Skip to main content

Computer virus and types of computer virus-computer world

 Computer virus

 A computer virus is a small program that can copy itself and infect the system without the permission of other user. How we recognize viruses virus if It meet to criteria

 It must execute itself

 It must application itself, it may replace other executable file with a copy of the virus infected file.

 viruses can increase their chance of spreading two other computers by affecting files on a network file system or a file system that is accessed by another computer, it can carried it on a removable medium such as a floppy disk, CD, DVD or USB drives. The term "computer virus" means is sometime used as a catch all phrase to include all type of Malware. File infected virus boot sector viruses,  Master boot record viruses, multi. participate. viruses and macro viruses. This classification depend upon their target area a mode of operation. 

virus can be divided into two types based on their behavior when They are executed. 

  1. Non resident viruses : Non resident viruses immediately search for other host that can be infected, infect those targets, and transfer control to the application program they infected.
  2. Resident viruses : Resident viruses to note search for host when they are started. Instead resident virus load itself into memory on execution and transfer control to the host program. The virus stay active in the background and infects new post when those files are accessed by other programs for the operating system itself.

Comments

Post a Comment

Popular posts from this blog

Deadlock in operating system-computer world

  Deadlock in operating system-computer world Deadlock :  In a multi-programming environment, many process may complete for a minute number of resources. A process make a request for a resource and if the resource is not available at that time, the process enter In a waiting state. A waiting state process is never again-able to change state because the resource it has requested is held by other waiting process. This situation is called deadlock. So we can say that a process is said to be deadlock when it is waiting for an event or resources which will never occurs.   so we can say that in this situation none of the process gets executed  since the resource it needs, is held by some other process which is also waits for some other resource to be released.  Let's assume that there are three process P1, P2, p3 and three different resources R1, R2 and R3. R1 is assigned to p1, R2 is assigned to P2 and R3 is assigned to P3.   After sometime P1 demands for R1 which is being used by  P2.
9 comments
Read more

CPU scheduling in operating system-computer world

  CPU scheduling in operating system CPU scheduling :  Whenever the CPU becomes idle, the operating system must select one of the processes. The selection process is carried by the short-term scheduler. The scheduler selects a process from the processes in memory that that are ready to execute and allocate the CPU to that process. The objective of time sharing is to skip the CPU among processes that user interact with each program while the program is in running position. As we discuss above the process scheduler selects an process for execution on the CPU. There will never more then one running process for a single processor system. If there are many processes, the process will have to wait until the CPU is free CPU Scheduling is basis of multi-programming operating system. In CPU scheduling many processes are kept in memory at a time. The CPU scheduler select a process from the many processes. The process scheduler scheduled different processes to be assigned to the CPU based on part
3 comments
Read more

Single partition allocation, Multiple-partition allocation and Fixed Equal-size partitions in operating system-computer world

  Single partition allocation, Multiple-partition allocation and Fixed Equal-size partitions in operating system Single partition allocation In this scheme operating system is residing in law memory and user process are executing in higher memory. Advantages It is simple  It is easy to understand and use Disadvantages User job is limited to the size of available memory. It leads to poor Utilization of processor and memory. Multiple-partition allocation  It is the simplest method for allocating  memory is divided memory into several fixed size partitions. Fixed Equal-size partitions It divides the main memory Into equal number of fixed sized partitions, operating system occupies some fixed portion and remaining portion of main memory is available for user processes. Advantages It supports multi programming. A process whose size is less then or equal to the partitions size can be loaded into any available partition. Disadvantages If a program is big to fit into a partition use overlay te
Post a Comment
Read more