The range of addresses whICh a processor or process can access, or at whICh a devICe can be accessed. The term may refer to either physICal address or virtual address. The size of a processor' s address space depends on the width of the processor' s address bus and address registers. Each devICe, such as a memory integrated circuit, will have its own local address space whICh starts at zero. This will be mapped to a range of addresses whICh starts at some base address in the processor' s address space. Similarly, each process will have its own address space, whICh may be all or a part of the processor' s address space. In a multitasking system this may depend on where in memory the process happens to have been loaded. For a process to be able to run at any address it must consist of position-independent code. Alternatively, each process may see the same local address space, with the {memory management unit} mapping this to the process' s own part of the processor' s address space. (1999-11-01)