Abstract: A method and apparatus of managing a memory (2) having a number of pages (5) involves mapping the physical pages (5) to corresponding pages (4) in a logical address space (1) using a map table (3). When the number of pages utilised by an application increases or decreases, or if an application is deleted or a new application is loaded, the physical pages used by the remaining applications are unchanged, but the logical pages are moved so that the logical pages used by a single application are contiguous and so that the unused pages are contiguous. Thus, after moving the logical pages, the mapping of the logical pages to the physical pages is updated and a free page pointer (6) indicates the next available free logical page.

Abstract: A method of detecting illegal execution of code sequences includes the steps of: setting an active identifier to a first sequence identifier of a first code sequence, executing at least part of the first code sequence, calling, from the first code sequence, a second code sequence having a second sequence identifier, providing (20) a caller sequence identifier and a callee sequence identifier, checking (21) whether the callee sequence identifier is the same as the second sequence identifier, checking (23) whether the caller sequence identifier is the same as the active identifier, and generating (27) an alarm signal if either of the checks provide incorrect results.