Long LBA, 3TB Drives, and Backup Appliances

Seagate has a problem.  The company is reportedly readying a 3TB drive.  However, most systems, and by that I mean both hardware and software, use a technique known as LBA (Logical Block Addressing) to address the blocks on a disk drive.  LBA is capable of addressing a maximum of 2.1TB.  LBA was created originally decades ago by IBM and Microsoft.

Long LBA is the solution.  Long LBA simply increases the number of bytes in the address of a block on the  disk drive.

Simple enough, right?  Well – not so fast.  It turns out that you need a 64-bit operating system in order to implement Long LBA.  And it gets worse.  Firmware on motherboards and I/O adapters will need to be rewritten to use the long LBA standard as well.

Another issue surrounds the GUID partition table (GPT) for the master boot record. Because current MBR partitions are limited in size to 2.1TB, a system would need the new table to see beyond that amount of storage. An updated GPT is part of Intel’s proposed Extensible Firmware Interface specification, which would replace the traditional BIOS and is supported by the United EFI Forum (UEFI), but most motherboards don’t currently feature the Interface.

Should make for an interesting remainder of 2010.


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