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Q119497: Boot Partition Created During Setup Limited to 4 Gigabytes

Article: Q119497
Product(s): Microsoft Windows NT
Version(s): 3.1 3.5 3.51 4.0
Operating System(s): 
Keyword(s): kbother
Last Modified: 08-AUG-2001

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The information in this article applies to:

- Microsoft Windows NT Server version 3.1 
- Microsoft Windows NT Workstation version 3.1 
- Microsoft Windows NT Advanced Server, version 3.1 
- Microsoft Windows NT Workstation versions 3.5, 3.51, 4.0 
- Microsoft Windows NT Server versions 3.5, 3.51, 4.0 
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SUMMARY
=======

The size of the boot partition generated by Windows NT setup is limited to 4
gigabytes (GB) because Windows NT Setup must first format the partition to the
FAT file system. Although it is possible to select NTFS for the boot partition
during Setup, this partition is first formatted to FAT, Setup completes, then
the partition is converted to NTFS. Because the FAT file system is limited to a
4-GB partition size, the boot partition for Windows NT is also effectively
limited to 4 GB.

MORE INFORMATION
================

Windows NT versions 3.1 and 3.5 Setup does not load the full Windows NT Kernel
and related drivers, so it is not possible for Setup to read an NTFS partition.
During setup, even if you choose NTFS for the boot partition, it must be
formatted to FAT (limited to 4 GB) so that Setup can write to it. Thus, the
Windows NT boot partition is limited to 4 GB.


WORKAROUND
==========

Move the hard drive to another system running Windows NT and attach it to the
same make, model controller as on the original system. Run disk administrator
and make a larger NTFS partition of up to 7.8gb formatted. As long as the drive
is being translated, the partition table entry should contain valid starting
Cylinder, Side, and sector values used for booting. The drive can then be moved
back to the original system and ready for Windows NT installation.

Starting and Ending Cylinder, Side, and Sector
----------------------------------------------

The Starting and Ending Side, Cylinder and Sector fields are very important with
respect to how Windows NT interacts with the disk.

The maximum number of Sides (read/write heads) that can be represented with 1
byte is 256. The maximum number of Cylinders that can be represented with 10
bits is 1024. The maximum number of Sectors that can be represented with 6 bits
is 63 because Sectors start counting with 1 (versus Cylinders and Sides which
start counting with 0).

With a standard sector size of 512 bytes, the 24 bits used to record the starting
and ending sector addresses translates into a maximum possible partition size of
7.8GB (8,455,716,864 bytes) which can be described with these fields. This is
particularly important because the same field sizes are employed by the INT 13
BIOS interface which defines how the system BIOS interacts with the hard disk
and is used while booting.

For additional information on file system limits in Windows NT, please see the
following article in the Microsoft Knowledge Base:

  ARTICLE -ID: Q114841
  TITLE : Windows NT Boot Process and Hard Disk Constraints

Additional query words: prodnt maximum

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Keywords          : kbother 
Technology        : kbWinNTsearch kbWinNTWsearch kbWinNTW400 kbWinNTW400search kbWinNT351search kbWinNT350search kbWinNT400search kbWinNTW350 kbWinNTW350search kbWinNTW351search kbWinNTW351 kbWinNTW310 kbWinNTSsearch kbWinNTS400search kbWinNTS400 kbWinNTS351 kbWinNTS350 kbWinNTS310 kbWinNTAdvSerSearch kbWinNTAdvServ310 kbWinNTS351search kbWinNTS350search kbWinNTS310search kbWinNT310Search kbWinNTW310Search
Version           : 3.1 3.5 3.51 4.0

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