# Multi-Processing in Operating System

## Multi-Processing Operating System
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- Multiprocessor Operating System refers to the use of two or more central processing units (CPU) within a single computer system.
- These multiple CPUs are in close communication sharing the computer bus, memory, and other peripheral devices.
- These systems are referred to as tightly coupled systems.

### Types
There are two types of multiprocessing
- Shared nothing MP. The processors share nothing (each has its own memory, caches, and disks), but they are interconnected.
- Shared disks MP.
- Shared Memory Cluster.
- Shared memory MP.

### Examples
Operating systems like Windows NT, 2000, XP, and Unix. Although Unix is one of the most widely used multiprocessing systems, there are others.

### Functions
An operating system has three main functions:
- Manage the computer’s resources, such as the central processing unit, memory, disk drives, and printers.
- Establish a user interface.
- Execute and provide services for applications software.

### Advantages
The advantages of the multiprocessing system are: 
- **Increased Throughput **− By increasing the number of processors, more work can be completed in a unit of time. 
- **Cost-Saving** − Parallel system shares the memory, buses, peripherals, etc.
- Multiprocessor system thus **saves money** as compared to multiple single systems.