M4 | Disks and Filesystem Types

File System

Used to keep track of files and file storage on a disk. Without it, the operating system wouldn't know how to organize files.

NTFS

The default file system for Windows.

ext4

The recommended file system for Linux.

FAT32

A file system that supports reading and writing data on Windows, Linux, and Mac OS, but has limitations like not supporting files larger than 4GB or file systems larger than 32GB.

Partition

A piece of a disk that can be managed separately, giving the illusion of physically dividing a disk into separate disks.

Volume

A partition that has been formatted with a file system.

Partition Table

Tells the OS how the disk is partitioned, including which partitions can be booted from and how much space is allocated to each partition.

MBR (Master Boot Record)

A traditional partition table scheme used mostly in Windows, allowing only four primary partitions and volume sizes of 2TB or less.

GPT (GUID Partition Table)

A modern partition table scheme that supports volume sizes greater than 2TB and allows for an unlimited number of partitions.

Disk Management Utility (Windows)

A native Windows tool used to partition and format disks, accessible via the Computer Management console.

diskpart

A command-line tool in Windows for managing disks, including partitioning and formatting.

Parted (Linux)

A partitioning tool in Linux that supports both MBR and GPT schemes.

Mounting

The process of making a file system accessible to the computer, such as assigning a drive letter in Windows or a directory in Linux.

Virtual Memory

A memory management technique where the OS uses disk space to extend RAM, storing less frequently used data in a paging file or swap space.

Pagefile.sys (Windows)

A hidden file on Windows used to store pages of memory when virtual memory is employed.

Swap Space (Linux)

A dedicated area on a Linux disk used for virtual memory, created using the mkswap and swapon commands.

Master File Table (MFT)

A structure in NTFS that contains metadata about every file on the volume, including attributes like file name, timestamps, and data location.

Symbolic Link

A file system-level shortcut that points to another file by name and is treated by the OS as a substitute for the original file.

Hard Link

A file system entry that points directly to the inode (Linux) or file record number (Windows) of another file, remaining valid even if the original file is renamed.

Inode (Linux)

A data structure that stores metadata about a file (e.g., permissions, owner, size) but not the file name or actual data.

Soft Link (Linux)

Another term for a symbolic link in Linux, which points to another file by name.

Disk Usage (du)

A Linux command that shows the disk usage of files and directories, with the -h flag for human-readable output.

Disk Free (df)

A Linux command that displays the free space available on all mounted file systems, with the -h flag for human-readable output.

Data Buffer

A region of RAM used to temporarily store data being moved between devices, such as when copying files to a USB drive.

Journaling (NTFS)

A feature that logs changes to file metadata in a log file, allowing the file system to recover to a consistent state after a crash.

Self-Healing (NTFS)

A mechanism in NTFS that automatically repairs minor file system corruptions in the background without requiring a reboot.

chkdsk

A Windows utility for checking and repairing disk errors, with the /F flag to fix problems.

fsck

A Linux command for checking and repairing file systems, which should only be run on unmounted partitions.

Defragmentation

The process of reorganizing files on a disk to store them in contiguous blocks, improving performance on HDDs.

Trim (SSDs)

A process used by SSDs to reclaim unused portions of the disk, improving performance and longevity.

Disk Cleanup (cleanmgr.exe)

A Windows tool that frees up disk space by deleting temporary files, compressing old files, and emptying the Recycle Bin.

Network File Systems

A file system type that enables file sharing between multiple operating systems without file limitations.

Primary Partition (MBR)

One of up to four main partitions allowed on a disk using the MBR scheme.

Extended Partition (MBR)

A special partition in MBR that can contain logical partitions to bypass the 4-partition limit.

Logical Partition (MBR)

A partition created within an extended partition to allow more than four partitions on an MBR disk.

Allocation Unit Size

The block size used when formatting a partition (e.g., NTFS), affecting how files are stored in chunks. Smaller sizes save space for small files; larger sizes improve performance for large files.

Quick Format

This type of formatting removes file references but doesn't erase actual data, making recovery possible with special tools. It's suitable for healthy drives when speed is a priority.

Full Format

This type of format scans for bad sectors and performs a thorough erase.

File/Folder Compression (NTFS)

An NTFS feature to reduce file size at the cost of increased CPU usage when accessing files.

UEFI

A modern BIOS standard that requires disks to use the GPT partition scheme for booting.

/etc/fstab (Linux)

A configuration file that defines how and where file systems are mounted at boot, including swap space.

blkid (Linux)

A command to display UUIDs (Universal Unique Identifiers) of block devices, used for mounting in /etc/fstab.

mkswap (Linux)

A command to format a partition as swap space.

swapon (Linux)

A command to activate swap space for use by the system.

File Metadata (NTFS)

Attributes stored in the MFT, including file name, timestamps, permissions, and data location.

Shortcut (Windows)

A file that references another file or location but does not act as a substitute at the file system level.

fsutil repair query (Windows)

A command to check the status of NTFS self-healing on a drive.

Data Corruption

Damage to data caused by unsafe removal of disks, power failures, or software bugs, mitigated by journaling and self-healing.

ln (Linux)

A command to create hard (ln target link) or soft (ln -s target link) links.

Hard Link Count (Linux)

The number of hard links pointing to an inode, shown in ls -l. A file is deleted when this count reaches zero.

cleanmgr.exe (Windows)

The executable for Disk Cleanup, which deletes temporary files and frees disk space.

Defragmentation (HDDs)

Reorganizes fragmented files on HDDs to improve read/write speed by reducing actuator arm movement.

du -h (Linux)

Displays directory disk usage in human-readable format (e.g., KB, MB).

df -h (Linux)

Shows free disk space across all mounted file systems in human-readable format.

Unsafe Ejection

Removing a disk without unmounting, risking data corruption due to pending writes in the buffer.

Journaling (NTFS Log)

A log file tracking file system changes to enable recovery after crashes.

chkdsk /F (Windows)

Fixes disk errors during a manual check (vs. read-only mode by default).

fsck (Linux)

Checks and repairs unmounted Linux file systems, often run automatically at boot.