Structure of Computers and their Working

Primary Function of a Computer

The computer system consists of three components namely the input where we feed the data to the computer and then the processing, where the computer analysis the data given in the CPU and processes the data and finally the output in which is the result is displayed.

Components of the computer

  1. The Input component-This consists of common user devices like microphones, webcams, keyboards, mouse and touchscreen
  2. Processing Component- These components are responsible for the processing of information within the computer system. This includes devices such as the CPU, Memory and Motherboard.
  3. Output Components- It is any information processed by and sent out from a computer and anything viewed on the computer such as monitor printer and speaker is an example.

Storage Components

A storage device is a part of the computer hardware which stores information and data to process the result of any computational work.

The two main types of storage are:
  • Short-Term Storage(Volatile): RAM is one of the short-term storage.RAM also known as Random Access Memory is an important part of the computer to run efficiently. The more RAM, the more smoothly will the computer run.

  • Long-Term Storage(Non-Volatile): Long-term data storage is considered to be permanent and is also called persistent storage, is any computer data storage device that retains its data when the device is unpowered. Examples are Hard drives, DVDs, Flash drives and Media cards.

Personal Computer Hardware

Motherboard

It is a printed circuit board containing the principal components of a computer or other device, with connectors for other circuit boards to be slotted into.

Computer Bus Fundamentals

A bus is a communication system that transfers data between components inside a computer, or between computers.

There are three types of Buses:
  1. Data Bus: Carry data signals from main memory to CPU or from main memory to I/O devices and vice versa.
  2. Address Bus: Carry address signals and allows the CPU to send the address to RAM. It also transmits the location of the stored information.
  3. Control Bus: Carry control signal from the processor to other components and it is bidirectional.

I/O Polling and Interrupt

An interrupt is a process with the help of which the CPU is notified of required attention. Polling is the process in which the CPU constantly checks the status of a device to see if it needs the CPU's attention.

Hard Drive Fundamentals

It is an electromechanical data storage device that uses magnetic storage to store and retrieve digital information using one or more rapidly rotating disks coated with magnetic materials and is primary long-term storage.

Solid State Drives

 Solid-state drive (SSD) is a new generation of storage device used in computers. SSDs store data using flash-based memory, which is much faster than the traditional hard disks they've come to replace. SSDs also have no moving parts, and upgrading to one is a great way to speed up your computer and make it more resilient.

BIOS/CMOS

BIOS(basic input/output system) is the program a computer's processor uses to start the computer system after it is powered on. It also manages data flow between the computer's operating system and attached devices.

Network Communication

Network communication is a set of rules that allows application programs to talk with each other without the hardware and operating systems where they run.





Network Interface Card(NIC): It creates and mediates the connection between a computer and the networking medium. The wireless NICs connect to the network using service set identifier.

Bits and Bytes

One byte is equal to eight bits and a bit is considered to be the smallest unit of data measurement.
A bit can be either 0 or 1.

The presence of electricity can represent 1 bit and the absence of voltage can represent 0 bit.

Functional Units

  • Primary Memory: Organized into words of 32 bits and their program and their data must be in this memory to be executed.
  • Cache Memory: Cache memory is a chip-based computer component that makes retrieving data more efficient. It acts as a temporary storage to retrieve data easily

Processor

  • Arithmetic and Logic unit: This is a unit that performs the solving and thinking of the computer.
  • Control unit: The control unit fetches instructions from the CPU's memory, represented in bits, and translates those instructions into control signals in the form of pulses of electricity or light.

Instruction Cycle

This process consists of various steps which include:
  1. Fetching the instruction and increasing the program counter
  2. Decoding the instruction and reading registers from the register file
  3. Perform an ALU operation.
  4. Read or write memory data if the instruction involves a memory operand.
  5. Write the result into the destination register.

Instruction and Programs

A sequence of instructions executed one after another, constitute a program and both a program and its data are stored in the main memory.

The  three basic instruction types are:
  1. Load which reads data from memory or input devices.
  2. Store which writes data from a processor register to memory or output devices.
  3. Operate which performs an ALU operation on data operands in the processor register.

Processor Components

Program Counter: It holds the memory address of the instruction. It also increases after fetching an instruction and holds the memory address of the next instruction that would be executed.
As each instruction gets fetched, the program counter increases its stored value by 1 and the program counter points to the next instruction on the sequence. When the computer restarts or reset, the program counter normally reverts to 0.

Instruction Register: It holds the current instruction.

General-Purpose Register: It holds data and address

Control circuits and the ALU: This fetch and execute the instruction.


Fetching and Executing Instructions

The processor control circuit sends the address in the PC to memory and then the issue read load instruction from memory into IR increment PC to point to the next instruction. It then sends the address to memory and it reads and load word from memory into register R2.

Handling I/O Devices

The application program can read data from an input device and write data to an output screen and then sense the readiness of an I/O device to perform a transfer.

Performance

It is to see how fast a program can be done.

Factors
  1. Speed of the Electronic circuits in the processor
  2. Access time to the cache and main memory
  3. Design of the instruction set
  4. Number of operations that can be done at the same time
A multi-core processor is an integrated circuit that has two or more processor cores attached for enhanced performance and reduced power consumption.