A data bus is a computer subsystem that allows the transfer of data from one component to another on a motherboard or system board, or between two computers. This may include transferring data to and from memory, or from the central processing unit (CPU) to other components. Each is designed to handle so many bits of data at the same time. The amount of data that a data bus can handle is called bandwidth.
Data can be transferred between two computers using a data bus.
A typical data bus is 32 bits wide. This means that up to 32 bits of data can travel over a data bus every second. Newer computers are building data buses that can handle 64-bit and even 96-bit data paths. At the same time they are building data buses to handle more bits, they are also building devices that can handle higher bit rates.
USB stands for Universal Serial Bus, a type of data bus.
In the early days of the personal computer, manufacturers created motherboards with data buses that connected directly to the computer’s memory and peripherals. These electric buses were designed to run parallel to each other and had multiple connections. This direct connection was problematic for a number of reasons, but especially since all devices were forced to run at the same speed.
To eliminate this problem, the developers used a bus controller to separate the CPU and memory from peripheral devices, allowing the CPU speed to be increased without requiring the same increase in peripheral speeds. This system also allowed the expansion cards to talk to each other without going through the CPU, making data transfer faster. All devices must still communicate with each other at the same speed, however, low bus speeds can slow down an entire computer system.
Parallel and serial data buses
Modern computers use both parallel and serial data buses. Parallel data buses carry data on many wires simultaneously. Each wire, or path as it is sometimes called, carries one bit of data. The most common parallel buses found in computers today are the ATA, which stands for Advanced Technology Attachment; the PC card, which stands for personal computer and is used in laptops, and the SCSI, or Small Computer System Interface. A serial data bus has a wire or path and carries all the bits one after the other. The most common serial data buses include USB, also known as the Universal Serial Bus; FireWire; Serial ATA; and SCSI with serial connection.
Internal and external data buses
Almost all computers contain both internal and external data buses. The internal data bus, also known as the local bus, connects all the components that are on the motherboard, such as the CPU and memory. The external data bus connects all peripheral devices to the motherboard. A variety of different external data buses are available; the appropriate type of data bus depends on the peripheral being connected to the computer.