CSCI 1101 INTRODUCTION TO COMPUTERS 5. Basic Computer Architecture

ACS Computer Concepts - Chapter 1 2 What is a computer? Before 1940, a computer was defined as a person who performs calculations. The modern definition of the term “computer” emerged in the 1940’s.  developed as a response to World War II military needs

ACS Computer Concepts - Chapter 1 3 Von Neumann’s Definition Von Neumann, eminent mathematician, wrote a report describing plans for first computer, the EDVAC. His report has been described as the most influential paper in the history of computer science A computer is a device that accepts input, processes data, stores data, and produces output.

ACS Computer Concepts - Chapter 1 4 n Computer input is whatever you put into a computer system. n Input means to feed information into a computer.  words and symbols in a document  numbers for a calculation  pictures What kinds of input can a computer use?

ACS Computer Concepts - Chapter 1 5 Data refers to the symbols that represent facts and ideas. Processing is the way that a computer manipulates data.  performing calculations  sorting lists and numbers  drawing graphs

ACS Computer Concepts - Chapter 1 6 Why does a computer store data? A computer stores data so that it will be available for processing. Memory is an area of a computer that holds data that is waiting to be processed. Storage is the area where data can be left on a permanent basis.

ACS Computer Concepts - Chapter 1 7 What kinds of output does a computer produce? Computer output is the results produced by the computer.  reports  documents  music  graphs  pictures An output device displays, prints or transmits the results of processing.

ACS Computer Concepts - Chapter 1 8 Computer System Basics A computer system includes a computer, peripheral devices, and software. Hardware refers to the computer itself. Peripheral devices are components that expand the computer’s input, output, and storage capabilities. Software is a set of instructions that tells the computer how to perform a particular task.

ACS Computer Concepts - Chapter 1 9 Why does a computer need software? A computer needs software to tell it how to interact with the user, and specifies how to process the user’s data. There are many software programs that you can buy including software for producing resumes, teaching Spanish, and helping you plan your diet.

ACS Computer Concepts - Chapter 1 10 How and why are computers categorized? Computers are categorized into four categories from least to most powerful:  microcomputers  minicomputers  mainframe computers  supercomputers A computer is categorized based on its technology, function, size, performance, and cost.

ACS Computer Concepts - Chapter 1 11 Microcomputers also known as personal computers typically found in homes and small businesses cost about $2000 speed can exceed 1,500 mm operations per second may be stand-alone or may be connected to other computers in order to share data and software with other users

ACS Computer Concepts - Chapter 1 12 A laptop computer is light, and runs on batteries or electricity A personal digital assistant (PDA) accepts info on a touch-sensitive screen Desktop microcomputer Microcomputers

ACS Computer Concepts - Chapter 1 13 Mainframes large, fast, and fairly expensive computers used by business or government provide centralized storage, processing, and management for large amounts of data like minicomputers, process requests from terminals and can support thousands of users often include several central processing units

ACS Computer Concepts - Chapter 1 14 Supercomputers fastest and most expensive type of computer. cost between $500,000 and $35 million have expanded into business markets to handle large volumes of data process more than 1 trillion instructions per second create realistic animations

ACS Computer Concepts - Chapter 1 15 Computer Platforms Two major computer platforms are PCs and Macs. PCs  originally created by IBM Macs  manufactured by Apple Computer, Inc. Computers that operate the same way are compatible.

ACS Computer Concepts - Chapter 1 16 n If someone knows your password and logs on sending offensive messages, it will look as though you did it. User ID Password Password Security

ACS Computer Concepts - Chapter 1 17 n The Internet is the world’s largest computer network.  provides connections for millions of computers all over the globe  provides many information services, the most popular being the World Wide Web, or Web n The Web is a sort of “flea market” for information  includes weather maps, census data, product information, course syllabi, music, and images What's the Internet?

ACS Computer Concepts - Chapter 1 18 The User Interface The means by which humans and computers communicate is referred to as the user interface. A good user interface is easy to learn and use. User interfaces are still evolving.

ACS Computer Concepts - Chapter 1 19 n A command is an instruction you input to tell the computer to carry out a task. n Command words are often English words, such as print, begin, save, and erase, but they can also be more cryptic. Computer Commands

ACS Computer Concepts - Chapter 1 20 n Syntax specifies the sequence and punctuation for command words and parameters. n A syntax error occurs when you misspell a command word, leave out punctuation, or type the commands out of order. n A command-line interface is an interface that requires the user to type commands. More about Computer Commands

ACS Computer Concepts - Chapter 1 21 A menu displays a list of commands or options. Menus were developed in response to the difficulties people experienced with command-line user interfaces. Submenus are additional sets of commands that the computer displays after you make a selection from the main menu. Dialog boxes display the options associated with a command. Menus versus command line

ACS Computer Concepts - Chapter 1 22 n Graphical objects are small pictures on the screen that you can manipulate using a mouse or other input device. n Graphical objects include icons, buttons, and windows. Icon Selected icon

ACS Computer Concepts - Chapter 1 23 Why are GUIs so popular? Graphical objects are a key element of the graphical user interfaces, or GUIs, found on most of today’s microcomputers.  display menus and prompts in addition to graphical objects  based on metaphors that represent real-world objects  Recycle bin