Lesson 1: The System Unit

“ We are using computer everyday without know what inside it and how it works.. ”

02 Apr 2016

By “ Syahmi Fauzi ”

Syahmi Fauzi

What is System Unit?

  • Also known as a computer chasis (system chasis), computer case or computer tower
  • A container that houses electronic components to make up a computer
  • To protect the sensitive electronic parts from the outside elements

System Unit

Four most common types of personal computers:

Desktops
  • Desktop system units located in separate case, called tower unit (or tower computer)
  • Has vertical system unit
Laptops
  • Laptop (notebook) system units are portable and much more smaller than desktops
  • Ultrabooks (ultra-portables or mini notebooks) are lighter, thinner and have longer battery life than other laptops
Tablets
  • Tablet system units (tablets computers) are located behind the monitor
  • Smaller, lighter and generally less powerful than laptops
  • Use a virtual keyboards
Mobile Devices
  • Mobile devices (handheld computers) smallest and fit comfortably in one hand
  • The most popular type of personal computer
  • System units located behind the display screen (monitor)
Components

Similar basic components in all types of personal computer mention above are:

  • System Board
  • Microprocessor
  • Memory

System Board

  • Other names - mainboard or motherboard.
  • Controls all communication for the computer system.
  • Connect with all external and internal devices and components
    • Sockets - provide connection points for chips (silicon chips, semiconductors, integrated circuit).
    • Slots - provide connection points for specialized card or circuit board.
    • Bus lines - provide pathways to support communication.

Motherboard

Microprocessor

CPU

In most personal computers, the Central Processing Unit (CPU) or processor is contained on a single chip called the microprocessor. It has two basic components:

  1. Control Unit (CU)
  2. Arithmetic Logic Unit (ALU)

Memory

Holds data, instructions and informations
Three type of memory chips:

1) Random Access Memory (RAM)
Volatile or temporary memory (storage) because their contents are lost if power is disrupted.
  • Cache memory is a high-speed holding area for frequenly used data and information.
  • DIMM is used to expand memory.
  • Virtual memory devides large programs into parts that are read into RAM as needed.
2) Read-Only Memory (ROM)
Non-volatile memory and control essential system operations.
Information stored by manufacturer
3) Flash Memory
Combination of both RAM and ROM
Does not lose its contents when power is removed

RAM

Expansion Slots & Cards

Most computers allow users to expland their systems by providing expansion slots on their system boards to accept expansion cards.
Examples of expansion cards:

  • Graphics Cards
  • Sound Cards
  • Network Adapter Cards/Network Interface Cards (NIC)
  • Wireless Network Cards
Plug and play is the ability for a computer to recognize and configure a device without human interaction.

Bus Lines

  • Also knows as buses
  • Provide data pathways that connect various system components
  • Bus width - the number of bits that can travel simultaneously
  • System buses - connect CPU and memory
  • Expansion buses - connect CPU and slots

Expansion Buses

Three types of principal expansion buses:

  • Universal Serial Bus (USB) can connect from one USB device to another)
  • Firewire bus is similar to USB bus but more specialized.
  • PCI Express (PCIe) bus provides a single dedicated path for each connected device.

Ports

  • Connecting sockets on the outside of the system unit
Standard Ports
Four standard ports are:
  • Video Graphics Adapter (VGA) and Digital Video Interface (DVI) - provide connections to system unit
  • Universal Serial Bus (USB) - to connect keyboards, mice, printers and storage devices
  • Firewire - provides high-speed connections to Firewire devices between devices and perconal computer such as camcorders and storage devices
  • Ethernet - high-speed networking port for Local Area Network (LAN) that has become a standard for many of today's computers
Specialized Ports
Five speciality ports are:
  • External Serial Advanced Technology Attachment (eSATA) - for high-speed connection to large secondary storage devices.
  • High Definition Multimedia Interfave (HDMI) - for high-definition digital audio and video.
  • Musical Instrument Digital Interface (MIDI) - for digital music.
  • Mini DisplayPort (MiniDP. mDP) - for large monitors.
  • Thunderbolt - for high-speed connections to up to seven separate devices connected one to another.
Cables - used to connect external devices to the system unit via ports.

Power Supply

  • Convert Alternating Current (AC) to Direct Current (DC)
  • Supply electrical energy to our personal computer

Power Supply Unit

Source:
Computing Essentials 2015
By:(Timothy J./Linda l./Daniel A.)O'Leary

  • Lesson 2: Input & Output >>>