The computer virus is an outcome of the computer overgrowth in  the 1980s．The  cause  of  the  term "computer  virus" is the likeness between the biological virus and the evil program infected with computers．The origin of this term came from an American science fiction“ The  Adolescence of P－1“　written  by Thomas J. Ryan，published in 1977．Human viruses invade a living cell and turn it into a factory for manufacturing viruses. However, computer virusesare small programs. They replicate by attaching a copy of themselves to another program.

   Once attached to me host Program

，the viruses then look for other programs to "infect"．In this way， he virus can spread quickly throughout a hard disk or an entire organization when it infects a LAN or a multi-user system． At some point，determined by how the virus was programmed the virus attacks．The timing of the attack can be linked to a number of situations，including a certain time or date， the presence of a particular file，the security privilege level of the user
，and the number of times a file is used．Likewise，the  mode  of  attack varies．So－called "benign"  viruses might simply display a message，like the one that infected IBM’s main computer system last Christmas with a season's greeting．Malignant  viruses  are  designed to damage the system．The attack is to wipe out data， to delete flies
， or to format the hard disk.

What Kind of Viruses Are There
？

There are four main types of viruses: shell, intrusive, operating  system  and  source  ode．

    Shell viruses wrap themselves around a host program and don't modify the original program．Shell programs are easy to write，which is why about half of viruses are of this type．

    Intrusive viruses Invade an existing program and actually insert a portion of themselves into the host program．Intrusive viruses are hard to write and very difficult to remove without damaging the host file.

    Shell and intrusive viruses most commonly attack executable program flies－those with a．corn or．exe extension

， although data flies are also at some risk．

    Operating system viruses work by replacing parts of the operating system with their own logic．It is very difficult to write operating system viruses and these viruses have the ability once booted up， to take total control of your System．FOF example，some operating system viruses have hidden large amounts of attack logic in falsely marked bad disk sectors．

    Source code viruses are intrusive programs and they are also inserted into a source program such as those written in Pascal prior to the program being complied．There are the least－common viruses because they are not only hard to write
，but also have a limited number of hosts compared to the other types．

Be Wary of the Second Network Viruses

    Do you believe it

？ Network viruses can steal money！So far Internet has become the main channel through which the computer viruses spread．Look

，here come the second network computer viruses．Even without "snatching" information from  the network your computer can be infected by the second network computer viruses， which are hidden in some machines on the network． Your computer is
， so to speak， in danger once being connected to the network to browse．

    The virus that can steal your money belongs to a kind of the second network viruses.  It was designed and put in some machines on the network． When your computer is linked to one of these machines
，the virus will invade your hard disk and search whether Intuit Quicken， an accounting software， is installed． One of this accounting software's functions is to transfer accounts automatically. Once infected
， your money will be transferred to an additional account opened by the virus program without anybody knowing it．

計算機病毒

    計(ji)算(suan)機(ji)病(bing)毒(du)是(shi)八(ba)十(shi)年(nian)代(dai)計(ji)算(suan)機(ji)飛(fei)速(su)發(fa)展(zhan)帶(dai)來(lai)的(de)結(jie)果(guo)
，計(ji)算(suan)機(ji)病(bing)毒(du)這(zhe)一(yi)名(ming)詞(ci)起(qi)因(yin)於(yu)在(zai)計(ji)算(suan)機(ji)上(shang)傳(chuan)染(ran)的(de)有(you)害(hai)程(cheng)序(xu)與(yu)生(sheng)物(wu)學(xue)中(zhong)病(bing)毒(du)的(de)相(xiang)似(si)性(xing)


，該(gai)名(ming)詞(ci)起(qi)源(yuan)於(yu)1977年出版的、由 Thomas J． Ryan寫的一本美國科幻小說《p-1的青春》。rentibingduruqinhuodexibaohou，jiubatazhuanbianchengzhizaobingdudegongchang。erjisuanjibingdushiyixiexiaochengxu，tamenbazijideyigefubenfujiadaolingyigechengxushangmianjinxingfuzhi。

    病毒程序一旦附加到一個主程序上
，就開始尋找其他可以進行“感染”的(de)程(cheng)序(xu)。這(zhe)樣(yang)，病(bing)毒(du)就(jiu)很(hen)快(kuai)地(di)布(bu)滿(man)整(zheng)個(ge)硬(ying)盤(pan)，如(ru)果(guo)病(bing)毒(du)感(gan)染(ran)了(le)一(yi)個(ge)局(ju)域(yu)網(wang)或(huo)者(zhe)一(yi)個(ge)多(duo)用(yong)戶(hu)係(xi)統(tong)，那(na)麼(me)就(jiu)在(zai)整(zheng)個(ge)組(zu)織(zhi)內(nei)進(jin)行(xing)擴(kuo)散(san)。隻(zhi)有(you)在(zai)某(mou)個(ge)點(dian)上(shang)病(bing)毒(du)程(cheng)序(xu)才(cai)會(hui)發(fa)作(zuo)（這是由病毒程序的設計所決定的）。攻擊的時間與多種情況有關，包括：某個時間或日期、特定用戶識別符的出現
、用戶的安全保密等級和一個文件使用的次數。同樣，攻擊的方式也是各種各樣的。所謂的“良性”病毒可能隻是簡單地顯示一個消息，如在去年聖誕節時
，受感染的IBM公司的主要計算機係統顯示節日問候。惡性病毒被設計出來破壞係統。常見的攻擊方式是消除數據
、刪除文件或者格式化硬盤。

病毒程序有哪幾種

？

    有四種類型的病毒程序：外殼型、入侵型
、操作係統型和源碼型。

    外wai殼ke型xing病bing毒du將jiang它ta們men自zi己ji包bao裹guo在zai主zhu程cheng序xu的de四si周zhou，對dui源yuan程cheng序xu不bu作zuo修xiu改gai。外wai殼ke型xing病bing毒du容rong易yi編bian寫xie，這zhe也ye正zheng是shi約yue有you一yi半ban病bing毒du程cheng序xu是shi這zhe種zhong類lei型xing的de原yuan因yin。

    入侵型病毒侵入已有的程序，實際上是把病毒程序的一部分插入到主程序中。入侵型病毒難以編寫，在去除它們時常常會破壞主文件。

    外殼型和入侵型病毒通常攻擊可執行文件，即帶有.COM或．EXE擴展名的文件。當然數據文件也有受攻擊的危險。

    操cao作zuo係xi統tong型xing病bing毒du發fa作zuo時shi用yong自zi己ji的de邏luo輯ji代dai替ti部bu分fen操cao作zuo係xi統tong。這zhe些xie病bing毒du程cheng序xu的de編bian寫xie非fei常chang困kun難nan
，它ta們men一yi旦dan得de手shou就jiu有you能neng力li控kong製zhi整zheng個ge係xi統tong。例li如ru，一yi些xie操cao作zuo係xi統tong型xing病bing毒du把ba自zi身shen的de邏luo輯ji隱yin藏zang在zai那na些xie標biao識shi“壞”的磁盤扇區中。

  源碼型病毒是入侵程序，它們在程序被編譯之前插入到諸如用PASCAL編寫的源程序中
，它們是最少見的病毒程序，因為它們不僅編寫困難
，而且與其他類型的病毒相比
，受它們破壞的主程序數目也有限。

小心第二代網絡病毒

    相信嗎
？網絡病毒會偷錢！ 目前
，因特網已成為電腦病毒傳播的主要渠道。瞧，第二代網絡病毒又來了。無需從網上“抓取”資zi料liao
，你ni的de機ji器qi就jiu會hui感gan染ran上shang第di二er代dai網wang絡luo病bing毒du，這zhe種zhong病bing毒du匿ni藏zang於yu網wang絡luo上shang的de一yi些xie機ji器qi中zhong。一yi旦dan連lian接jie上shang網wang測ce覽lan，你ni的de機ji器qi就jiu可ke以yi說shuo是shi處chu於yu危wei險xian之zhi中zhong了le。

    huitouqiandebingdushudierdaiwangluobingdu。zhezhongbingdubeishejichulaizhihou
，jiufangzhizaiwangshangdeyixiejiqizhong。dangnidejisuanjilianjiedaozheyangdejiqishangshi，bingdujiuhuiruqindaoqiyingpannei，bingsouxunqizhongshifouzhuangyou“Intuit Quicken”licairuanjian。cilicairuanjiandegongnengzhiyijiushizidongzhuanzhang。yidanganrandierdaibingdu


，nideqianjiuhuishenbuzhiguibujiaodibeibingduchengxuzhuandaotasuojianlideqitazhanghushangle。