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Hard disk drive (HDD)
A
computer hard disk drive (HDD) is the mechanism that controls the positioning,
reading and writing of the hard disk, which furnishes data storage. A hard disk drive -- often
shortened to hard drive -- and hard disk are not the same thing, but
they are packaged as a unit and either term can refer to the whole unit. Hard
disk drives can be found in desktop computers, mobile devices, consumer
electronics and enterprise storage arrays in data centers.
5 Data Storage Technologies to Watch in 2016
For
the past 13 years, the experts at SearchStorage.com have honored the best and
brightest technologies for the upcoming year. As always, we're proud to present
a batch of technologies we believe will make a big impact on the data storage
market.
History of hard disk drives
The
hard disk was created in 1953 by engineers at IBM who wanted to find a way to provide
random access to high capacities of data at a low cost. The disk drives
developed were the size of refrigerators, could store 3.75 megabytes of data and began shipping in
1956. Memorex, Seagate and Western Digital were other early vendors of hard
disk drive technology.
Hard
disk drive form-factor size has continued to decrease
as the technology evolves. By the mid-1980s, 3.5-inch and 2.5-inch form factors
were introduced, and it was at this time they first became a standard in
personal computers (PCs).
Hard
disk drive density has increased since the technology
was first developed. The first hard disk drives were able to store megabytes of
data, while today they are in the terabyte (TB) range. Hitachi released the first 1 TB
hard drives in 2007. In 2015, HGST announced the first 10 TB hard drive.
Hard disk drive components
Most
basic hard drives consist of a number of disk platters that are positioned
around a spindle inside a sealed chamber. The
chamber also includes read-and-write heads and motors.
Hard disk drive components
The
motor is used to spin the platters, which hold the data, at up to 15,000
rotations per minute (a higher rpm number results in faster performance). As
the platters spin, a second motor controls the position of the read-and-write
heads that record information to, and read information from, tracks on each
platter.
HDD vs. SSD
The
main alternative to hard disk drives in PCs and the enterprise are solid-state
drives (SSDs).
Unlike
hard disks, SSDs contain no moving parts. SSDs also have a lower latency
than HDDs, and are therefore often favored to store critical data that needs to
be accessed quickly and for applications with a high input/output demand. However, SSDs are more
expensive than HDDs from a price-per-gigabyte standpoint. Many enterprise
storage arrays ship with a mix of HDDs and SSDs to reduce costs while providing
better performance.
HDD technology developments
In
2013, Seagate announced hard disk drives that use shingled magnetic recording (SMR) technology. SMR increases storage
density in hard disk drives by layering the magnetic tracks on each disk, rather than
placing them parallel to each other. It is referred to
as shingled because the tracks overlap similar to shingles on a roof.
Harddisk is device data storage on a laptop and computer
source : http://searchstorage.techtarget.com/definition/hard-disk-drive
