Lesson 1 Computers and Computer Systems 1. Objectives Understand the importance of computers. Define computers and computer systems. Classify computers

Lesson 1Computers and Computer Systems

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2Objectives

• Understand the importance of computers.• Define computers and computer systems.• Classify computers.• Use computer systems.• Identify system components.• Identify types of storage devices.• Care for storage media.• Explore computers in your future.

3Vocabulary

• Arithmetic/logic unit (ALU): Performs arithmetic computations and logical operations.

• Central processing unit (CPU): Also called the microprocessor or central processor, is the brains of the computer.

• Circuit board: A thin plate or board that contains electronic components.

• Computer: An electronic device that receives data (input), processes data, stores data, and produces a result (output).

• Control unit: The boss, so to speak, and coordinates all of the processor’s activities.

• Data: Text, numbers, sound, images, or video.• Hard disk: Used to store data inside the computer, although

external hard disks are also available.

4Vocabulary

• Hardware: The actual machine—wires, transistors, and circuits.

• Information: Output.• Memory: Where data is stored on the motherboard.• Mobile device: Computers that can fit into the palm of

your hand. • Motherboard: A circuit board that contains many

integral components.• Notebook computer: Today’s most widely used personal

computer, designed for one person to use at a time.

5Vocabulary

• Random access memory (RAM): The main memory or primary memory on the motherboard.

• Read-only memory (ROM): The permanent storage of data, usually burned onto chips.

• Server: A computer generally used by small to medium-size companies and can support a few users or hundreds of users.

• Software: Consists of instructions or programs for controlling the computer.

• Supercomputer: The fastest type of computer used to process enormous amounts of data.

• Tablet PC: A personal computer similar in size and thickness to a notepad.

• USB flash drive: A small removable data storage device.

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Understanding the Importance of Computers

Invention of Computer• The computer is one of the most important

inventions of the past century.• You find computers and computer technology

everywhere throughout society—from businesses and financial organizations, to home electronics and appliances, and to personal applications such as clothing embedded with iPod controls.


A Brief History of the Computer• The first computers were developed in the late 1940s

and early 1950s for use by the military and government.• UNIVAC and ENIAC• Less processing power than an iPhone• Occupied a small building or city block• Cost millions of dollars

• Computers in mid 50s—70s were smaller and more powerful but still limited

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A Brief History of the Computer (cont.)• In 1971, Dr. Ted Hoff developed the

microprocessor.• The first Apple computer was built in 1976 by

Steve Jobs and Steve Wozniak. The IBM PC was introduced in 1981.

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FIGURES on PAGES Mod 1-4 & 1-5• Students doing online research• Early computers• The Apple II and IBM PC

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• Above and Beyond: The first IBM PC ran on a 4.77 MHz Intel 8088 microprocessor. The PC came equipped with 16 kilobytes (KB) of memory, expandable to 256 KB. The PC came with one or two 160KB floppy disk drives and an optional color monitor.

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Defining Computers and Computer Systems

• A computer is an electronic device that receives data (input), processes data, stores data, and produces a result (output).• A computer system includes hardware,

software, data, and people.• The actual machine — wires, transistors,

and circuits — is called hardware.

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• Software consists of instructions or programs for controlling the computer.• Data is text, numbers, sound, images, or

video.• The computer receives data through an

input device, processes the data, produces the output (or information), and stores the data and information on a storage device.

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FIGURES on PAGES Mod 1-6 & 1-7• Using a mobile computer to process data

into information• Information processing cycle• Consists of four steps: I-P-O-S

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• IPOS example:• Inputs Data: Store clerk enters customer’s name and

scans the barcode of an item with an input devices such as keyboard and digital scanner.

• Processes Data: Computer uses stored instructions to process data into information.

• Outputs Information: Output device, such as monitor or printer, displays the information.

• Stores Data & Information: Data and information stored in temporary memory and then to permanent storage.

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• Computers performs only two operations:• Arithmetic computations• add, subtract, multiply, and divide as well as comparisons

such as greater than, less than, or equal to.

• Logical operations• using logical operators, such a AND, OR, and NOT

• Above and Beyond: Deep Blue was a chess-playing computer developed by IBM. On May 11, 1997, the machine won a six-game match by two wins to one with three draws against world champion Garry Kasparov.

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Classifying Computers

• Special-purpose computers are used mostly to control something else.• Dishwashers• Bathroom Scales• Airport Radar Systems

• General-purpose computers are divided into categories, based on their physical size, function, cost, and performance.

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• Types General Purpose Computers• Desktop and Notebook/Laptop

are today’s most widely used personal computers, which are designed for one person to use at a time.• PCs and Macs

• Tablet PCs are similar in size to a notepad. They function as a PC as well as a portable note-taking device.

• Mobile devices fit in the palm of your hand.• Calculators, Smartphones,

electronic organizers, etc.

All-in-One

Smaller version of laptop

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• Types of computers (cont.)• Servers are used by small/medium companies

to support few to hundreds of users. Usually referred to as network/application servers.• Web = delivers web pages• Database = stores/manages database info• File = stores remote programs and files that can be

shared by users

• Mainframe computers are a large, expensive computer capable of supporting hundreds/thousands ofusers.

• Supercomputers are the fastest typesof computers. These are used by the Government and large corporations.• Cost = millions of dollars

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FIGURE on PAGE 1-10• Electronic book reader• Nook, Kindle, etc.

• Above and Beyond: Supercomputers are often used to conduct and test medical experiments

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Using Computer Systems

• Computers are used for all kinds of tasks.• Computers take raw data and change it into

information. An example of the procedure: • You enter programs and data with some type of

input device.• The computer uses instructions to process the

data and to turn it into information.• You send the information to some type of

output device.• You store it for later retrieval.

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• Technology Careers - Computers on the Job:In the past few decades, computers have had dramatic effects on how we live, learn, and work. For example, the kinds of jobs available have changed because of computers. Fifty years ago, only a handful of people were computer programmers, and none were Web designers or software entrepreneurs. Today, nearly all jobs require some computer skills.

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• Time-consuming, labor-intensive communication tasks that used to require face-to-face meetings, telephone calls, overnight deliveries, or paging through printed materials are now performed quickly and efficiently using Internet browsers and e-mail. Students can participate in distance-learning classes to take courses not available where they live. Even the electric-meter reader and delivery person now carry hand-held computers that track a consumer’s electricity use or the location of a package. Cashiers use computers for retail sales, and managers use them to update the store’s inventory, handle customer calls, and advertise products. All of these advances, now taken for granted by many of us, are recent innovations.

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FIGURE on PAGE Mod 1-11• Computer system

components contained within the system’s case

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Identifying System Components

• The motherboard (aka: system board)is a circuit boardthat contains integral components — central processing unit, memory, connectors, and expansion ports and slots.

Motherboard

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The Central Processing Unit • The central processing unit (CPU) is the brains of the

computer. It is housed on a tiny silicon chip.• Contains millions of switches and pathways• Programs (aka: Software) are a special set of instructions to

control the activities of the computer.• Dual-core contains two separate processors on a single chip• Multicore is expansion for more than two (2) separate

processors• Speeds are generally measured in Gigahertz• Current speeds are 2GHz – 4GHz

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The Central Processing Unit (cont.)• The CPU has two primary sections: the arithmetic/logic unit

and the control unit.• The Arithmetic/Logic Unit (ALU)• Performs arithmetic computations• Addition, Subtraction, Multiplication, and Division

• Performs logical operations• Comparisons (AND, OR, NOT)• Two numbers equal or if one number is greater than or less than

another number

• Can execute complex tasks by combining arithmetic and logical operations:• Video Games use arithmetic operations and comparisons to determine

what appears on screen

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• The Control Unit• The control unit coordinates all of the processor’s

activities.• You communicate with the computer through

programming languages.• The computer uses machine language, or binary code,

which contains only 1s and 0s.• Communicate with computer via programming

languages:• Java, COBOL, C++

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Recognizing How a Computer Represents Data• Control Unit reads and interprets program

instruction into machine language. When electricity travel through processor pathways, it turns switches on and off. This represents the 1s and 0s.• Electricity Present = 1• Electricity Absence = 0

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Recognizing How a Computer Represents Data (cont.)• The control unit sends out necessary messages to

execute the instructions. A single zero (0) or a single one (1) is a bit, whichis the smallest unit ofinformation storage. Abyte is a single character,such as a letter or number.

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Memory• Memory is where data is stored on the

motherboard.• Memory can be short term or long term.• When you want to store a file or information

permanently, you use secondary storage devices such as the computer’s hard drive or a USB drive. You might think of this as long term memory.

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Random Access Memory• The memory on the motherboard is short term, called random

access memory (RAM). • Data, information, and program start-up instructions are

stored temporarily on a RAM chip and disappear when the computer is turned off or there is a power loss.

• The instruction cycle is the amount of time it takes to retrieve instructions to perform a specified task and complete the command.

• The execution cycle refers to the amount of time it takes the CPU to execute the instruction and store the results in RAM.

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Random Access Memory (cont.)• Together, the instruction cycle and one or more execution

cycles create a machine cycle.• For every instruction, a processor repeats a set of four

basic operations, which compose a machine cycle• Fetching – Obtaining a program instruction or data from RAM• Decoding – Process of translating the instruction into signals• Executing – Process of carrying out commands• Storing – Writing result to memory

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Machine Cycle

Processing Cycle

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Read-Only Memory• Another type of memory found on the motherboard is read-only

memory (ROM).• ROM chips store specific instructions that are needed for

computer operations. These instructions remain on the chip even when the power is turned off, because ROM chips are nonvolatile.

• The more common of these is the BIOS ROM, containing instructions to start the system when you turn on the computer.

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• Above and Beyond: Cache memory is another type of memory. This high-speed RAM is used to increase the speed of the processing cycle.

• Above and Beyond: If you read computer ads, you are likely to see the abbreviations MHz (megahertz) and GHz (gigahertz). These speed specifications indicate the speed of the microprocessor clock—a timing device that specifies the speed for executing instructions.

• Above and Beyond: In the time it takes to blink your eyes, certain computers can perform certain operations 10 billion times.

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RAM Microprocessor

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Identifying Types of Storage Devices

To keep a permanent copy of data, you must store it on a storage device.• Magnetic Storage Devices• Data is stored in numbered tracks in a special log on the disk called a

file allocation table (FAT).• Hard Disks• Magnetic Tape• Zip Disks• 3½” Disks

• Hard Disks (aka: Hard Drives)• Store data inside computer, or outside via external HD• Advantages: speed and capacity.• Measured in Gigabytes or Terabytes

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• Removable Disks• Removable magnetic media are rarely used and include 3½” disks and Zip

disks.

• Optical Storage Devices• Use laser technology to read and write data on plastic platters that contain a

metal layer, like CDs, DVDs, etc.• CD-DA = audio CD• CD-R = Write once CD• CD-ROM = Store up to 1 GB but common size is 650 MB or 74 minutes• CD-RW = Rewritable CD; erase data and write multiple times• DVD-ROM = Movies and Games; Capacities from 4.7–17 GB• DVD-R = Write once DVD• DVD-RW = Rewritable DVD; erase data and write multiple times• Blu-Ray = 5 times storage capacity of DVD; Capacities from 25-50 GB

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• Solid-State Storage Media • Nonvolatile, removable medium that uses integrated circuits• USB flash drive• AKA: Key Drive, Thumb Drive, Jump Drive, USB Flash Memory,

and USB Stick

• SD Cards• Compact Flash Card

• Network Drives• Hard drive or tape drive located on computer other than user’s

computer• Connected to a network server and is available to and shared by

multiple users.• Remote storage is used to extend disk space on a server and to

eliminate the addition of more hard disks or other storage devices.

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• Above and Beyond: Blu-ray optical discs use a blue-violet laser to read and write data, unlike earlier optical discs such as DVDs, which use a red laser. Although they use different lasers, Blu-ray products can be backwards compatible with CDs and DVDs.

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PlatterSpindleHeadActuator ArmActuator

Internals of Hard Drive

42Identifying Types of Storage Devices

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Miniature Mobile Storage Media

Examples of USB Flash

Drives

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Caring for Storage Media

• Keep away from magnetic fields.• Avoid extreme temperatures.• Remove media from drives and store them

properly when not in use.• When handling DVDs and other optical discs,

hold them at the edges.• Never try to remove the media from a drive when

the drive indicator light is on.• Keep discs in a sturdy case when transporting.

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Exploring Computers in Your Future

• A major focus of new types of computers is connectivity, or the ability to connect with other computers.

• Wireless and mobile devices are now as common as wired desktop machines.

• Computer literacy, which is the knowledge and understanding of computers and their uses, will become even more important.

46QUICK QUIZZES

1) Who built the first Apple computer?

Answer: Steve Jobs and Steve Wozniak

2) True or False? Many people consider the computer to be the single most important invention of the 20th century.

Answer: True.

3) True or False? Machines like the UNIVAC and ENIAC were designed initially for use by schools.

Answer: False. Machines like the UNIVAC and ENIAC were designed initially for use by the military and government.

47QUICK QUIZZES

4) A computer __________ includes hardware, software, data, and people.

Answer: system

5) __________ is text, numbers, sound, images, or video.

Answer: Data

6) Which type of computer is designed for one person to use at a time?

A. personal computer B. server

Answer: A

7) Tiny chips embedded in dishwashers, bathroom scales, or airport radar systems are classified as __________ computers.

A. general-purpose B. special-purpose

Answer: B

48QUICK QUIZZES

8) True or False? Just about all computers, regardless of size, take raw data and change it into information.

Answer: True.

9) The __________ that the computer uses to process data are contained within the system case.

Answer: components

10) Computers follow the __________ procedure—input, processing, output, and storage.

Answer: IPOS

49QUICK QUIZZES

11) The central processing unit (CPU), also called the microprocessor or central processor, is the __________ of the computer.

Answer: brains

12) True or False? The arithmetic/logic unit (ALU) is the boss of the CPU.

Answer: False. The arithmetic/logic unit (ALU) performs arithmetic computations and logical operations.

13) True or False? The computer does not understand human language.

Answer: True.

14) A __________ is the smallest unit of information storage.

Answer: bit

50QUICK QUIZZES

15) True or False? Random access memory, or RAM, is considered short term memory.

Answer: True.

16) __________is the process of obtaining a program instruction or data item from RAM.

Answer: Fetching

17) __________ is a nonvolatile, removable medium that uses integrated circuits.

A. Optical storage

B. Magnetic storage

C. Solid-state storage

D. None of the above

Answer: D

51QUICK QUIZZES

18) True or False? Most hard disks are used to store data inside the computer.

Answer: True.

19) True or False? A network drive is located on a computer other than the user’s local system.

Answer: True

20) True or False? You should hold DVDs at the edges.

Answer: True.

52QUICK QUIZZES

21) True or False? It is okay to remove media from a drive when the drive indicator light is on.

Answer: False.

22) True or False? Wireless and mobile devices are not as common as wired desktop machines.

Answer: False.

23) True or False? Computer literacy is the knowledge and understanding of computers and their uses.

Answer: True.

Documents

Lesson 1 Computers and Computer Systems 1. Objectives Understand the importance of computers. Define computers and computer systems. Classify computers