Hard Disk Drives: Long-Term Storage

Another important physical component inside your system unit is the hard disk drive. The hard disk permanently stores all your important data. Some hard disks can store more than 100 gigabytes of data. (Contrast this to your system's random access memory, which stores only a few hundred megabytes of data temporarily.)

caution

If you try to reformat your hard disk, you'll erase all the programs and data that have been installed so don't do it unless you know what you're doing and are prepared to lose your stuff!

A hard disk consists of numerous metallic platters. These platters store data magnetically. Special read/write heads realign magnetic particles on the platters, much like a recording head records data onto magnetic recording tape.

Before data can be stored on any disk, including your system's hard disk, that disk must first be formatted. A disk that has not been formatted cannot accept any data. When you format a hard disk, your computer prepares the surface of the disk to accept and store data magnetically.

Of course, when you buy a new PC, your hard disk is already formatted for you. (And, in most cases, your operating system and key programs also are preinstalled.)

Your hard disk can cause you a great deal of trouble if you don't treat it right. Because a hard disk is a physical device that spins at a high rate of speed, it can actually wear out over time. The disk might start spinning at the wrong speed, or the platters that make up the disk might themselves become damaged. If your system is located in an area with too much dust or smoke, the disk platters can become contaminated; a contaminated disk might not read or write data correctly. In addition, a rough jolt to your system unit (and thus to the hard disk) can cause the disk's read/write heads to collide with the platters and result in damaged hardware and data which is a good reason to turn off your PC before moving it.

Eventually, too, the platters and the read/write head might become misaligned, due to nothing more than age and use. When this happens, consult a technician. Your disk might be salvageable, or it might have to be replaced.

The data on your hard disk also can be subject to various problems, many of which are caused by human error. If you accidentally format a hard disk that has data on it, for example, you lose all that data. You can accidentally erase varying amounts of data on your hard disk, too, if you're careless in deleting files. What's more, if computer viruses manage to infect your system, they can scramble your valuable data, making your hard disk function abnormally, if at all. So always take extra care when working with your hard disk; if you don't, all its gigabytes of data can very suddenly and quite painfully become inaccessible.