Computer Science is…
Lecture 1 Introduction to the Computers CSCS100 - Spring 2008 – Forman Christian College Asher Imtiaz Wajeeha Akram
[Britannica] Study of computers, their design, and their uses for computation, data processing, and systems control, including design and development of computer hardware and software, and programming. [Wikipedia] Computer science, or computing science, is the study of the theoretical foundations of information and computation and their implementation and application in computer systems.
*Several of these slides have been adapted and modified from LUMS CS101 course (Dr Sohaib Khan and Dr Arif Zaman), VU CS101 slides (Dr. Altaf A. Khan) and Peter Norton’s supplementary material.
What can computers do, or not do?
About Computers… What is it, and what can it do?
• A computer does what it is told to do… • You tell a computer what to do by giving it a list of precise, unambiguous (clear) instructions: a computer program • Why are computer programs not written in English? • Because languages such as English are inherently ambiguous (unclear) Time flies like an arrow
What is a Computer? •
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[Norton] A Computer is an electronic device that processes data, converting it into information that is useful to people. [Wikipedia] A Computer is a programmable device, usually electronic in nature, that can store, retrieve and process data. [The American Heritage Dictionary]
What is a computer?
Input
Processing / Computation
Output
1. A device that computes… especially a programmable electronic machine that performs high-speed mathematical or logical operations or that assembles, stores, correlates, or otherwise processes information 2. One who computes
Calculator – A Simple Computer
Categorization of Computer Systems
Photographed by Adrian Pingstone in March 2004, and released to the public domain. Thanks to Kodabar for removing the shadow.
Computers Everywhere
Computers For Individual Use
• Not just Desktops, Workstations, Tablet PCs, Handheld PCs (PDAs), Servers, Mainframe computers, Minicomputers • But also…
• Desktop computers • The most common type of computer • Sits on the desk or floor • Traditional design with monitor stacked on top of the system unit. • Tower design.
• Performs a variety of tasks
• Cell phones • Alarm Clocks • Microwave Ovens • Lighting control in a building • Washing Machines Image credit: www.classiccmp.org/dunfield/pc/index.htm , www.comandati.ro
Computers For Individual Use
Computers For Individual Use
• Workstations
• Notebook computers
• Specialized computers • Optimized for science or graphics
• Engineering design, modeling, animation, video editing.
• More powerful than a desktop • Often have high-resolution monitors, accelerated graphics capabilities. • More expensive than the average desktop, typically by at least more than double the price
• • • • • • •
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 Also called laptop computers Power optimization (battery life: at least 2 hours) • About 1.5 times or higher than the cost of desktops. Image credits: http://gizmodo.com
Image from http://www.pcaccessoriesparts.com/
Image credits: images.businessweek.com
Computers For Individual Use • Tablet computers • Newest development in portable computers • Input is through a pen • Run specialized versions of office products
Computers For Individual Use • Handheld computers • • • • •
Very small computers Personal Digital Assistants (PDA) Note taking or contact management Data can synchronize with a desktop $200 onwards
• Smart phones
• Hybrid of cell phone and PDA • Web surfing, e-mail access
Image credits: www.techpuddle.com
Computers For Organizations
Computers For Organizations
• Network servers
• Mainframes
• Centralized computer • All other computers connect • Provides access to network resources • Multiple servers are called server farms • Often simply a powerful desktop
• Used in large organizations, banks, e-commerce systems, military. • Also called “Enterprise Servers” • Handle thousands of users • Users access through a terminal • High reliability
Computers For Organizations
Computers For Organizations
• Minicomputers
• Supercomputers
• • • • • •
Called midrange computers Power between mainframe and desktop Handle hundreds of users Used in smaller organizations Users access through a terminal Now, very high-end desktop computers – called lowend or mid-range servers – have taken over the role that was previously played by minicomputers • Servers are more powerful and reliable than desktop computers. • Used by medium, small scale organizations, as filestores, e-email service and to host websites • 2 or more processors, GB’s of memory, TBs of storage
Wearable Computers • A different interaction idea. • Small in size, carried in a pocket, worn on the arm, waist, or head or elsewhere on the body • Capability similar to PDA’s, but more expensive • They are always ON, and always accessible. • “A person's computer should be worn, much as eyeglasses or clothing are worn, and interact with the user based on the context of the situation” http://www.media.mit.edu/wearables/
• Example usage scenarios: military (e.g. land warrior) industry, health care
• The most powerful computers made. IBM Deep Blue 1997. • Handle large and complex calculations • Process trillions of operations per second • Cost tens of millions of dollars • Found in research organizations • Designed to focus on one task at a time • In the past, single high end processor. • Modern supercomputers, 1000s of processors working in parallel. • Why would we want to do this?
Wearable computers
www.gatech.edu/innovations/wearable/
Video Conferencing http://wearcam.org/wristcam/dusting/
Computers In Society
Computers In Society
• More impact than any other invention
• Computers at home
• 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
• Many homes have multiple computers • Most American homes have Internet • Computers are used for • Business • Entertainment • Communication • Education
Computers In Society
Computers In Society
• Computers in education
• Computers in government
• 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
• Necessary to track data for population • Police officers • Tax calculation and collection
• Governments were the first computer users
Computers In Society
Summary
• Computers in health care
• At a low (processor) level, computer are pretty dumb and have to be told exactly what to do • However, with intelligently written computer programs, computers can behave quite intelligently • A computer is simply a device that computes, taking some input, processing it, and producing some output • Computers can come in all sorts of forms, and not just the types you may be familiar with
• Revolutionized health care • New treatments possible • Scheduling of patients has improved • Delivery of medicine is safer
