1. ITC 4 ESO
3rd TERM
Operating Systems
YEAR

2. DEFINITION
An operating system, or "OS," is software that communicates with the hardware and allows other programs to run.

3. 2. EVOLUTION OF OPERATING SYSTEMS
MS-DOS : MicroSoft Disk Operating System was developed by Microsoft in 1981

4. Microsoft Windows: In 1995 appeared the first Windows OS, windows 95
Microsoft Windows: In 1995 appeared the first Windows OS, windows 95. Nowadays Windows is the most used OS.

5. GNU / LINUX is similar to UNIX based on the standard POSIX that works with comands.

6. Mac OS is the computer operating system for Apple Computer's Macintosh line of personal computers and workstations.