What Are Computer Storage Devices?

Computers can collect and sort data and create documents, but the end result needs to be stored, if not printed and used immediately. Data and document storage needs to be stored on one of several available storage devices for later retrieval, printing, changing or manipulating. The computer's internal RAM (random access memory) stores and runs application programs and work that is currently in use, such as a letter that is being typed. But RAM memory contents are lost when the computer is turned off.

Floppy Disks

3½-inch floppy disk

The first invention that revolutionized storage for the personal computer industry was the introduction of floppy disks. Similar to tape, these magnetic storage devices were flat discs that rotated within a sleeve. The original 5-inch size soon had an 8-inch larger version to store more data, and both of these were eventually replaced by a smaller 3½-inch size that actually stored more data--up to 1.44 megabytes. These were great improvements, but speed and reliability were still a problem. Today, floppy disks have been almost entirely replaced by other storage devices, such as CDs and DVDs, that are faster, more reliable, and have huge storage capacities.

Hard Disk Drives

Modern external hard drive

The addition of hard disk drives finally gave personal computers more reliable storage, with faster loading and saving of programs and data. Similar to the concept of floppy disks, the magnetic medium was placed on a hard metal platter that could spin much faster. Hard drives soon became standard internal devices on PCs, although storage capacities of 20, 32 and 40 megabytes were filled rather rapidly. External hard drives, which are still in use, became desirable add-ons. Today, however, external hard drives are small, fast, inexpensive and available in storage capacities of 500 gigabytes and even 1 terabyte (1,000 gigabytes).

Flash Drives

Flash drive

Solid state memory devices called "flash drives" have become a welcomed storage medium for personal computer users. These small devices are only about 2 inches long and conveniently plug into a computer's USB port. This makes them portable, enabling an easy transfer of files between desktop and laptop computers, and even between PCs and Apple computers. To the computer user, flash drives appear as another hard drive to which data can be written and read at high speeds. Because there are no moving parts, flash drives are very reliable and can sustain "bumps and bruises." Storage capacities of up to 32 megabytes are common. Flash drives are also referred to as "travel drives" and "removable disks."

CDs and DVDs

Flash drive

CDs and DVDs are optical storage media that are well suited for external storage, with DVDs storing up to 4.7 gigabytes. These discs are easy to read and write, and are very reliable, though scratches caused by mishandling can cause problems.

The Future Is Here

Now, even DVDs are being improved upon, with Blu-Ray versions increasing storage capacity and "light scribe" technology enabling users to utilize the laser in their DVD drives to etch labels on their discs.