The mass memories are generalized in most of the spacecraft's and now used by both platform and payload. The definition of a new standard interface for managing the data storage unit shall benefit in term of flexibility through equipment interchangeability. The emergence of the new PUS file management service and File Based Operations concept is a good opportunity to standardize the mass memory interfaces .The activities aims at defining a standard set of services to be supported by Mass Memory Devices to match the requirements from platform and payload applications as well as operations (CFDP, PUS, File Bases Operations, etc.).

SAVOIR is an initiative to federate the space avionics community and to work together in order to improve the way that the European Space community builds avionics subsystems. In particular, it is aimed at getting equipment interchangeability. In particular, the group provides a set of standard avionics external and internal interfaces, the definition of building blocks composing the architecture and the functional specification of selected building blocks. One of the building block of the On-Board Reference Architecture is the Solid State Mass Memory. Several instances of this building block can coexist in a same spacecraft:- For storing the science data, - For storing the platform applications and housekeeping telemetry - Safeguard mass memory for storing critical data as the current status of the spacecraft to be used in case of reconfiguration. All these instantiations of a same building block provides different interfaces and services so their integration in the reference architecture requires a large amount of efforts to implement the upper level of services related to data management as Packet Utilization Services (PUS) defined in ECSS-E-70-41A (large data transfer service, on-board storage and retrieval service and in the next version of the standard, the file management service), CCSDS File Delivery Protocol (CFDP) and to future needs emerging from the File Based Operations concept.All these services are independent from the data storage units but require a set of common services to access and manage the data. CFDP assumes a minimum set of capabilities from the virtual filestore as: create file, delete file, rename file, append file, replace file, create directory, remove directory, list the content of a directory. The incoming PUS file management service should require additional services to manage file attributes for protection purpose and file search.The proposed study aims at specifying a standard interface for mass memory building blocks that ease their integration into the on-board reference architecture.- The existing applications and services accessing a mass memory storage device shall be identified and investigated in order to identify generic functional data stream (for spacecraft management, telemetry, payload data storage, etc.) and required services. This study shall take into account new services that are not yet implemented in systems (File Based Operations concept) as well as the services required by file management libraries (e.g. RTEMS file system, ERTFS, VxWorks dosFs and HRFS, ext2/3/4, etc.).- The existing mass memory units shall be identified and investigated in order to identify their characteristics and constraints (type of memory, maximum capacity, maximum throughput, number of cycles, number and type of interfaces, smallest allocable unit, etc.) . In addition, this study shall take into account the next generation of mass memory units providing new features (e.g. RAID 1/5 support, compression, etc.) as well as on-going activities in the domain of mass memories (TRP study "OBC Mass Memories ")- Taking into consideration the needs of the mass memory users and the characteristics of mass memory units, a standard interface shall be proposed. This work shall take into account the characteristics of recent mass memory units that may provide processing capabilities. The tasks related to this activity are then:1. Establishment of requirements concerning the services in charge to manage files on-board compatible with existing services (CFDP, PUS Services) and application needs. Identification of representative Use Cases based on these services.2. Investigation on the characteristics and services provided by existing mass memory units and identification of the future trends.3. Specification of a standard interface supporting the needs of applications.4. Development of a functional prototype supporting the new interface. This prototype shall support the interface previously defined and data storage capability.5. Integration with existing services: CFDP, platform application (e.g. logging, OBCP management) and payload applications (e.g. science data storage).6. Analysis of the results, assessment and proposition for improvements.7. Produce a SAVOIR interface and functional specification document