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Question 1

2026 Slot Set2 PYQ

To keep track of free blocks in a file system, one of the two approaches is generally used - using bitmaps (bit vectors) or using linked lists. Consider that the linked list approach is used to keep track of free blocks in a file system. Assume that the disk size is 16 GB, block size is 2 KB, and block numbers used are 32-bit long. A single pointer of size 4 bytes is used in each block of the list to point to the next block of the list. The number of blocks required to hold the free disk block numbers is ____________. (answer in integer) Note: 1 K = 2^{10} and 1 G = 2^{30}

Question 2

2025 Slot Set1 PYQ

A disk of size 512M bytes is divided into blocks of 64K bytes. A file is stored in the disk using linked allocation. In linked allocation, each data block reserves 4 bytes to store the pointer to the next data block. The link part of the last data block contains a NULL pointer (also of 4 bytes). Suppose a file of 1M bytes needs to be stored in the disk. Assume, 1 K = 2^{10} and 1 M = 2^{20} . The amount of space in bytes that will be wasted due to internal fragmentation is ______. (Answer in integer)

Question 3

2022 PYQ

Consider two files systems A and B, that use contiguous allocation and linked allocation, respectively. A file of size 100 blocks is already stored in A and also in B . Now, consider inserting a new block in the middle of the file (between 5 0^{th} and 5 1^{st} block), whose data is already available in the memory. Assume that there are enough free blocks at the end of the file and that the file control blocks are already in memory. Let the number of disk accesses required to insert a block in the middle of the file in A and B are n_{A} and n_{B}, respectively, then the value of n_{A} + n_{B} is_________.

Question 4

2021 Slot Set1 PYQ

Consider a linear list based directory implementation in a file system. Each directory is a list of nodes, where each node contains the file name along with the file metadata, such as the list of pointers to the data blocks. Consider a given directory foo. Which of the following operations will necessarily require a full scan of foo for successful completion?

File Systems and Storage Allocation PYQs for GATE CS

Solve 4+ File Systems and Storage Allocation previous year questions for GATE CS with answers and detailed solutions. Free sample questions below.

Chapter Roadmap: File Systems and Storage Allocation

Chapter Journey

File Systems & Storage Allocation

1. Contiguous & Linked Allocation

Mapping logical files to physical disk blocks. Trade-offs between linear and chained storage.

2. Directory Search & Operations

Locating files, managing metadata, and analyzing search efficiencies.

3. Free-Space Management

Tracking available disk blocks using bitmaps and linked lists.

Why start here? Understanding how individual files are stored is the foundational step before analyzing directories and free space.

Hero Concept: The File Allocation Problem

The File Allocation Problem

How do we map the logical blocks of a file to the physical blocks on a disk?

Efficient Access

Minimize disk head movement

Space Efficiency

Minimize fragmentation

Dynamic Growth

Expand without moving data

Foundational Strategies

Contiguous Allocation

Blocks are stored in adjacent physical sectors.

Linked Allocation

Blocks are scattered, but chained together via pointers.

File Systems and Storage Allocation: Solved Questions with Step-by-Step Explanations (4 Problems)

Question 1 · Operating System · 2026_Set2 NAT

To keep track of free blocks in a file system, one of the two approaches is generally used – using bitmaps (bit vectors) or using linked lists. Consider that the linked list approach is used to keep track of free blocks in a file system. Assume that the disk size is 16 GB, block size is 2 KB, and block numbers used are 32-bit long. A single pointer of size 4 bytes is used in each block of the list to point to the next block of the list. The number of blocks required to hold the free disk block numbers is ____________. (answer in integer)

Note:

1 K = 2^{10}

and

1 G = 2^{30}

Question 2 · Operating System · 2025_Set1 NAT

A disk of size 512M bytes is divided into blocks of 64K bytes. A file is stored in the disk using linked allocation. In linked allocation, each data block reserves 4 bytes to store the pointer to the next data block. The link part of the last data block contains a NULL pointer (also of 4 bytes). Suppose a file of 1M bytes needs to be stored in the disk. Assume, $1 K = 2^{10}$ and $1 M = 2^{20}$ . The amount of space in bytes that will be wasted due to internal fragmentation is ______. (Answer in integer)

Question 3 · Operating System · 2022 NAT

Consider two files systems $A$ and $B$ , that use contiguous allocation and linked allocation, respectively. A file of size 100 blocks is already stored in $A$ and also in $B$ . Now, consider inserting a new block in the middle of the file (between $5 0^{th}$ and $5 1^{st}$ block), whose data is already available in the memory. Assume that there are enough free blocks at the end of the file and that the file control blocks are already in memory. Let the number of disk accesses required to insert a block in the middle of the file in $A$ and $B$ are $n_{A}$ and $n_{B}$ , respectively, then the value of $n_{A} + n_{B}$ is_________.

Question 4 · Operating System · 2021_Set1 MSQ

Consider a linear list based directory implementation in a file system. Each directory is a list of nodes, where each node contains the file name along with the file metadata, such as the list of pointers to the data blocks. Consider a given directory foo.
Which of the following operations will necessarily require a full scan of foo for successful completion?

A.
Creation of a new file in foo
B.
Deletion of an existing file from foo
C.
Renaming of an existing file in foo
D.
Opening of an existing file in foo

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