1. Chapter 2: Computer Hardware
Hardware H/W: The physical components of the computer (touchable), either Electronic or Mechanical parts.
Since Most of the computer's Hardware is housed within the System Unit and the Mother Board; we will briefly describe these two units:
Chapter 2 - Computer Hardware

2. The System Unit (Case or Chassis)
The "system unit" is the name given to the main PC box that houses the various elements that go together to make up the PC.
For instance, within the system unit is the computer system's motherboard, which contains all the main components, such as the CPU and Primary memory.
Chapter 2 - Computer Hardware

3. The System Unit (Case or Chassis)
The system unit also houses items such as the hard disk, the floppy disk and CD-ROM and DVD drives etc. System units come in two basic varieties:
1- The tower version,
2- Desktop version, which is designed to be laid on your desk and you can place your monitor on top of the system unit.
Chapter 2 - Computer Hardware

4. The System Unit (Case or Chassis)
Tower Box
Desktop Box
Chapter 2 - Computer Hardware

5. The System Board (Motherboard)
The system (Mother) board is contained within your system unit and all the vital computer peripherals like printer or scanner are plugged directly into the motherboard.
The CPU is normally housed on the motherboard along with all the other electronic components.
Chapter 2 - Computer Hardware

6. The System Board (Motherboard)
Other items such as the hard disk are attached to the motherboard, either directly or via cables. These boards are getting smaller and smaller as the components become more integrated.
Chapter 2 - Computer Hardware

7. Looking at the System Unit
Essential Skills for Digital Literacy
Computing Fundamentals
Looking at the System Unit
RAM Slots
AGP Slot
CPU Slot/ Microprocessor
Expansion/PCI Slots
Pg 15
Descriptions of the components labeled here are on the next slide.
Input/Output Slots
Chapter 2 - Computer Hardware 7
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Recognizing Computers – Slide 7

8. diagram for the Computer's Hardware
Chapter 2 - Computer Hardware

9. Central Processing Unit (CPU)
The CPU is the brain of your computer.
As we have previously shown, It performs the following:
Mathematical calculations.
Logical Operations.
Chapter 2 - Computer Hardware

10. Central Processing Unit (CPU)
Also CPU is responsible for the smooth running of your operating system (Microsoft Windows) as well as your application software, such as word-processors, spreadsheets, databases etc.
It also accesses and uses the main memory (RAM - Random Access Memory) storing data and programs temporally before and after processing.
Chapter 2 - Computer Hardware

11. Central Processing Unit (CPU)
CPU's speed: It determines how fast your computer will run. This relates to the number of basic operations executed in one second, which is measured by Hertz units)
CPU speed is measured in Mega Hertz (MHz) or Giga Hertz (GHz); the higher the Hz rating of your CPU the faster your computer will run.
Chapter 2 - Computer Hardware

12. Central Processing Unit (CPU)
To give you some indication of how PCs have advanced over the years, the original IBM PC released in 1981 ran at 4.77 MHz while modern PCs run at speeds above 2.8 GHz!
Chapter 2 - Computer Hardware

13. Chapter 2 - Computer Hardware
Components of CPU
Chapter 2 - Computer Hardware

14. Arithmetic and Logic Unit (ALU)
The arithmetic/logic unit (ALU) contains the electronic circuitry that executes all arithmetic and logical operations.
The arithmetic/logic unit can perform four kinds of arithmetic operations, or mathematical calculations: addition, subtraction, multiplication, and division.
Chapter 2 - Computer Hardware

15. Arithmetic and Logic Unit (ALU)
As its name implies, the arithmetic/logic unit also performs logical operations.
A logical operation is usually a comparison. The unit can compare numbers, letters, or special characters. For example (a=b, a<b, a>b, a>=b), the computer can then take action based on the result of the comparison.
Chapter 2 - Computer Hardware

16. Chapter 2 - Computer Hardware
Control Unit
It carries out the following tasks:
Reading and interpreting program instructions.
Directing and controlling data flow within the CPU and between the CPU and Primary Memory.
Note: The control unit does not execute program instructions; rather, it directs the ALU to do so.
Chapter 2 - Computer Hardware

17. Chapter 2 - Computer Hardware
Registers
Registers are very high speed, immediate access storage locations where program instructions are decoded and data stored temporarily before and after execution by the ALU.
Note: Registers are not part of the Main memory; rather they are special additional storage locations within the CPU.
Chapter 2 - Computer Hardware

18. Chapter 2 - Computer Hardware
Registers
Registers work under the direction of the control unit to accept, hold, and transfer instructions or data and perform arithmetic or logical comparisons at a very high speed.
Chapter 2 - Computer Hardware

19. Chapter 2 - Computer Hardware
Cache Memory
It is a high speed memory that allows a CPU to access data more rapidly than from a memory located elsewhere on the motherboard.
Chapter 2 - Computer Hardware

20. Chapter 2 - Computer Hardware
Internal Buses
Groups of wires used to simultaneously transport all bits of a data between Special registers, and between deferent components of the CPU.
Chapter 2 - Computer Hardware

21. Chapter 2 - Computer Hardware
Examples of CPUs
The following are some examples of CPUs:
Intel CPUs or Microprocessors. Intel is the world’s largest chipmaker; it supplies a high percentage of microprocessors that powers PCs. In 1971, Intel introduced the world’s first microprocessor, the 4004.
Motorola CPUs or Microprocessors.
Chapter 2 - Computer Hardware

22. Primary Storage (Main Memory)
RAM
Random Access Memory (RAM) is the Primary memory used by the computer. When the operating system loads from Hard disk when you first switch on the computer, it is copied into RAM.
Data and programs stored in RAM are volatile (i.e. the information is lost when you switch off the computer).
Chapter 2 - Computer Hardware

23. Chapter 2 - Computer Hardware
RAM
Commonly modern computers are supplied with over 64 MB of RAM. As a rule, a Microsoft Windows based computer will operate faster if you install more RAM.
Functions of RAM:
Store data and programs before being processed in the CPU.
Store results of processing before being transmitted to the output unit.
Chapter 2 - Computer Hardware

24. Chapter 2 - Computer Hardware
ROM
Read Only Memory (ROM) as the name suggests is a special type of memory chip that holds software that can be read but not written to.
A good example is the ROM-BIOS chip, which contains read-only software that controls the basic input and output service in the computer.
Chapter 2 - Computer Hardware

25. Chapter 2 - Computer Hardware
ROM
This software performs a variety of tasks. When you first switch on the computer the ROM-BIOS software performs a self-diagnostic to check that the computer is working properly.
This software then loads your operating system from the disk into the RAM.
Chapter 2 - Computer Hardware

26. Chapter 2 - Computer Hardware
Measuring Memory
It is important to realize that the term digital computer refers to the fact that the computer works in what is called binary numbers. Humans work in decimal numbers (because we have 10 fingers).
A digital computer uses the numbers 0 and 1 (or on and off). Thus when we talk about computer storage, either the size of memory (RAM) or the hard disk capacity we are talking about numbers that are multiples of 0 or 1.
Chapter 2 - Computer Hardware

27. Chapter 2 - Computer Hardware
Measuring Memory
All computers work on a binary numbering system, i.e. they process data in ones or zeros. This 1 or 0 level of storage is called a bit. Often hardware is specified as a 32-bit computer, which means that the hardware can process 32 bits at a time.
Chapter 2 - Computer Hardware

28. Chapter 2 - Computer Hardware
Measuring Memory
A Byte consists of eight bits.
A Kilobyte (KB) consists of 1024 bytes.
A Megabyte (MB) consists of 1024 kilobytes.
A Gigabyte (GB) consists of 1024 megabytes.
Chapter 2 - Computer Hardware