Software running on a processor, microprocessor, and/or processing unit to provide certain functionality often changes over time. The changes can result from the need to correct bugs, or errors, in the software files, adapt to evolving technologies, or add new features, to name a few. In particular, embedded software components hosted on mobile processing devices, for example mobile wireless devices, often include numerous software bugs that require correction. Software includes one or more files in the form of human-readable American Standard Code for Information Interchange (ASCII) plain text files or binary code. Software files can be divided into smaller units that are often referred to as modules or components.
Portable processor-based devices like mobile processing devices typically include a real-time operating system (RTOS) in which all software components of the device are linked as a single large file. Further, no file system support is typically provided in these mobile wireless devices. In addition, the single large file needs to be preloaded, or embedded, into the device using a slow communication link like a radio, infrared, or serial link.
Obstacles to updating the large files of mobile processing devices via slow communication links include the time, bandwidth, and cost associated with delivering the updated file to the device. One existing solution to the problem of delivering large files to mobile processing devices includes the use of compression. While a number of existing compression algorithms are commonly used, often, however, even the compressed file is too large for download to a device via a slow, costly, narrowband communication link.
Another typical solution for updating files uses difference programs to generate a description of how a revised file differs from an original file. There are available difference programs that produce such difference data. However, as with compression, the difference files produced using these difference programs can sometimes be too large for transfer via the associated communication protocols.