An OS is a type of software application that is installed on a computer to work as the "brain" that triggers all the hardware to collaborate. It is the software part of a computer that is responsible for the management and coordination of activities in, addition to the sharing of the resources on the computer system. Common PC operating systems include Microsoft Windows, Apple MacOS and Linux.
As a host, one of the functions of running system software is to handle the details of the operation of the hardware. Practically all computer systems, consisting of hand-held computers, desktop computers, and even contemporary video game consoles and CAD workstations, use an operating system of some type.
Modern OS software applications give computers the ability to run numerous application programs at the same time, which is described as multiprogramming. Each program running is represented by a procedure in the OS. The OS supplies an execution environment for each process by sharing the hardware resources so that each application does not have to know the execution of other procedures.
The central processing unit (CPU) of the computer can be used by just one program at a time, in most cases. The OS software allows the CPU to be shared among the procedures using a method known as time slicing or multi-threading. In this way, the procedures take turns using the CPU. Single-user desktop computers (PCs) might streamline this even further by giving the CPU whichever application the user has presently selected, and allowing the user to switch in between applications at will.
Operating system software likewise is responsible for computer security by avoiding unapproved access to the computer system's resources. This is a key factor in prevented unwanted activitiy, like viruses and trojan horses, from taking root. Lots of operating systems also prevent users from accidentally or purposefully interfering with each other. The security policies that an operating system enforces ranges from none in the case of a video game console, to simple password defense for hand-held and home computer, to extremely elaborate schemes for usage in high-security environments. In fact, weak passwords and password re-use is reponsible for most computer on online account break-ins. You should consider using an app like Roboform or LastPass to make this job easier, rather than choosing simple passworks or writing down where they might be discovered. I could go on with this topic.