Chapter 3: File Management

Vocabulary flashcards covering Operating System File Management, including file structures, organization techniques, directory models, allocation methods, free space management, access control mechanisms, and backup strategies.

File

A named collection of data residing on secondary storage that can be manipulated as a single unit by operations such as open, close, create, destroy, copy, rename, and list.

File System

An operating system component that organizes files, manages access to data, and is responsible for storage management, file integrity, and access methods.

File Management System

A system used by an operating system to keep track of files and provide a convenient programming environment for users.

Byte Sequence

An unstructured or linear file structure consisting of a sequence of bytes, commonly used in Unix and Windows.

Record Sequence

A file structure where a file is viewed as a sequence of fixed or variable length records, historically used in punch card systems.

Tree File Structure

A file structure where records contain keys and are organized in a tree (typically a B-tree sorted on key), commonly used in mainframes for commercial data processing.

Volatility of Data

A file characteristic describing the frequency with which additions and deletions are made to a file.

Activity of File

A file characteristic defined as the percentage ($\%$) of records processed during a given run.

Response Time

The amount of time a user is willing to wait before a requested file operation is completed.

File Organization

The technique of arranging records of a file on secondary storage and selecting the characteristics of the storage medium.

Sequential File Organization

A file organization method where records are stored and retrieved serially, one after another.

Direct File Organization (Random)

A file organization technique using relative addresses computed via hashing algorithms, allowing users to access any record in any order without starting from the beginning.

Collision

A disadvantage in direct file organization occurring when several records with unique keys produce the same logical address via a hashing algorithm.

Indexed Sequential File Organization

A file organization technique that combines sequential and direct access by arranging records in logical sequence by key and maintaining an index file of physical block locations.

Directory

A file containing the names and locations of other files in order to organize and quickly locate them within a file system.

Directory Entry

A record within a directory storing information about a file, including file name, location, size, type, access rights, and access/modification/creation timestamps.

Single-Level Directory Structure

A directory organization where all files are contained in a single common directory.

Two-Level Directory Structure

A directory organization featuring a Master File Directory (MFD) that points to individual User File Directories (UFD) for each user.

Contiguous Allocation

A file allocation method where each file occupies a set of contiguous disk blocks, defined by a starting disk address and length in blocks.

Linked Allocation

A file allocation method where each file is a linked list of disk blocks, with each block containing a pointer to the next block.

File-Allocation Table (FAT)

A variation of linked allocation where all block pointers are consolidated into a separate table located at the beginning of the disk.

Indexed Allocation

A file allocation method where each file has a dedicated index block containing pointers to all of its individual allocated disk blocks.

Free List

A free space management technique that maintains a linked list of blocks containing the locations of available (free) disk blocks.

Bitmap (Bit Vector)

A free space management method using a bit-array where each bit represents a specific disk block, indicating whether it is free or occupied.

Access Control Matrix

A two-dimensional table listing subjects (processes) as rows, objects (files) as columns, and matrix entries as specific access rights.

Access Control List (ACL)

An access control protection approach derived from an access control matrix by attaching a list of permitted users and their rights to each object.

Capability List

An access control protection approach derived from an access control matrix by attaching a list of accessible objects and permitted rights to each user or subject.

Physical Backup

A data loss prevention technique that duplicates all data on a storage device at the bit level.

Logical Backup

A data loss prevention technique that inspects directory structures and backs up file system data and its logical layout into a archival format.

Incremental Backup

A type of logical backup that backs up only the file system data that has changed since the previous backup.