Filesystems and File Management in Computer Architecture

File

A collection of (usually related) data.

Block

A unit of data storage, typically between 256 and 4096 bytes.

Cluster

Groups of one or more blocks that correspond to one or more sectors on a disk's single track or cylinder.

File extension

Part of a file name that identifies the file type.

Logical view

The contents and attributes of files as viewed by the user.

Physical view

The actual way a file is stored within the computer system.

Sequential access

Access method for data files where records must be retrieved from the beginning.

Random or relative access

Access method for data files where records can be retrieved from anywhere in the file in a random sequence.

Contiguous

Storage method where the blocks holding a file are stored together.

Noncontiguous

Storage method where the blocks holding a file are scattered all over the device.

Access control list (ACL)

A list of users who may access a file for each form of protection.

File Directory

A structure that provides organization for locating files efficiently.

Sequential Access

Reading a file in sequence from beginning to end.

Random Access

Assumes a file is made up of fixed-length logical records.

Indexed Access

A method for accessing and viewing records in a file through key indexes.

Contiguous Storage Allocation

Assigning blocks in a row to hold a file, allowing simple access for both sequential and random methods.

Linked Allocation

Noncontiguous storage method where each block contains a link to the next physical block.

Indexed Allocation

Noncontiguous storage method where all link pointers for a file are stored together in a single block called the index block.

File Allocation Table (FAT)

A linked allocation system with links stored in a table, used in DOS/Windows.

Bit map method

A free space management method using one bit for each block to indicate if it is used or free.

Linked list method

A free space management method where each free block has a pointer to the next.

Tree-Structure Directory

A hierarchical directory structure with a top-level root directory from which all other directories stem.

Pathname

A representation of the file's location in the directory structure.

Search Paths

Directory locations used by the operating system to locate files.

Hard Links

Direct pointers to the file's inode, providing multiple directory entries for the same file.

Symbolic Links

Pointers to the file's pathname, creating shortcuts to the target file or directory.

(S)FTP

File Transfer Protocol, a part of the TCP/IP protocol family.