Operative System

Operative System

1. ¿What is OS?

   • Operating System is a software, which makes a computer to actually work.
     • ¿What OS does?
       • An operating system performs basic tasks such as
         • controlling and allocating memory, prioritizing system requests, controlling input and output devices, facilitating networking and managing file systems.

2. Structure of Operating System:

   • Application programs: This is dependent on users need. Ex. Railway reservation system, Bank database management etc.,
   • Software (Operating System): Software includes process management routines, memory management routines, I/O control routines, file management routines.
   • Hardware: Hardware consists of CPU, Main memory, I/O Devices, etc,
   • System programs: This layer consists of compilers, Assemblers, linker etc.

3. Multiprogramming:

   • Multiprogramming is a technique to execute number of programs simultaneously by a single processor. In Multiprogramming, number of processes reside in main memory at a time. The OS picks and begins to executes one of the jobs in the main memory. If any I/O wait happened in a process, then CPU switches from that job to another job. Hence CPU in not idle at any time.

4. Operating Systems functions:

   • The main functions of operating systems are: Program creation Program execution Input/Output operations Error detection Resource allocation Accounting protection