TITLE: 930917 DO MAXIMUM FILE SIZES AND PARTITION SIZES CHANGE
              IN OS/2 V2.1?


OS/2 2.0 could support the following:

FAT --> Max file size = 2GB, Max partition size = 2GB
HPFS ->      "          2GB          "            64GB

The file size and volume size data are the same as they were
in OS/2 2.0.  This has not changed for 2.1.

 The HPFS file system under OS/2 Version 2.1 supports a maximum file
 size of 2GB.  The maximum size for an HPFS volume is 64GB.

 The FAT file system under OS/2 Version 2.1 supports a maximum file size
 of 2GB.  The maximum supported size for a FAT volume is also 2GB.

 The maximum size for a disk volume under OS/2 Version 2.1 is 64GB using
 HPFS and 2GB using the FAT file system, with the following conditions:

   1. OS/2 V2.1 requires that the bootable partition be within
      the 1023rd cylinder of the disk

      When a machine's BIOS reports on the characteristics of a
      disk, it returns three values; it determines the number of
      sectors per head, the number of heads per cylinder, and
      the number of cylinders. The IBM BIOS sets the disk
      geometry such that one cylinder equals one megabyte of disk
      storage.  For IBM disk drives, 1023 cylinders corresponds
      to one gigabyte. Other manufacturers may use different
      sector and head values causing the 1023 cylinder limit
      to be greater than or less than one gigabyte.
   2. A FAT file system volume must not exceed the 1023rd
      cylinder of the disk drive.
      It may also not exceed 2GB even if, due to the
      manufacturer's disk geometry, the 1023rd cylinder is beyond
      2GB.

      Imagine a 10GB disk where the geometry of the disk has
      sector/head/cylinder values such that the 1023rd cylinder
      corresponds to 7.4GB, as is the case with some OEM SCSI
      disks.  Using the FAT file system, the way to configure the
      volumes to maximize their size would be to have three
      volumes of 2GB and one volume of 1.4GB.  In this case the
      2.6GB of free space (beyond the 1023rd cylinder) would be
      unusable by OS/2 using the FAT file system.  These volumes
      may exist in primary partitions or an extended partition,
      or both.  In an extended partition, the volume would occupy
      one or more of the logical partitions defined in the
      extended partition.
    Although an HPFS volume can take up the entire disk, for
    performance reasons the practical limit is much less than
    64GB.  It is around 7 or 8GB.

  There are 24 drive letters available for hard disk drives
  (a: and b: are reserved for diskette drives), and currently
  the largest tested IBM SCSI hard disk available for the PS/2
  is 400MB.  Using 24 single SCSI disks chained on four SCSI
  adapters we would get a maximum of 24 x 400MB, or 9.6GB of
  online DASD.
  Depending on how you array the drives will determine of available disk
  space. By using the above specifications, you can determine the space
  for the drives.

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