Hard Drive

Hard drives are a high capacity storage medium which is very prevalent in modern PC’s. All PC’s tend to have a large hard drive which is used to store the operating system, software and user data. As hard drives have a fast transfer rate and a fairly fast access time they provide a good compromise between storage capacity and performance.

Hard drives are a magnetic medium and store data on a hard drive platter.  to run slower (due to power drain) and run at 5,400 RPM.

Data is read and saved using arm and a special read head. The disc will spin and the arm will travel across the disc. Both these movements mean that the head can reach every sector on the hard drive. In order to read or write data a small magnetic flux is introduced. The oxide on the hard drive platter will remember this flux and as such will store the data. Computers work with binary and as such only two values will ever need to be stored which are 1 and 0. Data is then encoded using standard binary techniques.

The faster the platter spins the faster data can be read off the disc. This speed is measured in revolutions per minute. 7,200 RPM is a common speed but they can vary. So every minute this hard drive is in use the platter will of spun a full 360 degrees 7,200 times. In fact it is possible to get hard drives running at 15,000 RPM but these tend to be expensive and do not tend to store great amounts of data. These faster hard drives tend to be used in servers. Standard desktop PC’s tend to use 7,200 RPM. Laptops tend to use slower RPM to conserve power.

Multiple hard drives are sometimes linked together in what is known as a RAID.