Core software which allows the computer to run as a useful device. Manages hardwar, user interface and any other software. Handles files, acts as security, allocates resorces on networks, schedules the cpu cycles, moves data, provides other sevices.
User interface is being able to interact with the computer: input data in response to outputted data etc to get a result. E.G. GUI allows you to manage windows opened on desktop.
The operating system stores as much as it can all over the computer, so that when it needs opening all parts can be loaded. If extra memory needs to be used it can be accessed. If something isnt used it can be removed from memory.
A device driver is used to interact between the software and the hardware. This is loaded into memory when being turned on or plugged in.
Single user O.S.
Has to deal with one person using one or many different applications at one time.
A supercomputer is shared by many people which can run several different programs for several different people at the same time.
A computer attached to a network e.g. school. Computers can be connected to several pieces of hardware across a network, and usernames can be used on all computers on the network.
User interface types
Command line interface: allows the user to interact directly with the computer system Menu interface: lets you interact with a computer by using screens/menus. Forms interface: a method of interacting with an application. Graphical user interface: uses windows, icons, menus and pointers to show, select and manage the computer.