Real Time OS

Real Time OS: 

A real time system is often using as a control device in a dedicated application. Transducers and sensors bring data to the computer. The computer must analyse the data and possibly adjust controls to sensor inputs. Systems which control scientific experiments, medical systems, industrial controls systems and some display systems are the examples of real time systems.

Figure: Real Time OS

Time Sharing OS

Time Sharing OS: 

Time sharing is a mechanism to provide simultaneous, interactive use of a computer system by many users in such a way that each user in given the impression that he can his own computer. It uses multi-programming with a special CPU scheduling algorithm to achieve this. A time sharing system has many user terminals simultaneously connected to the same computer. Using these terminals, multiple users can simultaneously work on the system. Example: Windows 95/ 98/ 2000.

Figure: Time Sharing OS

Multi-programming OS

Multi-programming OS: 

Multi-programming is the interleave execution of two or more processes be a single CPU computer system. Here, jobs are broadly classified into the following two types:

1. CPU-bound jobs.
2. I/O-bound jobs.

Requirements of multi-programming system:

1. Large memory
2. Memory protection
3. Job status preservation
4. Proper job mix
5. CPU scheduling

Example: UNIX, IBM VM

Figure: Multi-programming OS

Multi-Processing OS

Multi-Processing OS: 

Multiprocessing is the simultaneous execution of two or more processes by a computer system having more than one CPU.
There are two types of multiprocessing systems. They are:

1. Tightly coupled system.
2. Loosely coupled system.

Example: Linux, windows

figure: Multi-Processing OS

Batch Processing OS

Batch Processing OS: 

The batch processing mechanism helped reducing the idle time of a computer cause transition from one job to another and not require any operator intervention. Example: MS-DOS

Figure: Batch Processing OS