An extended delta compression algorithm and the recovery of failed updating in embedded systems

In this paper, a new program-updating method for embedded systems adopting the RISC architecture is presented. Previously "a delta compression algorithm" is used but when the algorithm is actually implemented with devices, the transmission time is longer than the assumed time. To overcome this problem "extended delta compression algorithm" is proposed. The target of this algorithm is to create a delta file that is 10% smaller than those currently available. A new restoring method is also proposed here to overcome the problem of data overwritten of flash memory in the restoring process. A characteristic of this system is that the expanded data are stored in "nonvolatile" memory before being written into the flash memory, and the flash memory is not restored until the data for the next block has been expanded.