i) Multiuser OS:
In a multiuser OS, more than one user can use the same system at a same time through the multi I/O terminal or through the network.
For example: windows, Linux, Mac, etc.
A multiuser OS uses timesharing to support multiple users.
ii) Multiprocessing OS:
A multiprocessing OS can support the execution of multiple processes at the same time. It uses multiple number of CPU. It is expensive in cost however, the processing speed will be faster. It is complex in its execution. Operating system like Unix, 64 bit edition of windows, server edition of windows, etc. are multiprocessing.
iii) Multiprogramming OS:
In a multiprogramming OS more than one programs can be used at the same time. It may or may not be multiprocessing. In a single CPU system , multiple program are executed one after another by dividing the CPU into small time slice.
example: Windows, Mac, Linux,etc.
iv) Multitasking OS:
In a multitasking system more than one task can be performed at the same time but they are executed one after another through a single CPU by time sharing. For example: Windows, Linux, Mac, Unix,etc.
Multitasking OS are of two types:
a) Pre-empetive multitasking
b) Co-operative multitasking
In the pre-empetive multitasking, the OS allows CPU times slice to each program. After each time slice, CPU executes another task. Example: Windows XP
In co-operative multitasking a task can control CPU as long as it requires . However, it will free CPU to execute another program if it doesn’t require CPU. Exaample: windows 3.x, multifinder,etc.
A program in execution is known as process. A process can be further divided into multiple sub-processers. These sub-processers are known as threads. A multi-threading OS can divide process into threads and execute those threads. This increases operating speed but also increases the complexity. For example: Unix, Server edition of Linux and windows.
vi) Batch Processing:
A batch processing is a group of processing system in which all the required input of all the processing task is provided initially. The result of all the task is provided after the completion of all the processing. Its main functions are:
- Multiple task are processed
- User cannot provide input in between the processing
- It is appropriate only when all the inputs are known in advance
- It requires large memory
- CPU ideal time is less
- Printer is the appropriate output device
- It is old processing technique and rarely used at present
vii) Online Processing:
It is an individual processing system in which the task is processed on individual basis as soon as they are provided by the user. It has features like:
- Individual task is processed at a time
- User can provide input in between processing
- It is appropriate when all inputs ate not known in advance
- It doesn’t require large memory
- CPU ideal time is more
- Monitor is appropriate output device
- It is modern processing technique and mostly used in present
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