Voyager 2 Neptune Encounter CDROM Planetary Plasma Interactions Node of the Planetary Data System ============================================================================== Introduction ============================================================================== This disk contains Neptune encounter data submitted to the Planetary Data System (PDS) by Voyager project investigators. Every effort has been made to assure that the data are of the best quality available. However, the PDS and the Planetary Plasma Interactions (PPI) Node in particular, assume no liability for this disk or its contents. All users are encouraged to verify the "correctness" of the data prior to submitting any publications or other work based on these data. ============================================================================== Disk Format ============================================================================== The disk is organized into a hierarchical directory structure which the PPI Node hopes will be both intuitive for the user as well as easy to use. The disk is formatted according to both ISO 9660 and POSIX (Unix) standards in order to accommodate users on a wide variety of platforms. All of the label, table, and text files are ascii with CR/LF (VAX / IBM-PC) format. The basic organization of the disk is as follows: CATALOG contains instrument, dataset, and data quality templates organized into instrument sub-directories. MANAGE contains data management information for the DITDOS software. Users do not need to make use of any of these files directly, however, the software which allows DITDOS to extract and reformat data files needs to have this information. INDEX contains a cumulative index table which describes the location of all files on the disk for users who do not wish to make use of the DITDOS software. SOFTWARE contains information about software to extract data from this disk to IBM-PC, VAX-VMS, and Sun workstations. DATA contains all data in a branching tree structure of sub-directories. Instrument directories are divided into coordinate system (mag) or subsystem sub-directories. These in turn are divided into sample rate sub-directories. Data files are given either a date filename of the form "Tyymmdd.DAT" or a spacecraft clock file name of the form "Cmajormf.DAT" where "major" is the major frame counter and "mf" is the minor frame counter. ============================================================================== File Format ============================================================================== All files on this disk are described by detached version 3.0 PDS labels. Version 3.0 of the PDS label does not support detached TEXT file labels, however, TEXT file labels are detached on this disk. Most of the data files are time-series which are organized as IGPP flatfiles. An IGPP flatfile is a collection of 4 files each of which could be considered a table. The data file (.DAT) is a binary table of data values. The other three files are used by the UCLA/IGPP Data Flow System (a software package) and they contain header type information (.DES, .HED, .ABS). The Plasma Wave and Planetary Radio Astronomy (PWS / PRA) datasets are repeated twice in their appropriate directories - once as an IGPP flatfile and once in the native form provided by the instrument team. The reason for repeating these data in nearly identical files is to allow the instrument teams to access their data using software they have developed which is dependent on the file structure. The data extraction software provided with this disk expects IGPP flatfiles and could not be modified in time for this disk release. PDS labels are identified by a .LBL file name extension. There is one label file for each text and data file contained on this disk and the file name prefix is the same as the file the label describes. If the dataset is is stored as multiple files (as most of them are), there will be a single format file which describes the physical structure of the data. This format file is then pointed to by all of the labels. Both the label files and the format files files (.FMT) are all grouped in the same directories as the data they describe. ============================================================================== Volume Contents ============================================================================== This section describes the volume structure and naming conventions. This basic disk structure is described in the disk format section. Here we give a little insight in to why some of these choices were made. Catalog Directory: This directory is sub-divided into instrument directories in order to organize catalog information by instrument. Since this disk contains many datasets from many instruments, a single CATALOG.CAT file would be far too large and cumbersome to be useful. Our approach is to divide the information first into instrument groups and then to separate the individual catalog templates. The names of the files and the templates they contain are as follows: CATALOG directory MISSION.CAT Mission template SC.CAT Spacecraft template Instrument sub-directories INST.CAT Instrument template DATASET.CAT All dataset templates associated with the instrument DSPROC.CAT All dataset processing templates PARM.CAT Dataset and instrument parameter description templates SOFTWARE.CAT Dataset processing software template COORD.CAT Coordinate system description template (if necessary) In addition, the Planetary Plasma Interactions Node of the PDS provides detailed level catalog information along with its data distribution. This information is stored in a DLC subdirectory. The detailed level catalog contains information specific to a particular instrument that could not be captured in the catalog templates. The DLC also contains data quality, contamination, and percentage availability information at hourly granularity. Software Directory: Software is provided for this disk which is compatible with a number of different platforms (IBM-PC, VAX-VMS, SUN-UNIX). We have made every effort to make distributed software platform independent. However, some of the software is data provider supplied and may only be supported on a single platform. The "INFO.TXT" files will help the user to determine if a desired program or application can be used on their platform. Software is available from the PPI Node via an anonymous ftp account. The basic structure of the remote software directory is as follows: +- bin (executable versions of applications) | +- include (all include files) | +- lib (compiled object libraries) | +- man (manual pages - if there are any) | +- src (source code for everything) | +- app (source code for applications) | | | +- ditdos (The ditdos client) | | | +- ditdos_server (The ditdos server) | | | +- scripts ( Various scripts) | +- lib (source code for libraries) | +- bc (Binary conversion functions) | +- dfs (Data Flow System functions) | +- ditdos (ditdos client/server functions) | +- ffio (IGPP Flatfile I/O library) | +- fnc (File Name Conversion library) | +- igpp_sql (The IGPP SQL parser library) | +- list (Object oriented list manager functions) | +- message (Generic message reporting functions) | +- packet (tagged packet library) | +- parserc (string parsing functions) Installation procedures will be provided for all software on this disk in the INSTALL. file. In general, if the installation location is fully compatible with the development platform, the executable will be moved to the installation area. If there are minor incompatibilities (operating system version or compiler version differences) a new executable will be generated from the object code. If there are major incompatibilities (i.e. unsupported platform) and source code is available, the user will have to port the code to the platform needed. File naming will be freeform, however, the file name extensions will follow the standard naming for Unix platforms (.F - Fortran source code, .C - "C" source code, .O - object code, etc.) Index Directory: The index directory contains a cumulative index which points to every file on this disk. The index is an ascii table which could be easily loaded into a database or spreadsheet program. The index file is described by a detached PDS label. Manage Directory: This directory contains several IGPP flatfiles which are used by some of the software in the software directory. These files are not intended for direct use by a user so there are no PDS labels. Data Directory: The data directory is subdivided into multiple levels such that each dataset is in a sub-directory of its own. Sub-directories are organized according to the following levels: DATA INSTRUMENT SUBSYSTEM or COORDINATE SYSTEM SAMPLE RATE The data files and labels are contained in the sample rate subdirectory. Any files which apply to all datasets further down the tree, are placed at the level at which this transition occurs. This applies to calibration files or ancillary information files. Data files are named using the date or spacecraft clock count of the first record in the file. Files whose names are date/times begin with the letter "T" and give the date in the year-month-day format YYMMDD. Files whose names are clock counts begin with the letter "C" and follow a major frame (F) - minor frame (M) format of FFFFFMM. If the number of files within a single sample rate directory would exceed the ISO 9660 CDROM standard of 255, an additional directory level is added. This level is given a date or clock count name which follows the convention just described. In this case, the directory is given the same name as the first file in that directory. ============================================================================== Driver and Hardware Information ============================================================================== This disk has been formatted according to the ISO standard for CDROM production (9660) with level 1 compliance. Any system which complies with this standard (all of them should) should be able to access this disk. ============================================================================== Point of Contact ============================================================================== If the user has problems reading this disk or can not make use of it on one or more of the platforms which should be supported, please contact the PPI pds_operator. This person can be reached in the following ways: SPAN/DEC-NET uclasp::pds_operator Internet pds_operator@igpp.ucla.edu Telephone (310) 206-6073 U.S. Mail PDS Operator c/o Dr. Raymond Walker 3845 Slichter Hall UCLA - IGPP Los Angeles, CA 90024-1567 ============================================================================== Cognizant Persons ============================================================================== The person most directly responsible for the construction and release of this CDROM is Mr. Steven Joy. He was the PPI Node Manager at the time this disk was created and he understands as much about the disk structure and data organization as anyone. The construction of the PDS labels and templates was done by Ms. Eva Fried of the PPI Node and Ms. Sue Hess and Ms. Ruth Monarrez of the Central Node at JPL. Mike Martin of JPL has helped to insure this disk conforms to PDS standards although this disk structure has not yet been adopted as an excepted standard at the time of its release. PPI Personnel JPL Personnel Steven Joy / Eva Fried Sue Hess / Ruth Monarrez / Mike Martin 3845 Slichter Hall 4800 Oak Grove Dr. UCLA - IGPP Mail Stop 525-3610 Los Angeles, CA 90024-1567 Pasadena, CA 91109