Method and apparatus for executing applications in place from write

Abstract

A number of new utility and runtime functions are provided to an otherwise conventional operating system of a computer system that supports virtual memory and multitasking, including new linker, installer, memory management, loader and task management functions. The new linker function is used to partially resolve unresolved references of a conventional 'RAM based' application, such that in conjunction with the new runtime functions, the partially resolved application can be executed in place from a 'write once/seldom' storage medium. The new installer function is used to install the partially resolved application onto a 'write seldom' storage medium. The new memory management function is used to reserve a predetermined portion of the operating system's memory management data structure for 'mapping' the physical address span(s) of an installed application into a logical address space, thereby enabling the 'mapped' application to be executed in place. The new loader function is used to pseudo-load and start execution of an XIP application. The new task management function is used to facilitate sharing of the predetermined portion of the operating system's memory management data structure by multiple XIP applications, thereby allowing multi-tasking of XIP applications as well as non-XIP or conventional 'RAM based' applications by the operating system.