Objectives of this Tutorial

• Identify the different components in a PC
• Explain the function of each component in a PC
• Correctly reconnect PC peripherals to a system unit

Topics

• Introduction to Hardware
• The System Unit
• Disk Drives
• Display Screen
• Binary and Units of Measurement

Introduction to Hardware

The term hardware refers to the various components that make up a PC. This term is used generally to indicate any part of the PC that can be physically touched. Each item of hardware influences the way the PC works.

This section explains the functions of the basic hardware components in the PC.

The System Unit



The system unit is the main component of the PC to which other components are connected. The system unit contains:

• Motherboard
• Microprocessor or Central Processing Unit (CPU)
• Memory (RAM and ROM)
• Disk drives
• Power supply unit

The Motherboard





The motherboard holds the microprocessor, memory chips (RAM and ROM), expansion slots, power connectors and any other microchips required for the PC to function.

The term motherboard is fully interchangeable with the terms system board, baseboard or main board. The Microprocessor

The microprocessor can be referred to as the brain of the PC. The microprocessor is also known as the CPU (Central Processing Unit). The microprocessor does the following:

• Carries out commands to make the hardware components perform actions.
• Processes data. This involves:
  • Performing logical instructions such as comparing
  • Performing mathematical instructions such as adding and subtracting

Although the instructions performed by the CPU are relatively simple, the CPU can execute many millions of instructions every second. This is what makes the PC such a powerful tool.

Intel is the most common microprocessor manufacturer. Cyrix, AMD and IBM also make microprocessors; these microprocessors are known and marketed as Intel compatible processors.

Measurements of Performance

System Clock Speed

The system clock is a part of the motherboard. It synchronizes the operation of all the components on the motherboard, just like the conductor of an orchestra synchronizes all of the musicians. Its speed is measured in megahertz (1 million clock ticks per second). The higher the megahertz number, the faster the processor is.

MIPS (Millions of Instructions Per Second)

This measures the number of instructions a microprocessor is capable of performing in a second. Once again, the higher the number, the faster the processor.

The table below shows the main types of Intel microprocessor (up to the Pentium MMX) with their speeds measured in MIPS:



While clock speed is the most commonly used indicator of performance, it does not always provide an accurate guide. For example, a 486 processor with an internal clock speed of 100Mhz will be slower than Pentium 90Mhz or even 75Mhz, due to their different internal architecture.

Pentium PCs are now commonly available with MMX (MultiMedia eXtension) technology, providing better video and audio reproduction. This is achieved by using the extra instructions within the processor (called microcode), which enhances the performance of multi-media software. The difference is particularly noticeable when running software that has been specifically written for the MMX processor.

MMX technology is included in the Pentium II and III processors.

The Pentium 4 processor has a new architecture called NetBurst which has a faster system bus and uses a new cache system called execution trace cache. It also has improved floating point which enhances 3D graphics.