A8.2 Interface Characteristics

A8.2.1 Hardware Characteristics and Limitations

Special Equipment and Device Interfaces. None identified. SEDR tapes for the PIs will be in IBM compatible format.

Special Setup Requirements. None identified.

A8.2.2 Volume and Size

The size of the SEDR file on tape will be less than 3000 tracks. A track contains 1792 32-bit words for the UNISYS computer. This is only an operational restriction set by DMT to ensure that an SEDR file will not require more than one reel of tape to write. Under the current plan of generating one SEDR file per month, the SEDR file should be less than 100 tracks per tape. DMT can adjust the size of the SEDR file by changing the processing time interval of the processing run.

A8.2.3 Interface Medium Characteristics

SEDR records are comprised of 32-bit words. These words contain integer or floating point SEDR quantities depending upon the format requested. The SEDR file is written to a nine-track unlabelled tape at a density of 1600 bpi.

Logs and printed summaries on the start and stop times of the SEDR file and the number of records per tape are included in each SEDR shipment.

A8.2.4 Failure Protection, Detection, and Recovery Procedures

File Backup Requirements. DMT will retain backup copies of the SEDR master files until end of mission plus three years, or until transfer of said data to a permanent archive center, whichever occurs earlier.

Security/Integrity Measures. DMT will restrict the release of SEDR to the ULS PIs. No other security measures are planned.

For data traceability, each SEDRGEN run will output an audit trail which identifies the source and version of the input data.

A8.3 Access

A8.3.1 Programs Using the Interface Data

PI software is not identified in this document. It will be the sole responsibility of the PI to produce software which accepts properly made SEDRs as its input.

A8.3.2 Synchronization Considerations

Timing and Sequencing Characteristics. The records in the SEDR files will be in increasing Spacecraft Event Time (SCET) order (UTC).

Effective Duration. If the SEDR data are considered “final,” the data will be within project science accuracy requirements for the time (UTC) indicated in each record.

Next: A8.4 Detailed Interface Specification

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