ccna 200-301 exam schedule

ccna 200-301 exam schedule.Viruses are malware that performs certain undesired and harmful specific functions on a computer. Worms execute arbitrary code and install copies of themselves into the memory of the infected computer, and the infected computer re-infects other hosts. The main purpose of a worm is to make a copy of itself and then spread it across the network between systems.Trojans are a class of malware that do not replicate themselves, usually contain malicious code, and that look similar to something else (such as a legitimate application or file). When an infected application or file is downloaded and opened, the Trojan will attack the end device from the inside.1.2.1.2 Comparison between human viruses and computer virusesThe term virus is traditionally used to refer to an infectious organism that requires a host cell to grow and replicate. A University of Southern CaliforniaA student at the University of Southern California, Frederick Cohen, introduced the term "computer virus" in 1983. A computer virus (referred to in the rest of this book as aviruses) are programs that can replicate themselves and infect a computer without the user noticing.A virus is a malicious piece of code that attaches to a legitimate program or executable file. Most viruses require end-user activation and can lie dormant for a period of time, then strike at a specific time or date. A simple virus may install itself in the first line of code of an executable file. When activated, the virus may check the disk and look for other executables so that it can infect all the files it has not yet infected. Viruses can be harmless, such as those that display a picture on the screen, destructive, such as those that modify or delete hard disk files, or they can have the ability to mutate to evade detection.In the past, viruses were usually spread via floppy disks and computer modems. Nowadays, most viruses are spread via USB memory sticks, CDs, DVDs, network shares, or email. Email viruses are the most common type of virus today.1.2.2 Worms1.2.2.1 Worms