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BuildOrBuy News -
images/bullet2.gifmx_tu-0597.pdf - Maxtor 1997 HD Barriers & Limitations.
Bios & Windows OS Limitations for SATA & PATA Hard Drives: - Storage Capacity Measurement Standards -
Q: Why does my Hard Drive show less space than advertised?
A: Hard Drive Capacity Measurement Standards = Hexadecimal vs. Binary -

Two Different Measurements Systems


What's the simplest Solution for overcoming PATA Hard Drive Capacity Barriers? Past: Get A Promise PCI Controller Card! IF you can still find one! See: !!! Use to be available from - For PCI PATA Controller, Search: Promise Ultra133 TX2. Now... A SATA to PATA Converter or USB Converter.

Need more Storage Capacity than your MotherBoard allows? Get another Controller Card! Either of the variety above or this, depending upon your needs  - For PCIe SATA , Search: SIG SATA Controller. Same location or your preferred Vendor... Enjoy!

Hard drive Capacity Barriers...

Since so many people continue to confuse the issue and mix disproportionate ATA Storage Technologies including SATA I, II & III, PATA HD's, PATA Controller cards and MotherBoard Controllers, we've included the FYI Info below as a refresher quoting Tech Bulletins. ATA Controllers are cheap - IF you're in doubt as to whether your System will support the newer, larger HD's - Get one! And be particular which PCI Slot you use in case you have a Resource conflict with your AGP Slot. Using a PCI Express MotherBoard will be less likely to have this issue. Consult your MotherBoard Manual when in doubt!

The BIOS limitation or BIOS capacity barrier is the computer’s inability to recognize hard drive capacities larger than allowed by the hard-coded programming contained in your system BIOS. For example, your system BIOS might only be capable of understanding a hard drive capacity of up to 32 GB. If you then attempt to install and auto-detect a 40 GB hard drive, the system will freeze because the BIOS is not capable of understanding the capacity reported by the hard drive. In short, that particular BIOS cannot count past 32 GB.

  1. - Definition of a BIOS Limitation or BIOS Capacity Barrier 137 GB, 32 GB, 8.4 GB
  2. - Operating System and BIOS Limitations: 137 GB, 32 GB, 8.4 GB
  3. - Hard Drive Size Barriers, In Depth:


Seven Major BIOS Limitations:
  1. Systems with BIOS dated prior to July 1994 (504 MB {binary} / 528 MB {decimal} Limitation).
    Typically these BIOS will have a 504 MegaByte (1,024 cylinder) limitation. Prior to this date, most MotherBoard Manufacturers' BIOS did not provide the Logical Block Address (LBA) feature needed for proper translation. Some BIOS had LBA mode in the Bios Setup, but the feature did not work properly.
    1. 126855 - Windows Support for Large IDE Hard Disks:
    2. 122052 - Logical Block Addressing (LBA) Defined: LBA is a run-time function of the system BIOS.

  2. Systems with BIOS dated after July of 1994 (2.048 GB Limitation).
    Typically, these BIOS provide support for HD Drives with capacities larger than 504 MegaBytes. However, depending on the Manufacturer's release date and version number, different limitations may be encountered. The major limitation is the 4,093-4,096 cylinder limitation. This barrier is derived from the fact that some BIOS Manufacturers implemented Logical Block Addressing (LBA) translation in their BIOS with a 4,093 - 4,096 cylinder limitation. System hangs would occur when the cylinder limitation threshold is exceeded. A System hang is defined when the Operating System hangs during initial loading, either from Floppy Diskette or existing HD Drives. If these symptoms of System hang occur or there are questions whether the system BIOS will support the HD Drive, contact the System or MotherBoard Manufacturer for assistance.
    1. 127851 - Problems Accessing FAT16 Drives Larger Than 2 GB:
    2. DOS - The DOS operating system has a 2.048 GB per drive letter (e.g., C:, D,: E:) barrier, also has an 8.4 GB total drive capacity barrier.
    3. Windows 95A (FAT-16) - The Windows 95 (FAT 16) operating system has a 2.048 GB per drive letter barrier. See: Win9x Versions.
    4. OS/2 using FAT-16 - The OS/2 using FAT 16 operating system has a 2.1 GB per drive letter barrier. Older versions of Warp cannot address drive capacities greater than 4.2 GB. User's MUST contact IBM for possible Driver Pack Upgrades to bypass this limitation.

  3. 4.2 GB Limitation (FAT16).
    The maximum parameters at the 4.2 GB barrier are 8,190 cylinders, 16 heads and 63 sectors for a capacity of 4.2 GB. A system hang is defined when the Operating System stops responding during initial loading, either from Floppy Diskette or existing Hard Drives. This can be caused by the BIOS reporting the number of heads to the operating system as 256 (100h). The register size DOS/Windows 95 uses for the head count has a capacity of two hex digits. This is equivalent to decimal values 255. If these symptoms of system hang occur or there are questions whether the system BIOS will support the drive, contact the system or motherboard manufacturer for assistance.
    1. 118335 - Maximum Partition Size Using FAT16 File System:
    2. Windows NT 4.0 using FAT-16 - Windows NT 4.0 using FAT 16-File System has a 4.2 GB limit. Hard drives greater than 4.2 GB will require multiple partitions if using the FAT 16 File System.

  4. 8.4 GB Limitation - January 1998.
    The maximum parameters at the 8.4 GB barrier are 16,383 cylinders, 16 heads and 63 sectors for a capacity of 8.455 GB. To go beyond this boundary, a new extended INT 13 function [extended BIOS functions] is needed from the BIOS as a support feature for the drives. Even though a BIOS is dated correctly or is the current version, it may not be able to support extended interrupt 13 because of modification done to the "CORE" of the BIOS from the MotherBoard Manufacturer.
    1. 153550 - Hard Disk Limited to 8-GB Partition: "This behavior can occur if the Hard Disk Controller does not fully support the interrupt 13 extensions. This information applies to both IDE and SCSI hard disk drives."
    2. 197667 - Installing Windows NT on a Large IDE Hard Disk:

  5. 32 GB Limitation - June 1999.
    This condition is caused by the Award BIOS inability to address HD Drives greater than 32GB. Award has been made aware of this issue and has fixed their "core" BIOS as of 6/99. They are passing this information along to the MotherBoard Manufacturers' using their BIOS. Updates for the BIOS should be available soon from individual MotherBoard Manufacturers' to correct this problem. The following are options to overcome the 32 GB BIOS capacity barriers:
    1. Please contact your Motherboard Manufacturer, not Award, for a BIOS Update.

      [1st! Most Motherboard Manufacturers have Free Bios Updates. Take advantage of that feature!]

    2. (Recommended) Purchase a PCI ATA Controller card that will support the capacity of the drive. The two benefits of ATA controller cards are: (1) the ability to support large capacity drives and (2) the ability to support the faster transfer rates of the drive. Maxtor's online store,, has a complete selection of ATA Controller cards that support the full capacity of all Maxtor drives. [Or... - Get a Promise Parallel ATA Controller Card. Safer and simpler in the long run!]
    3. Or Maxtor's MaxBlast 3 "Set Drive Size" utility. Please reference Answer ID: 1361.

  6. 64 GB Limitation
    There is no 64 GB BIOS Capacity Barrier. If you use FDISK to format a drive that is larger than 64 GB, FDISK will report the incorrect disk size. Please refer to Answer ID 775 for a resolution. [Get the fdisk Update - Read: Win9xVer]
    1. Q263044 - Fdisk Does Not Recognize Full Size of Hard Disks Larger than 64 GB - FAT32 Partitions

    "NOTE: This hotfix is not designed for 48-bit logical block addressing (LBA) Hard Disks, and is not supported on Hard Disks larger than 137 GB."

  7. 137 GB (128 GB binary) Limitation - October 29, 2001.
    Most system BIOS's are limited to 137 GB because it can only support 28 bit Logical Block Addressing (LBA). For a resolution please refer to Answer ID 960.
    1. 303013 - How to Enable 48-bit Logical Block Addressing Support for ATAPI Disk Drives in Windows XP: (12/26/2003)
      • You must have a 48-bit LBA compatible BIOS.
      • You must have a hard disk that has a capacity that is greater than 137 GB.
      • You must have Windows XP SP1 installed.
    2. 305098 - 48-Bit LBA Support for ATAPI Disk Drives in Windows 2000: Applies to Win2000 Pro, Server & Advanced Server.
    3. 327202 - PRB BIOS May Limit Fdisk.exe When Partitioning Hard Disks Larger Than 128 GB: Update System Bios if possible. "IDE Hard Disk Dives larger than 128 GB use 48-bit logical block addressing (LBA) as defined in the ATA/ATAPI-6 Specification." See also: Win9x Versions for fdisk Update Info.
    4. Promise's New Ultra133 TX2 Controller Card Supports Maxtor's Fast Drive And Big Drive Technology: (October 29, 2001).
    5. Maxtor Big Drive Enabler: "A one step executable enabling support for drives larger than 137 Gigabytes in Windows 2000 Service Pack 3 and XP Service Pack 1. This utility takes the guess work out of editing the Windows registry. The Big Drive Enabler fixes an Operating System limitation. This utility is needed anytime a Hard Disk Drive larger than 137 GB is connected to the motherboard's ATA bus, regardless of any system BIOS supporting 48-bit LBA."
    6. - Why can I only see 127 to 137 GBytes of my 160+ GB drive
    7. Quoting: - Online Help Answer:

      The Windows 137GB (137.4 GB) Capacity Barrier a.k.a. 48-bit Logical Block Addressing (LBA) Support for ATA/ATAPI (IDE) & Serial ATA HD Drives. The 137GB limitation does not affect SCSI Interface HD Drives.

      ATA/ATAPI-6 defines 48-bit addressing on a single drive, allowing more than 144 Petabytes (144,000,000 Gigabytes) of Storage.

    8. images/bullet2.gifIntel Application Accelerator - 48-bit LBA BIOS Support: Instructions for Win2000 & WinXP flavors differ from Instructions for Win98 flavors.
    9. Intel Application Accelerator - Large Hard Drive Installation Instructions: Although No fault on Intel, Catch 22 for Users with Sony DVD Burners since Sony says this Driver must be removed to Flash the Sony DVD Burner (Sony DRU-500A/X /DRX-500UL/X Firmware Update). Smart?!? Storage Growing Pains...  Users Be Aware!
    10. 327202 - PRB BIOS May Limit Fdisk.exe When Partitioning Hard Disks Larger Than 128 GB: "Fdisk.exe is limited to the disk capacity as reported by the BIOS." Relates to: Win98 flavors.
    11. - EnableBigLBA: A better alternative solution to Maxtor's Big Drive Enabler since in WinXP Pro + SP1.
  8. Next Limit... 2.2 terabytes (2,200 gigabytes).
    According to Maxtor, "This barrier exists because many of today's Operating Systems are based on 32-bit addressing. Windows XP/64-bit also has the limit because of leveraged 32-bit code."

    Update from RAID, Beyond the 2TB Barrier -

    "The current AMCC Storage 9000 series controllers support [RAID] array greater than 2TB. However, not all Operating Systems support array sizes great than 2TB. Under Linux, use the "parted" tool to create arrays of greater than 2TB. Current releases of the Windows Operating System do not support greater than 2TB. If an array of 3TB is selected, the current version of Windows will recognize and format the first 1.99 (2TB) of storage space. Windows 2003 is still in beta. It is yet to [be] seen if Windows 2003 will provide more than 2TB support in its final release. The 3Ware firmware will support 64-bit LBA, which will satisfy the array capacity requirements up to 9 zettabytes. 264x512 bytes = 9,444,732,965,739,290,427,392 bytes." (6/4/2004)

    Same issue according to Microsoft... Details on FAT Chart: Maximum Volume Size - "Volumes larger than 2 terabytes (TB) are possible by using 64KB clusters to achieve a 256TB volume. Volumes larger than 2TB must be dynamic, not basic." Read it twice. Both are correct.


    Analogue Number Perspectives from

    1. 131 kilobytes = 131,000 bytes a little more than 30 pages of text.
    2. 33 megabytes = 33,000,000 bytes more than 8,000 pages of text or 25 300-page books.
    3. 137 gigabytes = 137,000,000,000 bytes more than 100,000 books, or the contents of a good library.
    4. 2.2 terabytes = 2,200,000,000,000 bytes almost 2,000,000 books, or about the content of the Library of Congress. [In 2011 we now have 3 TB HDs.]
    5. 144 petabytes = 144,000,000,000,000,000 bytes 120 billion books (more than all that man has written).
    6. Etabyte = 1024 Petabytes
    7. 9.4 zettabytes = 9,400,000,000,000,000,000,000 bytes.


  9. - Hard Disk Drive Capacity Limitations on Serial ATA: Updated: July 18, 2003

    "The ATA command set support in a driver limits the addressable hard disk drive capacity. Because both Serial ATA and parallel ATA connections use the ATA commands, both Serial ATA and parallel ATA have the same capacity limitations.

    Drivers that use the 28-bit logical block addressing (LBA) ATA commands are limited to 137 gigabytes (GB). Drivers that use the new 48-bit LBA ATA commands are limited to 144 petabytes (PB)."

  10. - Windows and GPT FAQ Version 1.1 Posted: May 3, 2006; Updated: July 8, 2008; Updated: June 15, 2011

    "The maximum partition (and disk) size is a function of the operating system version. Windows XP and the original release of Windows Server 2003 have a limit of 2TB per physical disk, including all partitions. For Windows Server 2003 SP1 Windows XP x64 edition, and later versions, the maximum raw partition of 18 exabytes can be supported. (Windows file systems currently are limited to 256 terabytes each.)"

    1. A [Motherboard] BIOS [Firmware] uses a Master Boot Record (MBR).

    2. MBR can only support up to 4 partitions and up to 2TB per partition.

    3. EFI (Extensible Firmware Interface) supports legacy MBR + GPT (GUID Partition Table).

    4. GPT does not have the MBR limitations. UEFI is the successor to the Bios. Plus an EFI-aware O/S defined by EFI spec. See: Specification Overview or Unified Extensible Firmware Interface (UEFI) websites respectively (1/19/2009)

  11. - Windows and GPT FAQ: 3 TB HDs & Windows Updated: June 15, 2011 (8/11/2011)

    "GUID Partition Table (GPT) introduced as part of Unified Extensible Firmware Interface (UEFI) initiative. GPT provides more flexible mechanism for partitioning disks than previous Master Boot Record (MBR) partitioning scheme on PCs."

    1. "Q. Can Windows 7, Windows Vista, and Windows Server 2008 read, write, and boot from GPT disks?

      A. Yes, all versions can use GPT partitioned disks for data. Booting is only supported for 64-bit editions on UEFI-based systems."

    2. WDC - Large Capacity Drives

      "Technological Challenges of 3 TB SATA Hard Drive implementation. Required: Advanced Host Controller Interface (ACHI)-compliant HBA (Host Bus Adapter) with supporting Chipset & Drivers."

    3.  Hitachi Global Storage Technologies - Above 2TB -

      "As a Boot Drive ...a Windows boot drive requires an EFI (Extensible Firmware Interface) BIOS and a 64-bit version of Windows Vista or Windows 7. Linux does not require an EFI BIOS." 

    4. - Change a Master Boot Record Disk into a GUID Partition Table Disk - Applies To: Windows 7

      "GPT is required for disks larger than 2 terabytes; You can change a disk from MBR to GPT partition style as long as disk does not contain any partitions or volumes."

    5. UEFI - UEFI Specifications and Tools

    6. - Frequently asked questions about the GUID Partitioning Table disk architecture

      GUID (globally unique identifier)
      "The GUID Partition Table disk architecture was introduced as part of the Extensible
      Firmware Interface initiative. GUID Partition Table is a new disk architecture expanding
      on the older Master Boot Record (MBR) partitioning scheme common to x86 - based computers.

      GUID Partition Table disks can grow to a very large size. As of July 2001, the Microsoft
      implementation supports a hard disk of up to 18 EB (512 KB LBAs)

      [Etabyte = 1024 Petabytes]

    7. - An update that improves the compatibility of Windows 7 and Windows Server 2008 R2 with Advanced Format Disks is available

    8. - Product Features - Large Capacity Drives - Meeting the technological challenges of 3 TB SATA hard drive implementation.

    9. - Using GPT Drives - "A GPT disk uses the GUID partition table (GPT) disk partitioning system. Highlighted Benefits include:

      1. Allows a much larger partition size--greater than 2 terabytes (TB) - Limit for MBR disks.

      2. Provides greater reliability due to replication and cyclical redundancy check (CRC) protection of partition table."

    10. Considering a GPT Disk Manager? PARAGON Software Group - Hitachi GPT Disk Manager

      1. Paragon Drive Copy - Professional Hard Disk Copy, Disk Cloning and System Migration - deploy new hard drive easily! "Drive Copy - MBR OS migration to Retained GPT (also known as Hybrid GPT) drives.

  12.  Current Limit... Largest Desktop HD Available = 3TB as of 8-11-2011 - Keep It Simple - EFI Bios!
  13. Installing 3TB HDs
Data Recovery
FAT Chart
File Systems
Floppy Disk
Trade Associations

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Web Development, Gill Boyd & Team - Posted 08/28/2003; Updated 11/19/2011