Operating System Concepts. General Definition. An OS is a program which acts as an interface between computer system users and the computer hardware. It provides a user-friendly environment in which a user may easily develop and execute programs.
OS is responsible for the following activities in connection with process management:
Systems generally first distinguish among users, to determine who can do what
Hardware Interface/ Privileged Instructions
HARDWARELayers of a Computer System
Manages all resources (CPU time, memory space, storage space, I/O and so on) Decides between conflicting requests for efficient and fair resource use
Controls execution of programs to prevent errors and improper use of the computer
There are three classical views
(DISK OPERATING SYSTEM)
1. CD Change Directory Command :
2. DIR (Directory) Command:
3.Wildcard Characters ? * program.
Example 1: Display only those files in the root of C whose name ends with the .COM extension
Example 2: Display those files in the DOS directory which start with DISK, are followed by 4 characters, and have any extension.
5.RMDIR/RD Remove Directory:
6. REN Rename Command:
7. program. COPY
9. PRINT - prints a text file program.
Example : Print two text files
10. TREE - displays the directory structure
Example 1: Display the structure of the DOCS directory
Example 2: Display the directory structure and files of C