Lecture

EC & Networked Computing Electronic commerce (EC) is the use of Web-based systems to support buying, selling, and customer service. Click-and-mortar companies add some EC activities to their regular business. Networked computing connects several computers and other electronic devices via telecommunication networks. Information technology (IT) refers to the collection of computer systems used by an organization.

The Digital Economy The digital economy refers to an economy that is based on digital technologies, including digital communication networks, computers, and software. The digital economy is also sometimes called the Internet economy , the New economy , or the Web economy .

Information Systems Information systems (IS) collect, process, store, analyze, and disseminate information for a specific purpose. Information Systems are comprised of; inputs (data, instructions) outputs (reports, calculations) feedback mechanisms that controls the operation an environment that it works within

Components of Information Systems Hardware Software Database Network Procedures People

Case: The Phil. Presidential Election 2010 The Comelec contracted the SMARTMATIC and its partner TIM PCOS – Precint Count Optical Scanner reads the form of Optical Mark Reader machines that function by reading the markings made on the ballots.

General Technological Trends Cost Performance Ratio Object-Oriented Environment & Document Management . Networked Computing Mobile Commerce Integrated Home Computing . The Internet General trends within computing systems include the following: Intranets and Extranets Corporate Portals The Networked Enterprise Optical Networks

Cost Performance Ratio Cost Performance Ratio: Improvement by a Factor of at Least 100. In about 10 years, a computer will cost the same as its costs today but will be about 50 times more powerful. Moore’s Law: Gordon Moore, the co-founder of Intel, predicted in 1965 that the processing power of silicon chips would double every 18 months.

Network Computing Network technology enables users to reach other users and access databases anywhere in the organization. Metcalfe’s Law: Robert Metcalfe, a pioneer of computer networks, claims that the value of a network grows roughly in line with the square of the number of its users. Kelly’s Extension: The value of the Internet is much larger, according to Kelly (1999). On the Internet we can make multiple simultaneous connections between groups of people.

Mobile-Commerce  M-commerce (mobile commerce) refers to the conduct of e-Commerce via wireless devices. It is the commercial application of mobile computing which is based on wireless networks. There is an increased interest in m-commerce because the number of mobile devices is projected to top 1 billion by 2004.  Location-based commerce (L-commerce) is an application of m-commerce that offers customers the location information of anything they want to purchase.

Network Computers & Home Computing The Network Computer, first introduced in 1997, does not have a hard drive. Instead, it is served by a central computing station, and temporarily receives and can use applications and data stored elsewhere on the network. Integrated Home Computing. Soon, home computing, television, telephone, home security systems, and other devices will be integrated and managed in one unit. Smart appliances refer to home appliances that are connected to the Internet.

The Internet, Intranets & Extranets The Internet. From about 50 million Internet users in 1997, there could be as many as 750 million by 2007. Intranets utilize information technology to provide organizations with internal communication systems. Extranets combine intranets with the Internet to create a powerful interorganizational systems for collaboration.

What is a Computer System Computer hardware is composed of the following components: Central processing unit (CPU) Input devices Output devices Primary storage Secondary storage Communication devices

Representing Data Today’s computers are based on integrated circuits (chips), each of which include millions of subminiature transistors. The “on-off” states of the transistors are used to establish a binary 1 or 0 for storing one binary digit , or bit . A byte is a sufficient number of bits to represent specific characters— usually 8 bits. The two most commonly used coding schemes are: ASCII (American National Standard Code for Information Interchange) EBCDIC (Extended Binary Coded Decimal Interchange Code)

Representing Pictures Pictures are represented by a grid overlay of the picture. The computer measures the color (or light level) of each cell of the grid. The unit measurement of this is called a pixel.

Evolution of Computers The first generation of computers, 1946–1956 Used vacuum tubes to store process information The second generation of computers, 1957–1963 Used transistors for storage and processing information Third-generation of computers, 1964–1979 Used integrated circuits for storing and processing information Early to middle fourth-generation computers, 1980–1995 Used very large-scale integrated (VLSI) circuits to store/ process information

Evolution of Computers (cont.) Late fourth-generation computers, 1996–present Use grand-scale integrated (GSI) circuits to store/ process information Fifth Generation of Computers, Present Uses massively parallel processing to process multiple instructions simultaneously Future Generations of computers DNA Computers Optical Computers

Types of Computers Supercomputers The computers with the most processing power Use the technology of parallel processing Massively parallel computers Uses a large number of processors The processors divide up and independently work on small chunks of a large problem Mainframes Not as powerful and generally not as expensive as supercomputers Most often used by large corporations

Types of Computers (cont.) Minicomputers ( midrange computers) Smaller and less expensive than mainframe computers Designed to accomplish specific tasks Workstations Based on RISC (reduced instruction set computing) architecture Provide high-speed calculations and high-resolution graphic displays Microcomputers (micros or personal computers, PCs) The smallest and least expensive category of general-purpose computers F our classifications based on their size: Desktops - Note books Laptops - Palmtops

Types of Computers (cont.) Personal digital assistant (PDA) A palmtop computer that combines a fast processor with a multitasking operating system Smart Card An even smaller form of computer that has resulted from the continuing shrinkage of integrated circuits Uses for smart cards are appearing rapidly and include; Checkbooks a bank ATM that can “deposit money” into the card’s memory for “withdrawal” at retail stores transporting data between computers

Network Computers & Terminals Network computer (NC) “ thin” computer desktop terminal that does not store software programs or data permanently Windows-based terminals (WBTs) subset of the Network computer reduces maintenance & support costs

Central Processing Unit The central processing unit (CPU) is also referred to as a microprocessor because of its small size. The CPU is the center of all computer-processing activities, where all processing is controlled, data are manipulated, arithmetic computations are performed, and logical comparisons are made. The CPU consists of the ; C ontrol unit A rithmetic-logic unit (ALU) P rimary storage (or main memory)

Primary Storage To store data that have been input until they are transferred to the ALU for processing. To store data that have been input until they are transferred to the ALU for processing. To hold data after processing until they are transferred to an output device. To hold program statements or instructions received from input devices and from secondary storage. Primary storage, or main memory, stores data and program statements for the CPU. It has four basic purposes.

Control Unit The control unit reads instructions and directs the other components of the computer system to perform the functions required by the program. The control unit does not actually change or create data; it merely directs the data flow within the CPU. The Machine cycle is t he series of operations required to process a single machine instruction . Each machine cycle consists of the ; instruction cycle, and the execution cycle

Memory There are two categories of memory: The register This is part of the CPU and is very fast. It allows for the fast storage and retrieval of data and instructions during the processing. Internal memory chips These reside outside the CPU and are slower. The internal memory is used to store data just before they are processed by the CPU.

Random-Access Memory Random-access memory (RAM) is the place in which the CPU stores the instructions and data it is processing. The advantage of RAM is that it is very fast in storing and retrieving any type of data. Dynamic random access memories (DRAMs) are the most widely used RAM chips. Synchronous DRAM (SDRAM) is a relatively new and different kind of RAM.

Read-Only Memory Read-only memory (ROM) is that portion of primary storage that cannot be changed or erased. Programmable read-only memory (PROM) is a memory chip on which a program can be stored. Erasable programmable read-only memory (EPROM) is a special type of PROM that can be erased by exposing it to ultraviolet light.

Microprocessor Speed The speed of a chip depends on four things: Clock speed Word length Data bus width Design of the chip

Microprocessor Evolution Microprocessors have become dramatically faster, more complex, with increasing numbers of transistors embedded in the silicon wafer. Chips are now being manufactured from gallium arsenide (GaAs), a semiconductor material inherently much faster than silicon. Intel has incorporated MMX (multimedia extension) technology in its Pentium microprocessors. MMX improves video compression/decompression, image manipulation, encryption, and input/output processing.

Microprocessor Architecture Computer architecture refers to the arrangement of the components and their interactions. It includes; t he instruction set the number of the processors the structure of the internal buses the use of caches the types and arrangements of input/output (I/O) device interfaces. An instruction set is the set of machine instructions that a processor recognizes and can execute. Today, there are two main instruction set strategies: Complex instruction set computer (CISC) Reduced instruction set computer (RISC)

Input/ Output Devices The input/output (I/O) devices of a computer are not part of the CPU, but are channels for communicating between the external environment and the CPU. Input devices deliver data and instructions into the computer. Output devices provide processing results. I/O devices are subclassified into the following categories; S econdary storage devices : primarily disk and tape drives P eripheral devices : any input/output device that is attached to the computer

Secondary Storage Secondary Storage is separate from primary storage and the CPU, but directly connected to it. It provides the computer with vastly increased space for storing and processing large quantities of software and data. Secondary storage media include ; M agnetic tape M agnetic disk M agnetic diskette O ptical storage D igital videodis k (DVD)

Input Devices Users can command the computer and communicate with it by using one or more of the following input devices. Keyboard. The most common input device is the keyboard . The keyboard is designed like a typewriter but with many additional special keys. Mouse. The computer mouse is a hand-held device used to point a cursor at a desired place on the screen. Touch Screen. The user activates an object on the screen by touching it with his or her finger.

Input Devices (cont.) Touchpad. A touchpad or trackpad is a small, flat, rectangular pointing device that is sensitive to pressure and motion. Light Pen. A light pen is a special device with a light-sensing mechanism, which is used to touch the screen. Joystick. Joysticks are used primarily at workstations that can display dynamic graphics. They are also used in playing video games. The joystick moves and positions the cursor at the desired object on the screen.

Output Devices (cont.) Monitors Impact Printers Nonimpact Printers Plotters Voice Output The output generated by a computer can be transmitted to the user via several devices and media.

Communications Media Computer CRT and terminals CD-ROM Computer interactive videodisc Digital video interactive Compact disc interactive Computer simulation Motion image Videodisc (cassette) Motion pictures Broadcast television Teleconference/videoconference Animation & Virtual Reality

Communications Media (cont.) Projected still visuals Slide & Overhead Graphic materials Pictures Printed job aids Visual Displays Text Printouts Audio Tape/cassette/record Teleconference Audioconference Sound digitizing Microphone Compact disc Music

Types of Software Application software is a set of computer instructions, written in a programming language that direct computer hardware to perform specific processing activities. An application program applies a computer to a need, such as increasing productivity of accountants. Application programming is either the creation or the modification and improvement of application software. Systems software acts primarily as an intermediary between computer hardware and application programs, and knowledgeable users may also directly manipulate it. Systems programming is either the creation or modification of systems software.

General Purpose Application Software Spreadsheet software transforms a computer screen into a ledger sheet, or grid, of coded rows and columns. Data management software supports the storage, retrieval, and manipulation of data. There are two basic types of data management software: Simple filing programs Database management systems (DBMSs) Word processing software allows the user to manipulate text rather than just numbers. Desktop publishing software allows users to do lay outs for specialized documents.

General Purpose Application Software Graphics software allows the user to create, store, and display or print charts, graphs, maps, and drawings. The three main types of graphic software are; Presentation Graphics Analysis Graphics Engineering Graphics Multimedia. There are two general types of multimedia software: Presentation software Interactive software

General Purpose Application Software Communications Software. To share, relate or exchange information, computers utilize communications software . Software suites are collections of application software packages in a bundle. Workgroup software , or Groupware , helps groups and teams work together by sharing information and by controlling workflow within the group. Integrated enterprise software consists of programs that manage a company’s vital operations, from order taking to manufacturing to accounting.

System Software Systems software is the class of programs that controls and supports the computer hardware and its information processing activities. T hree major functional categories of Systems Software : System control programs System support programs System development programs

Operating Systems The main component of systems software is a set of programs collectively known as the Operating System . e.g., Windows 98 Portability means that the same operating system software can be run on different computers.

Operating System Functions Job management is the preparing, scheduling, and monitoring of jobs for continuous processing by the computer system. Resource management is controlling the use of computer system resources employed by the other systems software and application software programs being executed on the computer. Data management is the controlling of the input/output of data as well as their location, storage, and retrieval.

Graphical User Interface The graphical user interface (GUI) is a system in which users have direct control of visible objects (such as icons) and actions that replace complex command syntax. The most well-known GUIs are Windows from Microsoft Corporation and the built-in interfaces in Apple’s computers. Windows 95 is a 32-bit operating system that provides a streamlined GUI that arranges icons to provide instant access to common tasks.

Processing Tasks Operating systems manage processing activities with some processing task management features that allocate computer resources to optimize each system’s assets. The most notable features are: Multiprogramming Multiprocessing Time Sharing

Virtual Memory Virtual Memory allows the user to write a program as if primary memory were larger than it actually is. Users are provided with “virtually” all the primary storage they need. Virtual Machine Operating System is a computer system that appears to the user as a real computer but, in fact, has been created by the operating system. The most popular virtual machine operating system is IBM’s VM/ESA.

System Support Programs System Utility Programs are programs that have been written to accomplish common tasks such as sorting records, merging sets of data, or creating directories and subdirectories. System Performance Monitors supervise computer system performance and produce reports containing detailed statistics concerning the use of system resources. System Security Monitors are programs that monitor the use of a computer system to protect it and its resources from unauthorized use, fraud, or destruction.

Programming Languages 1 st Generation: Machine language is the lowest-level computer language, consisting of the internal representation of instructions and data. 2 nd Generation: Assembly language is a more user-oriented language that represents instructions and data locations by using mnemonics, or memory aids, which people can more easily use.

Programming Languages (cont.) 3 rd Generation: Procedural languages require the programmer to specify—step by step—exactly how the computer will accomplish a task. A language translator converts the high-level program, called source code , into machine language code, called object code . There are two types of language translators : Compilers Interpreters

Programming Languages (cont.) 4 th Generation: Nonprocedural Languages allow the user to specify the desired results without having to specify the detailed procedures needed to achieve the results. 5 th Generation: Natural language programming languages (NLP) translate natural languages into a structured, machine-readable form. 6 th Generation Languages. Some people call advanced machine learning languages 6 th generation languages, yet there are no current commercial languages that are closer to human languages than NLP.

Object-oriented Programming (OOP) Object-oriented programming (OOP) models a system as a set of cooperating objects . The object-oriented approach involves programming, operating systems environment, object-oriented databases, and a new way of approaching business applications.

Concepts of OOP Object-oriented systems view software as a collection of interacting objects . When we refer to an object, we can have two possible meanings, a class or an instance . A class is a template or general framework that defines the methods and attributes to be included in a particular type of object An object is a specific instance of a class, able to perform services and hold data. Objects have data elements that are referred to as attributes , or as variables because their values can change.

Concepts of OOP (cont.) Programming with OOP. Building programs and applications using object-oriented programming languages is similar to constructing a building using prefabricated parts. The same objects can be used repeatedly, a process called reusability . Visual Programming Languages are programming languages that are used within a graphical environment.

Internet Oriented Languages Hypertext Markup Language (HTML) is the standard language the Web uses for creating and recognizing hypermedia documents. Hypertext is an approach to data management in which data are stored in a network of nodes connected by hyperlinks . Uniform Resource Locators (URLs) are used on the WWW to represent hypermedia links & links to network services within HTML documents. Dynamic HTML makes Web pages more like dynamic applications and less like static content.

Lecture

More Related Content

What's hot (17)

Viewers also liked (9)

Similar to Lecture (20)

More from Franklin Go (11)

Lecture