Functional Units of System
A computer organization outlines the functions and design of the different components within a digital system.
A general-purpose computer system is the most well-known example of a digital system. Additional examples include telephone switching exchanges, digital voltmeters, digital counters, electronic calculators, and digital displays.
Computer architecture involves defining the instruction set and the hardware components that execute these instructions.
Computer hardware includes electronic circuits, displays, magnetic and optical storage media, as well as communication facilities.
Functional units are components of a CPU that execute the operations and calculations required by a computer program.
Functional units within a computer system are components of the CPU (Central Processing Unit) responsible for executing the operations and calculations specified by a computer program. A computer is comprised of five main components: the Input unit, Central Processing Unit, Memory unit, Arithmetic & Logical unit, Control unit, and Output unit.
Input unit
Input units allow the computer to read data. Common input devices include keyboards, mice, joysticks, trackballs, and microphones.
The keyboard is the most commonly recognized input device. When a key is pressed, the corresponding letter or digit is automatically converted into its binary code and sent through a cable to the memory or processor.
Central Processing Unit
The Central Processing Unit, or CPU, is an electronic circuit within a computer that executes instructions provided by a computer program. It performs basic arithmetic, logical, control, and input/output (I/O) operations as directed by the instructions.
Memory Unit
The Memory unit serves as the storage area where running programs are kept and where data required by these programs is stored.
The Memory unit can be divided into two categories: primary memory and secondary memory.
It allows the processor to access running applications and services that are temporarily stored in specific memory locations.
Primary storage is the fastest type of memory, operating at electronic speeds. It consists of numerous semiconductor storage cells, each capable of holding a single bit of information. The word length of a computer typically ranges from 16 to 64 bits.
This type of memory, known as volatile memory, means that when the computer is shut down, all data stored in RAM is lost.
Cache memory is a type of memory designed for rapid data retrieval. It is closely integrated with the processor to enhance performance.
The most common types of primary memory are RAM and ROM.
Secondary memory is used for storing large amounts of data and programs on a long-term basis.
This type of memory, known as non-volatile memory, stores data permanently, even when the computer is shut down.
Common examples of secondary memory include magnetic disks, magnetic tapes, and optical disks.
Arithmetic & Logical Unit
Most arithmetic and logical operations in a computer are carried out by the ALU (Arithmetic and Logical Unit) within the processor. The ALU performs arithmetic operations such as addition, subtraction, multiplication, and division, as well as logical operations like AND, OR, and NOT.
Control Unit
The control unit is a component of the computer's central processing unit that orchestrates the processor's operations. It directs the memory, arithmetic/logic unit, and input/output devices on how to execute the instructions provided by a program.
The control unit is also known as the nerve center of a computer system.
Consider the example of adding two operands using the instruction `Add LOCA, RO`. This instruction adds the value at the memory location LOCA to the operand in register RO and stores the result back in register RO. The execution of this instruction involves several internal steps.
Output Unit
The primary function of the output unit is to deliver processed results to the user. Output devices present information in a format that is understandable to the user.
Output devices are equipment used to produce information or responses generated by the computer. They display data that has been processed or stored within the computer.
A common example of an output device is a monitor.
