Logical address

In computing, a logical address is the address at which an item (memory cell, storage element, network host) appears to reside from the perspective of an executing application program.

A logical address may be different from the physical address due to the operation of an address translator or mapping function. Such mapping functions may be, in the case of a computer memory architecture, a memory management unit (MMU) between the CPU and the memory bus.

There may be more than one level of mapping. For example, on multiprocessor configurations of the IBM S/360, S/370 and successors, IBM distinguishes among

  1. Virtual address seen by the program
  2. Real address, the result of translating a virtual address
  3. Absolute address, the result of mapping a real address using a low-storage prefix assigned to each CPU.
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