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The range of addresses whicha processor or process can access, or at which a device canbe accessed. The term may refer to either physical addressor virtual address.The size of a processor's address space depends on the widthof the processor's address bus and address registers.Each device, such as a memory integrated circuit, will haveits own local address space which starts at zero. This willbe mapped to a range of addresses which starts at some baseaddress 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 memorythe process happens to have been loaded. For a process to beable to run at any address it must consist ofposition-independent code. Alternatively, each process maysee the same local address space, with the memory managementunit mapping this to the process's own part of theprocessor's address space.