Computer :: science

ComputerAbout two hundred years before, the word computer started to appear in the dictionary. Some population even didnt know what is a computer. However, roughly of the people today not sightly knowing what is a computer, but understand how to use a computer. Therefore, computer become more than and more popular and important to our society. We pot use computer everywhere and they are very useful and helpful to our life. The speed and accuracy of computer made people felt confident and reliable. Therefore, many important information or data are saved in the computer. Such as your diary, the financial situation of a oil company or some secret intelligence of the military department. A lot of important information can be found in the memory of computer. So, people may ask a question Can we make sure that the information in the computer is safe and nobody can steal it from the memory of the computer? Physical hazard is one of the causes of destroying the data in the computer. For example, send a flood of coffee toward a personal computer. The large(p) disk of the computer could be endangered by the flood of coffee. Besides, human caretaker of computer system can cause as much as trauma as any physical hazard. For example, a cashier in a bank can transfer some money from one of his customers account to his aver account. Nonetheless, the most dangerous thief are not those who work with computer every day, but youthful amateurs who experiment at night --- the cyber-terrorists. The term hacker may have originated at M.I.T. as students jargon for classmates who labored nights in the computer lab. In the beginning, hackers are not so dangerous at all. They just stole computer time from the university. However, in the early 1980s, hackers became a group of criminals who steal information from other peoples computer. For preventing the hackers and other criminals, people need to set up a good security system to protect the data in the computer. The most importa nt thing is that we cannot allow those hackers and criminals entering our computers. It means that we need to chassis a lock to lock up all our data or using identification to verify the identity of someone seeking access to our computers. The most common method to lock up the data is using a password system. Passwords are a multi-user computer systems usual first line of demurrer against hackers.