Computer Dictionary of Information Technology

Translation Look-aside Buffer

(TLB) A table used in a virtual memory system, that lists the physical address page number associated with each virtual address page number. A TLB is used in conjunction with a cache whose tags are based on virtual addresses. The virtual address is presented simultaneously to the TLB and to the cache so that cache access and the virtual-to-physical address translation can proceed in parallel (the translation is done "on the side"). If the requested address is not cached then the physical address is used to locate the data in main memory. The alternative would be to place the translation table between the cache and main memory so that it will only be activated once there was a cache miss.