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Copyright © 2006 by The McGraw-Hill Companies, Inc. All rights reserved.
McGraw-Hill Technology Education
Chapter 1A
Introducing Computer Systems
Copyright © 2006 by The McGraw-Hill Companies, Inc. All rights reserved.
McGraw-Hill Technology Education
ComputersTools for an information Age
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Question 1Question 1
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Index• What is a computer?• The beginning of Computer
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What is a computer?• In a dictionary before 1940,
– Compute + er– computer : a person who performs
calculations.
• The modern definition– emerged in 1940s, when the first electronic
computing devices were developed
1A-6
The Computer Defined• Electronic device• Converts data into information• Modern computers are digital
– Two digits combine to make data• Older computers were analog
– A range of values made data
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The beginning of Computer• ABC (Atanasoff-Berry Computer)
– 1942, John Atanasoff and Clifford Berry - 1st Electronic digital computer
• MARK-1– 1944, Howard Aiken
• ENIAC (Electronic Numerical Integrator and Calculator)– 1946, John W. Mauchly and J.Presper Eckert, Jr. - 1st Large scale electronic digital computer
• EDSAC (Electronic Delay Storage Automatic Calculator)– Maurice Wilkes
• UNIVAC-I (UNIVersal Automatic Computer)– John W. Mauchly and J.Presper Eckert, Jr.
• EDVAC (Electronic Discrete Variable Automatic Computer)
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ABC(Atanasoff Berry Computer)ABC(Atanasoff Berry Computer)
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ENIAC computer
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EDVAC• When : in 1952• Where : in the United States• Who : a team of engineers on a secret military project• Why : as a response to World War II military needs. (to process
complex calculation automatically)
• How : – 2000 multiplication in one second – addition or subtraction 100,000 times in the same period– Its memory : 1,024 numbers of 12 decimal places each
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Plans for EDVAC
• Described in a report by the famous mathematician John von Neumann.
• “The most influential paper in the history of computer science”
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What is a computer?• Von Neumann’s report
– define the components of a computer and describe their functions
– used the term “automatic computing system”
• Today, just “computer”, or “computer system.
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A computer is…
• Based on the concepts presented in von Neumann’s paper
• Computer : a device that 1) accepts input, 2) processes data, 3) stores data, 4) and produces output.
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1) A computer accepts input• Computer input : whatever is put into a computer
system.• Examples
– words and symbols in a document– numbers for a calculation, – pictures, temperatures, audio signals
• Main input device : keyboard
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2) A computer processes data• Data : symbols that represent facts and ideas.
– processing : data manipulation of computer
• Process : a systematic series of actions that a computer uses to manipulate data
• Some of the ways : – performing calculations, – sorting lists of words or numbers, – modifying documents and pictures – drawing graphs.
• A device : central processing unit (CPU)
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3) A computer stores data• A computer stores data for processing• Places for storing data
– Memory : an area of a computer that holds data that is waiting to be processed
Ex) RAM, ROM– Storage : the area where data can be left on a permanent basis
while it is not needed for processing ex) diskette, CD-ROM,HDD
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4) A computer produces output• Computer output : the results produced by a computer ex) reports, documents, music, graphs, and pictures
• Output device : the device that displays, prints, or transmits the results of processing.
ex) monitor, printer
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Example
• Fundamental computer function: 7+2=9– Input : 7, +, 2– Memory : 7, +, 2– Processing : Add 2 to 7– Memory : 9– Output : 9– Storage : 9
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Fundamental characteristics• Speed
– Provide the processing speed essential to our fast-paced society for quick service
• Reliability– Extremely reliable, compute correctly– Most computer error : by human errors
• Storage Capability– Store tremendous amounts data, which can be located and retrieved
efficiently
• By-products characteristics by above three– Productivity, decision making, cost reduction
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Classification of Computer
• By processing capabilities –Microcomputers–Minicomputers–Mainframe computers–Supercomputers
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MicrocomputersUsing the Microprocessor. A small computer that
contains a microprocessor as its central processor.• Personal Computers (PC)• In home and small businesses
– Desktop computer– Portable Computer
• Palmtop, Notebook(Laptop)• PDA (Personal Digital Assistant)
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PalmtopPalmtop
1A-24
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
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Minicomputer• More powerful than microcomputer. A
computer of medium power, more than a microcomputer but less than a mainframe.
• Stores data for all users in one centralized location
• Used in school or small company • Ex) VAX, MV 4000, MV 8000, SSM 032
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1A-27
Computers For Organizations• Mainframes
– Used in large organizations
– Handle thousands of users
– Users access through a terminal
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Mainframes
• Large, fast and fairly expensive computers
• Used by business or government to provide centralized storage
• EX) IBM 4381, 9300, 3090, Cyber 180
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Computers For Organizations• Supercomputers
– The most powerful computers made
– Handle large and complex calculations
– Process trillions of operations per second
– Found in research organizations
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Supercomputers• The fastest and most expensive type of
computer• Used for code breaking, weather
prediction and molecular modeling• The first : CRAY-1• Intel’s ASCI Red, SGI’s ASCI Blue
Mountain, IBM’s ASCI Blue Pacific
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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
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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
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Computers For Individual Use• Tablet computers
– Newest development in portable computers
– Input is through a pen
– Run specialized versions of office products
1A-34
• 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, e-mail access
Computers For Individual Use
1A-35
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
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Computers In Society• More impact than any other invention
– Changed work and leisure activities– Used by all demographic groups
• Computers are important because:– Provide information to users– Information is critical to our society– Managing information is difficult
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Computers In Society• Computers at home
– Many homes have multiple computers– Most American homes have Internet– Computers are used for
• Business• Entertainment• Communication• Education
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Computers In Society• Computers in education
– Computer literacy required at all levels• Computers in small business
– Makes businesses more profitable– Allows owners to manage
• Computers in industry– Computers are used to design products– Assembly lines are automated
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Computers In Society• Computers in government
– Necessary to track data for population• Police officers• Tax calculation and collection
– Governments were the first computer users
1A-40
Computers In Society• Computers in health care
– Revolutionized health care– New treatments possible– Scheduling of patients has improved– Delivery of medicine is safer
Copyright © 2006 by The McGraw-Hill Companies, Inc. All rights reserved.
McGraw-Hill Technology Education
Chapter 1A
End of Chapter