In computing , an aperture is a portion of physical address space (ie physical memory ) that is associated with a particular peripheral device or a memory unit. Apertures may reach ROM or RAM chips, or internal memory on the CPU itself.
Typically, a memory device attached to a computer accepts addresses starting at zero, and has a system with more than one such device would have ambiguous addressing. To resolve this issue, the memory logic will contain several aperture selectors , each containing a range selector and an interface to one of the memory devices. The set of selector addresses ranges of apertures are disjoint. When the CPU presents an aperture, the aperture unit routes the request (with the address remapped to a zero base) to the attached device. THUS, apertures form a layer of address translation below the level of the usual virtual-to-physical mapping.
- Address bus
- AGP aperture
- Memory-mapped I / O