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FileHandling Subtopology — Software Design Document (SDD)

The FileHandling subtopology packages the core file-transfer services commonly needed in F´ deployments: file uplink (ground → flight), file downlink (flight → ground), on-board file management, and parameter management via filesystem. By providing these as a pre-wired subgraph, integration engineers avoid repetitive wiring and get a consistent, reusable baseline for file operations.

1. Requirements

ID Description Validation
SVC-FILEHANDLING-001 The subtopology shall provide file uplink functionality to receive and reconstruct files from ground. Inspection
SVC-FILEHANDLING-002 The subtopology shall provide file downlink functionality to segment and transmit files to ground. Inspection
SVC-FILEHANDLING-003 The subtopology shall provide on-board file management functionality (e.g., list, remove, hash, mkdir). Inspection
SVC-FILEHANDLING-004 The subtopology shall provide parameter management via the filesystem. Inspection
SVC-FILEHANDLING-005 The subtopology shall support configurable instance properties (IDs, queue sizes, stack sizes, priorities). Inspection
SVC-FILEHANDLING-006 The subtopology shall expose rate-group connection points for any rate-drive components it contains. Inspection

2. Design & Core Functions

2.1 Instance Summary

Instance name Type (Svc) Kind Purpose (core function)
fileUplink FileUplink Active Ingest deframed file packets; reconstruct files.
fileDownlink FileDownlink Active Read files; segment into packets for downlink.
fileManager FileManager Active Local file operations.
prmDb PrmDb Active Filesystem based parameter management.

2.2 Configuration Hooks inside the Subtopology

  • Uses instance properties (IDs, queue sizes, stack sizes, priorities) defined in FileHandlingConfig for these static instances (see §4).

2.3 Required Inputs for Operation

  • Rate Groups: Connect scheduler outputs to the Run (scheduling) ports of fileDownlink.
  • Communication/Framing Stack: Wire file-packet ports between FileHandling and your COM/framing subtopology (e.g., ComCcsds, ComFprime, FramingFprime, FramingCcsds) to complete uplink/downlink paths.

2.4 Limitations

Focused on file transfer and on-board file ops only. It does not provide general uplink/downlink routing for non-file traffic, framing/deframing for non-file data, or broader CDH services.

3. Usage

3.1 Example Usage

topology Flight {
  import FileHandling.Subtopology

  param connections instance FileHandling.prmDb

  # Schedule the active/queued file components (example)
  connections RateGroups {
    rg.RateGroupMemberOut[0] -> FileHandling.fileDownlink.Run
  }

  connections ComCcsds_FileHandling {
    # File Downlink <-> ComQueue
    FileHandling.fileDownlink.bufferSendOut -> ComCcsds.comQueue.bufferQueueIn[ComCcsds.Ports_ComBufferQueue.FILE]
    ComCcsds.comQueue.bufferReturnOut[ComCcsds.Ports_ComBufferQueue.FILE] -> FileHandling.fileDownlink.bufferReturn

    # Router <-> FileUplink
    ComCcsds.fprimeRouter.fileOut     -> FileHandling.fileUplink.bufferSendIn
    FileHandling.fileUplink.bufferSendOut -> ComCcsds.fprimeRouter.fileBufferReturnIn
  }

4. Configuration

Configure only the instance properties for the static instances owned by the subtopology. All knobs live under: Svc/Subtopologies/FileHandling/FileHandlingConfig/FileHandlingConfig.fpp. The generated constants header for this module (e.g., FppConstantsAc.hpp) reflects these settings. ([FPrime][2])

4.1 Component properties (FileHandlingConfig.fpp)

  • Base ID — Base identifier for the subtopology; component IDs are offset from this base.
  • Queue sizes — Queue depths for fileUplink, fileDownlink, fileManager.
  • Stack sizes — Task stacks for active components (fileUplink, fileDownlink).
  • Priorities — RTOS priorities for the active/queued components as applicable.

These knobs tailor runtime footprint and scheduling without modifying the subtopology wiring.

5. Traceability Matrix

Requirement ID Satisfied by
SVC-FILEHANDLING-001 fileUplink — Svc.FileUplink
SVC-FILEHANDLING-002 fileDownlink — Svc.FileDownlink
SVC-FILEHANDLING-003 fileManager — Svc.FileManager
SVC-FILEHANDLING-004 prmDb — Svc.PrmDb
SVC-FILEHANDLING-005 FileHandlingConfig (instance properties)
SVC-FILEHANDLING-006 Run/scheduling connection specifiers