What is a Multitasking system and mention its advantages.

Q. What is a Multitasking system and mention its advantages.

Ans=>    

1)    The following are the different views of the operating system.

As a scheduler/allocator:
• The operating system has resources for which it is in charge. 
• Responsible for handing them out (and later recovering them). 
• Resources include CPU, memory, I/O devices, and disk space. 

As a virtual machine:  

• Operating system provides a “new” machine. 

             • This machine could be the same as the underlying machine. Allows many users to believe they have an entire piece of hardware to themselves.

             • This could implement a different, perhaps more powerful, machine. Or just a different machine entirely. It may be useful to be able to completely simulate another machine with your current hardware.

As a multiplexer: 

 • Allows sharing of resources, and provides protection from interference. 

 • Provides for a level of cooperation between users. 

 • Economic reasons: we have to take turns. 

2)    Batch Processing: This strategy involves reading a series of jobs (called a batch) into the machine and then executing the programs for each job in the batch. This approach does not allow users to interact with programs while they operate. 

Time Sharing: This strategy supports multiple interactive users. Rather than preparing a job for execution ahead of time, users establish an interactive session with the computer and then provide commands, programs and data as they are needed during the session. 

Real Time: This strategy supports real-time and process control systems. These are the types of systems which control satellites, robots, and air-traffic control. The dedicated strategy must guarantee certain response times for particular computing tasks or the application is useless.