1. Transforming Data Into Information
Chapter 5A
Transforming Data Into Information

2. How Computers Represent Data
Number systems
A manner of counting
Several different number systems exist
Decimal Number System
Binary Number System
Octal Number System
Hexadecimal Number System

3. How Computers Represent Data
Decimal number system
Used by humans to count
Contains ten distinct digits
Digits combine to make larger numbers

4. Decimal Number System
The number system that we use in our day to day life is called the Decimal Number System.
It has 10 digits = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9}.
Base of decimal number system is 10.
Example: Decimal Number = 2585
Each digits 2, 5, 8, 5 are from 0 – 9.
Base 10 is used to represent a decimal number:

5. How Computers Represent Data
Binary number system
Used by computers to count
Two distinct digits, 0 and 1
0 and 1 combine to make numbers
Teaching Tip
Table 5A.1 on page 187 provides the first 17 binary numbers and their decimal equivalent. A fun exercise is to teach the students to count in binary on their fingers.

6. Binary Number System
Each digit of a number in Binary Number System is also known as ‘bit’ in computer systems.
It has 2 digits = {0, 1}.
Base of binary number systems is 2.
Example: Binary Number = 11001
Each digits 1, 1, 0, 0, 1 are from 0 – 1
Base 2 is used to represent a binary number:
Position 4 3 2 1
Digits

7. How Computers Represent Data
Bits and bytes
Binary numbers are made of bits
Bit represents a switch
A byte is 8 bits
Byte represents one character

8. How Computers Represent Data
Text codes
Converts letters into binary
Standard codes necessary for data transfer
EBCDIC: Extended binary coded decimal interchange code,
ASCII
American English symbols
Extended ASCII
Graphics and other symbols
Unicode
All languages on the planet
Insider information
Windows XP, Mac OS X and newer flavors of Linux are fully Unicode compatible.

9. How Computers Process Data
The CPU
Central Processing Unit
Brain of the computer
Two operational Units:
Arithmetic logic unit (ALU)
Simple math operations
Registers
Control unit (CU)
Controls resources
Instruction set
Teaching tip
Table 5A.4 on page 190 lists the operations handled by the common ALU.

10. Arithmetic Logic Unit (ALU)
The place where the actual execution of the instructions takes place during the processing operation.
All calculations are performed and all comparisons are made in the ALU
Data may thus move from primary storage to ALU and back again to storage many times before the processing is over.
After the completion of processing, the final results which are stored in the storage unit are released to an output device.

11. Arithmetic Logic Unit (ALU)
The type and number of arithmetic and logic operations that a computer can perform is determined by the engineering design of the ALU.
However almost all ALU’s are designed to perform the four basic arithmetic operations - add, subtract, multiply, divide and logic operations or comparisons such as less than, equal to, or greater than.

12. Control Unit (CU)
Acts as central nervous system for the components of the computer system.
Does not perform any actual processing on data.
Manages and coordinates the entire computer system.
Obtains instructions from the program stored in the primary storage, interprets the instructions, and issues signals, which cause other units of the system to execute them.

13. Central Processing Unit (CPU)
The control unit (CU) and the arithmetic logic unit (ALU) of a computer system are jointly known as the Central Processing Unit (CPU).
The CPU is the brain of any computer system.
All major calculations and instructions are made inside the CPU and the CPU is also responsible for activating and controlling the operations of other units of a computer system

14. How Computers Process Data
Machine cycles
Steps by CPU to process data
Instruction cycle
CPU gets the instruction
Execution cycle
CPU performs the instruction
Billions of cycles per second
Pipelining processes more data
Multitasking allows multiple instructions
Insider information
More pipelines mean a faster and more efficient CPU. The current fastest CPU on the market, the Apple G5 has 80 pipelines!

15. How Computers Process Data
Instruction Cycle
Fetching
Decoding
Execution Cycle
c) Execution
d) Storing

16. How Computers Process Data
Memory
Stores open programs and data
Small chips on the motherboard
More memory makes a computer faster

17. How Computers Process Data
Nonvolatile memory
Holds data when power is off
Read Only Memory (ROM)
Basic Input Output System (BIOS)
Power On Self Test (POST)
Teaching tip
If you are in a computer lab, spend a few minutes exploring your BIOS. Demonstrate what happens when values are adjusted. Walk through a POST check. Unplug a device and generate POST errors. Be sure to reset everything before moving on with the lecture!

18. How Computers Process Data
Flash memory
Data is stored using physical switches
Special form of nonvolatile memory
Camera cards, USB key chains

19. How Computers Process Data
Volatile memory
Requires power to hold data
Random Access Memory (RAM)
Data in RAM has an address
CPU reads data using the address
CPU can read any address
Teaching tip
One of the most commonly asked questions is “How do I speed up my computer”. The simplest answer is to add RAM. The Productivity Tip on page 200 provides some guidelines when to add RAM.

20. Components affecting Speed

21. Affecting Processing Speed
Registers
Number of bits processor can handle
Larger indicates more powerful computer
Increase by purchasing new CPU

22. Affecting Processing Speed
The computer’s internal clock
Quartz crystal
Every tick causes a cycle
Speeds measured in Hertz (Hz)
Modern machines use Giga Hertz (GHz)
Teaching tip
Spend a little time here discussing over clocking. Over clocking causes the computer to run faster than designed. Possibly, you have students that can share stories of over clocking.

23. Affecting Processing Speed
Cache memory
Very fast memory
Holds common or recently used data
Speeds up computer processing
Most computers have several caches
L1 holds recently used data
L2 holds upcoming data
L3 holds possible upcoming data

24. Affecting Processing Speed
The bus
Electronic pathway between components
System/Local bus connects CPU and RAM
Expansion bus connects to peripherals
Bus width is measured in bits
Speed is tied to the clock

25. Affecting Processing Speed
The Data bus & The Address bus:
All buses consist of two parts -- an address bus and a data bus. The data bus transfers actual data whereas the address bus transfers information about where the data should go.

26. External Bus Standards
Industry Standard Architecture (ISA)
Peripheral Control Interface (PCI)
Accelerated Graphics Port (AGP)
Universal Serial Bus (USB)
IEEE 1394 (FireWire)
PC Card
High Definition Media Input (HDMI)

27. External Bus Standards
Peripheral control interface (PCI)
Connects modems and sound cards
Found in most modern computers

28. External Bus Standards
Accelerated Graphics Port (AGP)
Connects video card to motherboard
Extremely fast bus
Found in all modern computers

29. External Bus Standards
Universal Serial Bus (USB)
Connects external devices
Hot swappable
Allows up to 127 devices
Cameras, printers, and scanners
Two types (A and B)

30. External Bus Standards
PC Card
Used on laptops
Hot swappable
Devices are the size of a credit card

31. External Bus Standards
HDMI Interface
Fastest and most modern
Best for viewing High Definition video

32. Questions:
What is the difference between data, information and knowledge?
What is the difference between Binary and decimal numbers?
What is meant by word size?
What is the differences between Arithmetic Operation and Logical operation?
Differences between RAM and ROM?