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。

    waikexingbingdujiangtamenzijibaoguozaizhuchengxudesizhou，duiyuanchengxubuzuoxiugai。waikexingbingdurongyibianxie，zheyezhengshiyueyouyibanbingduchengxushizhezhongleixingdeyuanyin。

    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)。

    會hui偷tou錢qian的de病bing毒du屬shu第di二er代dai網wang絡luo病bing毒du。這zhe種zhong病bing毒du被bei設she計ji出chu來lai之zhi後hou，就jiu放fang置zhi在zai網wang上shang的de一yi些xie機ji器qi中zhong。當dang你ni的de計ji算suan機ji連lian接jie到dao這zhe樣yang的de機ji器qi上shang時shi，病bing毒du就jiu會hui入ru侵qin到dao其qi硬ying盤pan內nei，並bing搜sou尋xun其qi中zhong是shi否fou裝zhuang有you“Intuit Quicken”理li財cai軟ruan件jian。此ci理li財cai軟ruan件jian的de功gong能neng之zhi一yi就jiu是shi自zi動dong轉zhuan帳zhang。一yi旦dan感gan染ran第di二er代dai病bing毒du
，你ni的de錢qian就jiu會hui神shen不bu知zhi鬼gui不bu覺jiao地di被bei病bing毒du程cheng序xu轉zhuan到dao它ta所suo建jian立li的de其qi他ta帳zhang戶hu上shang了le。