1.3.2 NTFS

NTFS (NT file system) is a file system that was invented for Windows NT (NT stands for ``new technology'', but also known as ``not there''). It is a file system that is completely different from FAT, and has its root originated from VMS.

NTFS has various versions. Windows XP can access all NTFS partitions upto version 5.x. The actual implementation of NTFS is never disclosed from Microsoft. However, third party vendors have reverse engineered the work NTFS works.

In short, NTFS uses a tree structure (B+ tree, to be exact) to maintain the illustion of a file from raw clusters. In contrast, FAT uses a linked list (linear) of clusters to provide the illustion of a file. As a result, NTFS is more efficient with random access operations (read/write contents of a file at ``random'' spots).

NTFS also uses a flexible method to store the ``metadata'' of files. A master file table (MFT) maintains the metadata of every file and directory in an NTFS partition. The ``metadata'' of a file includes the name, creation date, modification date and etc. One huge advantage of NTFS over FAT is the extensive number of attributes that can be associated with a file. It is also relatively easy to add even more attributes as extensions.

The theoretical max partition size is $2^80$ bytes. In reality, Windows XP supports only up to 256TiB, assuming a cluster size of 64kiB.

The max file size of a file is $2^{60}$. This is still larger than the practical partition max size!