Chapter 11: File System Implementation

A comprehensive set of flashcards covering key concepts in File System Implementation from Chapter 11 of Operating System Concepts Essentials.

File Structure

Logical storage unit; a collection of related information.

File System

Resides on secondary storage (disks) and provides a user interface to storage.

File Control Block

Storage structure consisting of information about a file.

Device Driver

Controls the physical device.

Layered File System

Organizes file systems into layers, including application programs and the I/O control.

Boot Control Block

Contains info needed by the system to boot the OS from that volume.

Volume Control Block

Contains volume details including total number of blocks and free block pointers.

Directory Structure

Organizes the files with names and inode numbers.

Per-File File Control Block (FCB)

Contains details about the file such as inode number, permissions, and size.

NTFS

New Technology File System that uses relational DB structures.

Virtual File System (VFS)

Provides an object-oriented way of implementing file systems.

API

Application Programming Interface; a set of system calls for interaction with the file system.

Linear List Directory Implementation

A list of file names with a pointer to the data blocks; simple but time-consuming.

Hash Table Directory Implementation

A linear list with a hash data structure that decreases search time.

Contiguous Allocation

Each file occupies a set of contiguous blocks for best performance.

External Fragmentation

Unused storage space that cannot be used due to fragmentation.

Extent-Based Systems

File systems that allocate disk blocks in extents.

Linked Allocation

Each file is a linked list of blocks; no external fragmentation.

File Allocation Table (FAT)

A table indexed by block number used for file allocation.

Indexed Allocation

Each file has its own index block of pointers to its data blocks.

Free Space Management

Managing free disk blocks through linked lists or counts.

Clustering

Improves efficiency by grouping blocks together but may cause internal fragmentation.

Logical to Physical Mapping

Mapping logical block addresses to physical block addresses.

I/O Control Devices

Layer in the file system that manages I/O operations.

User Space

Area in memory where user applications run.

Kernel Memory

Memory allocated for the operating system and its processes.

Inode

Data structure containing file metadata.

File System Implementation

Process of implementing system calls and structures for file systems.

Directory Entry

Information in a directory that points to data blocks.

Disk Block

Smallest unit of data that can be read from or written to disk.

Background Job

A job that runs in the background of operating systems.

File Name

Identifier used to access files in the file system.

File Size

The total amount of data contained within a file.

Kernel

Core part of the operating system managing operations.

System Call

A programmatic way for a program to request a service from the operating system.

Storage Medium

Physical medium where data is stored.

Data Blocks

Units of storage on disks used for storing file data.

File Metadata

Details and attributes about a file including size and permissions.

Network File System

A file system that allows file access over a network.

Collision

When two file names hash to the same location in a hash table.

Chained-Overflow Method

A method to resolve collisions in a hash table.

Relational Database Structures

Database structure used by NTFS for organizing file information.

Off-line Compaction

Cleaning of disk space that requires downtime.

On-line Compaction

Cleaning of disk space performed without downtime.

Directory Implementation Efficiency

Time and space complexities of implementing directory structures.

B+ Tree Directory Structure

A data structure used to keep directory entries ordered.

Free-Space List

A list indicating free blocks available on the disk.

Counting in Free-Space Management

Keeping track of the number of free blocks in a contiguous space.