Local bus

A local bus is a computer bus that connects the expansion slot (s) directly or almost directly to the CPU . The usefulness of such a direct connection is that it eliminates the bottleneck created by the expansion bus . This allows you to speed up work with selected system devices that are most critical to this, for example, with a graphics card, RAM and / or disk controller. Due to differences in the arrangement of processors, local buses are almost always not universal.

A well-known example of a local bus specific to the IBM PC platform is the VESA Local Bus (VL-Bus), first proposed by engineer and entrepreneur Dado Banatao. ^[one]

It should be noted that the first implementations of the 8- and 16-bit versions of the ISA bus had a local bus architecture, since they worked at the processor frequency and were connected directly to it. Later ISA implementations already worked in expansion bus mode.

Prior to the IBM PC, this approach was also repeatedly used, in particular, the first implementations of VMEbus , which evolved from a local bus to an expansion bus and Multibus iLBX, could be considered local buses.

Despite the fact that, subsequently, the VL-Bus was replaced by the AGP bus, AGP would be incorrectly considered a local bus, because It was originally designed in a different way.