What are layered structures and its benefits in OS?

Operating SystemHardwareSoftware & Coding

The operating system can be broken into pieces that are smaller in size and this type of operating system is called MS-DOS, an UNIX OS and OS which is having greater control over the computer.

When a layered structure is used then we can divide the OS into different layers and the OS is broken into a number of layers, the bottom layer is layer 0 and highest layer is layer N and a user interface connects all layers with each other.

The different layers in a layered structure are as follows −

  • Layer 0 deals with the allocation of processors, it always switches between processes when interrupts occur or timers expire.

  • Layer 1 function is memory management. It allocated space for processes in main memory.

  • Layer 2 handled operator-process communication between each process and the operator console.

  • Layer 3 managing the I/O devices and buffering the information streams.

  • Layer 4 deals with the user programs.

  • In Layer 5, the system operator process was located.

The figure given below depicts the layered structure in an operating system −

Benefits

The benefits of using layered structure are as follows −

  • Different OS are able to reuse the functionality exposed by your layers.

  • We can distribute layers over multiple physical tiers. This can make a very good impact on your OS by improving performance (sometimes), scalability and fault tolerance.

  • The maintenance of the OS is easier because of the low coupling between layers.

  • Adding more functionality to the OS is made easier.

  • Layers make the OS more testable.

  • Building well formed layers makes the orientation in OS easier.

  • Having an OS not layered means that you have to deal with all security threats in one place which is very difficult.

  • Having an OS that is distributed to layers makes it much easier to design and implement.

  • Without a good deployment plan it is not trivial to distribute your layers over multiple physical tiers in distributed computing. You need to plan ahead your layers when you create a distributed OS.

Functions

The function of each layer is shown below −

LayerFunction
5The Operator
4User programs
3Input/Output management
2Operator-process management
1Memory and drum management
0Processor allocation and multiprogramming
raja
Published on 29-Nov-2021 10:32:59

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