Back-side bus

In personal computer microprocessor architecture, a back-side bus (BSB), or backside bus, was a computer bus used on early Intel platforms to connect the CPU to CPU cache memory, usually off-die L2. If a design utilizes a back-side bus along with a front-side bus (FSB), the design is said to use a dual-bus architecture, or in Intel's terminology Dual Independent Bus (DIB)^[1] architecture. The back-side bus architecture evolved when newer processors like the second-generation Pentium III began to incorporate on-die L2 cache, which at the time was advertised as Advanced Transfer Cache, but Intel continued to refer to the Dual Independent Bus till the end of Pentium III.^[2]