The System Unit

Flash Memory

*A computer chip with a read-only memory that retains its data when the power is turned off and that can be electronically erased and reprogrammed without being removed from the circuit board, often used in fax machines.

Graphics Card

*Graphics cards are PCBs (printed circuit boards) that perform the dual role of sending pixels to the display and providing a specific type of processing using a GPU (graphical processing unit).

*One of the main features of a graphics card is the ability to draw 3D graphics in realtime using a technique called rasterization. This involves converting 3D coordinates into areas of pixels and filling the areas with either a transformed image called a texture or a flat surface.

Sound Cards

*A sound card (also known as an audio card) is a computer expansion card that facilitates the input and output of audio signals to and from a computer under control of computer programs. Typical uses of sound cards include providing the audio component for multimedia applications such as music composition, editing video or audio, presentation, education, and entertainment (games). Many computers have sound capabilities built in, while others require additional expansion cards to provide for audio capability.

Network Interface Card (NIC)

A device that allows computers to be joined together in a LAN, or local area network. Networked computers communicate with each other using a given protocol or agreed-upon language for transmitting data packets between the different machines, known as nodes. The network interface card acts as the liaison for the machine to both send and receive data on the LAN.

Plug & Play

Plug and Play (PnP) is a capability developed by Microsoft for its Windows 95 and later operating systems that gives users the ability to plug a device into a computer and have the computer recognize that the device is there. The user doesn't have to tell the computer. In many earlier computer systems, the user was required to explicitly tell the operating system when a new device had been added. Microsoft made Plug and Play a selling point for its Windows operating systems. A similar capability had long been built into Macintosh computers.

Bus Line

The bus (or bus lines) are all those little wires that can be seen on the back of a circuit board. They are usually made from copper, though very high-end boards use gold. As electricity is sent across these lines, the receiving components convert the electricity into machine language (binary system).

HDMI

(High-Definition Multimedia Interface) A digital interface for audio and video that provides a single-cable solution for home theater and consumer electronics equipment. Introduced in 2002, one HDMI cable commonly replaces from two to five cables, and in some cases even as many as 11 cables, when connecting devices such as TVs, DVD players, set-top boxes and A/V receivers.

Cache Memory

Cache (pronounced cash) memory is extremely fast memory that is built into a computer’s central processing unit (CPU), or located next to it on a separate chip. The CPU uses cache memory to store instructions that are repeatedly required to run programs, improving overall system speed. The advantage of cache memory is that the CPU does not have to use the motherboard’s system bus for data transfer. Whenever data must be passed through the system bus, the data transfer speed slows to the motherboard’s capability. The CPU can process data much faster by avoiding the bottleneck created by the system bus.