NTFS Overview

The NTFS (New Technology File System) is the primary file system for Windows. It was developed by Microsoft and first introduced with Windows NT. NTFS is a robust, high-performance file system that provides enhanced security, reliability, and scalability compared to its predecessors like FAT32.

Key Features of NTFS

• Journaling: NTFS maintains a log of changes made to the file system before they are committed. This journaling capability helps in quick recovery from system crashes or power failures, ensuring data integrity.
• Security: NTFS supports Access Control Lists (ACLs), which allow administrators to set granular permissions for files and directories. This ensures that only authorized users can access specific data.
• Large File and Volume Sizes: NTFS supports very large files and volumes, allowing for the storage of massive amounts of data. The theoretical limit for a file size is 16 Exabytes, and for a volume, it's 256 Terabytes (though practical limits are often imposed by hardware).
• Compression: NTFS can compress files and directories to save disk space. This is a transparent operation, meaning applications and users don't need to be aware that files are compressed.
• Encryption (EFS): The Encrypting File System (EFS) allows users to encrypt files and folders, providing an additional layer of security.
• Disk Quotas: Administrators can set disk quotas to limit the amount of disk space users can consume on a volume.
• Hard Links and Symbolic Links: NTFS supports both hard links (multiple directory entries pointing to the same file data) and symbolic links (shortcuts that point to files or directories).
• Alternate Data Streams (ADS): Allows for multiple streams of data to be associated with a single file, which can be used for metadata or other purposes.

NTFS Structure

NTFS organizes data using a Master File Table (MFT). The MFT is a database that contains records for every file and directory on the volume. Each record describes the file's attributes, such as its name, size, timestamps, security permissions, and the location of its data clusters on the disk.

Master File Table (MFT)

The MFT is typically located at the beginning of the NTFS partition. It consists of a series of records, where each record represents an item (file or directory). For small files, their data might even be stored directly within the MFT record itself as "resident" data.

Attributes

Each MFT record contains various attributes, including:

• $STANDARD_INFORMATION: Contains file timestamps (creation, modification, access), file attributes (read-only, hidden, etc.), and hard link count.
• $FILE_NAME: Stores the file name, its parent directory, and timestamps specific to that name.
• $DATA: Contains the actual data of the file. For large files, this attribute will point to the clusters where the data is stored.
• $SECURITY_DESCRIPTOR: Holds the Access Control List (ACL) for the file.
• $INDEX_ALLOCATION and $INDEX_ROOT: Used for directories to manage their contents.

Journaling in NTFS

The NTFS log file ($LogFile) records all file system operations before they are performed. If the system crashes during an operation, NTFS can replay the log file during the next boot-up to complete or undo the incomplete operations, ensuring file system consistency.

Use Cases

NTFS is the default file system for all modern Windows operating systems, including Windows 11, Windows 10, Windows Server, and their predecessors. It is suitable for all types of storage, from internal hard drives and SSDs to external storage devices.