What Is Partition Table

Partition table can describe the partitions on disk. If the disk partition table is lost, users are unable to read disk data and write new data on it.

MBR Partition Table

The traditional partitioning scheme (MBR partitioning) saves partition information on the first sector of disk (MBR sector). Each partition entry is 16 bytes, and the total is 64 bytes. Therefore, the partition table is limited to a maximum of 4 entries. In other words, MBR-based hard disk can support up to 4 partitions. But, many people want to create more than 4 partitions. So the extended partition is introduced for this demand. What's more, the size of a single partition in MBR disk can only amount to 2TB. Therefore, the MBR-based partitioning scheme cannot meet the increasing needs.

Partition Table

GPT Partition Table

GUID Partition Table (GPT) is a standard for the layout of the partition table on a physical hard disk, using globally unique identifies. It has many good features over the MBR partition table. To be specific, it allows users to create up to 128 partitions on hard disk. And it supports 18EB volume, while MBR supports 2TB volume at most. What's more, all important data are stored in partitions rather than hidden sectors. In addition, GPT disk provides backup-partition-table to improve the integrity of data structure.

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MBR disk and GPT disk are widely used in the world. But, which one is your best choice? Please find the answer in this post: MBR vs. GPT Guide: What's The Difference and Which One Is Better.

FAT

FAT (File Allocation Table) is used to record the location of file. If the FAT is lost, disk data cannot be read since the OS cannot find the accurate location. Different operating systems use different file systems. DOS 6 and Windows 3.x would like to use FAT16. OS/2 operating system uses HPFS. And Windows NT uses NTFS. In fact, FAT32 and NTFS are the most two common file systems.

The partition table subdivides a storage medium using units of cylinders, heads, and sectors.

FAT32 file system divides the logical drive into Boot area, FAT area and DATA area. The system area consists of Boot and FAT area. Boot area occupies three sectors, and it contains sector bytes, boot record and other important information. After that, there are some reserved sectors on this area. However, the Boot area of FAT16 file system only occupies one sector.

FAT can manage the free space and storage space (cluster chain). File system will manage the storage space of data area via cluster. Cluster is the smallest storage unit in Windows OS and influences utilization ratio and performance of disk space. A file always occupies multiple clusters. Thus, the remaining space of the last cluster will be wasted. If the cluster size is too large, more free space will be wasted when users store files. Therefore, cluster size determines the utilization ration of disk to a large extent.

In addition, users who use the FAT16 file system should not set the partition capacity as the lower limit of a range.

The size and location of ROOT directory area may no longer be fixed. It can be considered as a part of DATA area. The root directory has been changed to the root directory of file, which adopts the subdirectory file management. Thus, it starts from the second sector, and the size can be change if needed. But, the Boot sector of FAT16 has a fixed size and location.

Common Partition Table

FAT32: In order to overcome the volume size limit of FAT16, Microsoft designed FAT32, which can support small cluster and large capacity.

NTFS: NTFS has several technical improvements over FAT, including system security, reliability and advanced features. In addition, NTFS can use log file and checkpoint to restore the consistency of file system. Besides, under Windows 2000 and Windows XP, NTFS provides some advanced features including folder permission, encryption, disk quotas, etc.

Note: Windows 2000 can use FAT32 and NTFS file system. And, FAT32 can relocate the ROOT directory. In addition, FAT32 partition boot record is contained in a fatal data structure, which can reduce the possibility of computer crashes. The compressed NTFS files will automatically compress or decompress themselves according to users' needs.

exFAT: exFAT (Extended File Allocation Table File System) is a file system mainly for flash storage. It was released to solve the problem that FAT32 is unable to support files larger than 4GB.

EXT3: EXT3 (third extended file system) is the third generation of extended file system. It is a journaling file system and is widely used in Linux operating system. What's more, it is the default file system for Linux operating system.

Here, you can use MiniTool Partition Wizard to create these kinds of partition on your computer.