The ISPM experiment data tapes were originally magnetic tapes written at 9-track, 1600 bpi with odd parity, but now they are being replaced by CD-ROMs starting with the September 1991 issue.

The following sections describe the format and content of the Ulysses CD-ROM.

CD-ROM data shall be formatted in accordance with ISO and CCSDS specifications.

Disc Format. The Ulysses CD-ROM format shall be compatible with various computer systems including IBM PC, Macintosh, Sun, and the VAX. The Ulysses CD-ROM format shall be in accordance with ISO 9660 level 1 Interchange Standard, with file attributes specified by Extended Attribute Records (XARs) (logical blocks of 512 bytes), to provide a file system of directories, sub-directories, and data files. Computer systems that do not support XARs will either ignore them or append them to the beginning of the file. In the latter case, the user must ignore the first 512 bytes of each file.

File Formats. The following paragraphs describe file formats for the various kinds of files contained on CD-ROMs.

• ASCII Files: ASCII files (TXT suffix) contain lines terminated by a carriage return character and a line feed character (ASCII 10). This allows the files to be read by most operating systems.
• PDS Files: Tabular files (.TAB suffix) exist in the index directory. Tabular files are ASCII files formatted for direct reading into many database management systems on various computers. PDS label files (.LBL suffix) are descriptive labels for other files.
• Experiment Data Records (EDR) Files: Experiment Data Records (EDR) files are created from spacecraft telemetry and ground monitor data provided by the “front end” processor called the Advanced Multi-Mission Operations System (AMMOS). All nine EDRs will be present on each CD-ROM, each file containing one month of EDR data.
• Common Data File (CDF) Files: Common Data File (CDF) files are created from spacecraft telemetry data using EDRs as the source. These are two types of files. One contains CDF data from the Bame, Gloeckler-Geiss, Keppler, Lanzerotti, Simpson, and Stone experiments and the other contains CDF data from the Hedgecock experiment. Each file contains data for one calendar month.
• Supplementary Experiment Data Record (SEDR) Files: Supplementary Experiment Data Record files are derived from two sources: navigational parameters and spacecraft spin axis orientation information. There are two files: one contains floating point values and the other fixed point (IBM architecture). Each file contains data for one calendar month.
• Quality, Quantity, Continuity (QQC) Files: The Quality, Quantity, Continuity file contains quality, size, and coverage period information for the raw data from which the EDRs were created. For each data gap longer than three minutes, the reason that the data could not be recovered is given.
• Spacecraft Event Time/Spacecraft Clock count (SCET/SCLK) File: This file contains the coefficients that allow the calculation of Spacecraft Event Time given by the spacecraft clock.
• Command History File (CMDH): This file contains a list of the commands transmitted and aborted for the given month, along with the transmit and on-board times and the OWLT.
• Monitor File: TBS
• One Way Light Time File (OWLT): TBS

The set of Ulysses CD-ROMs contains all EDR, SEDR, CDR, and auxiliary files, including QQC, OWLT, Command History, Monitor, and SCET/SCLK files. A month of data sets is contained on each CD-ROM. The following paragraphs describe the content of the CD-ROMs.

Directories. The Ulysses CD-ROM directory structure consists of one root directory, an index subdirectory, a software subdirectory, and a document subdirectory. Files in the root directory provide data files, a volume label, and text describing the Ulysses CD-ROMs. Files in the index directory describe the contents of the data products on that CD and all previously produced CDs. Files in the document directory describe data products. The following tables describe the content and source of files in the Ulysses CD-ROM directories.

Table 2.1 Files in the Root Directory for ULS CD-ROMs

Table 2.2 Files in the index subdirectory

Table 2.3 Files in the document subdirectory