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The monitors at the gates of the plant building gave alarms________．
A.only whell Watras was leaving the building
B.whenever Watras's co-workers were leaving the building
C.only when Watras was passing through one day
D.whenever Watras was passing through．them
答案
更多“The monitors at the gates of the plant building gave alarms________．A.only whell Watras”相关的问题
第1题
What's the use of the position tracker on the HMD？
A．It monitors the location of the user's head.
B．It transfers information to update audio signals.
C．It measures the user's finger movements.
D．All of the above.
第2题
The major disadvantage of on-line ads is that, due to the limited screen space of computer monitors, many of them are too small .()
第3题
Computer Security
计算机安全
The techniques developed to protect single computers and network-linked computer systems from accidental or intentional harm are called computer security. Such harm includes destruction of computer hardware and software, physical loss of data, and the deliberate invasion of databases by unauthorized individuals.
Data may be protected by such basic methods as locking up terminals and replicating data in other storage facilities. More sophisticated methods include limiting data access by requiring the user to have an encoded card or to supply an identification number or passworＤ. Such procedures can apply to the computer data system as a whole or may be pinpointed for particular information banks or programs. Data are frequently ranked in computer files according to degree of confidentiality.
Operating systems and programs may also incorporate built in safeguards, and data may be encoded in various ways to prevent unauthorized persons from interpreting or even copying the material. The encoding system most widely used in the United States is the Data Encryption Standard (DES), designed by IBM and approved for use by the National Institute of Standards and Technology in 1976. DES involves a number of basic encrypting procedures that are then repeated several times. Very large scale computer systems, for example, the U. S. military Advanced Research Project Agency Network (ARPANET), may be broken up into smaller subsystems for security purposes, but smaller systems in government and industry are more prone to system-wide invasions. At the level of personal computers, security possibilities are fairly minimal.
Most invasions of computer systems are for international or corporate spying or sabotage, but computer hackers[1]may take the penetration of protected databanks as a challenge, often with no object in mind other than accomplishing a technological feat. Of growing concern is the deliberate implantation in computer programs of worms or viruses[2]that, if undetected, may progressively destroy databases and other software. Such infected programs have appeared in the electronic bulletin boards available to computer users. Other viruses have been incorporated into computer software sold commercially. No real protection is available against such bugs except the vigilance of manufacturer and user.
Anti-Virus Programs to the Rescue
There is a wide range of virus protection products available to combat the 11,000 known viruses that currently plague personal computers. These products range in technology from virus scanners to terminate and stay resident monitors, to integrity checkers to a combination of the three. Each of these techniques has its associated strengths and weaknesses.[3]
The most fundamental question that must be asked when considering and evaluating automated anti-virus tools is "how well does the product protect against the growing virus threat？" When developing a security program, companies must think long term. Not only must you choose a form of protection that can detect and safely eliminate today's varieties, but you must consider tomorrow's gully wash as well.[4]The real challenge lies in securing against the 38,000 new species that are expected to appear within the next two years. The 11,000 known viruses that have been documented to date represent what is only the tip of the iceberg in terms of what tomorrow will bring.
Virus Protection Methods
Today there exists three broad based categories of anti-virus techniques: scanners, memory resident monitors (TSRs), and integrity checkers.
Virus Scanners
Virus scanners are programs designed to examine a computer's boot block, system memory, partition table, and executable files,[5]looking for specific code patterns that are typical to known virus strains. Generally, a virus scanner is able to identify a virus by name and indicate where on the hard drive or floppy drive the infection has occurreＤ. Virus scanners are also able to detect a known virus before it is executeＤ. Virus scanners do a good job of detecting known viruses. They are generally able to find a virus signature if it is present and will identify the infected file and the virus. Some are faster than others, which is an advantage when checking a hard disk with thousands of files. But virus scanners have several major weaknesses.
First and foremost, scanners are completely ineffective against any virus whose code pattern is not recognizeＤ. In other words, scanners cannot identify a virus if they don't have a signature for it. Also, many of today's viruses are designed specifically to thwart scanners. These so-called stealth viruses know the correct file size and date for a program (i. e. , what they were before the virus infected them). They will intercept operations that ask for that information and return the pre-infection values, not the actual ones during a disk reaＤ. Some viruses can mutate slightly so that the original signature will be rendered ineffective against the new strain and can even result in file damage if recovery is based off virus signature assumptions. A new wave in virus authorship is the creation of self mutating viruses. These viruses infect a file in a different way each time, so it cannot be identified by a simple pattern search, rendering virus scanners ineffective.
Secondly, virus scanners are quickly rendered obsolete and require frequent, costly and time-consuming updates—which may be available only after serious damage has been done. The burden of constantly updating virus scanners, even if provided free of charge, can be a huge burden. In a corporate environment, where thousands of personal computers must be protected, simply distributing scanner updates in a timely and efficient manner and making sure they are installed is an enormous task.
I ntegrity Checkers
This is a relatively new approach, compared to scanners and monitors. Integrity checkers incorporate the principle modification detection. This technique safeguards against both known and unknown viruses by making use of complex file signatures and the known state of the computer environment rather than looking for specific virus signatures.
Each file has a unique signature (which is like a fingerprint-a unique identifier for that particular file) in the form of a CRC or a checksum. Changes in any character within the file will probably change the file's checksum. For a virus to spread, it must get into system memory and change some file or executable code.
An integrity checker will fingerprint and register all program files and various system parameters, such as the boot block, partition table, and system memory, storing this information in an on-line database. By recalculating the files checksum and comparing it to the original, integrity checkers can detect file changes that are indicative of a virus infection.
Industry experts agree that integrity checking is currently the only way to contend with tomorrow's growing virus threat. Since this methodology is non-reliant on virus signatures, it offers protection against all potential viruses, today's and tomorrow's.
Additionally, stealth viruses have historically been able to bypass integrity checkers. The only way users can be certain that their computer is 100 percent clean is to boot the system from a clean, DOS based disk and check the integrity of the information stored on this disk with the current state of the hard drive. Called the "Golden Rule" in virus protection, most integrity checkers fail to follow this security principle.
System Administrator
System Administrator, in computer science, is the person responsible for administering Use of a multiuser computer system, communications system, or both. A system administrator performs such duties as assigning user accounts and passwords, establishing security access levels, and allocating storage space, as well as being responsible for other tasks such as watching for unauthorized access and preventing virus or Trojan Horse[6]programs from entering the system. A related term, sysop (system operator), generally applies to a person in charge of a bulletin board system, although the distinction is only that a system administrator is associated with large systems owned by businesses and corporations, whereas a sysop usually administers a smaller, often home- based, system.
Hacker
Hacker, in computer science, originally, is a computerphile, a person totally engrossed in computer programming and computer technology. In the 1980s, with the advent of personal computers and dial up[7]computer networks, hackers acquired a pejorative connotation, often referring to someone who secretively invades others computers, inspecting or tampering with the programs or data stored on them. (More accurately, though, such a person would be called a cracker.) Hacker also means someone who, beyond mere programming, likes to take apart operating systems and programs to see what makes them tick.
Notes
[1]computer hackers：电脑黑客，指非法侵入他人计算机进行浏览或篡改程序或计算机上所存数据的人。
[2]Of growing concern is the deliberate implantation in computer programs of worms or viruses．越来越令人担心的是蓄意地把蠕虫程序或病毒植入计算机程序。
[3]These products range in technology from virus scanners to terminate and stay resident monitors，to integrity checkers to a combination of the three．Each of these techniques has its associated strengths and weaknesses．这些防病毒的产品从技术上有病毒扫描到内存驻留监督程序，从完整性检查到三者的结合程序，每一种有其相关的优点和缺点。
[4]gully wash：gully冲沟，檐槽。此处字面意义是“冲水槽”，可翻译成“但必须从长计议”或“考虑到未来的问题”。
[5]to examine a computer's boot block，system memory，partition table，and executable files：检查计算机的引导块、系统内存、分区表和可执行文件。
[6]Trojan Horse：特洛伊木马，一种欺骗程序。在计算机安全学中，一种计算机程序，表面上或实际上有某种有用功能，而含有附加的(隐藏的)可能利用了调用进程的合法特许来危害系统安全的功能。
[7]dial up：拨号呼叫，访问计算机的一种方法。计算机通过调制解调器连接到电话线路上，拨号上网。
Choose the best answer for each of the following:
第4题
How Green Is Your Computer？
您的计算机环保吗？
Reusable big handbag？ Check. Prius？ Check. Rooftop solar panels？ Check[1]. In the bid to secure your green bragging rights, you have the usual suspects covered.
But what about your personal computer？
After all, the object that, via the Internet, can provide you with more information on how to lead an environmentally sound life can also be one of the things that contributes to the very same problem.
Consider the following: A standard-issue PC, left on all the time, which is a not- uncommon situation, consumes 746 kilowatts per hour a year, according to estimates from the U. S. Environmental Protection Agency.[2]By comparison, a refrigerator uses about 500 kilowatts a year. Surely there are things that users can do to reduce their computer's environmental footprint. Read on to learn ways to run your PC more efficiently, make environmentally-intelligent purchasing decisions and to dispose of an old computer properly.
Power Corrupts
The first piece of advice is the simplest: Don't leave your computer on all the time. Shutting it down at night should reduce its power consumption by around 500 kilowatts annually. In addition, your computer should be set to go to sleep after periods of inactivity. Different parts of your system can be set to sleep at different times: Setting your energy-saving preferences to put your hard drive to sleep after 15 minutes of inactivity is a good benchmark; your entire computer, which takes more time to wake up, should be set to go to sleep after 30 minutes.
And dispose of your screensaver. Screensavers can use your hard drive to power up and photo screensavers require the extra use of a graphics card, which means you' ll have the hard drive, graphics card and monitor all in use.
Screensavers are "a throwback from the days of really old-school CRT monitors[3]," Barbara Grimes, spokeswoman for the Climate Savers Computing Initiative[4], said of cathode-ray tubes. "It's never been an energy-saving feature. "
There's also the issue of "phantom" or "vampire" power[5]: Just because your computer or laptop is shut down doesn't mean it's not using energy. Almost every piece of electronics uses power even when it is turned off. For example, your television turns on instantly because it is actually a little bit on already. In the case of your desktop, your computer stays in standby mode so it can keep data in its memory, its clock accurate and other functions. This means the average desktop PC wastes half its power.
To combat the vampires, take your computer (and peripherals) and plug it into a master power strip like the Smart Strip Power Strip[6], which can sense which devices have been turned off and then cut all power to them.
Finally, download a free power-management tool. These applications will show you how much energy you can save by adjusting various settings and will make those adjustments for you in one click. Google's Energy Saver[7]will, in addition, show you the collective energy savings of all users of the product; it also integrates into the Google's own Desktop application. Verdiem's Edison software[8], shows users estimated annual savings in terms of money, energy and carbon dioxide emissions. Edison's power management tool lets users choose how aggressive they want their energy savings to he by letting them slide the bar towards or away from the "save more" or "save less" tabs.
Out with the Old？
If you do decide to purchase a new computer, make sure that you choose both a computer and monitor that are Energy Star[9]computer. Energy Star computers must meet energy-use guidelines established by the environmental agency in three areas: standby, active, and sleep modes.
The Electronic Product Environmental Assessment Tool[10], or Epeat, is another environmental certification that evaluates electronic products according to 51 environmental criteria. To qualify for Epeat registration, the product must meet all 51.
In general, laptops are greener than desktops because they have been designed with power sensitivity.in mind, so they tend to use less power when plugged in than desktops. But desktops are easier to upgrade, and therefore may last longer.
Newer computers tend to be more energy efficient than older models. For example, Energy Star-qualified computers starting from July 2007 come with power management preenabled.
As for whether Macs[11]are greener than Pcs？ "It's system by system," said Grimes, the Climate Savers Computing Initiative spokeswoman. "Apple[12]is one manufacturer and when you say PC, there are dozens. They' re all using Intel processors or AMD processors. Apple is not using a proprietary processor anymore so they' re getting a lot more similar at the hardware level. "
One place where there is a difference is in how certain manufacturers' products are made. Apple, for example, has said it will "completely eliminate the use of polluting materials in its products, and arsenic in the glass of flat-panel displays by the end of 2008. " Unfortunately, that effort has not spread as quickly across the industry as some would like.
"I wish I could say that a lot of companies have eliminated their chemicals or had made some significant improvements, but that's just not where the industry is. " said Barbara, national coordinator of the Electronics Take Back Coalition.[13]
Reduce, Reuse, Recycle
When it comes to recycling your computer, picking the right program is key. If done right, recyclers should reuse the parts they can and manage waste responsibly, which means making sure that parts don't go to countries with poor eco-track records, and that items that do get exported (like circuit boards and leaded glass) to green-friendly sites.
In 2005, used or unwanted electronics amounted to about 1.9 million to 2.2 million tons of waste. Of that number, about 1.7 million tons were disposed of in landfills, and only 345,000 to 379,000 tons were recycled, according to the environmental agency.
The problem is that it's hard to figure out who's dumping and who's not. "There's no such certification program," said Barbara, "which would help promote responsible recycling and green design in the electronics industry. " Her organization, Computer Take Back, conducts initial screenings. Will people know 100 percent？ No, but it's a start.
Computer manufacturers like Apple, Hewlett Packard[14]and Sony[15]offer recycling programs, but Dell goes even further: It will recycle any Dell[16]brand product-no matter when it was bought-free (including pick up). Dell will also pick up other product brands for free if the consumer purchases a new Dell. Concerning manufacturer recycling programs, Kyle added that with a number of manufacturers, "you have to either pay them or you have to buy a new computer to get them to take your old PC back for free. There's a huge disconnect between what people want to do and what they can do, and that's where the manufacturers need to step up. "
Notes
[1] Reusable big handbag？ Check. Prius？ Check. Rooftop solar panels？ Check. In the bid to secure your green bragging rights, you have the usual suspects covered. Prius,普锐斯汽车(一汽丰田)，世界首款混合动力车。在仅利用电动机驱动时对环境没有任何污染；而且在减速、制动和下坡时还能回收能量以供再利用。
译文：你的大手提包可以多次使用吗？请检查。开的是普锐斯汽车吗？请检查。屋顶有太阳能板呢？请检查。为了确保你享有的环保权利，应当注意这些方面。
[2] U.S．Environmental Protection Agency美国环境保护署，简称EPA，成立于1970年，总部设在华盛顿。其任务是为人类提供更清洁和健康的自然环境，制订战略计划，年度报告和政策方针，在国家的环境科学及相关调查、教育和评估方面具有领导地位。
[3] CRT monitor映像管显示器，是一种使用阴极射线管(Cathode Ray Tube)的显示器。
[4] Climate Savers Computing Initiative电脑产业拯救气候计划。是一个国际信息与通讯产业环保组织，一个以计算机节能化为目标的非营利性团体。
[5]“phantom”or“vampire”power“幻影”电源或“吸血鬼”电源，指电器在被关掉后的能耗。
[6] Smart Strip Power Strip 一种智能型电源线，一旦计算机、屏幕、打印机或DVD进入省电模式，这种电源线会自动侦测到此状态，然后自动断电。
[7] Google's Energy Saver使用Google桌面的人可以免费下载Energy Saver这一小工具，它适用于Windows XP和Vista，可以为用户启用并优化显示器、硬盘和电脑的电源管理设置，还能显示您节省的电量，以及使用该小软件的人共同节省的电量。
[8] Verdiem's Edison software美国编程设计公司Verdiem推出的一款计算机节能软件Edison，用来降低个人电脑的耗电量，它能深入计算机操作系统，监控用电量，把系统调整到最“省电”的模式，还能帮用户设定省电功能，计算出节省了多少电费，少排放了多少二氧化碳等。
[9] Energy Star能源之星。1992年由美国环保署(EPA)启动的一项主要针对消费性电子产品的能源节约计划。在PC电源、显示器或是其他电器产品等上面常会见到“Energy Star”标志，表示其通过了美国环保署的低功耗认证，体现了产品良好的节能性能。
[10] Electronic Product Environmental Assessment Tool(美国)电子产品环境影响评价工具，简称EPEAT，是用来对电子产品在其寿命周期中就环境造成的影响进行评估的工具，是美国政府为了满足日益增长的大型机构采购绿色电子产品的需求而设计的。EPEAT由一系列产品评估标准和产品应用、维护管理系统两部分构成。
[11] Mac苹果机，苹果电脑。苹果电脑公司(Apple)于1984年成功推出Machintosh(简称Mac)个人电脑，产生了极大反响。苹果电脑在PC历史上是一座丰碑，以丰富的图形界面改变了单调的文字界面，以灵活的鼠标操纵取代了呆板的键盘控制，一时间畅销世界各地，但近年来市场份额出现下降。
[12] Apple苹果电脑公司，是美国著名的老牌计算机公司，成立于1977年，是个人电脑最早的倡导者和著名生产商。它所生产的苹果系列电脑，包括iMac，PowerMac，ibook，Powerbook等产品线的众多硬件产品，一直是个人电脑市场的主流产品之一，并曾提出过很多新概念，其产品也掀起过多次流行潮，风行一时。
[13] Electronics Take Back Coalition(美国)电子产品回收联盟。位于旧金山，致力于促进和推广消费类电子产品的回收。
[14] Hewlett Packard惠普公司。世界最大的计算机公司之一，该公司制造的产品正被个人使用或用于工业、商业、工程、科学和教育等领域。
[15] Sony索尼公司，创立于1946年5月，总部在日本东京，为横跨电子、金融、娱乐领域的世界巨擘。
[16] Dell戴尔公司。总部设在德克萨斯州奥斯汀，是全球领先的IT产品及服务提供商，其业务包括帮助客户建立自己的信息技术及互联网基础架构。
