Embedded flash file system uses partitioning, journaling and DMA to enhance availability and performance
Phoenix, AZ. January 30, 2012. DDC-I, a leading supplier of software and professional services for mission- and safety-critical applications, today announced the availability of the Certifiable Fast File System (CFFS) for DDC-I’s Deos™ safety-critical real-time operating system (RTOS). The embedded certifiable file system, which supports flash devices such as CompactFlash, uses time and space partitioning, journaling and direct memory access (DMA) to enhance performance and availability. CFFS is certifiable to DO-178B Level A, has achieved certification by the FAA, and is currently flying in avionics systems using CompactFlash devices as the storage media.
“DDC-I’s CFFS is the next valuable offering in our mission to deliver best-in-class certifiable COTS RTOS and layered products for the safety-critical, DO-178B-certifiable software market,” said Bob Morris, president and CEO of DDC-I. “We are committed to enhancing our product offering with the key features aviation manufacturers require to leverage COTS software to lower the development costs of their avionics devices.”
The CFFS is an embedded file service engine for the Deos RTOS. The CFFS is designed from the ground up to meet DO-178B certifiability and the most demanding real-time requirements, utilizing high-speed DMA to move file data between user applications and CompactFlash. To further boost performance, the CFFS also utilizes pipelining, which enables processes to cue up multiple operations (reads, writes) on one or more files, invoke them all concurrently (non-blocking), then service the data as it arrives. This minimizes the need to wait for completion of I/O operations.
The CFFS enhances reliability, safety and security by utilizing partitioning to separate critical processes and data. Each user process can own one or more CFFS partitions, and each partition may contain one or more files. Only the user process that owns a given CFFS partition can modify files stored in that partition. Other user processes can be granted read permission to that partition, but cannot modify the files therein.
To guarantee data integrity across power upsets or system restarts, the CFFS utilizes journaling. Through journaling, file system data structures are written to a temporary (but power cycle preserved) area before committing them to the flash disk destination.
The CFFS is highly configurable, making it easy for integrators and process designers to set file partitions, interrupt frequency, DMA transfer size, and access priorities for processes and files. The CFFS supports a variety of non-volatile memory including NVSRAM, EEPROM, flash memory and popular compact flash disks, including devices from SanDisk and Smart Modular Technologies.
Deos is a DO-178B Level A certifiable embedded RTOS that has been used in hundreds of safety critical avionics applications on commercial and military aircraft. The time and space partitioned RTOS features deterministic real-time response and employs patented “slack scheduling” to deliver higher CPU utilization than any other certifiable safety-critical COTS RTOS. Built from the ground up for safety-critical applications, Deos is the only certifiable time and space partitioned COTS RTOS that has been created using RTCA DO-178B, Level A processes from the very first day of its product development. It also provides the easiest, lowest cost path of any COTS RTOS to DO-178B Level A certification, the highest level of safety criticality.
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