Hardware Reference
In-Depth Information
on a single platter and are available in single-platter 40GB and dual-platter 80GB ver-
sions. These drives featured the highest areal density of any drives then on the market at
133Gb/sq. inch (206Mb/sq. mm). Although not normally used in PCs, these drives can be
found in some of the extremely small and lightweight laptop systems such as the Toshiba
Libretto.
In June 2006, Toshiba introduced a 200GB 2.5-inch PMR drive only 9.5mm thick and
weighing only 98 grams. This became the highest capacity 2.5-inch drive available at the
time, and it featured the world's highest areal density (178.8Gb/sq. inch or 277Mb/sq.
mm) in a production drive. In October 2006, Toshiba announced it had produced more
than one million drives using PMR technology.
Seagate introduced the world's first 2.5-inch PMR-based hard disk with the Momentus
5400.3 160, a 160GB 2.5-inch drive designed primarily for laptops. Although Seagate an-
nounced the drive in June 2005, it wasn't actually available for purchase until January
2006.InApril 2006,Seagate introduced the Barracuda 7200.10drive, which was both the
first 750GB drive on the market as well as the first 3.5-inch drive to use perpendicular
recording.
Other manufacturers have also developed PMR drives; in fact, virtually all hard drive
manufacturers have shifted the bulk of their product to PMR-based drives to continue
the incredible capacity growth trends in magnetic storage. In January 2007, Hitachi intro-
duced the Deskstar 7K1000, which used perpendicular recording to achieve the milestone
of being the world's first 1TB (terabyte) drive. At the introduction, Hitachi noted that it
took the storage industry 35 years to move drive capacity from 5MB to 1GB (1956 to
1991), 14 more years to get to 500GB (1991 to 2005), and only two more years (2005 to
2007)tohit1TB.ThisclearlyshowsMoore'sLawineffectformagneticstorage.Later,in
June 2007, Hitachi introduced the 5K250, a 250GB 2.5-inch drive storing data at 205Gb/
sq. inch areal density. Western Digital introduced the first 2TB drive in early 2009, and in
2010 both Seagate and Western Digital introduced the first 3TB drives (external and in-
ternal,respectively),andSamsunghasindicateditwillreleasethefirst4TBdrivein2011.
These new high-capacity drives store data at areal densities of 500Gb/sq. inch or higher.
