Computer Basics
Operating System
User->Programs->Operating System->Hardware
Operating System (O/S):
• It is system software that manages resources (hardware, software and applications) of computer
• It is an intermediary between user and computer hardware
• It loads the application program to memory and allocates it to CPU
• Manages security of the system
• Examples of operating system are Windows, Macintosh, Unix, Linux, IOS, Android etc
Ways the user interacts with Operating system:
• Through Graphical User Interface (GUI), with the help of graphics and icons. The input devices are mouse and keyboard
• Through touch screen GUI. It is same as GUI but fingers/stylus is used to operate. Examples are mobile phones
• Through Command Line Interface. In this case user has to type instructions. The input device
• Through voice. Example: Siri of iPhone
Functions of Operating System:
• Process Management
o Operating System has to manage multiple processes running by wisely allocating CPU among processes so that the tasks are completed in minimum time
• Memory Management
o Operating System has to allocate memory between processes and free memory when not required by a process
• Security Management
o Operating System has to see that authorised users access the applications.
o Passwords help in performing this function
• Storage Management
o Operating System manages storage resources to improve performance
• Resource Management
o Operating System manages the resources between processes
Types of Operating System:
• Real-time operating system
o The response time is very quick.
o The input is processed, and output given very fast
• Time-sharing operating system
o Multiple tasks get equal opportunity, and each user gets CPU time as if using a single system.
o These are also called multitasking systems
• Batch operating system
o The operator groups similar jobs into batches and sent to the computer.
o The operating system does not directly interact with the computer
• Distributed operating system
o In this type of operating system various computers which are connected communicate with each other.
o Remote access is possible here
• Networking operating system
o Many clients are connected to the server and share resources over a private network
Advantages of Operating System
• Mediates between hardware and software
• User need not know the details of the hardware
• Provides the environment to execute applications
• Easy to use with Graphic User Interface
• Provides resources to the computer system
Disadvantages of Operating System
• Problem of data loss if there is issue with Operating system
• Not secure
• Expensive
Examples of Operating System
• Windows
• Mac
• Ios
• Android
• Linux
• Unix
• Ubuntu