resmgr and iofunc layers

Like all QNX Neutrino device managers, the flash filesystem uses the standard resmgr/iofunc interface and accepts the standard set of resource manager messages. The flash filesystem turns these messages into read, write, and erase operations on the underlying flash devices.

For example, an open message would result in code being executed that would read the necessary filesystem data structures on the flash device and locate the requested file. A subsequent write message will modify the contents of the file on flash. Special functions, such as erasing the flash device, are implemented using devctl messages.