Abstract: To install software on a computing device, a decision phase is used to decide whether or not to install the software followed by an installation phase for installing the software. Information required by the decision phase is provided in the form of metadata having an integrity protected by a digital signature and including a respective hash for files to be installed so as to enable the integrity of the file data to be verified before commencing the installation phase.

Abstract: A first computing device in the form of a mobile phone is used to initiate a comparison of the entries stored in a contacts store associated with the first device with the entries stored in a contacts store associated with a second device. Mutual contacts are then advised to the second device. Digests of the contacts stores entries may be used to make the comparison. Communication may be directly between the devices, such as by using Bluetooth, or may be via a network operator. The respective contacts stores may be held on the devices or by the network operator. The network operator may be used to make the comparison of store entries.

Abstract: A method of operating a computing device having NAND flash memory for storage of program code and user data. At start up, only selected components of the computing device core operating system are shadowed into RAM. Other components, such as read only system files associated with the core operating system, are retained in the NAND flash memory and only shadowed into RAM upon demand. The program codes shadowed into RAM at start up and the program codes shadowed into RAM upon demand are presented to a file server of the computing device as a composite file system. The use of the composite file system reduces the amount of RAM permanently occupied by core operating system code during operation of the device and also enhances the use of the more power efficient NAND flash memory. Moreover, the boot up time of the device is also significantly reduced.