1.      Introduction 

        This data set has been generated under the Jet Propulsion Laboratory's
(JPL) Science Digital Data Converstion Task (SDDCT) contract with Raytheon ITTS.
This task preserves valuable data resident on aging magnetic tapes by writing 
the data to long lasting CD-ROM media. In addition to accomplishing data
preservation this process also reduces the space required for media storage and
improves the accessibility of the data to the user. The data is written in 
standard ISO 9660 format on the compact disc, a format which is usable on a
variety of platforms. Accompanying the data from each tape on the disk is a log
file which documents the contents of the tape and provides information 
indicating problems which were encountered while recovering the data from tape.


2.      Disc Format

        Each CD-ROM disc has been formatted so that a variety of computer
systems (e.g. IBM PC, Macintosh, Sun, VAX) may access the data.  Specifically,
the discs are formatted according to the ISO 9660 level 1 Interchange
Standard, and file attributes are specified by Extended Attribute Records
(XARs).  For computer software that fully supports XARs, access to the CD-ROM
volume will be straightforward; the disc will appear to the user to be
identical to a file system of directories, subdirectories and data files. Some
computer systems that do not support XARs will ignore them; others will append
the XAR to the beginning of the file, in which case the user must read past
the first 512 bytes of the file.  For further information, refer to the ISO
9660 Standard Document: RF# ISO 9660-1998, 15 April 1988. 


3.      CD-ROM Contents

        The files on this CD-ROM are organized as follows. At the top level is  
a "tapes" directory and a "readme" file which contains general information.
Within  the  "tapes" directory are separate directories corresponding to each
tape. Each tape directory contains a "data" subdirectory and a "logs" 
subdirectory. The "data" directory contains a file corresponding to each file on
the tape. The "logs" directory contains logs describing the contents of the 
tapes and errors encountered during data recovery.


4.      Text Files 

        All document files and copying logs contain a carriage return
character (ASCII 13) and a line feed character (ASCII 10) at the end of each
record.  This allows the files to be read by the MacOS, DOS, Unix, and VMS
operating systems. 


5.      Recommended CD-ROM Drives and Driver Software (Note that the 
        following list is not inclusive.)

    VAX/VMS
         Drive:  Digital Equipment Corporation (DEC) RRD40, RRD42, or RRD50.
         Driver:  DEC VFS CD-ROM driver V4.7 or V5.2 and up.

         Note:  The driver software may be obtained from Jason Hyon at  
                JPL (Files are: JPLPDS::DISK$USER1:[JHYON]VFS*.A).  It is 
                necessary to use this driver to access the XARs on the CD-ROM.

    VAX/Ultrix
         Drive:  DEC RRD40, RRD42, or RRD50.
         Driver:  Supplied with Ultrix 3.1. 

         Note:  Use the "cdio" software package (in "~ftp/src/cdio.shar"
                from the "space.mit.edu" server).

    IBM PC
         Drive:  Toshiba, Hitachi, Sony, or compatible.
         Driver:  Microsoft MSCDEX version 2.2.

         Note:  The newest version of MSCDEX (released in February 1990) 
                is generally available.

    Apple Macintosh
         Drive:  Apple CD SC (Sony) or Toshiba.
         Driver:  Apple CD-ROM driver.

         Note:  The Toshiba drive requires a separate driver, which may
                be obtained from Toshiba.

    Sun Micro
         Drive:  SUN Microsystems (Sony).
         Driver: SUN CD-ROM Driver.

         Note:  There is a patch to support structured files.

 >the following error, when >trying to do a "ls" on its directory contents:
 >      'hsfs: filetype(0X8) not supported'.
 >

The files that cause the error message are structured files.  They are
organized in records (fix or variable length).  Applications need to retrieve
additional file attributes (fix or variable length, and maximum record length)
from these files in order to access the contents correctly. 
 
Unfortunately, UNIX can only handle stream files (unstructured byte stream).
There is currently no application interface to access the extended file
attributes and data records in a record format file.  (Note: Philips is coming
up with an X/Open specification (XCDR) to provide an API to access the ISO
9660 CD-ROM format Disc.  It is too early to tell whether it will be approved
or not). 
 
The design decision when implementing the CD-ROM file system was to ignore all
record format files stored in a CD-ROM.  This is obviously a mistake. The best
way is at least to allow users to access these files. 
 
The following is a patch for SunOS 4.1 Sun4c (SPARCSTATION) to correct the
above problem: 
 
acuraintegra# adb -w vmunix
>>>> hs_parsedir+9c?X
_hs_parsedir+0x9c:              ba0da0ee
>>>> hs_parsedir+9c?Wba0da0e6
_hs_parsedir+0x9c:              0xba0da0ee      =       0xba0da0e6
>>>> hs_parsedir+14c?X
_hs_parsedir+0x14c:             ba0da0ee
>>>> hs_parsedir+14c?Wba0da0e6
_hs_parsedir+0x14c:             0xba0da0ee      =       0xba0da0e6
>>>> $q
 
Note: you can also patch hsfs_node.o with the above patch.
 
The patch for SunOS 4.0.3c (SPARCSTATION) is similar:

hs_parsedir+9c?X
_hs_parsedir+0x9c:              ba0de0ee
hs_parsedir+9c?Wba0de0e6
_hs_parsedir+0x9c:              0xba0de0ee      =       0xba0de0e6
hs_parsedir+14c?X
_hs_parsedir+0x14c:             ba0de0ee
hs_parsedir+14c?Wba0de0e6
_hs_parsedir+0x14c:             0xba0de0ee      =       0xba0de0e6
$q
 
The following is the patch for the sun3:
 
adb -w hsfs_node.o
hs_parsedir+56?X
_hs_parsedir+0x56:              ee6612
hs_parsedir+56?We66612
_hs_parsedir+0x56:              0xee6612        =       0xe66612
hs_parsedir+e4?X
_hs_parsedir+0xe4:              ee6612
hs_parsedir+e4?We66612
_hs_parsedir+0xe4:              0xee6612        =       0xe66612
$q


6.  Who to Contact for Information

    For questions about how to read CD-ROMs:

              Jason J. Hyon
              MS 171-264
              Jet Propulsion Laboratory
              4800 Oak Grove Drive
              Pasadena, CA  91109
              818-354-0730

              Electronic mail addresses:
              Internet:  jason.hyon@jpl.nasa.gov