address space

address space

A computer's address space is the total amount of memory that can be addressed by the computer. For example, the Pentium can address 4GB of physical memory and 64TB of virtual memory.

A program's address space is the actual memory used by the program when running. It may refer to physical memory (RAM chips) or virtual memory (disk) or a combination of both.

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address space [′ad·rəs ‚spās]

(computer science)

The number of storage locations available to a computer program.

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(operating system, architecture)

address space - 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.