In Todаy’s Sociеty, Protеcting Your Computer Is Very Important
Computer Sеcurity
Advаncеs in computer tеchnology is а doublе-еdgеd sword. On onе hаnd, it аffords us quick аnd еаsy аccess to numеrous convеniеncеs such аs bаnk stаtеmеnts, fаvoritе shopping cеnters, school аnd hеаlth rеcords, аnd morе. On thе othеr hаnd, it cаn аlso grаnt thе sаmе аccess to thosе who аrеn’t supposеd to gеt it. Although it’s а rаrе occurrеncе, hаcking hаs bеcomе thе biggеst criminаl nuisаncе in computer history.
Mаkе no bonеs аbout it. Thеrе’s nothing innocent or cutе аbout the hаckеr. Todаy’s hаckеrs аrеn’t the pimply-fаcеd tееn rеbеls thаt you might bе thinking of. Instеаd, this gеnеrаtion of hаckеrs аrе grown individuаls who аrе morе thаn likеly еаrning а living by stеаling thе idеntitiеs of innocеnt, lаw аbiding individuаls аnd thеn sеlling thosе idеntitiеs to othеrs who wаnt to slip by thе systеm. And thе only protеction аgаinst thеsе sееdy pеoplе is prеvеntion.
Computer sеcurity couldn’t bе morе importаnt thаn it is todаy аnd thаt’s why wе’vе tаkеn thе timе to introducе it to you. You cаn rеducе thе probаbility of еxpеriеncing idеntity thеft by mаking your computer аs hаckеr-proof аs possiblе. All thаt’s nееdеd is а littlе softwаrе аnd а lot of common sеnsе.
1. Instаll аn аnti-virus/аnti-spywаrе progrаm. Anti-virus/аnti-spywаrе softwаrе will stop mаlicious codе from downloаding аnd instаlling onto your computer while you pеrusе thе Internеt. Known аs virusеs, worms, or spywаrе, this mаlicious codе cаn dеstroy importаnt files аnd rеndеr your computer good for only onе thing: sеnding sеnsitivе dаtа bаck to thе sеrvеr of аn idеntity thiеf.
2. Don’t storе sеnsitivе dаtа on your computer in thе first plаcе. Should your computer gеt infеctеd with а virus, worm, or piеcе of spywаrе, you cаn thwаrt thе individuаls rеsponsiblе by not storing your pеrsonаl information on your PC so thаt whеn аnd if your computer doеs sеnd bаck dаtа – it won’t bе аnything vаluаblе. Hаckеrs look for things likе full nаmеs, sociаl sеcurity numbеrs, phone numbеrs, homе аddressеs, work-rеlаtеd information, аnd crеdit cаrd numbеrs. If thеsе things аrеn’t sаvеd onto а computer, thеrе’s nothing criticаl to worry аbout othеr thаn rеstoring your computer to а non-virus condition.
3. Don’t opеn files without scаnning thеm with аn аnti-virus/аnti-spywаrе progrаm. In thе pаst, thе wаrning wаs to аvoid opеning files from pеoplе thаt you don’t know. Todаy it’s rеаlly not sаfе to opеn files from аnyonе (without scаnning thе files) bеcаusе thаt’s how virusеs gеt sprеаd – through files – еvеn by mistаkе. So еvеn though your co-workеr mаy hаvе еmаiled а funny vidеo, it’s no morе sаfе to opеn thаn а vidеo downloаdеd from а complеtе strаngеr. Bе sаfе аnd scаn еаch аnd еvеry file you downloаd from thе Internеt or rеcеivе through еmаil rеgаrdless of whеrе it cаmе from.
4. Crеаtе а bаrriеr bеtwееn your computer аnd prying еyеs. Anti-virus/аnti-spywаrе programs аrе only еffеctivе аfter thе еffеct. But you cаn prеvеnt idеntity thеft from occurring by instаlling а firеwаll. A firеwаll is softwаrе thаt chеcks аll dаtа еntering аnd еxiting а computer аnd it thеn blocks thаt which doеsn’t mееt spеcifiеd sеcurity criteriа (usеr-dеfinеd rulеs).1
5. Don’t click on wеbsitе links in spаm messаgеs. In аn еffort to obtаin pеrsonаl information, somе spаmmеrs will sеnd еmаil thаt аsks you to click on а link. Thе еmаil messаgеs аrе oftеn disguisеd аs importаnt messаgеs from wеll-known onlinе еstаblishmеnts, аnd thеy oftеn try to scаrе thеir rеаdеrs into clicking links with thrеаts of closing аn аccount of somе sort. Somеtimеs thе links аrе hаrmless аnd аttеmpt to con thе rеаdеr into voluntееring pеrsonаl information (crеdit cаrd numbеr), but othеr timеs thе links аttеmpt to downloаd hаrmful softwаrе onto а computer.
Your bеst protеction аgаinst computer crimеs is your own knowlеdgе. Hopеfully thе suggеstions аbovе will prompt you into tаking аppropriаtе аction аnd into protеcting your computer with thе suggеstеd tools. In doing so, you’ll not only protеct yoursеlf, you’ll prеvеnt thе sprеаd of thеsе mаlicious аctivitiеs аnd protеct othеrs аt thе sаmе timе.
computer memory
RAM takes the form of separate microchip module that plug in slots on the computer’s motherboard.These slots connect through a line (BUS) or set of electrical paths to the computer’s processor.Before you turn on a computer,its RAM is a blank slate.As you start and use your computer the operating system files,programs,and any data currently being used by the processor are written to and stored in RAM so that the processor can access them quickly.How is this data written to and stored in RAM?In the most common form of RAM dynamic random access memory (DRAM),transistors(acting as switches)and a capacitor (as a data storage element)create a memory cell,which represents a single bit of data.
Memory cells are etched onto a silicon wafer in a series of columns (bitlines)and rows(wordlines),known as an array.The intersection of a column and row constitutes the address of the memory cell.Each memory cell has a unique address that can be found by counting across columns and then counting down by the row.The address of a character consists of a series of memory cell address put together.To write data to RAM,the processor sends the memory controller address of a memory cell in which to store data.The memory controller organizes the request and sends the column and row address in an electrical charge along the appropriate address lines,which are very thin electrical lines etched into the RAM chip.This causes the transistors along those address lines to close.
These transistors act as a switch to control the flow of electrical current in either a closed or opened circuit.While the transistors are closed,the software sends bursts of of electricity along selected data lines.When the electrical travelling down the data line reaches an address line where a transistor is closed,the charge flows through the closed transistor and charges the capacitor.A capacitor works as an electronic storage that holds an electrical charge.Each charged capacitor along the address line represents a 1 bit.An uncharged capacitor represents a 0 bit.The combination of 1s and 0s from eight data lines forms a single byte of data.
The capacitors used in dynamic RAM,however,lose their electrical.The processor or memory controller continously has to recharge all of the capacitors holding a charge (a 1 bit)before the capacitor discharges.During this refresh operation,which happens automatically thousands of times per second,the memory controller reads memory and then immediately rewrites it.This refresh operation is what gives dynamic RAM its name.Dynamic RAM has to be refreshed continually,or it loses the charges that represent bits of data.A specialized circuit called a counter tracks the refresh sequence to ensure that all of the rows are refreshed.
The process of reading data from RAM uses a similar,but reverse,series of steps.When the processor gets the next instruction it is to perform,the instruction may contain the address of a memory cell from which to read data.This address is sent to the memory controller.To locate the memory cell,the memory controller sends the column and row address in an electrical charge down the appropriate address lines.This electrical charge causes the transistors along the address line to close .At every point along the address line where a capacitor is holding a charge,the capacitor discharges through the circuit created by the closed transistors,sending electrical charges along the data lines.
A specialized circuit called a sense amplifier determines and amplifies the level of charge in the capacitor.A capacitor charge over a certain voltage level represents the value of 1;a capacitor charge below that level represent a 0.The sensed and amplified value is sent back down the address line to the processor.
As long as a computer is running,data continuously is being written to and read from RAM.As soon as you shut down a computer,RAM loses its data.The next time you turn on a computer,operating system files and other data are again loaded into RAM and the read/write process starts all over.
Three-dimensional (3-D)graphics,which appear to have height,width and depth,gives a real quality to objects in computer programs,especially computer games.3-D technology is a modern innovation which gives an experience by adding the appearance of depth.A game programmer can give single objects or an entire virtual world a 3-D appearance.
Creating a 3-D appearance involves that a wireframe is created. A wireframe is a series of lines,curves,and shapes arranged to resemble an object in a 3-D world.3-D wireframes consist of series of polygons.A completed wireframe enables you to identify the shape of the object,although it appears to be hollow.This hollow shape can be transformed into solid shape by adding a surface to the wireframe.Some 3-D graphics are composed of more than one wireframe.When adding a surface,it is important to make the object look as realistic as possible by adding colour,reflectance and texture.The amount of the objects’s surface reflects is termed Refelectance.With the surface added to the wireframe,we then consider how the object will be lit from one or more lightening sources.
3-D graphics could also be created by using a technique called ray-tracing.This involves drawing an imaginary path that rays of light follow as they leave source and then land on an object.The light intensity will be greater on some portions of the objects and lee on other portions.In addition,the object also might cast a shadow once it is lit from a particular angle.When creating a 3-Dworld,one also has to consider the perspective and depth of field.Perspective refers to the differences in how objects appear in relation to one another when they are close to you or farther away.Objects appearing close may seem to be spaced apart.As they move farther away from you,they become closer to one another.A common technique used to calculate which objects appear infront of or behind one another is called the Z-buffer.Depth of field gives the appearance that objects farther from the viewer are are less focused than closer objects.
Anti-aliasing is the final technique in creating a 3-D world.Anti-aliasing makes curved and diagonal lines appear straight.When computers render graphics with curved and diagonal lines,they often appear jagged.Anti-aliasing inserts additional coloured pixels that give the appearance of a smooth edge.All these techniques combined create a realistic graphic.
the complex nature of 3-D technology requires more computing power in order to render a graphic in an acceptable period of time .For instance,Computer gamers often have faster processors,several gigabytes of RAM,and one or more video cards containing at least 256 MB of RAM.These video cards also might support DirectX 11 standard,the video card also must support DierectX 11 standard for the video game to work.
Although game programmers spend many hours creating 3-D graphics for programs such as computer games,the results are rewarding when a player faces an experience so realistic that it is difficult to differentiate between the game and reality.
Operating Systems.
By Abdul.
Operating System is a type of system software,which has a set of programs containing instructions that functions to control most or all of the actions among hardware resources.Functions of operating system varies from Starting and shutting down a computer,providing a user interface,managing programs,managing memory,coordinating tasks,establishing an internet connection,providing file management and other utilities,and automatically updating itself and certain utility programs.There are some operating system which allows its users to control a network and administer security.An operating system can run from an optical disc or flash memory mobile media,in common cases,the OS is installed and resides on the computer’s hard disk.In smartphones,the Operating system reside on a ROM chip.
Sizes of operating system varies in computers because they are written to run on specific type of computer.Mainframe computers does not use the same operating system as a personal computer.when purchasing an application software,one should be sure that it works with the operating system installed on the computer or mobile device.The operating system that a computer uses could also be refered to as the platform.A cross -platform program is one that runs the same on multiple operating systems.The operating system handles many functions automatically,without requiring any instructions from the user.Functions of Operating system includes the following.
Starting and shorting down a computer: The process of starting or restarting of a computer is refered to as Booting.there are two types of booting,which are warm boot and cold boot.A typical illustration of warm boot is turning on a computer that has been powered off completely,while warm boot is the process of using the operating system to restart a computer.A warm boot properly closes any running processes and programs,but it does not save any unsaved work.With windows you can perform a warm boot by clicking on the start button on the task bar ,clicking the arrow next to the shut down button on the start menu,and then clicking restart.When you install a new software,often an on-screen prompt instructs you to restart the computer.In this case a warn boot is most appropriate to use.Each time you boot a computer,the kernel and other frequently used operating system instructions are loaded ,copied,from storage into the computer’s memory.The kernel manages memory and devices,maintains the computer’s clock,starts programs,data and information.
Providing a Graphic user Interface:Computer users work with a Graphical user interface(GUI),this controls how you enter data and instructions and hoe information is displayed on the screen.Most recent GUI operating systems incorporate futures similar to those of a web browser,e.g links and navigation buttons.some GUI operating systems provide access to command -line interface.Windows for example, offers two different GUIs,depending on the hardware configuration.computers with less than 1 GB of RAM work with windows 7 Basic interface,while computers with with more than 1GB of RAM that has the required hardware may be able to work with the windows 7 Aero interface,which provides an enhanced visual look,additional navigation options and animation.
Managing Programs:some operating system support a single user and only one program running at a time.others support thousands of users running multiple programs.A single user/single tasking operating system allows only one user to run one program at a time.for instance,if you are working on windows media players and you want to check your e-mail,you have to quit the windows media player program before you can run your e-mail program.smart phone and other mobile device are typical examples of single user/single tasking.A single user/multitasking operating system allows a single user to run more than one program.for instance e-mail program and windows media player can run simultaneously.when a computer is running two programs at the same time,one program is in the foreground and the others in the background.The one in the foreground is active program(in use).the other programs running but not in use are in the background.The foreground program usually displays on the desktop,while the background programs are hidden partially or completely behind the foreground program.
Managing Memory:The purpose of memory management is to optimize the use of random access memory(RAM).The operating system allocates,or assigns data and instructions to an area of memory while they are being processed.then,it carefully monitors the contents of memory.lastly,the OS releases these items from being monitored in memory when the processor no longer requires them.If you have multiple programs running simultaneously ,it is possible to run out of RAM.If the RAM is exhausted,the operating system may have to use virtual memory.operating system allocates a portion of a storage medium,usually the hard disk,to function as additional RAM with Virtual memory.As you interact with a program,part of it may be in physical RAM,while the rest of it is on the hard disk as virtual memory.Virtual memory is slower than RAM ,this is why a user may notice the computer slowing down while it uses virtual memory.
Coordinating Tasks:The operating system determines the order in which tasks are processed.A task,or job,is an operation the processor manages.This includes receiving data from an input device,and transferring items from storage to memory and from memory to storage.Multiuser operating system does not always process tasks on first come ,first served basis.sometimes,one user may have a higher priority than other users.In this case,the operating system adjusts the schedule of tasks.a device already may be busy processing one task when it receives a second task.This occurs because the processor at a much faster rate of speed compared to the peripheral devices.for example,if the processor sends five documents to a printer,the printer can print only one at a time and store as many documents as its memory can handle.While waiting for the device to be idle,the operating system places items in buffers.A buffer is a segment of memory in which items are placed while waiting to be transfered from an input device or to an output device.
Providing file management and other Utilities:Operating systems often provide users with the capability of managing files,searching for files,viewing images,securing a computer from unauthorised access,uninstalling programs,cleaning up disks,defragmenting disks,diagnosing problems,backing up files and disks,and setting up screen savers.
Updating Software Automatically:Many popular programs,including most operating systems,include an automatic update future that automatically provides updates to the program.with an operating system,these updates can include fixes to program bugs,or errors,enhancement to security,modifications to device drivers,access to new or expanded components such as desktop themes or games.Many software makers provide free downloadable updates,sometimes called a service pack,to users who have registered or activated their software.With operating systems,the automatic update future automatically alerts users when an update is available,further it can be configured to download and install the update automatically.
Controlling Networks:Some operating systems are designed to work with a server on a network.A server operating system is an operating system that organizes and coordinates how multiple users access and shares resources on a network.some operating systems have network futures built into them.In other cases,the server operating system is a set of programs separate from the client computers that access the network.When not connected to the network,the server operating system may assume some of the operating system functions. Compare colour laser printers provides color print output which are compatible with a wide range of operating systems.
