Transforming Data Into Information Chapter 5A Transforming Data Into Information

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

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

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: 258510.

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.

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: 110012. Position 4 3 2 1 Digits

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

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.

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.

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.

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.

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.

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

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!

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

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

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!

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

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.

Components affecting Speed

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

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.

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

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

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.

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)

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

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

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)

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

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

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?