Computer folks often throw around words, terms and acronyms assuming everyone else knows what they mean. I recently learned that’s a bad assumption, though, as a customer discussing backing up files to an external hard drive remarked, “You know, I don’t think I really know what a hard drive is. What is a computer ‘drive,’ anyway?”
Wow, good question. In a nutshell, a computer “drive,” also called a “disk drive,” is a device that stores digital information from your computer, sort of like keeping beans in a jar. Beans can be added to or removed from the jar as desired, just as the zeroes and ones (0 and 1) that comprise digital information can be added to or removed from a computer disk drive as the computer user so chooses.
All computer information is made up of various combinations of two numbers: zeroes and ones. Those numbers are the “digital” components of the language that computers speak. When discussing computer “files,” and the need for you to “back up” your files, we are talking about large groups of zeros and ones that have been created when you type a manuscript, take a photograph with a digital camera or send a text message from your phone. That picture of the kids at Thanksgiving dinner is, in its basic form, nothing more than a big batch of numbers called a “file.” Computers have the ability to take that group of numbers and turn it into an image on a screen.
Computer drives are designed to allow us to store our files and retrieve them when needed. They were originally called “disk” drives because the files were recorded on round things called “disks.” “Floppy” disks kept the information on a very thin, round piece of spinning material about the thickness of a piece of paper, and were about 3-1/2, 5-1/4 or 8 inches in diameter. Housed inside a plastic or paper sheath, they were used in floppy disk drives. Very few people continue to use floppy disk drives.
“Hard” disks use round platters made of very stiff material, usually aluminum, glass and/or ceramic. As with floppy disks, hard disks are coated with a layer of magnetic material that allows information to be stored, similar to the magnetic tape used in tape recorders. Hard disks, and the electronic circuits that make them work, are mounted inside rigid housings, and the entire assembly is called a hard disk drive, or, simply, “hard drive.” Hard drives can be mounted inside computers, or inside enclosures that allow them to be easily moved from one location to another. Drives like this are called “external” or “portable” hard drives.
Music CDs (Compact Disks) and DVDs (Digital Video Disks) are called “optical” disks because, rather than using magnetic technology to store information, they use optical technology in the form of lasers. A powerful but very small laser beam scans the spinning disk to read and/or record the zeros and ones that comprise the stored information. If someone mentions an “optical” drive, they are talking about a drive that uses CDs, DVDs or Blu-ray disks. Sometimes these drives, if they are capable of recording CDs or DVDs, are called “burners” because, when recording a CD or DVD, the laser beam actually “burns” spots on a layer of dye embedded in the disk, which the drive and computer can detect and interpret as zeroes and ones.
“Flash” drives, sometimes called jump drives, thumb drives and USB drives, are also used to store digital files, but use “solid-state” memory technology, rather than moving parts like motors and spinning disks. “Solid-state drives” (SSDs) use the same method, storing their information on digital integrated circuits (sometimes called “chips”) containing millions or billions of microscopic transistors, which act as switches. These switches, whether in an “on” or “off” state, are what store and process the zeroes and ones used by all computers.
Why are disk drives called “drives?” As near as I can tell, in electrical engineering, a drive is an electronic device used to provide power to a motor. That’s the best reason I’ve been able to come up with, so I hope it will do.