README

* Data

The contents of these files were recovered from 40, DDS-1 data tapes. The data 
tapes were read on a Python 02635 model DDS-2 tape drive mounted in a Sun 5-¼" 
external SCSI enclosure. The total amount of data recovered equals 24622680843 
bytes (23 GiB).

The data includes eleven seismic lines. Seven lines (1, 3, 5, 6, 7, 9, and 11) 
are longer, and their raw data could not fit on a single data tape. Thus these 
lines segmented and stored on multiple tapes, e.g.:

     TIB 3 SHOTS (1-55) SEGY
     TIB 3 SHOTS (56-110) SEGY
     TIB 3 SHOTS (111-165) SEGY
     TIB 3 SHOTS (166-221) SEGY
     ...

The raw data from the remaining four shorter lines (2, 4, 8, 10) were stored 
on one tape each.


 * Info

Contained within the info/ directory are three sub-directories, labels/, 
insets/, and sleeves/, which contain any written information found on the data 
tape case, or the data tape cartridge itself. These directories contain one 
file for each of the 40 original data tapes. Any typographical errors found in 
these files were preserved from their original source.

labels/: This directory contains the text written on the edge of the data tape 
cartridge which is opposite of the tape reading side. This is the edge of the 
cartridge that faces outwards while the data tape is loaded into a reader, and 
is also visible when the data tape is stored properly in the box. The text of 
this label is used to identify each tape in the TAPELIST and FILELIST 
supporting files, and is used as the base name of files contained in the 
labels/, insets/, and sleeves/ directories. The label also served as the basis 
for many of the resulting data file names, and also the directories in which 
they are organized.

insets/: Many of the data tape cases contained a small slip of folded paper 
with extra information about the data and processing methods used. Each file 
in the insets/ directory contains the text of these papers. An empty inset 
file signifies that no inset was included within the data tape case.

sleeves/: The sleeve is the manufacturer supplied paper label which encompasses 
two whole sides of the data tape case, and is provided to further identify the 
data tape. The sleeve typically also displays brand and make information about 
the data tape cartridge. Each file in the sleeves/ directory contains the text 
of the sleeves. On tapes which contain multiple files, the sleeve contains 
information identifying each file. This information was used to name each 
file in such cases.


 * Scans

The scan/ directory contains a series of PDF files which are scans of paper
documentation that arrived with the data tapes. Each of the thirteen PDF files
represents a bundle of papers which was stapled together. The papers where
scanned and converted to PDF files on a Ricoh Aficio MP 4001 copier.


 * Errors

Most of the tapes were read successfully, however four of the tapes had 
reading errors. Files which are presumed to be truncated by an incomplete read 
have the text "(error)" appended to their respective file name. These files 
are:

     raw/TIB 01 SHOTS (476-581) SEGY (error).sgy
     raw/TIB 11 SHOTS (001-053) SEGY (error).sgy
     processed/SEGY/SHOTS PROC w_cc/TIB-09 SEGY - SHOTS PROC w_cc (error).sgy
     processed/SEGY/STACK PROCESSED/TIB-10 SEGY - STACK PROCESSED (error).sgy


 * Notes

Two tapes (STN 200 DAS 6122 day 220, and ST200 (x-line-5) DAS 6122 day 221) 
contained three files each, of which their format is unknown. The data appears 
to be startup and acquisition logs for sensing equipment.


Although the preferred method to label tape files is to start at the number 
zero and increase by one for each file mark, the original creator of these 
tapes labeled multi-file tapes starting with the number one. I have adopted 
the start-at-one scheme in my supporting documentation as not to cause 
confusion between it and the original paper labels.