Application of B + tree in NTFS file system

Application of B + tree in NTFS file system

Flyfish 2015-7-6

Volume (volume)
The structure of NTFS starts first from the volume. The volume corresponds to a logical partition on the disk, and when you format a disk or part of a disk as NTFS, the volume is created. A disk can have one volume or several volumes. NTFS handles each volume independently of one another.
The volume corresponds to the C-drive, D-disk, e-disk and so on.

cluster (cluster)
In an NTFS volume, the size of the cluster, or cluster factor (cluster factor), is established when the disk hypervisor MMC loader formats the volume. The default cluster factor varies with the size of the volume, but it is an integer multiple of the physical sector and is always a power of 2. (1 sectors, 2 sectors, 4 sectors, 8 sectors) and so on.
The cluster factor is represented as a number of bytes in a cluster, such as 512 bytes 1KB or 2KB.
The hard disk reads and writes the sector as the basic unit. NTFS reads and writes with clusters as the basic unit.

NTFS only refers to the cluster level internally, and NTFS uses the cluster as its allocation unit to maintain its independence from the physical sector size.

logical Cluster number (Logical Cluster NUMBER,LCN)
LCN is a number from the beginning of a volume until the end of all clusters. NTFS relies on the logical number (LCN) to refer to the physical location.

Get Physical Disk Address method
LCN times the cluster factor, resulting in a physical byte offset on the volume.

Virtual cluster number (Vsan Cluster NUMBER,VCN)
VCN numbers all clusters of the same file, from 0 to M. NTFS relies on virtual cluster numbers (VCN) to refer to data inside a file.
VCN do not have to be physically contiguous. They can be mapped to any LCN number on the volume.

Master File Table (Master)
The MFT is the core of the NTFS volume structure. Relates to B + trees.

The structure is as follows

Referring to the deep parsing of the Windows operating system

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Application of B + tree in NTFS file system