Hard Drives
2011
Hard drives allow us to shop data. When you turn off your pc, information that is stored on the drive remains. This is the total opposite to data stored in RAM memory.
Any data stored in RAM may be much quicker to access, however it won't remain permanently in memory if the power goes off.
Most computers use internal hard drives, but you are able to also buy external drives that connect to your computer via USB or eSata connections which provide extra storage capacity.
Older hard drive formats consist of IDE and to some extent the newer SATA types. Whilst quicker SATA3 drives and SSD or solid state device drives are the newest, smallest and most expensive formats.
Generally speaking, you can by a 2.5 inch format drive for notebook computers and for external drive storage. The slightly larger 3.5 inch format drive is what you'll find inside of most desktop computers.
The speed at which the information disks or spindles rotate figure out how fast you can retrieve data from the hard drive. Slower drives are 5400 rpm, more contemporary drives are 7200 rpm and server disk rotate at 10000 rpm or 15000 rpm.
Hard drive producers are making more and more dense disk platters to ensure that disk capacities could be increased. Most hard drives have more than one disk platter, usually 2 or 3 and data can be stored on both side and retrieved using read/write heads.
The typical weight of a drive is much less than 1 kg. They normally need around 6 to 10 watts of energy to operate and cost in between $50 and $250 to buy. Hard drive pricing has dropped dramatically more than the last few years.
A 500MB drive use to cost $540 around the mid 1980's. Now in 2011, you could pay $54 and buy a 500GB drive that is 1000 times larger in capacity and a lot quicker than the older stepper motor format drives!
