Chapter 2 - The System Unit: Processing and Memory

Machine language

A binary-based language for representing computer programs that the computer can execute directly.

Expansion bus

A bus on the motherboard used to connects peripheral devices.

Volatile

A characteristic of memory or storage in which data is not retained when the power to the computer is tuned off.

Nonvolatile

A characteristic of memory or storage in which data is retained even when the power to the computer is tuned off.

Expansion card

A circuit board that can be inserted into an expansion slot location on a computer's motherboard to add additional functionality or to connect a peripheral device to that computer.

Optical computer

A computer that uses light, such as from laser beams or infrared beams, to perform digital computations.

Port

A connector on the exterior of a computer to which a device may be attached.

ASCII (American Standard Code for Information Interchange)

A fixed-length, binary coding system used to represent text-based data for computer processing on many types of computers.

Byte

A group of bits.

Cache memory

A group of fast memory circuitry located on or near the CPU to help speed up processing.

FireWire

A high-speed bus standard often used to connect digital video cameras and other multimedia hardware to a computer.

Expansion slot

A location on the motherboard into which expansion cards are inserted.

ExpressCard module

A module that can be inserted into a computer's ExpressCard slot to add additional functionality or to connect a peripheral device to that computer; commonly used with notebook computers.

Parallel processing

A processing technique that uses multiple processors or multiple processing cores simultaneously, usually to process a single job as fast as possible.

Quantum computing

A technology that applies the principles of quantum physics and quantum mechanics to computers to direct atoms or nuclei to work together as quantum bits (quits), which function simultaneously as the computer's processor and memory.

Universal Serial Bus (USB)

A universal bus used to connect up to 127 peripheral devices to a computer without requiring the use of additional expansion cards.

Bus

An electronic path on the motherboard or within the CPU or other computer component along which data is transferred.

Unicode

An international coding system that can be used to represent text-based data in any written language.

Gigabyte (GB)

Approximately 1 billion bytes.

Megabyte (MB)

Approximately 1 million bytes

Kilobyte (KB)

Approximately 1 thousand bytes (1,024 bytes to be precise).

Terabyte (TB)

Approximately 1 trillion bytes.

Zettabyte (ZB)

Approximately 1,000 exabytes.

Exabyte (EB)

Approximately 1,000 petabytes.

Petabyte (PB)

Approximately 1,000 terabytes

Yottabyte (YB)

Approximately 1,000 zettabytes

Memory

Chip-based storage.

RAM (random access memory)

Chips connected to the motherboard that provide a temporary location for the computer to hold data and program instructions while they are needed.

Register

High-speed memory built into the CPU that temporarily stores data during processing.

ROM (read-only memory)

Nonvolatile chips located on the motherboard into which data or programs have been permanently stored.

Flash memory

Nonvolatile memory chips that can be used for storage by the computer or suer; can be built into a computer or a storage medium.

PCI Express (PCIe) bus

One of the buses most commonly used to connect peripheral devices.

Bandwidth

The amount of data that can be transferred in a given period of time; also referred to as throughput.

Frontside bus (FSB)

The bus that connects the CPU (via the I/O bridge) to the rest of the bus architecture.

Pipelining

The capability of a CPU to begin processing a new instruction as soon as the previous instruction completes the first stage of the machine cycle.

Multiprocessing

The capability to use multiple processors or multiple processing cores in a single computer, usually to process multiple jobs at one time faster than could be performed with a single processor.

Memory bus

The connection between the CPU and RAM.

System unit

The main box of a computer that houses the CPU, motherboard, memory, and other devices.

Motherboard

The main circuit board of a computer, located inside the system unit, to which all computer system components connect.

Decimal numbering system

The numbering system that represents all numbers using 10 symbols (0-9).

Binary numbering system

The numbering system that represents all numbers using just two symbols (0 and 1).

Bus interface unit

The part of a CPU core that allows it to communicate with other CPU components.

Prefetch unit

The part of a CPU core that attempts to retrieve data and instructions before they are needed for processing in order to avoid delays.

Control unit

The part of a CPU core that coordinates its operations.

Floating point unit (FPU)

The part of a CPU core that performs decimal arithmetic.

Arithmetic/logic unit (ALU)

The part of a CPU core that performs logical operations and integer arithmetic.

Decode unit

The part of a CPU core that translates instructions into a form that can be proceeded by the ALU and FPU.

Nanotechnology

The science of creating tiny computers and opponents by working at the individual atomic and molecular levels.

Machine cycle

The series of operations involved int eh execution of a single machine level instruction.

Bit

The smallest unit of data a digital computer can recognize; represented by a 0 or a 1.

System clock

The timing mechanism within the computer system that synchronizes the computer's operations.

Carbon nanotubes

Tiny, hollow tubes made of carbon atoms.