A01: Basic Structure of Computer

 Basic Structure of Computers

• Computer 
• It is any electronic device that takes in input, process it and gives out an output. A calculator can also be a simple computer.
• It has three main components; Input devices, Central processing unit and output devices.
• Input components include keyboards, microphone, USB ports, etc.
• Output components include screen, printer, network cards, etc.
  
  
  

• CPU: Central Processing Unit
• It executes the instruction from computer program.
• It is composed of two or more processor called cores. Multicore CPUs enable computer to carryout instruction simultaneously.
• Storage Components
• The more storage the better the performance of the computer.
• There are two types:
1. Short-term storage(volatile storage): RAM (Random Access Memory) also known as working storage is crucial for computers to work efficiently. Virtual memory is a part of hard disk where less used data are stored.
2. Long-term storage(non-volatile storage):  It is used to store documents and multimedia files. Hard disk, USB flash drives are long-term storage.
• Personal Computer Hardware
• There are four major PC computer:
1. Motherboard: It is a main circuit board inside the computer connecting all the hardware components. It makes the house to CPU, RAM, expansion slots and various connectors.
•  Computer Bus Fundamentals
  
  • Bus is a collection of wires which transports signal from one part to another part.
  • It is of three types:
  1. Data Bus- Carries signal from RAM to CPU and vice versa/ carries data to be stored.
  2. Address Bus- gives location to where the data should be stored.
  3. Control Bus- Used to carry signal from CPU to memo

     I/O Polling and Interrupt
  • In polling the CPU checks I/O devices at regular to see whether the computer needs any service while in interrupt method, the I/O devices interrupts the processor and reminds/alerts it that computer needs service.
2. Hard Drive Fundamental
• Primary long-term storage
• Consists of magnetic disk called 'magnetic platters'.
• It stores document and application.
• Solid State Drives (SSD) are used due to speed and reliability. It is more expensive than hard drives.
3. RAM fundamental
• Main short-term storage
• It has no moving parts so accessing data in RAM is faster than in hard disk.
4. BIOS/CMOS Fundamental
• BIOs is the basic I/O system
• It is a set of instruction (performs POST-power-on self test) located in a chip on the mother board.
• Complementary metal-oxide-semiconductor (CMOS) is a small amount of memory on a computer to store BIOS setting.
• To boot a computer, an operating system(OS) is required. OS is a software installed in hard drives that enables the computer's hardware to communicate and operate with the computer's software.