Operating Systems

Operating Systems

1. Computer software is divided into two types of software

   • System Programs
     • Manage the operation of the computer
   • Application Programs
     • Solve problems for their users

2. To hide the complexities of the hardware from the user

3. Manage the hardware resources to give controlled and orderly allocation of the:

   • Processors
   • Memories
   • I/O Devices
   • Manage data storage

4. Collection of programs which make the hardware useable

   • Hardware is a collection of resources, stored data are also a resource

5. In a general purpose computer

   • One purpose of the OS is to manage the hardware so that a satisfactory performance is achieved

6. OS systems may be classified according to the resources they manage

   • Processors
     • Processor scheduling
   • Storage
     • Memory management
   • I/O Devices
     • I/O management
   • Data
     • File management

7. One of the challenges facing OS devolopers is keeping their systems flexible enough to to run hardware produced by many different sources

8. Virtual machine

   • Hide the complexities of the hardware and present a machine which is much easier to use
     • Achieved by placing lays of software on top of the hardware
       • Final layers are the user interface
         • And a way for the application programs to access the OS