Windows XP Maximum Harddrive Size 2

[TheAceMan1]

Howdy All!

Whats the [blue]maximum Harddrive Size[/blue] for windows XP (any service pak). I'm getting conflicting data in my searches. Currently I've narrowed it to 2 or 16 Terabytes but still shaky here.

See Ya! . . . . . .

Be sure to see faq219-2884 [blue]Worthy Reading![/blue]
Also faq181-2886 [blue]Worthy Reading![/blue]

 

[rclarke250]

With no service pack it was limited to 137Gb, as LBA 48-bit support didn't come out till SP1. per the wiki: The current 48-bit LBA scheme, introduced in 2003 with ATA-6 standard, allows addressing up to 128 PiB. Current PC-Compatible computers support INT 13H Extensions, which use 64-bit structures for LBA addressing and should encompass any future extension of LBA addressing, though modern operating systems implement direct disk access and do not use the BIOS subsystems, except at boot load time. However, the common DOS style Master boot record partition table only supports disk partitions up to 2 TiB in size. For large partitions this needs to be replaced by another scheme for instance the GUID Partition Table which has the same 64-bit limit as the current INT 13H Extensions. Support for this is poor as of 2010 due to Windows requiring Extensible Firmware Interface additions to the BIOS to boot using GPT.

It should be noted that this is the largest PARTITION. not the largest drive size, it will support the largest size available which is 3TB at this time, but it will not support this in a single partition. This would require a special overlay program

From a review of the WD 3tb green.
The problem is that older operating system, in combination with a legacy BIOS and master boot record (MBR) partition table scheme face a barrier at 2.19TB. Why? It's because they can only address up to 2^32 logical blocks, multiplied by sector size capacity. Since the most commonly used sector size is 512 bytes, mathematics tells us there is a capacity limit of 2,199,023,255,522 bytes or 2.19TB. Advances in technology make the use of large capacity drives possible. One way would be to use a larger sector size, while keeping the number of addressable blocks the same. For example, using 4096 (4k) byte sectors would allow for systems to address a maximum of 2^32 x 4096 bytes, or 17.59TB. Unfortunately, there are too many application incompatibility issues when you go over 512 bytes.

Western Digital has made the transition to physical sector sizes of 4096 bytes and calls it Advanced Format (AF) technology. To address the problem associated by making this move, the hard drive reports and emulates a disk using 512 bytes.

 

[BadBigBen]

rcarke250, correct... XP will only see 2 TB, actually 1.891TB and will not deal with GUID at all... there are RAID cards that overcome this by SLICING the capacities into chunks so that XP, W2k3, w2k, etc. can see and use the full capacity...

under Windows 7 (64bit at least) can use partitions larger than that...

Ben
"If it works don't fix it! If it doesn't use a sledgehammer..."
How to ask a question, when posting them to a professional forum.
Only ask questions with yes/no answers if you want "yes" or "no"

 

[TheAceMan1]

rclarke250, BadBigBen . . .

The dirve will be used for file storage only (no MBR or DOS partition). Will this allow XP to bridge the 2 TeraByte limit?

See Ya! . . . . . .

Be sure to see faq219-2884 [blue]Worthy Reading![/blue]
Also faq181-2886 [blue]Worthy Reading![/blue]

 

[rclarke250]

Doesn't matter, it has to do with addressable sectors. You can partition the drive into more than one partition, just not a huge D: drive. It would have to be D: and E: drives.

 

[BadBigBen]

(no MBR or DOS partition) - that would only leave GUID for partitioning, and XP can't do that...

if you need storage, thing about a small NAS, such as a Buffalo Linkstation, though more expensive than dropping a drive into the PC, but it does not have the limit of 2TB...

Ben
"If it works don't fix it! If it doesn't use a sledgehammer..."
How to ask a question, when posting them to a professional forum.
Only ask questions with yes/no answers if you want "yes" or "no"

 

[dbMark]

Windows Vista SP1 and newer are Advanced Format/4K Aware. Windows XP is left out in the cold.
Information about Microsoft support policy for large sector drives in Windows

http://support.microsoft.com/kb/2510009

One major reason XP isn't compatible with Advanced Format is that the disk alignment is offset whereas the new standard is a 0 offset. Clearly, Microsoft has no plans to upgrade XP's format or partitioning capabilities as it did with Vista SP1. (Apparently an AF drive can be formatted or partitioned in a newer OS and then used by XP, but don't even try to have XP to change the partitioning or reformat!

Western Digital has a controller card that can be installed for use with XP.

Seagate described the background:

http://consumer.media.seagate.com/2010/03/the-digital-den/4k-sector-hard-drive-primer/

Seagate's firmware solution ... SmartAlign:

http://consumer.media.seagate.com/2010/06/the-digital-den/advanced-format-drives-with-smartalign/

Be aware that SmartAlign will let XP break the 2TB disk size barrier but the 2TB partition size barrier remains.
Note that