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File Handling Subtopology

docs/reference/system-functional/subtopology-file-handling.md

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File Handling Subtopology

References

Overview

The File Handling subtopology packages the core file-transfer and file-management services commonly needed in F Prime deployments into a single reusable unit. It provides file uplink (ground to flight), file downlink (flight to ground), on-board file management operations, and filesystem-based parameter management.

Included Components

  • File Uplink (active) — Receives file packets from the communication stack and reconstructs files on the flight file system.
  • File Downlink (active) — Reads files from the file system, segments them into packets, and sends them through the communication stack for transmission to the ground.
  • File Manager (active) — Provides ground commands for common file operations (list, remove, create directory, move, copy, concatenate, hash).
  • Parameter Database (active) — Manages persistent parameter storage via the file system. Loads parameters at startup and saves them on command.

Required Inputs

  • Rate group connections to drive File Downlink's send cycle.
  • Communication stack connections for file packet exchange (wire to a ComFprime or ComCcsds subtopology's file ports).
  • Parameter connections from all components that use parameters.
  • A parameter-file name for prmDb: call FileHandling.prmDb.configure() during topology setup, before parameters are loaded.

Configuration

  • Base IDs, queue sizes, stack sizes, priorities, and CPU affinities via FileHandlingConfig.
  • The File Downlink send rate is determined by the connected rate group frequency.

Limitations

This subtopology focuses on file transfer, file operations, and parameter management. It does not provide framing, deframing, or CDH services — those are provided by the communication and CDH subtopologies.