4.1 Processor CPU Key Terms

Von Neumann architecture

• computer architecture which introduced the concept of the stored program in the 1940s.
• a register used in a computer to store the address of the instruction which is currently being executed.
• type of port connecting devices to a computer.
• signal sent from a device or software to a processor requesting its attention; the processor suspends all operations until the interrupt has been serviced.
• serial refers to a single wire being used to transmit bits of data one after the other. Asynchronous refers to a sender using its own clock/timer device rather sharing the same clock/timer with the recipient device.

Arithmetic logic unit (ALU)

• component in the processor which carries out all arithmetic and logical operations.
• temporary component in the processor which can be general or specific in its use that holds data or instructions as part of the fetch execute cycle.
• a register used to contain the instruction which is currently being executed or decoded.
• a unit made up of ALU, control unit and registers which is part of a CPU. A CPU may contain a number of cores.
• a unit made up of ALU, control unit and registers which is part of a CPU. A CPU may contain a number of cores.

Control unit

• ensures synchronisation of data flow and programs throughout the computer by sending out control signals along the control bus.
• type of port connecting devices to a computer.
• temporary component in the processor which can be general or specific in its use that holds data or instructions as part of the fetch execute cycle.
• carries signals from control unit to all other computer components.
• serial refers to a single wire being used to transmit bits of data one after the other. Asynchronous refers to a sender using its own clock/timer device rather sharing the same clock/timer with the recipient device.

System clock

• produces timing signals on the control bus to ensure synchronisation takes place.
• type of port connecting devices to a computer.
• indicates the status of a bit in the status register, for example, N = 1 indicates the result of an addition gives a negative value.
• signal sent from a device or software to a processor requesting its attention; the processor suspends all operations until the interrupt has been serviced.
• type of port connecting devices to a computer.

Immediate access store (IAS)

• holds all data and programs needed to be accessed by the control unit.
• component in the processor which carries out all arithmetic and logical operations.
• indicates the status of a bit in the status register, for example, N = 1 indicates the result of an addition gives a negative value.
• allows data to be carried from processor to memory (and vice versa) or to and from input/output devices.
• type of port connecting devices to a computer.

Accumulator

• temporary general purpose register which stores numerical values at any part of a given operation.
• a type of port connecting devices to a computer.
• allows data to be carried from processor to memory (and vice versa) or to and from input/output devices.
• ensures synchronisation of data flow and programs throughout the computer by sending out control signals along the control bus.
• group of bits used by a computer to represent a single unit.

Register

• temporary component in the processor which can be general or specific in its use that holds data or instructions as part of the fetch execute cycle.
• a register used to contain the instruction which is currently being executed or decoded.
• carries signals from control unit to all other computer components.
• used when an instruction requires some form of arithmetic or logical processing.
• carries the addresses throughout the computer system.

Status register

• used when an instruction requires some form of arithmetic or logical processing.
• indicates the status of a bit in the status register, for example, N = 1 indicates the result of an addition gives a negative value.
• external connection to a computer which allows it to communicate with various peripheral devices. A number of different port technologies exist.
• clock speeds are measured in terms of GHz; this is the vibrational frequency of the clock which sends out pulses along the control bus a 3.5 GHZ clock cycle means 3.5 billion clock cycles a second.
• a CPU containing two cores.

Flag

• indicates the status of a bit in the status register, for example, N = 1 indicates the result of an addition gives a negative value.
• external connection to a computer which allows it to communicate with various peripheral devices. A number of different port technologies exist.
• a high speed auxiliary memory which permits high speed data transfer and retrieval.
• holds all data and programs needed to be accessed by the control unit.
• short hand notation to show movement of data and instructions in a processor, can be used to represent the operation of the fetch execute cycle.

Address bus

• carries the addresses throughout the computer system.
• temporary general purpose register which stores numerical values at any part of a given operation.
• short hand notation to show movement of data and instructions in a processor, can be used to represent the operation of the fetch execute cycle.
• type of port connecting devices to a computer.
• changing the clock speed of a system clock to a value higher than the factory/recommended setting.