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Answer 1

The document describes a six-layer approach to operating systems, which includes the Hardware Layer, Kernel Layer, Device Drivers Layer, System Call Interface Layer, Library Layer, and Application Layer, each serving distinct functions from physical devices to user interaction. Additionally, it outlines three major methods of disk space allocation: Contiguous allocation for fast sequential access, Indexed allocation for efficient pointer management, and Linked allocation which uses linked lists for data blocks. These concepts are fundamental for understanding the structure and management of operating systems.

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8 views2 pages

Answer 1

The document describes a six-layer approach to operating systems, which includes the Hardware Layer, Kernel Layer, Device Drivers Layer, System Call Interface Layer, Library Layer, and Application Layer, each serving distinct functions from physical devices to user interaction. Additionally, it outlines three major methods of disk space allocation: Contiguous allocation for fast sequential access, Indexed allocation for efficient pointer management, and Linked allocation which uses linked lists for data blocks. These concepts are fundamental for understanding the structure and management of operating systems.

Uploaded by

Anik Dutta
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
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Download as DOCX, PDF, TXT or read online on Scribd
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1.A. Describe the Six layered approach in the operating system pointwise in brief.

Ans. There are six layers for approaching operating systems in layers:

1. Hardware Layer
 It Includes the physical devices like our CPU, RAM/ROM and I/O devices.
 It is the physical layer of the os which we can touch feel.

2. Kernel Layer
 This is also called the core or heart of the OS.
 It basically handles process management, memory management and low-level controls.

3. Device Drivers Layer


 It provides the specific instructions so that it can be interactful with the hardware devices.
 It basically helpful in communicating between the OS and the firmware.

4. System Call Interface Layer


 This is something that act as a interface between kernel and the users programs.
 It also provides the functions of processes that is related to system level for file creation.

5. Library Layer
 It is the collection of functions and other useful repositories for OS that is needed for
running OS smoothly.
 It simplifies the interaction between the systems calls.

6. Application Layer
 It Includes programs that is installed in the systems and through which user interacts.
 Like word, paint.

1.B. What are the three major methods of disk space allocation?
Ans. The three major methods are mentioned below:

a. Contiguous allocation: This means it allocates a series of consecutive disk blocks to a


single file for use cases. It is useful for making simple structures and provides fast access
to the sequential type of data.

b. Indexed Allocation: This means utilizing or using indexed approach to hold the pointers
in the memory or a disk block in a file. This Is useful to provide fast access and also
provide less workload to system.

c. Linked Allocation: This means each file is consisting a linked list of data blocks, where
each block contains a pointer for the next blocks. It very fast in nature as it knows the
address or linked with another address block directly.

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