计算机专业英语第八单元课文内容

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TSR (Terminate and Stay Resident) abbr. 终止驻留程序 lurk v. 潜伏
resident virus 驻留的病毒 polymorphic adj. 多态的
Introduction to Computer Viruses
Note that worms often take the opposite approach to spread as fast as possible. While this makes their detection virtually certain, they also have the effect of bringing down networks and denying access to the network. This is one of the goals of many worms. During the infection phase, in order to infect a computer, a virus has to have the chance to execute its code. Viruses usually ensure that this happens by behaving like a parasite, that is, by modifying another items so that the virus codes are executed when the legitimate items are run or opened. Good vehicles for viruses include the parts of a disk which contain codes executed whenever that disk is booted. As long as the virus is active on the computer, it can copy itself to files or disks that are accessed.
大连理工大学出版社
worm n. 蠕虫
parasite n. 寄生虫
Introduction to Computer Viruses
Viruses can be transmitted by: △ Booting a PC from an infected medium △ Executing an infected program △ Opening an infected file Common routes for virus infiltration include: △ Floppy disks or other media that users can exchange △ Email attachment △ Pirated software △ Shareware ◆ Attack Phase
Unit Eight
Security
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大连理工大学出版社
Introduction to Computer Viruses
passage One
Training target: In this part, our target is to train your reading comprehension. We have made the flexible sentences strong black and marked the subject, predicate and object of them. Try to grasp the main idea of these sentences.
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Introduction to Computer Viruses
What is computer virus? A computer virus is a special kind of computer program that reproduces its own code by attaching itself to other executable files, and spreads usually across disks and networks surreptitiously. Viruses have many different forms, but they all potentially have two phases to their execution: the infection phase and the attack phase. ◆ Infection Phase The virus has the potential to infect other programs when it executes. We often don’t clearly understand when the virus will infect the other programs. Some viruses infect other programs each time they are executed; other viruses infect only upon a certain trigger. This trigger could be anything: a day or a time, an external event on your PC, a counter within the virus, etc. Virus writers want their programs to spread as far as possible before anyone notices them.
infiltration n. 渗入 email attachment 邮件附件 pirated software 盗版软件
大连理工大学出版社
Introduction to Computer Viruses
Many viruses do unpleasant things such as deleting files or changing random data on your disk or merely slowing your PC down; some viruses do less harmful things such as playing music or creating messages or animation on your screen. Just as the infection phase can be triggered by some events, the attack phase also has its own trigger. Does this mean a virus without an attack phase is benign? No. Most viruses have bugs in them and these bugs often cause unintended negative side effects. In addition, even if the virus is perfect, it still steals system resources. Viruses often delay revealing their presence by launching their attack only after they have had ample opportunity to spread. This means the attack could be delayed for days, weeks, months, or even years after the first initial infection.
大连理工大学出版社
deleting file 删除文件
benign adj. 良性的 bug n. 漏洞
ample adj. 充足的 initial adj. 开始的，最初的
Introduction to Computer Viruses
The attack phase is optional, many viruses simply reproduce and have no trigger for an attack phase. Does this mean these are “good” viruses? No! Anything that writes itself to your disk without your permission is stealing storage and CPU cycles. What is worse is that viruses of “just infect” without an attack phase, often damage the program or disks they infect.. This is not an intentional act of virus, but simply a result of the fact that many viruses contain extremely poor defective codes. As an example, stoned, one of the most common viruses in the past was not intentionally harmful. Unfortunately, the author did not anticipate the use of anything other than 360K floppy disks. The original virus tried to hide its own code in an area of 1.2MB that resulted in corruption of the entire diskette.