Hardware

Disk drives can be a "physical drive" (the drive you can hold in your hand). A physical drive can then be partitioned into "logical drives" depending on which file systems your OS supports, and the bit-width of your OS. A 64-bit OS will support larger disk partitions than a 32-bit OS, etc. FAT32 is one file system type, and supports 32 bits, so it supports drive sizes up to 32 bits. Some USB hard drives come with their own partition software on it already, as the drive is already formatted. Some drives are formatted for a Mac OS, some are formatted for Windows.

Here are some abbreviations for drive sizes:

1. 1 Gigabyte (GB) = 1000 Metabytes (MB)
2. 1 Terabyte (TB) = 1000 GB
3. 1 Petabyte (PB) = 1000 TB (Source)
4. 1 Exabyte (EB) = 1000 PB (Source)

Here are some different file system types which make a partition: FAT, FAT16, FAT32, NTFS, GPT.

1. NTFS
   1. Max partition size: 256TB. From Wikipedia. There are several versions of NTFS.

General information

1. Disk partitions from Wikipedia.
2. Hard drive partitions from Microsoft.

Software

You will need to use special partition software if you want to change a disk partition. Normally you lose all data when you change a disk partition. Here is some free software.

1. Windows OS of various versions has partition software so you can try that. But you will normally lose data when using the Windows partition software.
2. Minitool partition wizard can change NTFS file systems to FAT32 without losing data.

File system limits on partition size

1. Windows 95: between 504MB and 46TB. When in doubt, go with the lower limit. Source.
2. Windows 98: max 128GB. Larger drives up to 500GB will need a patched driver. SATA drives larger than 128GB will need a SATA patch. Source.
   1. FAT16: 2GB Source.
   2. FAT32: 4GB
3. Windows 7
4. Windows 8
5. Windows 10
   1. FAT32: 2TB
      1. Break 2TB limit on Windows 10 disk partitions. Click here.
   2. GPT: Using UEFI and GPT partition with Windows 10 allows 10 Exabyte partitions (about 18.8 million TB). From Microsoft. GPT is newere, if you format an HDD as GPT it may not work on older computers! It will only work on computers where the OS supports GPT.
   3. NTFS:

Windows server operating systems:

1. Windows NT
   1. NTFS: max 16TB
   2. FAT: 4GB
   3. HPFS: 4GB
2. Windows Server 2012 Max partition size is: when using MBR max is 2TB.