Hard Disk Drive is one of several types of magnetic media used for storing data. Unlike floppy disks, hard disks are non-flexible and non-removable. They hold much more data than floppy disks, and are the principle long-term data storage for most personal computers. Non-removable hard disks are also known as "fixed disks".

Hard Disk Drives are mechanical with very sophisticated parts. Typically, a safe hard disk life-span is considered to be 5-years for home computing. Server- and Workstation hard disks have to be re-placed more often as they are operating on a 24/7 basis.

Hard Disk is basically not very different from a cassette tape. Both hard disks and cassette tapes use the same magnetic recording techniques. Hard disks and cassette tapes also share the major benefits of magnetic storage, the magnetic medium can be easily erased and rewritten, and the stored media with all the magnetic flux patterns stays stored onto the medium for many years.

Hard Disk Performance is measured in the speed that the platters spin and data is written / read. Hard disk spindle speeds can be from 5400 RPM, 7200 RPM, 10000 RPM or 15000 RPM. Notebook hard disks perform at 4200 RPM, 5100 RPM and 7200 RPM spindle speeds.
Hard Disk Tape
Hard Disk is a self-contained unit with built-in Read-Write Heads and magnetic platters. There are two parts to any tape magnetic recording system: the recorder itself (which also acts as the playback device) and the tape it uses as the storage medium.
The magnetic recording material is layered onto a high-precision aluminum or glass disk. The hard-disk platter is then polished to mirror-type smoothness. The magnetic recording material on a cassette tape is coated onto a thin plastic strip.
In a hard disk, the read/write head "flies" over the disk, never actually touching it. In a cassette-tape deck, the read/write head touches the tape directly.
Move to any point on the surface of the disk almost instantly. Fast-forward or reverse to get to any particular point on the tape. This can take several minutes with a long tape.
A hard-disk platter can spin underneath its head at speeds up to 3,000 inches per second (about 170 mph or 272 kph). The tape in a cassette-tape deck moves over the head at about 2 inches (about 5.08 cm) per second.


The information on a hard disk is stored in extremely small magnetic domains compared to a cassette tape's. The size of these domains is made possible by the precision of the platter and the speed of the medium.

Because of these differences, a modern hard disk is able to store an amazing amount of information in a small space. A hard disk can also access any of its information in a fraction of a second.

Basic Handling Precautions:

Never drop, jar, or bump the drive.
DO NOT connect/disconnect any drive cables when the power is on.
DO NOT force or rock the connectors into their sockets. Push them in straight until they are seated.
Allow the drive to reach room temperature before installing it in the computer.
Helpful hint - to avoid electrostatic discharge(ESD) damage touch the metal case of your PC system or use a grounding strap before handling. Connect your grounding strap to the system casing.