Operating system (O.S)An operating system (OS) is a setof programs that manage computerhardware resources and providecommon services for applicationsoftware. The operating system is themost important type of systemsoftware in a computer system. Auser cannot run an applicationprogram on the computer without anoperating system, unless theapplication program is self booting.
Operating Systems ServicesFollowing are the five services provided by an operating systems1] Program ExecutionThe purpose of a computersystems is to allow the user toexecute programs. So theoperating systems provides anenvironment where the user canconveniently run programs. Theuser does not have to worryabout the memory allocation ormultitasking or anything. Thesethings are taken care of by theoperating systems.
2] I/O OperationsEach program requires aninput and produces output.This involves the use of I/O.The operating systems hidesthe user the details ofunderlying hardware for theI/O. All the user sees is thatthe I/O has been performedwithout any details. So theoperating systems byproviding I/O makes itconvenient for the users torun programs.
3] File System ManipulationThe output of a program mayneed to be written into newfiles or input taken fromsome files. The operatingsystems provides this service.The user does not have toworry about secondarystorage management. Usergives a command for readingor writing to a file and seeshis her task accomplished.
4] CommunicationsThere are instanceswhere processes need tocommunicate with eachother to exchangeinformation. It may bebetween processesrunning on the samecomputer or running onthe different computers.
5] Error DetectionAn error is one part of thesystem may causemalfunctioning of thecomplete system. To avoidsuch a situation theoperating systemconstantly monitors thesystem for detecting theerrors.
Types of Operating systemsAs computers have progressed and developed so have theoperating systems. GUI - Short for Graphical User Interface, a GUI Operating System contains graphics and icons and is commonly navigated by using a computer mouse. Below are some examples of GUI Operating Systems. System 7.x Windows 98 Windows CE
Multi-user - A multi-user operating system allows formultiple users to use the same computer at the same timeand different times.LinuxUnixWindows 2000
Multiprocessing - An operating system capable of supporting andutilizing more than one computer processor.LinuxUnixWindows 2000
Multitasking - An operating system that is capable of allowingmultiple software processes to run at the same time.UnixWindows 2000
Multithreading - Operating systems that allow different parts ofa software program to run concurrently. Operating systems thatwould fall into this category are:LinuxUnixWindows 2000
Different Operating SystemsMicrosoft Windows isnt the only operating system for personal computers, oreven the best... its just the best-distributed. Its inconsistent behavior and aninterface that changes radically with every version are the main reasons peoplefind computers difficult to use.
MAC OSThe Mac OS user interface inspired the creation of Windows, and is stillthe target Microsoft is trying to equal. As a popular consumer product,theres plenty of software available for it, and its moving beyond itstraditional niches of graphic design, education, and home use, intogeneral business use.etc
Ubuntu (Linux)Linux ("LIH-nux") is a free Unix-like operating system, originallydeveloped by programmers who simply love the challenge of solvingproblems and producing quality software. even if that means giving theresulting product away.
Google Chrome OSGoogles Chrome OS is still vaporware so far, and its arguably justanother flavor of Linux, but it promises to be a viable alternative toWindows on small portable "netbooks" which will come with itpreinstalled.
HaikuHaiku is based on BeOS, which was designed with multimedia inmind, including the kinds of features that Microsoft is just recentlytaking onto Windows.
The BSD FamilyFreeBSD is commonly called "the free Unix". Its descended from theclassic 1970s Berkeley Software Distribution of Unix (from before the OSbecame "UNIX"®), making it one of the most mature and stable operatingsystems around.
OPENBSDOpenBSD is "the other free Unix". Its similar to FreeBSD both in theBerkeley code its based on, and the licensing terms. One key advantage ithas over its BSD siblings is that its incredibly secure from attack, as impliedby its blowfish mascot, and made explicit by their boast of only oneremotely-exploitable hole - ever - in their default installation.
NETBSDNetBSD is "the other free Unix". Its the work of another group ofvolunteer developers using the net to collaborate. Their mission is toget the OS to run - and run well - on hardware platforms no otherUnix supports.
SyllableSyllable is a free alternative OS for standard PCs. It uses some of thebetter ideas from Unix, BeOS, AmigaOS, and others, and is compatibleenough with portable software written for Unix that many have alreadybeen ported over to it.
And there are never ending O.S’sAmiga Did you know that there are a total of584+ Operating systems in the world . And a matter of fact ,MorphOS there are 605 Linux distributions (Small LinuxRISC OS based operating systems like android, symbian, Bada etc.)GNUMinix2warpMSDOS
A Small Talk about well known O.S Windows 98 (codenamed Memphis) is a graphical operating system by Microsoft. It is the second major release in the Windows 9x line of operating systems. It was released to manufacturing on 15 May 1998 and to retail on 25 June 1998. Windows 98 is the successor to Windows 95.
Windows NTWindows NT is a family of operating systems produced by Microsoft, the firstversion of which was released in July 1993. It was a powerful high-level-language-based, processor-independent, multiprocessing, multiuser operating system withfeatures comparable to Unix. It was intended to complement consumer versionsof Windows that were based on MS-DOS.
ITS NOT LINUX ! ITS UBUNTU !Ubuntu is an African Ubuntu 4.10 (Warty Warthog) Ubuntu 5.04 (Hoary Hedgehog)ethic or humanist Ubuntu 5.10 (Breezy Badger)philosophy focusing on Ubuntu 6.06 LTS (Dapper Drake) Ubuntu 6.10 (Edgy Eft)peoples allegiances Ubuntu 7.04 (Feisty Fawn)and relations with each Ubuntu 7.10 (Gutsy Gibbon)other. The real Ubuntu 8.04 LTS (Hardy Heron) Ubuntu 8.10 (Intrepid Ibex)meaning of “UBUNTU” Ubuntu 9.04 (Jaunty Jackalope)is “Humanity to Ubuntu 9.10 (Karmic Koala) Ubuntu 10.04 LTS (Lucid Lynx)others”. Ubuntu 10.10 (Maverick Meerkat) Ubuntu 11.04 (Natty Narwhal) Ubuntu 11.10 (Oneiric Ocelot) Ubuntu 12.04 LTS (Precise Pangolin)
The Birth Of LinuxIn 1991, Linus Benedict Torvalds was a second year student of ComputerScience at the University of Helsinki and a self-taught hacker. The 21 year oldsandy haired soft-spoken Finn loved to tinker with the power of thecomputers and the limits to which the system can be pushed.With his legendary technical wizardry, he alone outclassed entire groups ofprogrammers from commercial software vendors in creating GCC, consideredas one of the most efficient and robust compilers ever created.Linux is a Unix-like computer operating system assembled under the modelof free and open source software development and distribution. The definingcomponent of any Linux system is the Linux kernel, an operating systemkernel first released October 5, 1991 by Linus Torvalds. Linux systemdistributions may vary in many details of system operation, configuration,and software package selections.
The Mastermind Behind Linux Linus TorvaldsYou are what you are. Whatever youdo, Do it for the person in the mirror.
Graphical User Interface (GUI)A graphical user interface is a type of userinterface that allows users to interact withelectronic devices with images rather than textcommands.GUIs can be used in computers, hand-helddevices such as MP3 players, portable mediaplayers or gaming devices, household appliancesand office equipment .A GUI represents the information and actionsavailable to a user through graphical icons andvisual indicators such as secondary notation, asopposed to text-based interfaces, typed commandlabels or text navigation.
New Features of the GUI Pointing device Icons Desktop Menus Folders Toolbar Attachments Multiple windows On-line Help
Computer SecurityToday, many people rely on computers to do homework,work, and create or store useful information. Therefore, itis important for the information on the computer to bestored and kept properly. It is also extremely important forpeople on computers to protect their computer from dataloss, misuse, and abuse. For example, it is crucialfor businesses to keep information they have secure so thathackers cant access the information. Home users also needto take means to make sure that their credit cardnumbers are secure when they are participating in onlinetransactions.
A computer security risk is any action that couldcause loss of information, software, data,processing incompatibilities, or cause damage tocomputer hardware, a lot of these are planned todo damage. An intentional breach in computersecurity is known as a computer crime which isslightly different from a cybercrime. A cybercrimeis known as illegal acts based on the internet andis one of the FBIs top priorities.
There are several distinctcategories for people that causecybercrimes, and they are referredto as hacker, cracker, cyberterrorist, cyber extortionist,unethical employee, script kiddyand corporate spy.
“A good hacker isknown byeveryone but agreat hacker isknown by None.”:- Kevin Mitnick(World MostWanted Hacker)
“Hacking is easy asanyone can do, butnot so easy thateveryone can do.”:- Ankit Fadia(Indian Hacker)
The Hacker.The term hacker was actually known as a good word but now it has a verynegative view. A hacker is defined as someone who accesses a computeror computer network unlawfully. They often claim that they do this to find leaksin the security of a network.
The Cracker.The term cracker has never been associated with something positive this refers tosomeone how intentionally access a computer or computer network for evilreasons. Its basically an evil hacker. They access it with the intent of destroying, orstealing information. Both crackers and hackers are very advanced with networkskills.
The Cyber terrorist.A cyber terrorist is someone who uses a computer network or theinternet to destroy computers for political reasons. Its just like a regularterrorist attack because it requires highly skilled individuals, millions ofdollars to implement, and years of planning.
The Cyber extortionist.The term cyber extortionist refers to someone who uses emails as an offensiveforce. They would usually send a company a very threatening email stating thatthey will release some confidential information, exploit a security leak, orlaunch an attack that will harm a companys network. They will request a paidsum of money to prevent the threat from being carried out, a bit like blackmailing.
The Unethical Employee.An unethical employee is an employee that illegally accesses their companysnetwork for numerous reasons. One could be the money they can get from sellingtop secret information, or some may be bitter and want revenge.
The Script Kiddies.A script kiddy is someone who is like a cracker because they may have theintentions of doing harm, but they usually lack the technical skills. They areusually silly teenagers that use prewritten hacking and cracking programs
The Corporate Spy.A corporate spy has extremely highcomputer and network skills and ishired to break into a specificcomputer or computer network tosteal or delete data and information.Shady companies hire these typepeople in a practice known ascorporate espionage. They do this togain an advantage over theircompetition an illegal practice.
A Piece of AdviceBusiness and home users must do their best to protect orsafeguard their computers from security risks.However, one must remember that there is no one hundredpercent guarantee way to protect your computer so becomingmore knowledgeable about them is a must during these days.When you transfer information over a network it has a highsecurity risk compared to information transmitted in a businessnetwork because the administrators usually take some extrememeasures to help protect against security risks.
Computer Worms & VirusesA computer worm is a self-replicating malware computerprogram, which uses a computer network to send copies ofitself to other nodes (computers on the network) and it maydo so without any user intervention.
VirusesA computer virus is a computer program that can replicate itself andspread from one computer to another. A true virus can spread fromone computer to another when its host is taken to the targetcomputer; for instance because a user sent it over a network or theInternet, or carried it on a removable medium such as a floppy disk,CD, DVD, or USB drive.