Seagate skickade nyss ut denna info om hur man ska ”förbereda” sig eftersom större diskar kräver stöd för Long LBA. Men ingen specifik info om när nya diskar kommer.
http://kd77.seagatestorage.com/3A109F5455?elqPURLPage=4448&elq=565da77460ab4096bc2f56aa3fed969b
Prepare for 3TB
3TB is coming. Are you ready?
Consumer demand for more and more capacity is leading inevitably
to the 3TB drive. It’s a similar story at the corporate level with data centres
demanding more storage capacity within less physical space in order
to achieve cost efficiencies. But the real question is: are you ready
for hard drive capacities greater than 2.199TB? As Barbara Craig, Seagate
Senior Product Marketing Manager, warns ”System builders beware! You must
ensure your infrastructure is ready to support these higher capacity drives.”
3TB means a new LBA system
No one had any idea how storage capacities would grow back in 1981 when
Logical Block Address (LBA), the standard for HDD, was set. LBA specifies where
blocks of data are stored on a hard drive and sees data as 512-byte sectors.
Each needs an address but LBA was only designed to address up to 2.199TB
so cannot address a full 3TB drive. A new LBA system is needed and
its name is Long LBA or LLBA.
Long LBA–the solution
Long LBA addressing increases the bytes in a Command Descriptor Block (CDB). A CDB is a formatted chunk of data that is passed between a disk and a PC and contains the LBA information so the disk knows which sector to address. A standard CDB is made up of ten bytes, four of which are allocated for LBA information. However, with 16- or 32-byte CDB for Long LBA, eight bytes of LBA information are possible, doubling the addresses available, so the system can access the full capacity of a 3TB HDD. So the system must support at least 16 byte CDB and Dynamic Sense Data to access LBA counts above 2.199TB
How do you prepare for 3TB?
Ensure system, operating system, BIOS, HBA/controller and drivers all support Long LBA Addressing. Everybody has to be able to access these longer addresses with their products. When the system cannot access the full HDD capacity it will see the 3TB drive as only 2.199TB. Windows Vista, Windows 7 and Mac Snow Leopard can already use LLBA but not Windows XP. 3TB drives will only be useable by PC and server makers who have upgraded their products to handle drives with capacities of more than 2.199TB.
