Glossary terms: Microprocessors

ALU

Definition: Arithmetic and Logic Unit: the smart part of a processor chip that performs commands like adding, subtracting, multiplying and dividing. It also knows how to read logic commands like OR, AND, or NOT. Messages from the Control Unit instruct the ALU what to do and then it takes data from its close companion, the Registers, to perform the task.

Guides: ALU

Athlon XP

Definition: The brand name given to AMD's family of "extra performance" processors, dating from the time of the Athlon CPU's transition from the Thunderbird core to the Palomino core in 2001.

Guides: Athlon XP

Backside Bus

Definition: A dedicated channel between the CPU and a Level 2 cache. The so-called dual independent bus (DIB) architecture allows a processor to use both this and the frontside bus (which connects the CPU with main memory) simultaneously. See also Frontside Bus.

Guides: Backside Bus

BGA

Definition: Ball/Column Grid Array: a specification for pin lay-outs on micro chips, such as those used on a CPU chip.

Boolean Logic

Definition: Named after the nineteenth-century mathematician George Boole, Boolean logic is a form of algebra in which all values are reduced to either TRUE or FALSE. Boolean logic is especially important for computer science because of its suitably for use with the binary numbering system, in which each bit has a value of either 1 or 0. Another way of looking at it is that each bit has a value of either TRUE or FALSE.

Bus Unit

Definition: The Bus Unit is the place where instructions flow in and and out of the microprocessor from the computer's main memory.

Guides: Bus Unit

Capacitor

Definition: An electronic component that holds a charge.

CISC

Definition: Pronounced "sisk" and standing for Complex Instruction Set Computer, this relates to a microprocessor architecture that favours the richness of the instruction set (typically as many as 200 unique instructions) over the speed with which individual instructions are executed. See also RISC.

Guides: CISC

Clock Cycle

Definition: One complete transition from 0V to the CPU max voltage and back to 0V. So, for a 2V CPU running at 2GHz, there would be 2,000,000,000 (two thousand million or two billion) clock cycles from 0V to 2V and back to 0V every second.

Clock Doubling

Definition: Boosts CPU performance by increasing the internal CPU clock, while maintaining the same I/O speed (for compatibility).

Clock Multiplier

Definition: An integral part of the Processor, the multiplier allows the CPU to perform multiple cycles per ‘tick’ of the FSB. If an 11x multiplier is used, then 11 cycles will be performed.

Clock Rate

Definition: The number of pulses emitted from a computer's clock in one second; it determines the rate at which logical or arithmetic gating is performed in a synchronous computer.

Control Unit

Definition: The Control Unit is one of the most important parts of the microprocessor because it is in charge of the entire process. Based on instructions from the Decode Unit, it creates control signals that tell the Arithmetic Logic Unit (ALU) and the Registers how to operate, what to operate on, and what to do with the result. The Control Unit makes sure everything happens in the right place at the right time.

Guides: Control Unit

Core i7

Definition: The successor to the Intel Core 2 family, Core i7 is the release name of a range of quad core processors previously codenamed Bloomfield.

CPU

Definition: Central Processing Unit: a formal term for the microprocessor chip that powers a personal computer. The Intel Pentium chip is one example of a CPU. The term sometimes also refers to the case that houses this chip. See also FPU.

Guides: CPU

Data Cache

Definition: The Data Cache works very closely with the "processing partners", the ALU, Registers and the Decode Unit. This is where specially labelled data from the Decode Unit are stored for later use by the ALU and where final results are prepared for distribution to different parts of the computer.

Guides: Data Cache

Decode Unit

Definition: The Decode Unit does just that - it decodes or translates complex machine language instructions into a simple format understood by the Arithmetic Logic Unit (ALU) and the Registers. This makes processing more efficient.

Guides: Decode Unit

Depleted Substrate Transistor

Definition: A new generation of transistor built into an SOI substrate in such a way that its active silicon layer between source and drain is fully depleted so as to create a high conductivity channel.

Die

Definition: The formal term for an area of silicon containing an integrated circuit. A die has many layers, each designed for a specific function, and refers to a semiconductor component or part that has not yet been packaged. The popular term for a die is chip.

Dielectric

Definition: Substance that is a poor conductor of electricity and will sustain the force of an electric field passing through it. Also called an insulator.