How Computer Viruses Work

by Marshall Brain

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Please copy/paste the following text to properly cite this HowStuffWorks article:

Brain, Marshall. "How Computer Viruses Work." 01 April 2000. HowStuffWorks.com. 07 December 2009.

Inside this Article

1. Introduction to How Computer Viruses Work
2. Virus Origins
3. Virus History

4. Virus Evolution
5. E-mail Viruses
6. Worms
7. See more »
   7. How to Protect Your Computer from Viruses
   8. Lots More Information
   9. See all Computer & Internet Security articles

What Not to Do With Spam E-mails

• More Computer Videos »

Computer Image Gallery



A virus can spell doom for your computer. See more computer pictures.

Strange as it may sound, the computer virus is something of an Information Age marvel. On one hand, viruses show us how vulnerable we are -- a properly engineered virus can have a devastating effect, disrupting productivity and doing billions of dollars in damages. On the other hand, they show us how sophisticated and interconnected human beings have become.

For example, experts estimate that the Mydoom worm infected approximately a quarter-million computers in a single day in January 2004. Back in March 1999, the Melissa virus was so powerful that it forced Microsoft and a number of other very large companies to completely turn off their e-mail systems until the virus could be contained. The ILOVEYOU virus in 2000 had a similarly devastating effect. In January 2007, a worm called Storm appeared -- by October, experts believed up to 50 million computers were infected. That's pretty impressive when you consider that many viruses are incredibly simple.

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­­When you listen to the news, you hear about many different forms of electronic infection. The most common are:

• Viruses - A virus is a small piece of software that piggybacks on real programs. For example, a virus might attach itself to a program such as a spreadsheet program. Each time the spreadsheet program runs, the virus runs, too, and it has the chance to reproduce (by attaching to other programs) or wreak havoc.
• E-mail viruses - An e-mail virus travels as an attachment to e-mail messages, and usually replicates itself by automatically mailing itself to dozens of people in the victim's e-mail address book. Some e-mail viruses don't even require a double-click -- they launch when you view the infected message in the preview pane of your e-mail software [source: Johnson].
• Trojan horses - A Trojan horse is simply a computer program. The program claims to do one thing (it may claim to be a game) but instead does damage when you run it (it may erase your hard disk). Trojan horses have no way to replicate automatically.
• Worms - A worm is a small piece of software that uses computer networks and security holes to replicate itself. A copy of the worm scans the network for another machine that has a specific security hole. It copies itself to the new machine using the security hole, and then starts replicating from there, as well.

­In this article, we will discuss viruses -- both "traditional" viruses and e-mail viruses -- so that you can learn how they work and understand how to protect yourself.

Trademark status

Trademark status

Most dictionary definitions^[6] and common usages of the term are generic and not limited to the characters of any particular company or companies.

Nevertheless, variations on the term "Super Hero" are jointly claimed by DC Comics and Marvel Comics as trademarks. Registrations of "Super Hero" marks have been maintained by DC and Marvel since the 1960s.^[7] (U.S. Trademark Serial Nos. 72243225 and 73222079, among others).

Joint trademarks shared by competitors are rare in the United States.^[8] They are supported by a non-precedential 2003 Trademark Trial and Appeal Board decision upholding the "Swiss Army" knife trademark. Like the "Super Hero" marks, the "Swiss Army" mark was jointly registered by competitors. It was upheld on the basis that the registrants jointly "represent a single source" of the knives, due to their long-standing cooperation for quality control.^[9]

Critics in the legal community dispute whether the "Super Hero" marks meet the legal standard for trademark protection in the United States-distinctive designation of a single source of a product or service. Controversy exists over each element of that standard: whether "Super Hero" is distinctive rather than generic, whether "Super Hero" designates a source of products or services, and whether DC and Marvel jointly represent a single source.^[10] Some critics further characterize the marks as a misuse of trademark law to chill competition.^[11]

America's Best Comics, originally an imprint of Wildstorm, used the term science hero, coined by Alan Moore.

Birds of Paradise

Birds of Paradise
Indonesian From Wikipedia, the free encyclopedia
Jump to: navigation, search
? Birds of Paradise
Adult male Lesser Bird of Paradise, Paradisaea minor
Adult male Lesser Bird of Paradise,
Paradisaea minor
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Aves
Order: Passeriformes
Family: Paradise
Genera

13, see list below
Wikimedia Commons
Wikimedia Commons has media related to Birds of Paradise

The birds of paradise are members of the family of the order Passeriformes Paradise. They are found in eastern Indonesia, the islands of Torres Strait, Papua New Guinea, and Australia's east. This family of birds known as the male plumage of many kinds, especially the very long hair and a growing complex of the beak, wings or head. Sizes ranging from birds of paradise Bird of Paradise King at 50 grams and 15 cm to Paradise Black Sicklebill at 110 cm and Manukod crested Bird of rolling at 430 grams.

Birds of paradise most notably the members of the genus Paradisaea, including the type species, large yellow paradise, Paradisaea apoda. These types are described from specimens brought to Europe from trading expeditions. These specimens were prepared by native traders by removing the wings and legs to be used as decoration. It is not known by the explorers and led to the belief that these birds never landed but remain in the air because of the feathers. This is the origin of a bird of paradise ( 'bird paradise' by the British) and the name of apoda - which means 'legless'.

Many species have a complex mating ritual, mating system Paradisaea types are male birds gather to compete to show its beauty in the female bird to mate. While other types such as the types Cicinnurus and Carola had a regular wedding dance. Male birds in sexually dimorphic species are polygamous. Many birds are described as a hybrid of new species, and some species kevalidannya doubt.

The number of eggs a little less certain. In large type, perhaps almost always one egg. Small types can produce as many as 2-3 eggs (Mackay 1990).
Contents
[hide]

* 1 The types of Parasaeidae
* 2 Relationship with Man
* 3 References
* 4 External links

[edit] The types of Parasaeidae

Genus Lycocorax

* Paradise Crow, Lycocorax pyrrhopterus

Genus Manucodia

* Crinkle Glossy, Manucodia atra
* Jobi Jobi, Manucodia jobiensis
* Crinkle Neck-creased, Manucodia chalybata
* Crinkle-crested roll, Manucodia comrii
* Crinkle trumpet, Manucodia keraudrenii

Genus Paradigalla

* Long-tailed Paradigalla, Paradigalla carunculata
* Short-tailed Paradigalla, Paradigalla brevicauda

Genus Astrapia

* Arfak, Astrapia nigra
* Astrapia, Astrapia splendidissima
* Ribbon-tailed Astrapia, Astrapia mayeri
* Astrapia Stephanie, Astrapia stephaniae
* Astrapia Huon, Astrapia rothschildi

Genus Parotia

* Carola, Parotia sefilata
* Carola, Carola carolae
* Berlepsch's Parotia, Parotia berlepschi
* Lawes, Parotia lawesii
* East Carola, Carola helenae
* Wahnes, Parotia wahnesi

Genus Pteridophora

* Bird of Panji, Pteridophora alberti

Genus Lophorina

* Bird of Paradise, Lophorina superba

Genus Ptiloris

* Riflebird Ptiloris magnificus
* Eastern Riflebird Ptiloris intercedens
* Riflebird Heaven Ptiloris paradiseus
* Victoria's Riflebird Ptiloris victoriae

Genus Epimachus

* Sicklebill Kurikuri, Epimachus fastuosus
* Brown Sicklebill, Epimachus meyeri
* Sicklebill half-black, Epimachus albertisi
* Sicklebill Part-pale, Epimachus bruijnii

Genus Cicinnurus

* Paradise Cut-rattan, Cicinnurus magnificus
* Bird of Bald Head, Cicinnurus respublica
* Bird of Paradise King, Cicinnurus regius

Genus Semioptera

* Standardwing, Semioptera wallacii

Genus Seleucidis

*-Wired Bird of Paradise, Seleucidis melanoleuca

Genus Paradisaea

* Lesser Bird of Paradise, Paradisaea minor
* Bird of Paradise, Paradisaea apoda
* Raggiana Bird of Paradise, Paradisaea raggiana
* Bird of decora, decora Paradisaea
* Red Bird, Paradisaea rubra
* Bird of the Emperor, Paradisaea guilielmi
* Blue Bird, Paradisaea rudolphi


"Melampitta" Big

* Melampitta Great, "Melampitta" gigantea - are categorized here for a while

Previously classified here

* Bird of Paradise Loria, Cnemophilus loriae - perhaps more related to Melanocharitidae (pematuk berries) (Cracraft & Feinstein 2000).
* Paradise Crest, Cnemophilus macgregorii - perhaps more related to Melanocharitidae (Cracraft & Feinstein 2000).
* Yellow-breasted Bird of Paradise, Loboparadisea sericea - perhaps more related to Melanocharitidae (Cracraft & Feinstein 2000).
* Macgregor's Giant Honeyeater (formerly "beautiful Bird of Paradise"), Macgregoria pulchra - recently found to be Honeyeater (Cracraft & Feinstein 2000).
* Melampitta Small, Melampitta lugubris - some time while stationed here; may include Orthonychidae

Legacy

Legacy This section requires the development of ((((date)))) On June 19, 2008, the Cuban government issued a stamp with a picture of President Sukarno and Fidel Castro of Cuba. [2] Publishing the same birthday Fidel Castro and 80 warnings "visit of President of Indonesia, Sukarno, to Cuba". [edit] Naming Sukarno's full name at birth was Kusno Sosrodihardjo. [3] When I was little, because often ailing, according to the Javanese custom [citation needed]; by his parents changed its name as Sukarno [citation needed]. In later days when he became President of the Republic of Indonesia, Sukarno changed the spelling of the name of her own became Sukarno because he thought the spelling of the name used colonizers (Netherlands) [citation needed]. He still uses the name of Sukarno in his signature because the signature is the signature contained in the text of the Proclamation of Indonesian Independence should not be changed [citation needed]. The term familiar to Ir. Sukarno was the Bung Karno. [edit] Achmed Sukarno In some Western countries, Sukarno name is sometimes written Achmed Sukarno. This happens because when Sukarno first time visiting the United States, some reporters wondered, "Who's first name Sukarno?" because they do not understand the habit of some people in Indonesia who only uses one name only, or do not have family names. Somehow, then add the name of a person in front of the name of Achmed Sukarno. This also happened in some existing, such as wikipedia Czech language, the language of Wales, Danish, German, and Spanish. Sukarno Achmed mention that name in dapatnya when perform the pilgrimage. [4] And in some other versions, giving names mentioned in the name of Achmed Sukarno, carried out by Muslim diplomats from Indonesia who were conducting missions abroad in an effort to obtain recognition of Indonesian sovereignty of Arab countries. [edit] See also De-Soekarnoisasi List of Presidents of Indonesia Vivere pericoloso [edit] Notes ^ Http://kepustakaan-presiden.pnri.go.id/biography/index.asp?presiden=sukarno ^ ROY. "Cuba Stamps Publish Bung Karno and Fidel Castro", Kompas Cyber Media, June 3, 2008. Retrieved on June 3, 2008. ^ Figure: Ir. Sukarno. bangfauzi.com. Retrieved on June 3, 2009 ^ Adams, Cindy. 1965. Sukarno, an autobiography as told to Cindy Adams. New York: The Bobs Company Inc. Merryl. [edit] References (en) Dr. Syafiq A. Mughnie, M.A., PhD. Hassan Bandung, Radical Islamic Thinkers. PT. Bina Ilmu, 1994, pp 110-111. (en) Leslie H. Palmier. Sukarno, the Nationalist. Pacific Affairs, vol. 30, No. 2 (Jun. 1957), pp 101-119. (en) Bob Hering, 2001, Soekarno, architect of a nation, 1901-1970, KIT Publishers Amsterdam, ISBN 90-6832-510-8, KITLV Leiden, ISBN 90-6718-178-1 (nl) Lambert J. Giebels, 1999, Sukarno. Nederlandsch onderdaan. Biografie 1901-1950. Deel I, Uitgeverij Bert Bakker Amsterdam, ISBN 90-351-2114-7 (nl) Lambert J. Giebels, 2001, Sukarno. President, 1950-1970, Deel II, Uitgeverij Bert Bakker Amsterdam, ISBN 90-351-2294-1 geb., ISBN 90-351-2325-5 pbk. (nl) Lambert J. Giebels, 2005, De stille genocide: de fatale gebeurtenissen rond de val van de Indonesische president Soekarno, ISBN 90-351-2871-0 [edit] External links Wikiquote has a collection of quotations related to: SoekarnoWikisource has original text related to SoekarnoKepustakaan presidents of the Republic of Indonesia - Scripts speech - Soekarno Bung Karno And The Seeing Wife Women's Heart - Special Edition No. 29 Outstanding Gatra June 4, 2001 by Dewi Sri Utami Political office Preceded by: there is no (first President) President of the Republic of Indonesia 1945 - 1967 Succeeded by: Suharto [hide] v • b • s President of Indonesia Soekarno 1945 - 1967 Suharto 1967 - 1998 Baharuddin Jusuf Habibie 1998 - 1999 Abdurrahman Wahid 1999 - 2001 Megawati Sukarnoputri 2001 - 2004 Susilo Bambang Yudhoyono Since 2004 [show] v • b • national sPahlawan Indonesia

Educational Leaders in Public Schools

Educational Leaders in Public Schools

Public schools are well known for careful stratification and segregation of age groups. Public schools are so poorly run (take DPS for example) that all of those kids run across the county line to attend any school that will accept them. These kids are so far behind academically because of the crap that DPS taught or didn’t teach, that they will never be academically successful.

Public schools are not required to answer to parents, but they do need to heed the words of politicians and school boards-all of whom have their own political agendas. It would not be an exaggeration to say that these agendas are weakening the entire system.

Public schools are operated at the state level through departments of education, and locally by school districts and publicly elected or appointed school boards. Approximately 15,000 different school districts operate in the United States, and most are run by counties.

Educational leaders have focused in recent years on providing safe and disciplined school environments for students and teachers. Many schools have increased expulsions of violent students by adopting “zero tolerance policies” toward serious offenders. Education outcomes become irrelevant. Educators and parents can post a “viewpoint” page on the site that acts as an online profile, and they can participate in discussion forums, share links and resources, and review teaching materials.

Education reformers and policymakers who consider higher academic standards a centerpiece of their movement should not count on teachers to be a driving force, added Wadsworth. It may be that the academic energies of even the most motivated teachers are sapped by what they consider to be the stressful day-to-day demands of the classroom. Education costs have been rising faster than inflation. Many parents want, but cannot afford, these private alternatives. Educating for citizenship, work and the public good has been replaced with models of schooling in which students, especially poor minority youth, are viewed narrowly either as a threat or as perpetrators of violence. When not viewed as potential criminals, they are positioned as infantilized potential victims of crime (on the Internet, at school and in other youth spheres) who must endure modes of governing that are demeaning and repressive.

Educators must recover their higher motivation, a spirituality that comes from faith not in religion but in civilization, humanity’s sanctuary from the cruel vortex of nature. Educational alternatives would be unlimited. It would be the source of enormous progress, and a model for the nation.

3 Grades of Chemicals for Thames Kosmos Chemistry Sets

3 Grades of Chemicals for Thames Kosmos Chemistry Sets

Chemistry sets from brands like Thames Kosmos, Scientific Explorer and Powertech provide children with hours of educational entertainment. The great thing about these sets is they provide all the chemicals and materials required to conduct the experiments. But what do you do when the chemicals have all been used?

Walmart seems to have just about everything but have you ever found the chemicals aisle? Not only are chemicals hard to find but who even knows what to buy? This article explains the difference between 3 grades of chemicals so you can know the right chemicals for your next school experiment, homework assignment or science fair project.

Chemistry sets can awaken an interest in chemistry and the physical world, setting children on a path to a future career. Even the most basic chemistry sets are filled with experiments that will peak and keep the interest of children who already have a basic scientific interest or knowledge, or those who are absolute beginners. Chemistry experiments are designed to teach things like air pressure and water tension, and how everyday things function. Some of the experiments work with benign objects, while others require chemicals.

Not all the experiments found in chemistry sets like the Thames Kosmos series require the use of chemicals. For those that do, it’s good to know what you’re working with, and what your choices are when you need to purchase chemicals.

Most chemicals are graded, the grade representing the purity of the chemical. A chemical with a higher grade has fewer impurities, or other chemicals, such as metals and water, than those with a lower grade. The cost of chemicals is in keeping with its grade: a higher grade is more expensive than lower grades.

Although there are several different protocols for grading chemicals, there are three basic grades that are the most common and most likely to be used. They are, from highest to lowest, reagent grade, laboratory grade, and technical grade.

Reagent grade, also known as ACS, is the highest chemical grade there is, meaning it is the most pure. It meets or exceeds American Chemical Society standards. Chemicals graded as reagent grade can be used in all situations, from scientific to manufacturing. It is the only chemical grade that can be used in biological experiments.

Laboratory grade chemicals, which may also be referred to as lab, are less pure than reagent grade chemicals, but are still of a fairly high purity. These chemicals would not be pure enough to use in medical or food products, but they are usually more than adequate for science fair projects.

Technical grade chemicals are also called industrial grade, and are the least pure chemicals. Chemicals of this grade are typically used in industrial or commercial applications, but may be adequate for some science fair projects. These chemicals are not acceptable for use in food or medicinal purposes.

If your experiment has stringent requirements for chemical purity, your best bet would be purchasing from a chemical supply house where you can be assured of the grade of chemical you are purchasing. If you are unsure of what grade is needed for a particular experiment, laboratory grade is a safe choice.

So now that you have a handle on that, where do you go to find the chemicals you need? You don’t have to buy chemistry sets to get more chemicals. You can actually purchase just the chemicals at various stores (hardware store, drug store, even the grocery store) rather than a chemical supply house. However, before you get excited about that, there is a problem. When you buy from these types of stores, the chemicals are unlikely to be graded and may contain an unacceptable level of impurities for the experiment being performed.

Now you can buy the right chemical with confidence that it will get the job done. Having the proper chemicals allows you to successfully conduct experiments. It also allows you to replenish the supply of chemicals in your old Thames Kosmos chemistry sets so you can blow the dust off of the set and put it back to good use.

how anyone

How Anyone Who Knows How to Type Can Write an Article in 30 Minutes or Less
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