1. Introducing Computer Systems

2. The Computer Defined
A Computer is an electronic machine which is fast, accurate and controllable.
A computer is a device that accepts data, then perform arithmetic or logical operations that manipulate or change the data, and finally produces new results from that data.

3. Information Technology
Hardware, software,
telecommunications,
database management and
other information processing
technologies used in computer
based information systems.

4. Data and Information Data are facts. The raw material of information.
Information is data arranged in ordered and useful form.

7. Software and Hardware
Software: Any program (set of instructions) that causes a computer to carry out a task or function.
Hardware: The physical elements of the computer system.

8. Number Systems Decimal : Base 10, 0-9 Binary: Base 2, 0-1
Octal: Base 8, 0-7
Hexadecimal: Base 16, 0-9 & A-F

9. Bits and Bytes 1 Byte = 8 Bits 1 KB(Kilobyte)= 1024 bytes
1 MB(megabyte)= 1024 KB
1 GB(gigabyte)= 1024 MB
 1 TB(terabyte)= 1024 GB

10. Computers For Individual Use
Desktop computers
The most common type of computer
Sits on the desk or floor
Performs a variety of tasks
Workstations
Specialized computers
Optimized for science or graphics
More powerful than a desktop

11. Computers For Individual Use
Notebook computers
Small portable computers
Weighs between 3 and 8 pounds
About 8 ½ by 11 inches
Typically as powerful as a desktop
Can include a docking station

12. Computers For Individual Use
Tablet computers
Newest development in portable computers
Input is through a pen
Run specialized versions of office products

13. Computers For Individual Use
Handheld computers
Very small computers
Personal Digital Assistants (PDA)
Note taking or contact management
Data can synchronize with a desktop
Smart phones
Hybrid of cell phone and PDA
Web surfing, access
Teaching tip
At this point, refer the students to the productivity tip on page 13. This tip helps the student determine what type of PC is best for them.

14. Computers For Organizations
Network servers
Centralized computer
All other computers connect
Provides access to network resources
Multiple servers are called server farms
Often simply a powerful desktop

15. Computers For Organizations
Mainframes
Used in large organizations
Handle thousands of users
Users access through a terminal

16. Computers For Organizations
Minicomputers
Called midrange computers
Power between mainframe and desktop
Handle hundreds of users
Used in smaller organizations
Users access through a terminal

17. Computers For Organizations
Supercomputers
The most powerful computers made
Handle large and complex calculations
Process trillions of operations per second
Found in research organizations

18. Basic Structure of a Computer System
Input Unit
Output Unit
Arithmetic Logic Unit (ALU)
Control Unit
Memory Unit

19. Input Unit
Enter data into the computer.
Output Unit
Extract data from the computer.

20. Arithmetic Logic Unit (ALU)
Calculates data and compares data.
Basic arithmetic operations (add, subtract, multiply, divide etc. )
Logical operations (AND, OR).

21. Control Unit (CU)
Selects, interprets and carries out
the execution of program
instructions in their proper
sequence

22. Memory Unit
Holds data, instructions and
results of processing

23. Computer Clock Speed (Hz) is a measure of cycles per second.
Megahertz (MHz) means “millions of cycles per second”
Gigahertz (GHz) means “Billions of cycle per second”.

24. A processor can execute an instruction in a given number of clock cycles. As the system’s clock speed increases, so does the number of instructions it can carry out each second.

25. Input and Output Devices
Input Devices
- Keyboard
- Pointing Devices- Mouse,
Trackball, Joystick
- Scanners

26. Input and Output Devices
- Display Screen
CRT – Cathode Ray Tube
LCD – Liquid crystal display

27. Input and Output Devices
- Printers
Dot-matrix printer
Laser Printer
Ink-jet Printer
- Plotter

28. Computer Memory Main Memory RAM (Random Access Memory)
- Volatile memory
- Read-write memory
Everything stored there is lost when the computer’s power is shut off

29. Computer Memory Read Only Memory ROM - Non-Volatile memory
ROM holds the start up program that
begins when the computer is turned on

30. Secondary Storage Media & Devices
Sequential Access Storage Devices
Sequential Access Storage means the data is stored in particular order. So the computer must sequentially search for data. Today sequential access storage devices are most commonly used for backup purposes.
Magnetic Tape
Tape Cartridges

31. Secondary Storage Media & Devices
Direct Access Storage Devices
Direct access means the data is stored in a particular memory location with a specific address so that any data can be found quickly. Direct access storage devices are magnetic disk drives used for secondary storage.
Floppy Disk Hard Disk Drive
Optical Disk

32. Data Bus Address Bus BUS
The term bus refers to the paths between the components of a Computer.
Data Bus
Address Bus

33. CACHE MEMORY
High-speed memory that resides between the CPU and RAM in a computer. Cache memory stores data and instructions that the CPU is likely to need next. The CPU can retrieve data or instructions more quickly from cache than it can from RAM or a disk.

35. INPUT/OUTPUT PORTS
Every device that is external to the system unit must be attached by a cable to the bus. This point of attachment is called a port or connector. There are six common types of ports and they are keyboard port, video port (for the display), mouse port, parallel port, serial port and USB port.

37. DISPLAYS
The resolution of a computer monitor is classified by the number of pixels on the screen, expressed as a matrix.

38. A resolution of 640 X 480 means that there are 640 pixels horizontally across the screen and 480 pixels vertically down the screen. The higher the resolution, the sharper and crisper the characters or image formed
800 x 600 pixels
1024 x 768 pixels
1280 x 1024 pixels

39. VIDEO CARDS
The quality of the images that a monitor can display is defines as much by the Video card /video controller as by the monitor itself.
The video controller is an intermediary device between the CPU and the monitor, It contains the video-dedicated memory and other circuitry necessary to send information to the monitor to display on the screen

40. MOTHERBOARD
The main circuit board of the computer, which contains the processor, memory, expansion slots, bus, and video controller. Also called the system board or mainboard