AFSS

Adaptative File System for Space Application
Responsable
ROSSIER Daniel
Période
November 2012 - June 2014
Axes
Software-oriented Heterogeneous Device Support

Context

Today’s space missions take an ever growing number of instruments on board which generate a proportionally growing amount of data. This data needs to be temporarily stored and processed before being sent to a ground station on earth. This storage is typically done on flash memory-based mass memory modules. To leverage existing record-based storage architectures, a new architecture based on standard file system concepts is proposed. 

 
Satelite_AFSS

Challenges

  • Handle synchronous and asynchronous data streams with the same file system.
  • Support for specific geometry and hardware.
  • Small memory footprint for a file system handling huge capacities (Terabits).
  • Real-time handling of high input data rates
 

Architecture

The AFSS file system has been designed in multiple layers, each responsible for specific tasks and providing a consistent abstraction layer.

Virtual File System: provides a common and standardized file system interface.

AFSS File System: provides the core logic of the file system.

Flash Translation Layer: provides an abstracted block interface to higher layers.

Driver: handles all I/O operations and transactions with the hardware interface of the mass memory modules.

 
schema_1_AFSS
Schema_2_AFSS

Contributions

In the context of this project, engineers who have studied embedded software computing (IE orientation at HEIG-VD) and working at the REDS Institute were in charge of the software implementation of:

  1. The file system executed on the satellite computer and controlling the underlying mass memory hardware. 
  2. The intermediate abstraction layer between the device driver and the generic file system interface.
  3. An emulation framework to test and validate the file system before physical platform availability.
 
Mass_Memory_Equipment

Achievements

So far, the core functionalities of all layers have been implemented and are currently being tested and validated in the dedicated emulation environment.
Further activities will focus on advanced functionalities and optimizations of critical parts.

 

Acknowledgement

This work has been supported by the State Secretariat for Education and Research of the Swiss Confederation (SER) in the context of the “Mesures de positionnement 2012” program.