track 7 with 
  a discriminator of 3500Hz [these are not necessarily the same time code para-
  meters used at the time of dubbing].  The input daily tape came from Caltech,
  and the dub tape is named "CTEC800016".  This dub tape is archived in Build-
  ing 3A, and it is box number 0620.)

751230 0510 20 (8954) - 751230 0516 59 (8A17):  0FAOED3H001   -0751
  (This dub had no dropouts in the catalog.  There is an "F" in col. 50, which
  means the stop time in the catalog was adjusted to give an appropriate value;
  the difference in the stop hex footage and the start hex footage should be
  expected to correspond closely to a certain difference in the stop time and
  the start time.  The "O" in col. 52 means the dub file was in the old style
  before scatter dubbing.  The catalog time code was from IRIG-E on track 13
  [hexadecimal D] with a discriminator of 1020Hz.  The dub tape is "HNET001",
  which contains the Hawaii dubbing.)

821026 1323 17 (317E) - 821026 1327 40 (3274):   XC1   C82OC12-0370
  (The "X" in col. 50 means there was no catalog entry for this dub; the start
  time is the dub request time from the dub file, and the stop time is the
  start time plus the requested dub duration; the start and stop hex footages
  are also from the dub file.  There are blanks in col. 53-56 because there is
  no catalog information.  The dub tape contains Calnet dubbing and is named
  "CNET82OC12".)

760102 0214 30 (009D) - 760102 0217 30 (0523):   XAO   H001   -0751                            'X(3/5)'
  (There is no catalog entry for this dub; the start and stop times are derived
  from the dub file.  The "O" in col. 50 means the dub file was the old style
  before scatter dubbing; since the dub file contains no hex footage informa-
  tion, the start and stop hex footages represent a gap in the catalog where
  the dub is presumed to exist.  The remark "X(3/5)" means there are presumed
  to be 5 dubs in this gap and this dub should be the third one.)

840101 0458 40 (91B6) - 840101 0504 42 (9267):  0 B1E71C84JA01                                 'JD(366)'
  (The remark for this dub means the Julian date reads 366 instead of 001 for
  the time code parameters that were used in cataloging; the IRIG-E clock
  apparently did not get reset on time after the beginning of the new year.)


     The periods of time covered by the DUBCAT files vary according to the net:
          CNET: beginning (5/1/74) to present
          CTEC: beginning (12/21/75) to present
          HNET: beginning (10/1/75) to present
          ANET: beginning (1979) to 1983
          ENET: none
There is presently no intent to create the DUBCAT files for the ENET dubbing.
For the other nets, it is anticipated that the DUBCAT files will be updated per-
iodically when the dub files and catalog files become available.


     For most of the nets, dubbing presently plays a minor role in the record-
ing of earthquakes, with most of the work being done by the CUSP system; How-
ever, larger earthquakes and teleseisms are still dubbed.  For CNET, earth-
quakes of magnitude 3.5 and greater, and teleseisms of amplitude 5 mm. and
greater on the helicorders or 20 mm. and greater on film, are presently being
dubbed.  For HNET, dubbing is from a list generated at HVO.  For CTEC, dubbing
has stopped except for possible special requests.  For ANET, dubbing is from a
list generated by the Alaska group and is more extensive than the dubbing by
the other nets because CUSP is not working there.
