Module - 3 Computer Fundamentals, telecommunications, and Networks
Computer System • A system of interconnected computers that share a central storage system and various peripheral devices such as a printers, scanners, or routers. • Each computer connected to the system can operate independently, but has the ability to communicate with other external devices and computers.
First Generation (1940-1956) Vacuum Tubes • The first computers used vacuum tubes for circuitry and magnetic drumsfor memory, and were often enormous, taking up entire rooms. • They were very expensive to operate and in addition to using a great deal of electricity, generated a lot of heat, which was often the cause of malfunctions. • First generation computers relied on machine language, the lowest-level programming language understood by computers, to perform operations, and they could only solve one problem at a time. • Input was based on punched cards and paper tape, and output was displayed on printouts. • The UNIVAC and ENIAC computers are examples of first-generation computing devices. • The UNIVAC was the first commercial computer delivered to a business client, the U.S. Census Bureau in 1951.
Second Generation (1956-1963) Transistors • Transistors replaced vacuum tubes and ushered in the second generation of computers. The transistor was invented in 1947 but did not see widespread use in computers until the late 1950s. • The transistor was far superior to the vacuum tube, allowing computers to become smaller, faster, cheaper, more energy-efficient and more reliable than their first-generation predecessors. • Though the transistor still generated a great deal of heat that subjected the computer to damage, it was a vast improvement over the vacuum tube. Second-generation computers still relied on punched cards for input and printouts for output. • Second-generation computers moved from cryptic binary machine language to symbolic, or assembly, languages, which allowed programmers to specify instructions in words. • High-level programming languages were also being developed at this time, such as early versions of COBOL and FORTRAN. • These were also the first computers that stored their instructions in their memory, which moved from a magnetic drum to magnetic core technology. • The first computers of this generation were developed for the atomic energy industry.
Third Generation (1964-1971) Integrated Circuits • The development of the integrated circuit was the hallmark of the third generation of computers. • Transistors were miniaturized and placed on siliconchips, called semiconductors, which drastically increased the speed and efficiency of computers. • Instead of punched cards and printouts, users interacted with third generation computers throughkeyboards and monitors andinterfaced with an operating system, which allowed the device to run many different applications at one time with a central program that monitored the memory. • Computers for the first time became accessible to a mass audience because they were smaller and cheaper than their predecessors.
Fourth Generation (1971-Present) Microprocessors • Themicroprocessor brought the fourth generation of computers, as thousands of integrated circuits were built onto a single silicon chip. • The Intel 4004 chip, developed in 1971, located all the components of the computer—from the central processing unit and memory to input/output controls—on a single chip. • In 1981 IBM introduced its first computer for the home user, and in 1984 Apple introduced the Macintosh. • Microprocessors also moved out of the realm of desktop computers and into many areas of life as more and more everyday products began to use microprocessors. • As these small computers became more powerful, they could be linked together to form networks, which eventually led to the development of the Internet. • Fourth generation computers also saw the development of GUIs, the mouse and handheld devices.
Fifth Generation (Present and Beyond) Artificial Intelligence • Fifth generation computing devices, based on artificial intelligence, are still in development, though there are some applications, such as voice recognition, that are being used today. • The use of parallel processing and superconductors is helping to make artificial intelligence a reality. • Fifth generation computers will radically change the face of computers in years to come. • The goal of fifth-generation computing is to develop devices that respond to natural language input and are capable of learning and self-organization.
Classification of Computers • According to Size • According to Technology • According to Purpose
According to size • Supercomputers • Mainframe Computers • Minicomputers • Workstations • Microcomputers, or Personal Computers
Supercomputers • Are widely used in scientific applications such as aerodynamic design simulation, processing of geological data. • Supercomputers are the most powerful computers. They are used for problems requiring complex calculations. • Because of their size and expense, supercomputers are relatively rare. • Supercomputers are used by universities, government agencies, and large businesses.
Mainframe Computers • Are usually slower, less powerful and less expensive than supercomputers. • A technique that allows many people at terminals, to access the same computer at one time is called time sharing. • Mainframes are used by banks and many business to update inventory etc. • Mainframe computers can support hundreds or thousands of users, handling massive amounts of input, output, and storage. • Mainframe computers are used in large organizations where many users need access to shared data and programs. • Mainframes are also used as e-commerce servers, handling transactions over the Internet.
Minicomputers • Are smaller than mainframe, general purpose computers, and give computing power without adding the prohibitive expenses associated with larger systems. It is generally easier to use. • Minicomputers usually have multiple terminals. • Minicomputers may be used as network servers and Internet servers.
Workstations • Workstations are powerful single-user computers. • Workstations are used for tasks that require a great deal of number-crunching power, such as product design and computer animation. • Workstations are often used as network and Internet servers.
Microcomputers • Is the smallest, least expensive of all the computers. Micro computers have smallest memory and less power, are physically smaller and permit fewer peripherals to be attached. • Microcomputers are more commonly known as personal computers. • Desktop computers are the most common type of PC. • Notebook (laptop) computers are used by people who need the power of a desktop system, but also portability. • Handheld PCs (such as PDAs) lack the power of a desktop or notebook PC, but offer features for users who need limited functions and small size.
Personal Computers(PC) • DeskTop • Lap Top • Palm Top • PDA
According to Technology • Analog Computers • Digital Computers • Hybrid Computers
According to technology • Analog Computers:- These computers recognize data as a continuous measurement of a physical property ( voltage, pressure, speed and temperature). Example: Automobile speedometer. Amplifiers • Digital Computers:- These are high speed programmable electronic devices that perform mathematical calculations, compare values and store results. • They recognize data by counting discrete signal representing either a high or low voltage state of electricity. Example: voice processing, image processing, word processing etc. • Hybrid Computers:-A computer that processes both analog and digital data. Example: Cardiology
According to Purpose • General purpose Computers • Special Computers • General purpose Computers: A ‘General Purpose Computer’ is a machine that is capable of carrying out some general data processing under program control. • Refers to computers that follow instructions, thus virtually all computers from micro to mainframe are general purpose. Even computers in toys, games and single-function devices follow instructions in their built-in program. • Special purpose Computers: A computer that is designed to operate on a restricted class of problems.
Input and output devices • Input devices • Keyboard • Mouse • Track balls • Touch pads • Pointing sticks • Pen input • Touch screen • Light pen • Digitizer • Graphics tablet • Scanner • Microphone • Electronic white board • Video & Audio cards • Output devices • Monitor • Printers • Audio card • Plotters • LCD projection panels • Computer output microfilm • Speakers • Facsimile (FAX)
What is System Software? • System software refers to the files and programs that make up your computer's operating system. • System files include libraries of functions, system services, drivers for printers and other hardware, system preferences, and other configuration files. • The programs that are part of the system software include assemblers, compilers, file management tools, system utilities, and debuggers. • The system software is installed on your computer when you install your operating system. You can update the software by running programs such as "Windows Update" for Windows or "Software Update" for Mac OS X.
system software • Unlike application programs, however, system software is not meant to be run by the end user. For example, while you might use your Web browser every day, you probably don't have much use for an assembler program (unless, of course, you are a computer programmer). • Since system software runs at the most basic level of your computer, it is called "low-level" software. It generates the user interface and allows the operating system to interact with the hardware. • System software helps use the operating system and computer system. control the operation of computer... • There are 4 types of system software- operating systems, compilers, interpreters and assemblers. Examples of system software's: • BIOS (basic input/output system) • Microsoft Windows • MAC OS X • Linux
Application software • Application software, also known as an application or an "app", is computer software designed to help the user to perform specific tasks. • Examples include enterprise software, accounting software, office suites, graphics software and media players.
Application software classification • Business applications: Microsoft Office, OpenOffice.org • Enterprise software: financial systems, customer relationship management (CRM) systems and supply-chain management software • Educational software: Deliver evaluations (tests), track progress through material, or include collaborative capabilities. • Mobile applications: smart phones, tablet computers, portable media players, personal digital assistants and enterprise digital assistants • Product engineering software : CAD, CAE
Application software classification • Command line interface : DOS, UNIX • A graphical user interface (GUI) is one in which you select command choices from various menus, buttons and icons using a mouse. Microsoft Windows, Mac OS and Ubuntu are common examples of operating systems which bundle one or more graphical user interfaces. • A third party server side application that the user may choose to install in his or her account on a social media site or other Web 2.0 web site, for example a face book app.
Operating systems • A part of system software • O/S is a program which monitors ,controls and maintains the computer. • All computer systems have an operating system. Currently, there are three dominate typical user operating systems. • Macintosh OS, • Microsoft Windows OS, • Linux.
Functions • Process management • Resource management • File management • Communication management • Security management • Memory management
Process management • All process from start to shut down • Booting • Open • Save • Install • Copy • Print • Send ..etc.
Resource management • Installing drivers required for input, output, memory, power, communication devices. • Coordinating among peripherals.
File management • Names, • Folders • Locations, • Attributes, - Size, type, modified, protection, password etc.
Communication management • User- application s/w- hardware. • Connects one computer to another using LAN/WAN. • Command interpretation. • Downloading/uploading
Memory management • Primary RAM-ROM • Secondary – hard disk, CD, DVD, Pen drive Etc.
Security management • Virus management • Alert messages • Dialogue boxes • Firewall • Password/ Access protection
Features of Operating Systems • Software and hardware management • Constant API • Execution of programs • Interruptions • Managing memory • Networking • Security
Software and hardware management • The operating system is the bridge between computer hardware and software and makes the communication between them possible. • Also communication between different software's in the computer is also taken care by operating system.
Constant API • Application Program Interface (API) is a software that allows different applications that run on a computer to work on other computers also. • But they should have same operating system. So it is very vital to have consistent API in the operating system.
Execution of programs • Programs running in the computer are completely dependent on the operating system. • But program execution is a tough process. The multitasking and multithreading features of the operating system are dependent upon the type of program execution feature of O.S.
Interruptions • Interruption may happen at any time while using the computers. So the operating system should allow and handle many numbers of interrupts. • Whenever an interruption occurs, the operating system should respond to it by saving and stopping the current execution and work on the new execution. • This is the most hard-hitting process for the operating system.
Managing memory • The operating system provides the memory for the programs that are executed at any moment. • So the operating system should have good memory allocation facility to execute the programs smoothly. • The prioritization and allocation of memory to the applications running should be taken care by the operating systems.
Networking • Today computers are nothing without internet connection or some network connection. This is the age of networking. • So if computers are connected to a network, the there should be definitely communication between one computer and another. • So the operating system is what makes it possible for one computer to communicate with other computers.
Security • Security is the important feature that should be looked for in an operating system. An operating system in the computer takes care of all security issues of computer and data in it. • Log in passwords, firewall settings, and every such aspect related to security depends on the ability of the operating system. • Some of the computers in network may involve in file sharing, and other data sharing. So it is important in such cases to have powerful secured operating systems.
Business Application Trends • Telecommunications networks now play a vital and pervasive role in Web-enabled… • E-business processes • Electronic commerce • Enterprise collaboration • Other applications that support operations, management, and strategic objectives 6-48
The Internet • A network of networks • Popular uses • E-mail • Instant messaging • Browsing the World Wide Web • Newsgroups and chat rooms
The Internet Revolution • The Internet has become a global information superhighway • Millions of smaller, private networks operating independent of, or in harmony with, each other • 10 servers in 1991 to over 46 million today • Sustained growth in excess of 1 million servers per month • No central computer system • No governing body • Based on common standards 6-50