Dos versions
  PC/MSDOS 3.0
    Because of BIOS CHS protocols, only 32MiB possible.

  DOS 3.3
    Introduction of extended partition allowing larger drive to be split 
    into logical partitions up to 32GiB each labeled D-Z.

  Compaq (MS) DOS 3.31 November 1987 - Compaq and Microsoft combined effort.
    32 bit sector addressing supported by OS and Bios parameter block stored
    in the volume boot record.
      Although FAT addresses clusters, drive still addresses sectors.

    Using 64K cluster, capable of addressing 2GB drive.

  DOS 4.0
    Adopts Compaq DOS 32 bit sector addressing.
    1 cluster = 4 sector (2K)
    128 MB / partition * 4 partitions = 528MB
    Requires share.exe to use drives larger than 32MB.

  DOS 5.0
    Support for 8 hard drives instead of only 2. (support.microsoft.com).
    Support for up to 3 primary partions on a drive.
    1 cluster - up to 32K (64 sectors/cluster) 
    2 GiB limit.

  NT/2000/XP 
    Supports 128 sector/cluster.
    2-4 GiB. 
    However, filesystem not readable by other OSes.