48bitLBA.com

		Source for 48-bit LBA Information

Bios Upgrades

48-bit LBA Technology

What is 48-bit LBA?

48-bit Logical Block Addressing (LBA) is a technology which extends the capacity of IDE ATA/ATAPI devices beyond a previous limit of 137.4 GB. This limit applies to IDE ATA/ATAPI devices only and not to SCSI interface devices. The original design specification for the ATA interface only provided 28-bits with which to address the devices. This meant that a hard disk could only have a maximum of 268,435,456 sectors of 512 bytes of data thus limiting the ATA interface to a maximum of 137.4 gigabytes. With 48-bit addressing the limit is 144 petabytes (144,000,000 gigabytes).

Are there any major issues with 48-bit LBA?

Unfortunately, yes. Some versions of Microsoft Windows do not support hard drives greater than 137 GB at all, other versions do but it may be necessary to update the operating system with the latest Service Pack and a parameter may need to be defined and set properly in the Windows registry. There's also an issue with the BIOS where it may be necessary to install a BIOS upgrade for your system in order for the system to work properly with the new hard drive. In many cases the average user may find that installing their new large hard drive is not as simple as just plugging it in and it just works. If you've reached this site then it may be that you've found that to be the case. This site is devoted to providing you the help you need for making your new hard drive work with your system.

How can this site help?

We've done extensive research on this subject by searching the Internet for available information about 48-bit LBA technology. We've found much of the information confusing and some of it flat out wrong even on some major web sites. We've also run many tests with various combinations of operating systems, hard drives from all the major manufacturers under different configurations, and various partitioning tools. The results of our research and tests can be found with information available on this site. We've even developed a tool, HDINFO, which can help you if you're having trouble installing your new 48-bit LBA hard drive.

Information available on this site can be accessed from the menu on the left. If you are new to 48-bit LBA you may want to refer to the Overview section which contains a basic tutorial on the technology. For more in-depth information the Reference section contains more extensive information such as specifications, white papers, and Microsoft Knowledgebase articles. Major Issues contains information about the major issues with 48-bit LBA. If you are having trouble getting your large hard to work, Help should get you up and running. Tools and Drivers section contains quick links to all the tools and drivers you may need. Drive Manufacturers section will get you to your drive manufacturer's web site. Finally, if you have any comments at all about this site, refer to the Comments section.

HDINFO
Having trouble installing your 48-bit LBA Hard Drive?
48-bit LBA BIOS Test.

Quick Facts 48-bit LBA requirements checklist.

Companion Tool for Windows Vista.
vistacompanion.com