GK About Computer ( Set # 1 )

  

·        One of the earliest machines designed to assist people in calculations was the abacus which is still being used some 5000 years after its invention.

·        In 1642 Blaise Pascal (a famous French mathematician) invented an adding machine based on mechanical gears in which numbers were represented by the cogs on the wheels. Englishman, Charles Babbage, invented in the 1830's a "Difference Engine" made out of brass and pewter rods and gears, and also designed a further device which he called an "Analytical Engine". His design contained the five key characteristics of modern computers:-

1.      An input device

2.      Storage for numbers waiting to be processed

3.      A processor or number calculator

4.      A unit to control the task and the sequence of its calculations

5.      An output device

·        Augusta Ada Byron (later Countess of Lovelace) was an associate of Babbage who has become known as the first computer programmer.

·        An American, Herman Hollerith, developed (around 1890) the first electrically driven device. It utilised punched cards

·        In 1936 Howard Aiken of Harvard University convinced Thomas Watson of IBM to invest $1 million in the development of an electromechanical version of Babbage's analytical engine. The Harvard Mark 1 was completed in 1944 and was 8 feet high and 55 feet long.

·        At about the same time (the late 1930's) John Atanasoff of Iowa State University and his assistant Clifford Berry built the first digital computer that worked electronically, the ABC (Atanasoff-Berry Computer). This machine was basically a small calculator.

·        In 1943, as part of the British war effort, a series of vacuum tube based computers (named Colossus) were developed to crack German secret codes. The Colossus Mark 2 series (pictured) consisted of 2400 vacuum tubes.

·        In the late 1940's John von Neumann (at the time a special consultant to the ENIAC team) developed the EDVAC (Electronic Discrete Variable Automatic Computer) which pioneered the "stored program concept". This allowed programs to be read into the computer and so gave birth to the age of general-purpose computers.

The Generations of Computers

·        The First Generation (1943-1958): This generation is often described as starting with the delivery of the first commercial computer to a business client. This happened in 1951 with the delivery of the UNIVAC to the US Bureau of the Census The main defining feature of the first generation of computers was that vacuum tubes were used as internal computer components..

·        The Second Generation (1959-1964): In the mid-1950's Bell Labs developed the transistor. Transistors were capable of performing many of the same tasks as vacuum tubes but were only a fraction of the size. The first transistor-based computer was produced in 1959. Transistors were not only smaller, enabling computer size to be reduced, but they were faster, more reliable and consumed less electricity. The other main improvement of this period was the development of computer languages.Assembler languages or symbolic languages & Higher level languages .Two higher-level languages developed during this period (Fortran and Cobol) are still in use today though in a much more developed form.

·        The Third Generation (1965-1970): In 1965 the first integrated circuit (IC) was developed in which a complete circuit of hundreds of components were able to be placed on a single silicon chip 2 or 3 mm square. Computers using these IC's soon replaced transistor based machines. IC were much smaller and cheaper. Computers thus became accessible to a much larger audience. the speed of computers increased. Another feature of this period is that computer software became much more powerful and flexible and for the first time more than one program could share the computer's resources at the same time (multi-tasking). The majority of programming languages used today ( C, C++, C#, Java, BASIC and Pascal,) are often referred to as 3GL's (3rd generation languages) even though some of them originated during the 2nd generation.

·        The Fourth Generation (1971-present): In 1970 large-scale integration was achieved where the equivalent of thousands of integrated circuits were crammed onto a single silicon chip. This development again increased computer performance (especially reliability and speed) whilst reducing computer size and cost. Around this time the first complete general-purpose microprocessor became available on a single chip. In 1975 Very Large Scale Integration (VLSI) took the process one step further. Complete computer central processors could now be built into one chip. The microcomputer was born. Such chips are far more powerful than ENIAC and are only about 1cm square whilst ENIAC filled a large building. During this period Fourth Generation Languages (4GL's) have come into existence. Such languages are a step further removed from the computer hardware in that they use language much like natural language. Many database languages can be described as 4GL's. They are generally much easier to learn than are 3GL's.

·        The Fifth Generation (the future): The "fifth generation" of computers were defined by the Japanese government in 1980. The main requirements of the 5G machines was that they incorporate the features of Artificial Intelligence, Expert Systems, and Natural Language.

Computer Terminology

CD-ROM:  This one stands for Compact Disk-Read Only Memory.   CD-ROM disks are becoming the standard for delivering programs from the software developer to the computer user.  CD-ROM's come in a variety of flavors based on the language they are written in (PC, Mac, or Unix).  PC's cannot read a Mac CD-ROM, but Macs can read PC CD-ROMS.
CPU:  The brain of the computer.  This is located on a circuit board inside the desktop or tower computer case.  This component has terms associated with it such as "486", "Pentium" and "Celeron".  Most of the CPU's are manufactured by a company called Intel.  They are the Microsoft of the hardware world.

	Data:  Computer food.  Data can be numbers, letters, symbols, mathematical expressions, mouse clicks, or button presses.  The CPU translates all this activity to  series of zeroes and ones and then performs magic.
	Drivers:  Drivers are software packages that are needed to run certain peripheral devices.  Printers, monitors, scanners, and network cards all require software drivers so that the computer knows how to communicate and control the device.
	486:  An older CPU that was constructed at the beginning of the Windows 95 revolution.  This CPU works great if you are running MS-DOS or Windows 3.1.  In general, this is one of the things that should be considered when purchasing a computer.
	Hard Disk Drive (HDD):  This is the internal magnetic storage device housed inside the computer case.  These come in a variety of sizes, measured in how many bits of information they can contain.  A bit of information equals either zero (0) or one (1).  To a computer, this is equivalent to turning a light switch off (0) or on (1).  Computers operate on bits in groups of 8, called a byte.  Every byte contains 8 bits.  Bits and bytes can be stored magnetically on material that resembles cassette or 8-track recording tape.  The magnetic material stores information as sequences of the digits "0" and "1" (hence the name digital storage).  Since it takes many bytes to store such things as letters, words, and sentences, the amount of information that a Hard Drive can store is measured in multiples of 1000-bytes, 1,000,000 bytes, or 1,000,000,000 bytes.   Terms such as kilobyte (1000 bytes or 1KB), megabyte (1,000,000 bytes or 1MB), and gigabyte (1,000,000,000 bytes or 1GB) have evolved to represent these storage capacities.  When you purchase a computer, get as large a Hard Drive as you can afford.  The standard in 1998 was between 4GB and 8GB.  The Hard Disk Drive is often referred to as the "C:" drive.
	Floppy Diskette:  The floppy diskette is a removable storage device that is used by the Floppy Diskette Drive (also known as the A: drive or FDD).   This storage device is capable of holding 1,440,000 bytes (1.44MB) of data. The Floppy Diskette is inserted and removed from a slotted opening on the front of the computer case.
	Keyboard:  The main tool to get information into the computer and the most common way to tell the computer what you want it to do.  Most keyboards have the same arrangement of keys as a typical typewriter keyboard.  Computer keyboards have additional keys  that perform computer-specific functions.
	Modem:  A telecommunications peripheral device that allows computer to communicate with one another via conventional telephone lines.  Modems are required for home computers  to access the Internet or to send and receive facsimile transmissions (FAX).    Modems are rated by their speed in moving data from the computer to the telephone line.  This speed is measured in bits per second (bps).  Standard modern modems are rated at 28,800 bps, 33,600 bps and 56,400 bps.
	Monitor:  The "T.V" screen that allows you to see what the computer is doing.   Many newcomers to computing mistakenly think of the monitor as the computer itself.   Computers can operate without a monitor, but computer users cannot.
	Motherboard: The circuit board on which most of the major electronic components are situated.  Most manufacturers integrate cable attachment ports on the back-end of the motherboard.  They also include slots so that owners can add their own cable attachment ports.  The slots are designed to accept cards
	Mouse:  A common input device used to tell a computer what it needs to do.  With the invention of the Macintosh and Windows operating systems, computer users needed a device to point at objects on the screen and select them.
	MS-DOS:  An older operating system that powered personal computers through their beginning years.  Prior to the development of the graphics-oriented Macintosh and Windows operating systems, this system relied on typing commands one line at a time to tell the computer what you wanted it to do.  This system is still in use in the Windows family of software and still has many practical uses.  Windows 3.1 relies on MS-DOS to operate.  MS-DOS stands for Microsoft-Disk Operating System.
	Network Card:  A card that can be installed in one of the motherboard slots to give the computer the ability to talk to other computers with similar cards.  A collection of similarly equipped computers connected by specially designed cables is known as a network.  The mechanism (including languages and protocols) used to communicate on a network are varied, but the most common networking designs in use are Ethernet and Token Ring.
	Operating System Software (OS):   The instructions that allow the computer to start working and permit it to run other programs.  The major OS software types include MS-DOS, Windows 3.1, Windows 95, Windows NT, Macintosh, UNIX, and LINUX.   The most popular OS in use at present is Windows 95.  Most computers come with one of these pre-installed.
	Platform:  The computer operating system and/or architecture.  Computers that are capable of running  MS-DOS, Windows 3.1 or Windows95/NT operating system software typically have the Intel 486/Pentium CPU.  Computers running the Macintosh operating system software have a Motorola 68xxx/PowerPC CPU.  For the most part, these platforms are incompatible as they have different rules and instructions for performing their tasks.
	Pentium - Pentium II:  Faster, larger CPU devices that are designed to allow more computing instructions to occur per second.  Most computers manufactured in the past 3 to 4 years contain this device.
	Peripheral Device:  Any device that is connected to the computer in addition to the basic CPU-Monitor-Keyboard-Mouse configuration.  External speakers, microphones, joysticks, printers, and scanners are examples of peripherals.
	Printer:  A peripheral device that allows the computer user to produce paper copies of the information processed by the computer.  Common home printers spray ink on paper and are called ink-jet printers.  Office and school printers are typically laser printers which work on the same principle as a xerographic copy machine, using electrostatic charges and toner cartridges to place information on paper.
	Program:  A complex set of instructions that allow the computer user to process data.  Common programs include word-processing, spreadsheets, databases, drawing and painting, Internet tools, and games.   Programs are necessary for computers to be useful to humans.

Application: Application is another term for software program; basically a program you use on a computer, like Word, TurboTax, Outlook, etc. Bandwidth: A measurement of a data line's transmission speed, or the amount of data a network can transfer from one computer to another in a given amount of time. BIOS: Basic Input/Output System. This term is used to refer to ROM BIOS chip inside the computer. This chip starts and manages the computer bootup process Broadband: A bandwidth term that means a data line that will allow large amounts of data to be transferred very quickly. Basically a broadband line will be much, much faster than an old dial-up line. Burn: To “burn” a CD or DVD means to write data files to it using a special piece of hardware. Bus: A collection of (usually copper) wires through which data is transmitted from one part of a computer to another. You can think of a bus as a "highway" on which data travels within a computer. Cable vs DSL: Cable and DSL are types of broadband data lines. Cable internet access uses the same lines that bring cable television cable to your house, and DSL (Which stands for Digital Subscriber Line) is a type of high speed data compression which runs over plain old telephone service (POTS) lines. MOS: A type of computer chip which is able to operate with a very small amount of electricity from a battery. The term also refers to the contents of a CMOS chip within the computer, which holds information about the computer boot devices, the date and time and its peripherals even while the system is turned off. Computer Resource: This is a general computer terminology for the components that comprise the processing flow of a computer, including the memory, CPU, etc. You might hear someone say "this program is a resource hog", meaning it takes up a lot of the computer processing ability, and might make the computer run slower overall. CPU Sink: CPUs heat up as they work. A CPU sink is a mechanism to keep the CPU cool while it does its calculations. It usually consists of a cooling fan and an aluminum heat sink which draws the heat away the CPU chip. Defrag: Computers write information to a hard drive by filling in open places on the drive. They don’t write files all in one big block, which means your Word document might be spread out all over your hard drive. To defrag your computer means to basically rearrange the files on your computer’s hard drive so that file parts are closer together. Once rearranged, the computer will take less time to access the files. Defragging is usually recommended to speed up a slow computer. IP address: IP (Internet Protocol) addresses are assigned to each and every computer on a TCP/IP network. They work like your home address. Mail or any other package could not get to you if you had no address. IP addresses basically insure that data on a network goes where it is supposed to go. IP addresses look something like this: 192.168.1.25. ISP: Internet Service Provider: This would be the company that provides your internet access. Malware: a general term for any malicious piece of software, such as a virus, worm, or trojan. Network Interface Card (NIC): This is a part of the computer that allows it to talk to other computers (aka, a network) via a network “protocol” or language like TCP/IP. Operating system: This is the basic software that a computer runs on. Windows 98, Windows XP, Windows Vista, Linux, Unix, and Apple’s Mac OS X Leopard are all operating systems. Peripherals: This is a general term for computer add-ons like printers, mice, keyboards, scanners, monitor, etc.. POST: This stands for Power On Self Test. When you first turn on a computer, it checks to make sure all its parts are working; it makes sure a keyboard is attached, that memory loads, and that in general, its hardware is working and ready to load the operating system. This test is called the POST. Processor chip (or just processor): This is the brain of the computer. You’ve probably heard the commercials for the "Intel" chip or the "Xeon" chip. They are talking about the "brain" of the computer, which does all the calculations and task processing. RAM: this stands for Random Access Memory and is used generically as “memory”. This is the memory on a computer that allows you to hold and run a program so that you work with it on the monitor. More RAM is better. At the risk of repeating myself, RAM is dependent on electricity, meaning it is cleared or reset when the computer's power is turned off. So when your computer loses power or freezes up while you are writing an unsaved document, the document is lost. Train yourself to remember to press Control + S to save your documents when you are working on them. Saving them writes them to the hard drive where they will stay when the computer is turned off. ROM: Read Only Memory. Usually seen in conjunction with BIOS, as in ROM BIOS. Usually a chip onto which the information is permanently burned. Also denotes memory that can be accessed and read, but not written to. Routine: A series of instructions written to complete a specific but limited computing task. TCP/IP: Transmission Control Protocol and Internet Protocol. These are the basic data transmission protocols on which the internet and most commercial networks run. Uninterruptible Power Source (UPS): A constantly charging battery which will act as a fail safe if the electricity shuts down while you are using your computer. In the event of a total power failure, a UPS usually has just enough charge to power your computer for the time it takes you to save your work and shut down safely. URL: Universal Resource Locater. The address of any website on the internet. For instance, my website home page has a URL of http://www.sensible-computer-help.com. Worm: A worm is a virus that does not infect other programs. It makes copies of itself, and infects additional computers, usually via network connection. It does not attach itself to other programs, but it might alter, install, or destroy files and programs. It's also used in computer terminology as a short word any malware in general. Software: Computer productivity is determined by programs which are step by step instructions telling the computer how to process data. Software can be divided into two groups,1_system & 2_application 1_ System software - The operation of your computer is controlled by system software. As you boot the computer, the system software is stored in the computer's memory which instructs the computer to load, store, and execute an application. Examples of system software are Windows 95 and Windows 98 which use a graphical user interface (GUI) that provides visual clues (icons) to help the user. DOS, another disk operating system, is text based and not user friendly. 2_Application Software: Professional programmers write a variety of application software to satisfy needs of the public who wants to perform specific tasks on their computers. The basic types of application software are word processing, database, spreadsheet, desktop publishing, and communication. A_Word Processing - Word processing is the most commonly used software in schools, home, and business. A key advantage of word processing software is that users can make changes such as spelling, margins, additions, deletions, and movement of text. A beginning computer student should learn word processing, as it is the basis of most software. Once you have learned how a word processor functions, you will be able to learn other software quicker. B_Database Software - Database software allows us to store and manipulate large quantities of data using the computer. For example, a database can sort the names, addresses, grades and activities for all of the students in a school. It would be possible to add or delete data and produce printed reports using the database. C_Spreadsheet Software - Spreadsheets store numeric data that can be used in calculations. A spreadsheet is used to store a teachers grades and then calculate student averages. The primary advantage of a computerized spreadsheet is its ability to redo the calculations should the data it stores be changed. Calculations can be made automatically as formulas have been preset into the spreadsheet. D_Desktop Publishing - Desktop publishing applications allow the user to create newspapers, newsletters, brochures, and similar types of publications. It is similar to word processing except it allows the user to use text, graphics, pictures, lines, shapes, patterns, and borders. Desktop publishing requires more skill and computer knowledge of design and layout. Non-volatile memory:Will retain the stored information even if it is not constantly supplied with electric power. It is suitable for long-term storage of information. Volatile memory:Requires constant power to maintain the stored information. The fastest memory technologies of today are volatile ones (not a universal rule). Since primary storage is required to be very fast, it predominantly uses volatile memory. Dynamic random-access memory: A form of volatile memory which also requires the stored information to be periodically re-read and re-written, or refreshed, otherwise it would vanish. Static random-access memory: A form of volatile memory similar to DRAM with the exception that it never needs to be refreshed as long as power is applied. (It loses its content if power is removed.) COMPUTER STORAGE 1.      Primary Memory Primary memory is computer memory that a processor or computer accesses first or directly. It allows a processor to access running execution applications and services that are temporarily stored in a specific memory location. Primary memory is also known as primary storage or main memory.  RAM is one of the faster types of memory, and has the capacity to allow data to be read and written. When the computer is shut down, all of the content held in RAM is purged. Main memory is available in two types: Dynamic Random Access Memory (DRAM) and Static Random Access Memory (SRAM). DRAM: Dynamic random access memory (DRAM) is the most common kind of main memory in a computer. It is a prevalent memory source in PCs, as well as workstations. Dynamic random access memory is constantly restoring whatever information is being held in memory. It refreshes the data by sending millions of pulses per second to the memory storage cell. SRAM: Static Random Access Memory (SRAM) is the second type of main memory in a computer. It is commonly used as a source of memory in embedded devices. Data held in SRAM does not have to be continually refreshed; information in this main memory remains as a "static image" until it is overwritten or is deleted when the power is switched off. Since SRAM is less dense and more power-efficient when it is not in use; therefore, it is a better choice than DRAM for certain uses like memory caches located in CPUs. Conversely, DRAM's density makes it a better choice for main memory. Adequate RAM: The CPU is often considered the most important element in the performance of a personal computer. RAM probably comes in a close second. Having an adequate amount of RAM has a direct effect on the speed of the computer. A system that lacks enough main memory to run its applications must rely on the operating system to create additional memory resources from the hard drive by "swapping" data in and out. When the CPU must retrieve data from the disk instead of RAM, it slows down the performance of the computer. Many games, video-editing or graphics programs require a significant amount of memory to function at an optimal level. 2.      secondary memory Secondary memory (or secondary storage) is the slowest and cheapest form of memory. It cannot be processed directly by theCPU. It must first be copied into primary storage (also known asRAM ). Secondary memory devices include magnetic disks like hard drives and floppy disks ; optical disks such as CDs and CDROMs ; and magnetic tapes, which were the first forms of secondary memory. ASCII Acronym for the American Standard Code for InformationInterchange. Pronounced ask-ee, ASCII is a code for representing English characters as numbers, with each letter assigned a number from 0 to 127. For example, the ASCII code for uppercase M is 77. Most computers use ASCII codes to represent text, which makes it possible to transfer data from one computer to another. Introduction to the Internet The Internet The Internet is a vast, electronic network connecting many millions of computers from every corner of the world. A computer connected to the Internet is commonly referred to as a host. Connections are made using telephone lines, cable data lines, fiber-optic, or even wireless signals. This connected-ness allows computers to send and receive information in the form of digitized data on demand. The data is passed back and forth between host computers using packets andprotocols, such as electronic mail (e-mail) for messaging, file transfer protocol (FTP) for moving files, telnet for accessing information, hypertext transfer protocol (HTTP) for serving up Web sites, custom protocols, etc. Other common services of the Internet include the World Wide Web (WWW), Voice Over IP (VoIP), Instant Messaging (IM), streaming media, etc. The Internet itself is decentralized---no one entity is completely responsible or has total control; however, your connection to the Internet is probably controlled by an Internet Service Provider (ISP). When your computer is connected to the Internet you are online. Nowadays one typically has to plug-in to a network outlet, or select an active wireless signal, or dial into a service provider using a modem to get online. Sometimes one must authenticate one's computer with the controlling ISP in order to gain connectivity. The Internet vs. the Web The Internet is not the same as the World Wide Web (WWW or just the Web), though this is a common and understandable misperception. The World Wide Web consists of all the Web sites and pages served on the Internet via HTTP. In addition to the fact that Web pages are served by HTTP, a central identifying feature of Web pages is their use of hyperlinks, which allow a user to quickly move from one web page to another, even if the pages are on different servers in different parts of the world! Though the Web relies on the Internet to connect your web browser to different web servers, the Web is just a part of a number of systems that make up the Internet A Brief History of the Internet The Internet began as ARPANET back in 1969. ARPANET was a large wide-area network created by the United States Department of Defense Advanced Research Project Agency (ARPA). It served as a testbed for new networking technologies. It linked many universities and research centers. The intention here was to ensure that the transfer of information between servers was possible if there was a nuclear attack. The first two nodes that formed the ARPANET were UCLA and the Stanford Research Institute. The third followed shortly thereafter and was established right here in our own back yard at the University of Utah. Sending Data with TCP/IP Protocols are pre-established means of communication. It is just a fancy nerdy way of saying that there is an agreed-upon format for transmitting data between two devices. TCP/IPstands for Transmission Control Protocol/Internet Protocol and is the basic communication language or protocol of the Internet. It can also be used as a communications protocol in a private network. When you are set up with direct access to the Internet, your computer is provided with a copy of the TCP/IP program just as every other computer that you may send messages to or get information from also has a copy of TCP/IP. The term TCP/IP actually refers to a whole family of protocols, of which TCP and IP are just two. The key here is to understand what each does. TCP is the protocol that establishes a virtual connection between a destination and a source. TCP guarantees delivery of data and also guarantees that packets will be delivered in the same order in which they were sent.IP is the protocol that is responsible for packaging the little packets of information and delivering them. TCP/IP uses the client/server model of communication in which a computer user (a client) requests and is provided a service (such as sending a Web page) by another computer (aserver) in the network. The TCP/IP family of protocols are open protocols, meaning they are not proprietary or for-profit. Identifying Computers with IP Addresses In order for host computers to share information there needs to be a way to identify each computer. This is where the IP address comes in. IP stands for Internet Protocol and is metaphorically the postal address of your machine, identifying its location on the Internet. An IP address looks something like this: 199.199.254.254. The problem is that people have a hard time remembering an IP address, so along came Domain Name Services to make it easier on us. DNS: Names are Easier than Numbers Domain Name Services (DNS) attach text to our numeric IP addresses, allowing users to use the DNS as a proxy for the IP address. While IP addresses are often provided by your ISP, one must register a domain name for a cost through a DNS hosting service. DNS host servers then are used to convert our text DNS address to its digital IP address equivalent. For example: 161.28.224.138 is equivalent to www.uvsc.edu 216.239.57.104 is equivalent to www.google.com 66.94.230.41 is equivalent to www.yahoo.com URLs: Where Exactly Do You Want to Go? Universal Resource Locators, otherwise known as URL's, are a more precise way of identifying information on a server. Whereas a DNS simply specifies the general domain name of a server, a URL gives the protocol, the domain, the directory, and even the file. To continue the address metaphor, while a DNS will drop you off at a given location--typically putting you at the front door--a URL will send you to the domain and (if necessary) through the front door, into the room you want to be in, and right onto the chair you want to sit in. A URL consists of the following parts: protocol (such as http:// or ftp://) host name (the Web server's IP address or domain name) directory (i.e. folder) file name Intranets on the Internet Though the name might be confusingly similar to Internet, an Intranet is a subsystem that takes advantage of the larger Internet. An Intranet is a closed network that typically belongs to a specific organization and is accessible only to members of that organization as regulated via some security method. For example, if you were in employee at Novell you would have access to their Intranet, which is dubbed the Innerweb. Novell's Innerweb is a huge collection of web pages from each department. Using the Novell Intranet you could, for example, order food for a meeting from the catering department or request a purchase order from the purchasing department using an online form. How about getting some deals on tickets to local events or places like Lagoon? You can do that too. Only Novell's employees have access to Innerweb--Novell's company Intranet.