. According to a fourth aspect of the present invention there is provided an apparatus for controlling access to and modification of information stored on a storage medium of a computer system, the storage medium being divided into a plurality of non-overlapping partitions including a boot partition and at least one general partition, characterised in that at least one of said partitions comprises a Write Many Recoverable (WMR) partition wherein, in use, if a write command is issued to overwrite any information stored in a/the WMR partition prior to undertaking said write command said information is copied and stored elsewhere on the storage medium to be copied back to said WMR partition when requiredxe0x00x00for example upon a system reset. Preferably the apparatus further comprises a supervising means (a Supervisor) separate of a central processing unit (CPU) of the computer system for controlling the performance of read, write 