System Unit

Expansion Card

Also known as an add-on card, internal card or interface adapter, an expansion card is an electronic board or card added in a desktop computer or other non-portable computer to give that computer a new ability, such as the ability to connect to another computer using a network cable.

Network Interface Card

A network interface card is used to connect a computer to an Ethernet network. The card (shown in the figure below) provides an interface to the media. This may be either using an external transceiver (as shown) or through an internal integrated transceiver mounted on the network interface card PCB. The card usually also contains the protocol control firmware and Ethernet Controller needed to support the Medium Access Control (MAC) data link protocol used by Ethernet.

Cache Memory

Cache RAM is high-speed memory (usually SRAM) which is dedicated to storing frequently requested data. If the CPU needs data, it will check in the high-speed cache memory first before looking in the slower main memory. Cache memory may be three to five times faster than system DRAM. Most computers have two separate memory caches; L1 cache, located on the CPU, and L2 cache, located between the CPU and DRAM. L1 cache is faster than L2, and is the first place the CPU looks for its data. If data is not found in L1 cache, the search continues with L2 cache, and then on to DRAM.

Plug & Play

In computing, plug and play is a term used to describe the characteristic of a computer bus, or device specification, which facilitates the discovery of a hardware component in a system, without the need for physical device configuration, or user intervention in resolving resource conflicts.
Plug and play refers to both the traditional boot-time assignment of device resources and driver identification, as well as to hotplug systems such as USB and Firewire.

Sockets

A socket is an endpoint for communication between two machines.
The actual work of the socket is performed by an instance of the SocketImpl class. An application, by changing the socket factory that creates the socket implementation, can configure itself to create sockets appropriate to the local firewall.

Chips ( computer chips )

A small piece of semiconducting material (usually silicon) on which an integrated circuit is embedded. A typical chip is less than ¼-square inches and can contain millions of electronic components (transistors). Computers consist of many chips placed on electronic boards called printed circuit boards.
There are different types of chips. For example, CPU chips (also called microprocessors) contain an entire processing unit, whereas memory chips contain blank memory.

Slots

A narrow notch, groove, or opening, as a keyway in a piece of machinery, a slit for a coin in a vending machine, etc.
any of various openings in the wing or tail surface of an airplane used in connection with a high-lift or control device; specif., an air gap between the wing and an auxiliary airfoil, as an aileron or flap, providing for a smooth flow of air on the upper surface

Buslines

Motherboards are nothing more than very large and complex circuit boards. And like all circuit boards, motherboards send data in the form of electricity via the bus. 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. Machine language is represented as the binary system.

Serial Port

A port, or interface, that can be used for serial communication, in which only 1 bit is transmitted at a time.
Most serial ports on personal computers conform to the RS-232C or RS-422 standards. A serial port is a general-purpose interface that can be used for almost any type of device, including modems, mice, and printers (although most printers are connected to a parallel port).

Parallel Port



A port through which two or more data bits are passed simultaneously, such as all the bits of an 8-bit byte, and that requires as many input channels as the number of bits that are to be handled simultaneously. Contrast with serial port.

Universal Serial Bus

Short for Universal Serial Bus, an external bus standard that supports data transfer rates of 12 Mbps. A single USB port can be used to connect up to 127 peripheral devices, such as mice, modems, and keyboards. USB also supports Plug-and-Play installation and hot plugging.
Starting in 1996, a few computer manufacturers started including USB support in their new machines. It wasn't until the release of the best-selling iMac in 1998 that USB became widespread. It is expected to completely replace serial and parallel ports.

Firewire Port

FireWire is Apple Computer's version of a standard, IEEE 1394, High Performance Serial Bus, for connecting devices to your personal computer. FireWire provides a single plug-and-socket connection on which up to 63 devices can be attached with data transfer speeds up to 400 Mbps (megabits per second). The standard describes a serial bus or pathway between one or more peripheral devices and your computer's microprocessor.