Describe features of contemporary operating systems and their structures
Operating systems provide an environment
for the execution of programs and services to programs and users. One set of
operating-system services provides functions that are helpful to the user: User
interface - Almost all operating systems have a user interface (UI). Varies
between Command-Line (CLI), Graphics User Interface (GUI), Batch. Program
execution - The system must be able to load a program into memory and to run
that program, end execution, either normally or abnormally (indicating error).
I/O operations - A running program may require I/O, which may involve a file or
an I/O device.
Another set of OS functions exists for ensuring the efficient operation of the system itself via resource sharing. Resource allocation - When multiple users or multiple jobs running concurrently, resources must be allocated to each of them. Many types of resources - CPU cycles, main memory, file storage, I/O devices. Accounting - To keep track of which users use how much and what kinds of computer resources. Protection and security - The owners of information stored in a multiuser or networked computer system may want to control the use of that information, concurrent processes should not interfere with each other Protection involves ensuring that all access to system resources is controlled. Security of the system from outsiders requires user authentication, extends to defending external I/O devices from invalid access attempts.
Various ways to structure ones are Simple
structure – MS-DOS and Non-Simple Structure -Unix UNIX.
Reference:
Silberschatz, Galvin and Gagne ©2013
Operating System Concepts – 9 th Edition