The memory on the mobile device is divided Flash-ROM and RAM. The operating system and pre-installed applications are stored write-protected in the ROM (OS Disc). Besides that there is an area for the file system in the ROM under Windows CE 6.0, in which the user can save programs and files (user disc). After the system start parts of the operating system are kept in the RAM. The rest (Program Memory) is available to run programs.
Any changes to the registry are written to a cache. If you perform a reset operation, changes might be lost. You can flush the cash to disk by either switching the device off and on again or calling the RegFlushKey function from the Windows API.