Computer Hardware

In this article I would give you a brief overview about system unit, type of port and type of connector.

The System Unit

The System Unit houses the central processing unit, memory modules, expansion slots, and electronic circuitry as well as expansion cards that are all attached to the motherboard; along with disk drives, a fan or fans to keep it cool, and the power supply.

All other devices (monitor, keyboard, mouse, etc., are linked either directly or indirectly into the system unit.

Front of the System Unit

Drives are housed in drive bays which are accessed at the front of the case.

Internal drives, such as the hard disk drive, are installed in internal bays that are not typically as accessible as the external drives pictured here.

front pannel

System Unit cases come in a huge array of types and styles, depending upon hardware needs.

Types of Ports

serial port

Serial ports

transmit data one bit at a time, like the picture on the left illustrates.

Parallel ports

transmit more than one byte at a time.

These types of port designs are based on whether or not fast data transmission rates are required by the device or not.

Most computers come with basic types of ports (serial, parallel, keyboard, mouse, and USB); and expansion cards allow you to expand the available types needed by specific devices.

Different Types of Connectors


Understanding the differences among connector types is useful and important, as the cable required to attach a device to your computer is specific to its connector, not to mention the port on the computer.

Non-Volatile Storage Devices

Disk drives

  • Internal & External
  • Hard drives
  • Removable disk drives
  • Floppy disks (1.4 MB)
  • ZIP disks (100/250 MB)
  • CD-ROM (700MB), DVD-ROM (~5GB/side)
  • read only (-ROM), write once (-R), re-writeable (-RW)
  • Combination drive

Many other forms
Memory Stick, MultiMediaCard, CompactFlash, and SmartMedia