COMPUTER LITERACY OTS 251D
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Computer Literacy Communications Information OTS 251D 1 The Universal System Model1 Universal System Made of Technology ElyWinn ivninallprli39wsimnle mm m mlirlwmiriwwi WPLl r nu l Du r The slaps lnat lead in a resull The result mar combs out ul m sysiem Comparing me admslmenls a 0 me o39lglnal need Iolneir utsand mu c 2 Input Devices2 Input device From V kipedia the free encyclopedia An in ut device is any peripheral piece of computer hardware equipment used to provide data and control signals to an information processing system such as a computer Input and output devices make up the hardware interface between a computer as a scanner or 6DOF controller TERI MA DI Early devices Unit record equipment Punched card Keyboards A keyboard is a human interface device which is represented as a layout of buttons Each button or key can be used to either input a linguistic character to a computer or to call upon a particular function of the computer Traditional keyboards use springbased buttons though newer variations employ virtual keys or even projected keyboards Examples of types of keyboards include Computer keyboard Keyer Chorded keyboard LPFK Pointing devices A computer mouse httg WWW Scrlbd comd0d2083lQOUl ilversalrs stemsrlvlodel 2 httg el i Wlklgedla orgWlklll igut device Page 7 onA Computer Literacy Communications Information OTS 251D A pointing device is any human interface device that allows a userto input spatial data to a computer In the case of mice and touch screens this is usually achieved by detecting movement across a physical surface Analog devices such as 3D mice joysticks or pointing sticks function by reporting their angle of deflection Movements of the pointing device are echoed on the screen by movements of the cursor creating a simple intuitive way to navigate a computer39s GUI Highdegree of freedom input devices Some devices allow many continuous degrees of freedom as input These can be used as pointing devices but are generally used in ways that don39t involve pointing to a location in space such as the control of a camera angle while in 3D applications These kinds of devices are typically used in CAVEs where input may register 6DOF Composite devices Imaging and Video input devices Video input devices are used to digitize images or video from the outside world into the computer The information can be stored in a multitude of formats depending on the user39s requirement Webcam Image scanner Fingerprint scanner Barcode reader 3D scanner Laser rangefinder Medical Imaging Computed tomography Magnetic resonance imaging Positron emission tomography Medical ultrasonography Audio input devices In the fashion of video devices audio devices are used to either capture or create sound In some cases an audio output device can be used as an input device in order to capture produced sound and then you can play it back Microphone MIDI keyboard or other digital musical instrument Instrument to Computer cords such as the Stealth Plug forthe guitar 3 Output Devicesa An output device is any piece of computer hardware equipment used to communicate the results of data processing carried out by an information processing system such as a computer to the outside world In computing inputoutput or lO refers to the communication between an information processing system such as a computer and the outside world Inputs are the signals or data sent to the system and outputs are the signals or data sent by the 3 httpenwikigediaorgwikiOutgut device Page 2 of 24 Computer Literacy Communications Information OTS 251D system to the outside The most common input devices used by the computer are the keyboard and mouse The keyboard allows the entry of textual information while the mouse allows the selection of a point on the screen by moving a screen cursor to the point and pressing a mouse button The most common outputs are monitors and speakers Graphical user interfaces CAD Computercontrolled milling machines Rapid prototyping Digital image processing Vector graphics vs Raster graphics Graphics card Graphics chip Computer graphics 4 Storage Devices4 Computer data storage often called storage or memory refers to computer components devices and recording media that retain digital data used for computing for some interval of time Computer data storage provides one of the core functions of the modern computer that of information retention It is one of the fundamental components of all modern computers and coupled with a central processing unit CPU a processor implements the basic computer model used since the 19405 In contemporary usage memory usually refers to a form of semiconductor storage known as randomaccess memory RAM and sometimes other forms of fast but temporary storage Similarly storage today more commonly refers to mass storage optical discs forms of magnetic storage like hard disk drives and other types slower than RAM but of a more permanent nature Historically memory and storage were respectively called primary storage and secondary storage The contemporary distinctions are helpful because they are also fundamental to the architecture of computers in general The distinctions also reflect an important and significant technical difference between memory and mass storage devices which has been blurred by the historical usage of the term storage Nevertheless this article uses the traditional nomenclature Purpose of storage Many different forms of storage based on various natural phenomena have been invented So far no practical universal storage medium exists and all forms of storage have some drawbacks Therefore a computer system usually contains several kinds of storage each with an individual purpose A digital computer represents data using the binary numeral system Text numbers pictures audio and nearly any other form of information can be converted into a string of bits or binary digits each of which has a value of 1 or O The most common unit of storage is the byte equal to 8 bits A piece of information can be handled by any computer whose storage space is large enough to accommodate the binary representation of the piece of information or simply data AhttgenwikigediaorgwikiComguter data storage Page 3 of 24 Computer Literacy Communications Information OTS 251D For example using eight million bits or about one megabyte a typical computer could store a short novel Traditionally the most important part of every computer is the central processing unit CPU or simply a processor because it actually operates on data performs any calculations and controls all the other components Without a significant amount of memory a computer would merely be able to perform fixed operations and immediately output the result It would have to be reconfigured to change its behavior This is acceptable for devices such as desk calculators or simple digital signal processors Von Neumann machines differ in that they have a memory in which they store their operating instructions and data Such computers are more versatile in that they do not need to have their hardware reconfigured for each new program but can simply be reprogrammed with new inmemory instructions they also tend to be simpler to design in that a relatively simple processor may keep state between successive computations to build up complex procedural results Hierarchy of storage Various forms of storage divided according to their distance from the central processing unit The fundamental components of a generalpurpose computer are arithmetic and logic unit control circuitry storage space and inputoutput devices Technology and capacity as in common home computers around 2005 Primary storage Direct links to this section Primary storage Main memory Internal Memory Primary storage presently known as memory is the only one directly accessible to the CPU The CPU continuously reads instructions stored there and executes them as required Any data actively operated on is also stored there in uniform manner Historically early computers used delay lines Williams tubes or rotating magnetic drums as primary storage By 1954 those unreliable methods were mostly replaced by magnetic core memory which was still rather 39 l39 39 quot quot a 39 quot was started with the invention of a transistor that soon enabled thenunbelievable miniaturization of electronic memory via solidstate silicon chip technology This led to a modern randomaccess memory RAM It is smallsized light but quite expensive at the same time The particulartypes of RAM used for primary storage are also volatile ie they lose the information when not powered Main memory is directly or indirectly connected to the CPU via a memory bus It is actually comprised of two buses not on the diagram an address bus and a data bus The CPU firstly sends a numberthrough an address bus a number called memory address that indicates the desired location of data Then it reads or writes the data itself using the data bus Additionally a memory management unit MMU is a small device between CPU and RAM recalculating the actual memory address for example to provide an abstraction of virtual memory or other tasks As the RAM types used for primary storage are volatile cleared at start up a computer containing only such storage would not have a source to read instructions from in order to start the computer Hence nonvolatile primary storage containing a small startup program BIOS is Page 4 of 24 Computer Literacy Communications Information OTS 251D used to bootstrap the computer that is to read a larger program from nonvolatile secondary quot A 39 u u r r 39 39 quot ROM for A 39 o who 39 r r mm lvne are also capable of random access Many types of quotROMquot are not literally read only as updates are possible however it is slow and L L r m r similart t o r r39 rather use large capacities of secondary storage which is nonvolatile as well and not as costly Frlmary storage Central processan unlt 1 lnpmlompm channels Secondary storage Offrllrle storage Cornoutergtoragegyoeeevg eve llle nominally 705 x 1005 pixels nle 12233 KB Secondary storage A hard disk drive with protective cover rem d Secondary storage in popular usage differs fro a a tr m Th m primary storage in that it is not directly enumpuiei u wquot 39 39 r r L 39 om om quot quot 39 39 r 4 quotis nonvolatile er unitit39 r or 39 39 39 ag nnseniienllv quot r r39 nu an m r of quot storage than primary storage and data is kept for a longertime there ag The time taken second or milliseconds By contrast the time taken to access argiven byte of information stored Page 5 on4 Computer Literacy Communications Information OTS 251D in random access memory is measured in billionths of a second or nanoseconds This illustrates the very significant accesstime difference which distinguishes solidstate memory from rotating magnetic storage devices hard disks are typically about a million times slower than memory Rotating optical storage devices such as CD and DVD drives have even longer access times Some other examples of secondary storage technologies are flash memory eg USB flash drives or keys floppy disks magnetic tape paper tape punched cards standalone RAM disks and lomega Zip drives The secondary storage is often formatted according to a file system format which provides the abstraction necessary to organize data into files and directories providing also additional information called metadata describing the owner of a certain file the access time the access permissions and other information Most computer operating systems use the concept of virtual memory allowing utilization of more primary storage capacity than is physically available in the system As the primary memory fills up the system moves the leastused chunks pages to secondary storage devices to a swap file or page file retrieving them later when they are needed As more of these retrievals from slower secondary storage are necessary the more the overall system performance is degraded Tertiary storage Large tape library Tape cartridges placed on shelves in the front robotic arm moving in the back Visible height of the library is about 180 cm Tertiary storage or tertiary memory1 provides a third level of storage Typically it involves a robotic mechanism which will mount insert and dismount removable mass storage media into a storage device according to the system39s demands this data is often copied to secondary storage before use It is primarily used for archival of rarely accessed information since it is much slower than secondary storage eg 5 60 seconds vs 110 milliseconds This is primarily useful for extraordinarily large data stores accessed without human operators Typical examples include tape libraries and optical jukeboxes When a computer needs to read information from the tertiary storage it will first consult a catalog database to determine which tape or disc contains the information Next the computer will instruct a robotic arm to fetch the medium and place it in a drive When the computer has finished reading the information the robotic arm will return the medium to its place in the library Offline storage Offline storage also known as disconnected storage is a computer data storage on a medium or a device that is not under the control of a processing unit2 The medium is recorded usually in a secondary or tertiary storage device and then physically removed or disconnected It must be inserted or connected by a human operator before a computer can access it again Unlike tertiary storage it cannot be accessed without human interaction Offline storage is used to transfer information since the detached medium can be easily physically transported Additionally in case a disaster for example a fire destroys the original data a medium in a remote location will be probably unaffected enabling disaster recovery Off Page 6 of 24 Computer Literacy Communications Information OTS 251D line storage increases general information security since it is physically inaccessible from a computer and data confidentiality or integrity cannot be affected by computerbased attack techniques Also if the information stored for archival purposes is accessed seldom or never offline storage is less expensive than tertiary storage In modern personal computers most secondary and tertiary storage media are also used for off line storage Optical discs and flash memory devices are most popular and to much lesser extent removable hard disk drives In enterprise uses magnetic tape is predominant Older examples are floppy disks Zip disks or punched cards 5 Adaptive Technologies for users with disabilities in the workplace httpwww makna 39 A 1 a 6 Function of Operating Systems What is an Operating System The operating system is the core software component of your computer It performs many functions and is in very basic terms an interface between your computer and the outside world In the section about hardware a computer is described as consisting of several component parts including your monitor keyboard mouse and other parts The operating system provides an interface to these parts using what is referred to as quotdriversquot This is why sometimes when you install a new printer or other piece of hardware your system will ask you to install more software called a driver What does a driver do A driver is a specially written program which understands the operation of the device it interfaces to such as a printer video card sound card or CD ROM drive It translates commands from the operating system or user into commands understood by the component computer part it interfaces with It also translates responses from the component computer part back to responses that can be understood by the operating system application program or user The below diagram gives a graphical depiction of the interfaces between the operating system and the computer component Operating System Interfaces k mans Video Card Maniinx hymn Other Operating System Functions Page 7 of 24 Computer Literacy Communications Information OTS 251D The operating system provides for several other functions including System tools programs used to monitor computer performance debug problems or maintain parts of the system A set of libraries or functions which programs may use to perform specific tasks especially relating to interfacing with computer system components The operating system makes these interfacing functions along with its other functions operate smoothly and these functions are mostly transparent to the user Operating System Concerns As mentioned previously an operating system is a computer program Operating systems are written by human programmers who make mistakes Therefore there can be errors in the code even though there may be some testing before the product is released Some companies have better software quality control and testing than others so you may notice varying levels of quality from operating system to operating system Errors in operating systems cause three main types of problems System crashes and instabilities These can happen due to a software bug typically in the operating system although computer programs being run on the operating system can make the system more unstable or may even crash the system by themselves This varies depending on the type of operating system A system crash is the act of a system freezing and becoming unresponsive which would cause the user to need to reboot Security flaws Some software errors leave a door open for the system to be broken into by unauthorized intruders As these flaws are discovered unauthorized intruders may try to use these to gain illegal access to your system Patching these flaws often will help keep your computer system secure How this is done will be explained later Sometimes errors in the operating system will cause the computer not to work correctly with some peripheral devices such as printers Operating System Types There are many types of operating systems The most common is the Microsoft suite of operating systems They include from most recent to the oldest Windows XP Professional Edition A version used by many businesses on workstations It has the ability to become a member of a corporate domain Windows XP Home Edition A lower cost version of Windows XP which is for home use only and should not be used at a business Windows 2000 A better version of the Windows NT operating system which works well both at home and as a workstation at a business It includes technologies which allow hardware to be automatically detected and other enhancements over Windows NT Windows ME A upgraded version from windows 98 but it has been historically plagued with programming errors which may be frustrating for home users Windows 98 This was produced in two main versions The first Windows 98 version was Page 8 of 24 Computer Literacy Communications Information OTS 251D plagued with programming errors but the Windows 98 Second Edition which came out later was much better with many errors resolved Windows NT A version of Windows made specifically for businesses offering better control over workstation capabilities to help network administrators Windows 95 The first version of Windows after the older Windows 3x versions offering a better interface and better library functions for programs There are other worthwhile types of operating systems not made by Microsoft The greatest problem with these operating systems lies in the fact that not as many application programs are written for them However if you can get the type of application programs you are looking for one of the systems listed below may be a good choice Unix A system that has been around for many years and it is very stable It is primary used to be a server rather than a workstation and should not be used by anyone who does not understand the system It can be difficult to learn Unix must normally run an a computer made by the same company that produces the software Linux Linux is similar to Unix in operation but it is free It also should not be used by anyone who does not understand the system and can be difficult to learn Apple Macintosh Most recent versions are based on Unix but it has a good graphical interface so it is both stable does not crash often or have as many software problems as other systems may have and easy to learn One drawback to this system is that it can only be run on Apple produced hardware 7 Computer Operating Systems5 Multiple Computer Operating Systems in existence how many do you know of Proprletary Open source clorle avallable s Publlc Commodore TRlPOS asthe dlsk Workstation Home Proprletary Open sou ce clorle avallable s Publlc Arnlga lrlo 4 0 bundled Wlth hardware 4 0 VI rkstationY Home Workstation NetApp 5httgenwikigediaorgwikiComgarison of operating systems Page 9 of 24 Computer Literacy Communications Information OTS 251D TONaldSet GNU LGPL Bundled Wlth 68K and PowerPC Bundled Wlth hardware upgrades Open source core 13 Family Pack 9 229 5 User Mac Box Set 49 5 uUser Mac OS X Mac OS X Windows 28 Microso Windows NT Page 10 of 24 of Linux Workstation Home source core system Both Intel and PowerPC versions APSL GNU GPL others with proprietary higher level API Workstation Server Embedded Workstation Home Desktop me la center Tablet PC Computer Literacy Communications Information OTS 251D educational home Home Desktop Workstation cross STOP 6 domain solution Workstation Home 8 Command Driven6 Refers to programs and operating systems that accept commands in the form of special words or letters In contrast programs that allow you to choose from a list of options in a menu are said to be menu driven Commanddriven software is often more flexible than menudriven software but it is more difficult to learn 9 Graphical Operating System7 GEOS Graphic Environment Operating System was an operating system from Berkeley Softworks later GeoWorks Originally designed for the Commodore 64 and released in 1986 it provided a graphical user interface for this popular 8bit computer GEOS is currently owned and distributed by Breadbox Computer Company LLC at httpwwwbreadboxcom GEOS closely resembled early versions of Mac OS and included a graphical word processor geoWrite and paint program geoPaint For many years Commodore bundled GEOS with its redesigned and cost reduced C64 the C64C At its peak GEOS was the third most popular operating system in the world in terms of units shipped trailing only MSDOS and Mac 08 Other GEOScompatible software packages were available from Berkeley Softworks or from third parties including a reasonably sophisticated desktop publishing application called geoPublish and a spreadsheet called geoCalc While geoPublish was not as sophisticated as Aldus Pagemaker and geoCalc not as sophisticated as Microsoft Excel the packages provided reasonable functionality and Berkeley Softworks founder Brian Dougherty claimed the company ran its business using its own software on Commodore 8bit computers for several years Enhanced versions of GEOS later became available for the Commodore 128 and the Apple II family A lesserknown version was also briefly released for the Commodore Plus4 Written by a group of programmers led by Dougherty who cut theirteeth on limitedresource video game machines such as the Atari 2600 GEOS was revered for what it could accomplish on machines with 64 128 kB of RAM memory and 1 2 MHz of 8bit processing power 6 httgwwwwebogediacomTERMICcommand drivenhtml 7httgenwikigediaorgwikiGEOS 8bit operating system Page 11 of 24 Computer Literacy Communications Information OTS 251D Unlike many pieces of proprietary software for the C64 and C128 GEOS took full advantage of many of the addons and improvements available for these systems Commodore39s 1351 mouse was supported by GEOS as were its various RAM expansion units GEOS 128 also fully supported the C12839s 640gtlt200 highresolution VDC display mode through a compatible RGB monitor The C64 version of GEOS incorporated a builtin fast loader called diskTurbo that significantly increased the speed of drive access on the slow 1541 GEOS 128 could take advantage of the C12839s enhanced quotburst modequot in conjunction with the 1571 and 1581 drives Via Berkeley39s special geoCable interface converter or other thirdparty interfaces to connect standard RS232 or Centronics printers to the Commodore serial bus GEOS supported a wide variety of printers including HP PCL printers and the Apple LaserWriter This ability to print to highend printers was a major factor in making GEOS a desktop publishing platform The Apple II version of GEOS was released as freeware in August 2003 The Commodore 64128 versions followed in February 2004 The Apple II version is freely available for download from Breadbox at httpwwwbreadboxcom The latest GEOS desktop suite is Breadbox Ensemble Revivals were seen in the HP OmniGo handhelds Brother GeoBook line of laptopappliances and the New Deal Office package for PCs Related code found its way to earlier 39Zoomer39 PDAs creating an unclear lineage to Palm lnc39s later work Nokia used GEOS as a base operating system fortheir Nokia Communicator series before switching to EPOC Symbian 10 Trends in Operating System Development Faster Computers Permit New Applications The rapid increase in computer power creates new software opportunities such as photo and video editing Most developers of user applications create successive versions of the same product taking advantage of greater computer speed to improve products by making them faster or capable of handling new functions Foreign Staff Outsourcing Because the high cost of US programmers some software companies are outsourcing part of their production work to other countries especially India Developments in communication technology and software that allows multiple users to collaborate have made foreign outsourcing easy Linux Linux is an operating system with quotopen source codequot that is all parts are open to users to examine and modify if they desire The source code for Windows operating systems is a closelyguarded secret Linux is a lowcost and powerful alternative to proprietary versions of UNIX that are used to operate computer servers and has become more popular in recent years Video Games One software sector with high growth in recent years is video game development The US retail market for video games is new larger than the movie industry Companies develop video games for PCs and various quotconsolesquot specialty computers like PlayStation Xbox and GameCube made by Sony Microsoft and Nintendo respectively US retail sales of video games were over Page 12 of 24 Computer Literacy Communications Information OTS 251D 10 billion in 2005 according to the NPD Group whose tally includes console and portable hardware software and accessories Video Game Producers Depend on Hits Because of the high cost to develop and market computer games with the sophisticated visual features demanded by consumers sales of individual games must also be high Most revenue for new games comes within 60 to 90 days of release Copyright Protection Copyright infringement and piracy are widespread in the computer software industry because of the ease of copying most products and the difficulty of detecting copyright infringement While software companies try to build antipiracy features into their products or into computers themselves consumers have resisted these moves because they usually make products more difficult to use To ensure authenticity some software is now sold in a nonfunctional form and must be quotactivatedquot by connection with a company Internet site Distribution Costs8 Between 1994 and 1998 SONY migrated all of their repair manuals schematics diagrams and documentation to PDF in order to reduce printing and distribution costs Although this initiative effectively saved the company time and money they soon found that the electronic format had several disadvantages PDF was not suitable for displaying complex schematics because they were difficult to view on a monitor Users were unable to trace the countless connecting lines between components or to determine a part s description Navigating the content in the PDF files was a great challenge and it took an enormous amount of time Furthermore the average document size ranged from 150 to 175 pages so it was counterproductive to require users to print the schematics and physically highlight the connections By 2004 it was evident that SONY needed a method to help make their documentation readable and easier to view 11 Communicating with Computersg Providing various ways to communicate including emailing and instant messaging the Internet is a time and cost efficient tool for all companies The following guide can help with selection of connections and Internet services right for your office The Internet has been touted for its ECommerce capabilities Predictions have been made of the complete migration from instore phone and fax purchasing to complete online buying in just a few years Fortunately this view of the world has proven too optimistic and unreasonable ECommerce undoubtedly will grow However the lnternet39s viability as a lowcost datavoice communications vehicle is overlooked E httgwwwgdfonlinecomeasygdfsdksuccess storieshtm 9 David Frea quotCommunicating through computersquot Gases amp Welding Distributor FindArticIescom 20 Sep 2009 httn39lfinrlartirle 39 39 mOBFE s 5 47ai n27665513 Page 13 of 24 Computer Literacy Communications Information OTS 251D The Transmission Control ProtocolInternet Protocol TCPIIP developed in the late 19605 by the Department of Defense has become the de facto standard fortransmitting packets of information between separate computers lPbased communications package each block of data and transmit it through a series of routes to its final destination As such it enables multiple devices to communicate through the same circuit consecutively Furthermore the networks are redundant If one route between devices is unavailable the packet is rerouted automatically through alternate channels The Old WayLeased Data Circuits Traditional approaches to data communications to distributor39s branches has revolved around telephonebased dedicated data circuits These circuits while reliable were generally low in handwidth and expensive Variations included 9600 baud 96K hand analog pointtopoint 4 wire leased lines and 56000 baud 56K baud digital circuits Frame Relay circuits served a role too especially in geographically diverse areas In fact Frame Relay is a proprietary version of the Internet developed by telephone companies and sometimes it offers substantial savings over pointtopoint circuits Even dialup phone lines have been used for branch connectivity provided they are local and do not incur longdistance toll charges Costs for these pointtopoint circuits range between 50 per month for simple dialup to nearly 1000 per month for higher speed data circuits especially when they cross telephone company borders The costs have been held high due to tariffs and fees imposed by the local phone monopolies TerminalsPrinters vs lPBased Devices Equipment used on Leased Data Circuits generally used quotserial communicationsquot and required a onetoone connection between the host computer and terminal devices Examples range from simple terminals also known as quotdumbquot terminals and printers to more sophisticated IP based devices retrofitted to communicate via quotserialquot protocols Multiplexers are often used to support multiple serial devices over a single data circuit Communication equipment modems DSU39s multiplexors costs are moderately high but terminal equipment is affordable simple and easily maintained The use of lPbased networking in general and the Internet in specific as a vehicle to serve the internal needs of a business has brought forth a new nomenclature the intranet Remote Internet Terminal Access Remote Internet Terminal Access RITA also known as quottelnetquot represents a method of communicating between computers The remote computer acts as a simple data en trydisplay device with the host computer processing all keystrokes and controls access to the software and data This information technology architecture is prevalent in today39s mainframe or legacy systems While the remote user39s device must support lPbased protocols Le a Window39s PC the RITAtelnet protocol sends remote user traffic over the user39s Internet connection The advantage is the remote user can make a local call to an Internet Service Provider as opposed to a long distance call to the corporate system or use an expensive leased line This solution is ideal for a telecommuter or mobile sales force Page 14 of 24 Computer Literacy Communications Information OTS 251D Security concerns exist for simple RITAtelnet as the communications is unencrypted and could quot quot quot be 39 H 39on by 39 individuals Good hardwarebased firewalls should be employed to protect your sewers allowing only RITAtelnet services through This can be a restriction ifthe technology architecture requires use of other network services Furthermore loginpasswording must be well managed on the servers so that only authorized users can gain access Virtual Private Network VPN Forthose requiring better security VPN offers encrypted communications between devices Both ends of a VPN connection must use a common encryption key also known as a quotprivate keyquot Then the devices use that private key to encrypt all packets exchanged between them This technology is believed to be secure and reliable VPN TunnelingWide Area Network VPNs provide their services through the ability to quottunnelquot through the Internet Not only are the communications encrypted the two networks are connected in a virtual quotWide Area Networkquot WAN configuration This allows secure exchange of all types of networkedbased services from file and print sharing to Network File Systems NFS A correctly configured WAN can provide all services typically associated with a Local Area Network LAN and can save money in line costs and reduce overall expenses Other Networking Services Internet access also has a whole range of additional services many of which add great value to distributors information management technology Some of these services are Web BrowsingWeb Browsing enables PC users to visit manufacturers39 websites for product information and the ability to place orders Liquid Computing Showcases Converged Communications and Computing Platform at High performance computing and communications proceedings Networks security wireless communications and trusted computing EmailThis correspondence can replace phone calls to branches and the long distance toll charges they incur The ability to send email to multiple parties at the same time reduces duplicate efforts and increases awareness amongst all recipients Instant MessagingThis newest form of instant nonverbal communications rivals the telephone in its ability to interrupt and demand instant answers from quotbuddiesquot logged in anywhere on the Internet Care should be exercised when implementing this technology as abuse is easy and sometimes difficult to police Users can appear to be working on company business while actually chatting online VoiceOverlnternetProtocol VOIDVOP phones connect the handsets in the branch to the Page 15 of 24 Computer Literacy Communications Information OTS 251D main phone system in the central office Phone conversations are digitized and packaged for transmission through the Internet No more long distance toll charges to call the branch office Better yet with some phone systems the remote handset can operate as a full function telephone capable of accessing voice mail and transferring calls With a VOIP network a company can save money on interbranch long distance toll charges Types of ConnectionsnOne of the tremendous advantages of IP communications is their ability to utilize a variety of Internet connections T1 circuits provide the highest bandwidth available 1500K baud and at the highest price point too 9001500 per month DSL Digital Subscriber Line and cable modems offer similar broadband speeds at considerable price savings 80200 per month over T1 lines These circuits generally offer 128K baud 768K baud upload speeds with faster download speeds Even simple 56K baud dialup circuits offered by local Internet Service Providers can be used for 1525 per month plus the cost of the phone line However 56K baud dialup lines should he considered only as a last resort for small branches Furthermore static IP addresses are rarely available with dialup circuits and therefore don39t suffice for the main office connection Fulltime access is needed at the main office with the ability to connect at any hour of the day or night and the server needs to he online to take the call That Internet connection will require a publicly accessible quotstatic IP addressquot Within the Internet an IP address is akin to your telephone number Many dialup Internet connections are given a new quotDynamicquot IP address each tune the connection is established Just like in the telephone world it is difficult to receive incoming phone calls if your phone number changed every time it was used That is true for the Internet world it is difficult to connect to your server if it39s IP address is subject to change Hence a quotstatic IP addressquot doesn39t change overtime Pitfalls DSL and cable companies are struggling to ramp up to the demand for new lowcost broadband offerings and often promise services or installation schedules not met Research broadband availability and arrange its installation prior to disconnecting existing legacy equipment Longterm contracts for broadband service should be avoided if possible as costs continue to drop dramatically by vendors competing for market share Today39s quotbargainquot will certainly be overpriced in time New lPbased PC hardware is generally more expensive to buy and maintain than its quotdumbquot terminal counterpart Organizations must consider the deployment and maintenance costs for the new more sophisticated platform Case Study A mediumsized independent welding supplyindustrial gas distributor with three branches within 150 miles of the main office all a longdistance toll call to each other had traditional four wire 9600 baud analog leased lines to connect dumb terminals and printers in the branches to the mainframe system Performance of the devices were acceptable but newer technologies for Internet access were nonexistent Communication costs for the lines was about 1300 per month Page 16 of 24 Computer Literacy Communications Information OTS 251D A severe storm at one of the branches destroyed most of the serial communications hardware and dumb terminalsprinters so alternatives were investigated Fiftysix K baud digital pointto point circuits were initially promoted by the incumbent telco but had no significant cost savings or enhanced functionality The Frame Relay circuits did reduce the overall monthly cost slightly but required the a transition to lPbased terminal devices thereby making the investment paybacklong RITA plus VPN was investigated to connecting the branches though the Internet A typical DSL connection was about 79 per month per location with an 20 per month fee for the required static IP address at the main office One branch was not served by DSL or cable therefore 56K baud dialup was implemented about 50 per month Total monthly communication costs are now 300 yielding a savings of 1 000 per month This savings can be applied to the cost of the new lPbased PCs communications hardware and print sewers needed at the branches with a projected payback period of less than two years The additional benefits include Internet access email instant messaging between the branches and reduced long distance toll charges David J Frea is president of lnfonetics Inc He can be reached by phone at 6148752006 or email at d39finfonetxcom 12 Using Computers as Communication toolsquot The following are excerpts from a webposted paper providing insights on how one entity used the computer as a communication tool to reach a target population Communication is a skill which is used to provide and receive information How one receives and provides this information is one issue the other is what information is being provided or received At a basic human level communication can exist through verbal or nonverbal cues such as what is said how we say it and the position of our bodies What makes communication effective is the ability of the provider to have the skills and tools available to send information and the receiverto also have to the skills and tools to obtain the information Throughout the history of humankind communication has evolved from using basic sounds and visual images such as drumming or cave drawings to more advanced sounds such as music language and sirens and visually through written language The tools which make communication effective have also evolved The inventions of the telephone and printing press changed dramatically how people could communicate with each other as distance was no longer an obstacle and through books and newspapers numerous peoples could be reached Television film and radio has also created a medium by which communication could be provided The media of television newspapers radio have also been stifled as an completely effective tool of communication as these have always been owned by a source usually capitalist therefore the actual information is either edited or censored in order to meet the needs of the owners be it state or private Since the digital revolution of the 197039s new technology has changed the way in which information can be providedreceived How this technology works is not necessarily required in m THE TRADE UNION MOVEMENT AND THE INTERNET by Marie Dancsok Final Project Year II European Labour Studies South Bank University For Richard Ross June 26 1996 httgwwwabournetorguksbuinternethtm Page 17 of 24 Computer Literacy Communications Information OTS 251D order to discuss the fact that a product of technology the computer is being utilized to communicate Within capitalism time is of most importance as the more produced within a shorter period of time the more surplus value therefore the higher profit quotA fundamental prerequisite of the evolution of international production and of the transnational corporation is the technologies which overcome the frictions of space and timequot1 Through the use of computers as a tool of communication capitalism has been able to decrease the amount of time and increase 39 quot 1 an quot has 39 39 into international markets having further developed a global economy The information highway is a result of this internationalization and globalization of the economy quotThe highway is a webwork of powerful high capacity computercommunications networks capable of handling everything from video to voice text to computer data and graphics interchangeably interactively and at lightning speedsquot2 This information highway does to the technological revolution what the railway did forthe industrial revolution by changing the infrastructure of the economy Similar to the mass media the information highway is also predominantly owned by capitalism and uses it only to its own advantages therefore communication is used for transmission purposes only not necessarily as a public service The information highway is also utilized as tool for consumerism and information receiving thus creating only a one way path as the public does yet have the resources or the money to compete on the scale of the large corporations Not only is the tool which is used important in communication but also the information which is put into the system As described above the capitalists use the information highway in a transmission model that is information becomes a product or commodity3 Anotherform of information is the communitycommunications model4 that is information which is used for public service where time isn39t money and where everyone and anyone has access to provide andor receive information which may benefit all Within the information highway is 39The Internet39 which provides a forum for anyone to communicate by computer quot the Internet represents an alternative infrastructure model for the postindustrial society A network of networks including community freenets public discussion groups and organizational Websites and related home pages of multimedia information The Internet offers a userdriven infrastructuredevelopment path more along the lines of community communications than commodity transmissionquot The Internet is inexpensive to access but one does need a computer and hardware and software in order to use the service to it39s most advantage The capitalists are using the computer as tool to enhance their agenda of increased production with decreased time and therefore having effects such as structural changes to their companies These changes include redundancies segregation of the workforce and with segregation of the workforce comes a decline of working conditions and increased unemployment The workforce represented by trade unions need to also utilize the computer as Page 18 of 24 Computer Literacy Communications Information OTS 251D a form of communication in order to work at the same level as the capitalists and to fight back against the decline in working conditions and mass unemployment The following project will consider the utilization of computers as a tool of communication for the trade union movement Workers throughout the world can now be in control of receiving and providing information via the most democratic form of communication The Internet The five major components of the Internet are email mailing lists conferences the World Wide Web and the transfer of information between each other Anyone can have access to information viaemail anyone can be placed on mailing lists and global conferences can be held on the Internet Noone can stop people from accessing retrieving and reading information on the Internet The cost of engaging on the Internet can cost less than post fax and telexes which then makes access easier The trade union movement has been slow to realize the potential of the Internet but for those who have grasped the Internet it has become a tool which even the most disillusioned person could see its benefits One of the premier networks began in 1986 in Canada SOLINET Solidarity Computer Conferencing Network was created by Marc Belanger for CUPE Canadian Union of Public Employees and begun with only 1500 users which included CUPE locals and other unions Solinet was found 39to create a sense of community among CUPE locals by providing them with news information and support396 The network has acted as a model for other trade unions to get on line due to it39s successfulness Not only is the network a valuable tool for it39s members but also internationally since it39s creation of a World Wide Web page Another dominant network in the Labour pages of the World Wide Web is the American 39ICG Labornet39 which was established in 1992 It provides bulletin boards conferences and links to many labour organisations throughout the world It provides a forum where trade unionists from Russia can communicate freely with trade unionists from Britain etc etc The possibilities are endless 13 World Wide Web Resources11 Following is a small portion of WW search engine tools available to anyone with access to an Internet Service Provider ISP within a freeinformation market country M 1mgenWikigediaprgwikiList of search engines Page 19 of 24 Computer Literacy Communications Information Fall 2009 OTS 251D 20334 OTS 251D 20333 BY CONTENTTOPIC General Je Baidu Chinese Bing formerly MSN Search and Live Search Cuil Duck Duck Go Askcom formerly Ask eves Google Sogou Chinese Yahoo earch Yandex Russian Businesscom GlobalSpec Nexis Lexis Nexis Thomasnet United States Enterprise See also Enterprise search AskMeNow S3 Semantic Search Solution Concept Searching Limited concept search Navigation dtSearch dtSearch EngineSDK dtSearch Web Endeca Information Expert System SpA Cogito Fast Search amp Transfer Enterprise Search Platform ESP RetrievalWare formerly C vera Funne back Funnelback lSYS Search Software ISYSweb ISYSsdk Microso SharePoint Search Services Northern Light Open Text Hummingbird Search Server Livelink Information Access Platform MobileHandheld Taptu ta tu mobilesocial search Search Appliances roducts Google Google Search Business Dieselpoint Search amp Search Appliance 14 Computer Networks12 A computer network is a group of interconnected computers Networks may be classified according to a wide variety of characteristics This article provides a general overview of some types and categories and also presents the basic components of a network Connection method Computer networks can also be classified according to the hardware and software technology that is used to interconnect the individual devices in the network such as Optical fiber Ethernet Wireless LAN HomePNA Power line communication or Ghn Ethernet uses physical wiring to connect devices Frequently deployed devices include hubs switches bridges andor routers Wireless LAN technology is designed to connect devices without wiring These devices use radio waves or infrared signals as a transmission medium ITUT Ghn technology uses existing home wiring coaxial cable phone lines and power lines to create a highspeed up to 1 Gigabits local area network Wired Technologies TwistedPair Wire This is the most widely used medium for telecommunication Twistedpair wires are ordinary telephone wires which consist of two insulated copper wires twisted into pairs and are used for both voice and data transmission The use of two wires twisted together helps to reduce crosstalk and electromagnetic induction The transmission speed range from 2 million bits per second to 100 million bits per second Coaxial Cable These cables are widely used for cable television systems office buildings and other worksites for local area networks The cables consist of copper or aluminum wire wrapped with insulating layer typically of a flexible material with a high dielectric constant all of which are surrounded by a conductive layer The layers of insulation help minimize interference and distortion Transmission speed range from 200 million to more than 500 million bits per second Fiber Optics These cables consist of one or more thin filaments of glass fiber wrapped in a protective layer It transmits light which can travel over long distance and higher bandwidths 12 httpenw kigediaorgw kiComguter network Page 20 of 24 Computer Literacy Communications Information Fall 2009 OTS 251D 20334 OTS 251D 20333 Fiberoptic cables are not affected by electromagnetic radiation Transmission speed could go up to as high as trillions of bits per second The speed of fiber optics is hundreds of times faster than coaxial cables and thousands of times faster than twistedpair wire Terrestrial Microwave Terrestrial microwaves use Earthbased transmitter and receiver The equipment look similar to satellite dishes Terrestrial microwaves use lowgigahertz range which limits all communications to lineof sight Path between relay stations spaced approx 30 miles apart Microwave antennas are usually placed on top of buildings towers hills and mountain peaks Communications Satellites The satellites use microwave radio as their telecommunications medium which are not deflected by the Earth39s atmosphere The satellites are stationed in space typically 22000 miles above the equator These Earthorbiting systems are capable of receiving and relaying voice data and TV signals Cellular and PCS Systems Use several radio communications technologies The systems are divided to different geographic area Each area has lowpower transmitter or radio relay antenna device to relay calls from one area to the next area Wireless LANs Wireless local area network use a highfrequency radio technology similar to digital cellular and a lowfrequency radio technology Wireless LANS use spread spectrum technology to enable communication between multiple devices in a limited area Example of openstandard wireless radiowave technology is lEEE 8021 1 b Bluetooth A shortrange wireless technology Operate at approx 1Mbps with range from 10 to 100 meters Bluetooth is an open wireless protocol for data exchange over short distances The Wireless Web The wireless web refers to the use of the World Wide Web through equipments like cellular phones pagersPDAs and other portable communications devices The wireless web service offers anytimeanywhere connection Types of networks Below is a list of the most common types of computer networks in order of scale Personal area network A personal area network PAN is a computer network used for communication among computer devices close to one person Some examples of devices that are used in a PAN are printers fax machines telephones PDAs and scanners The reach of a PAN is typically about 2030 feet approximately 69 meters but this is expected to increase with technology improvements Local area network A local Area Network LAN is a computer network covering a small physical area like a home office or small group of buildings such as a school or an airport Current wired LANs are most likely to be based on Ethernet technology although new standards like lTUT Ghn also provide a way to create a wired LAN using existing home wires coaxial cables phone lines and power lines2 For example a library may have a wired or wireless LAN for users to interconnect local devices Page 21 of 24 Computer Literacy Communications Information Fall 2009 OTS 251D 20334 OTS 251D 20333 eg printers and servers and to connect to the internet On a wired LAN PCs in the library are typically connected by category 5 Cat5 cable running the IEEE 8023 protocol through a system of interconnected devices and eventually connect to the Internet The cables to the servers are typically on Cat 5e enhanced cable which will support IEEE 8023 at 1 Gbits A wireless LAN may exist using a different lEEE protocol 80211b 80211g or possibly 80211n The staff computers bright green in the figure can get to the color printer checkout records and the academic network and the Internet All user computers can get to the Internet and the card catalog Each workgroup can get to its local printer Note that the printers are not accessible from outside their workgroup Typical library network in a branching tree topology and controlled access to resources All interconnected devices must understand the network layer layer 3 because they are handling multiple subnets the different colors Those inside the library which have only 10100 Mbits Ethernet connections to the user device and a Gigabit Ethernet connection to the central router could be called quotlayer 3 switchesquot because they only have Ethernet interfaces and must understand IP It would be more correct to call them access routers where the router at the top is a distribution router that connects to the Internet and academic networks39 customer access routers The defining characteristics of LANs in contrast to WANs Wide Area Networks include their higher data transfer rates smaller geographic range and lack of a need for leased telecommunication lines Current Ethernet or other IEEE 8023 LAN technologies operate at speeds up to 10 Gbits This is the data transfer rate lEEE has projects investigating the standardization of 40 and 100 Gbits3 Campus area network A campus area network CAN is a computer network made up of an interconnection of local area networks LANs within a limited geographical area It can be considered one form of a metropolitan area network specific to an academic setting In the case of a university campusbased campus area network the network is likely to link a variety of campus buildings including academic departments the university library and student residence halls A campus area network is Iargerthan a local area network but smaller than a wide area network WAN in some cases The main aim of a campus area network is to facilitate students accessing internet and university resources This is a network that connects two or more LANs but that is limited to a specific and contiguous geographical area such as a college campus industrial complex office building or a military base A CAN may be considered a type of MAN metropolitan area network but is generally limited to a smaller area than a typical MAN This term is most often used to discuss the implementation of networks for a contiguous area This should not be confused with a Controller Area Network A LAN connects network devices over a relatively short distance A networked office building school or home usually contains a single LAN though sometimes one building will contain a few small LANs perhaps one per room and occasionally a LAN will span a group of nearby buildings Metropolitan area network A metropolitan area network MAN is a network that connects two or more local area networks or campus area networks together but does not extend beyond the boundaries of the immediate towncity Routers switches and hubs are connected to create a metropolitan area network Page 22 of 24 Computer Literacy Communications Information Fall 2009 OTS 251D 20334 OTS 251D 20333 Wide area network A wide area network WAN is a computer network that covers a broad area ie any network whose communications links cross metropolitan regional or national boundaries 1 Less formally a WAN is a network that uses routers and public communications links Contrast with personal area networks PANs local area networks LANs campus area networks CANs or metropolitan area networks MANs which are usually limited to a room building campus or specific metropolitan area eg a city respectively The largest and most wellknown example of a WAN is the Internet A WAN is a data communications network that covers a relatively broad geographic area ie one city to another and one country to another country and that often uses transmission facilities provided by common carriers such as telephone companies WAN technologies generally function at the lower three layers of the OSI reference model the physical layer the data link layer and the network layer Global area network A global area networks GAN see also IEEE 80220 specification is in development by several groups and there is no common definition In general however a GAN is a model for supporting mobile communications across an arbitrary number of wireless LANs satellite coverage areas etc The key challenge in mobile communications is quothanding offquot the user communications from one local coverage area to the next In IEEE Project 802 this involves a succession of terrestrial WIRELESS local area networks WLAN4 Virtual private network A virtual private network VPN is a computer network in which some of the links between nodes are carried by open connections or virtual circuits in some larger network eg the Internet instead of by physical wires The data link layer protocols ofthe virtual network are said to be tunneled through the larger network when this is the case One common application is secure communications through the public Internet but a VPN need not have explicit security features such as authentication or content encryption VPNs for example can be used to separate the traffic of different user communities over an underlying network with strong security features A VPN may have besteffort performance or may have a defined service level agreement SLA between the VPN customer and the VPN service provider Generally a VPN has a topology more complex than pointtopoint A VPN allows computer users to appear to be editing from an IP address location other than the one which connects the actual computer to the Internet Internetwork An Internetwork is the connection of two or more distinct computer networks or network segments via a common routing technology The result is called an internetwork often shortened to internet Two or more networks or network segments connected using devices that operate at layer 3 the 39network39 layer of the OSI Basic Reference Model such as a router Any interconnection among or between public private commercial industrial or governmental networks may also be defined as an internetwork In modern practice interconnected networks use the Internet Protocol There are at least three variants of internetworks depending on who administers and who participates in them 0 Intranet o Extranet 0 Internet Intranets and extranets may or may not have connections to the Internet If connected to the Internet the intranet or extranet is normally protected from being accessed from the Internet Page 23 of 24
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