What Is a Hard Drive?

What Is a Hard Drive?

A hard drive is a crucial element of our modern computer systems. The hard drive is the part of the computer where all of your programs and files are stored. Think of it as the file folder of your computer. A hard drive is also known as a hard disk drive.

The hard drive is so crucial to the computer that If the drive is somehow damaged, you will lose everything you have stored on your computer.

How Does a Hard Drive Work?

Strangely enough, a hard drive uses memory storage similar to VHS tapes or cassettes.

Where a VHS tape or a cassette uses long strips of black tape infused with a magnetic material to store information, hard drives contain little round mirrors covered in magnetic material that is able to record data. Looking at a hard drive next to a VHS tape, you wouldn’t think the two were at all similar. But just as your VCR reads data from a VHS tape, a piece inside your hard drive reads and writes data on the little mirror looking platters. If you were looking at a hard drive, you’d see a tiny arm attached to the memory platters — this arm moves back and forth over the memory, doing its work nearly silently.

What Is a Hard Drive?

Most hard disk drives these days contain multiple memory platters stacked one on top of the other something like a layer cake. There is a tiny space between each layer which gives the drive room to move around and move the arms back and forth to write and rewrite data. When you turn your computer on, the memory platters start spinning. If the vent fan on your computer isn’t running, you can hear the steady but quiet hum of the memory platters at work. You can hear them because they’re moving really fast — about 7,200 rotations per minute for a desktop or about 5,500 rpm for a laptop computer.

No matter if your computer is writing or searching for memory or not, the hard disk is always spinning. It is the arm that we talked about earlier that jumps into action whenever you run a progrem, open a file, alter, save, or delete a file, or a few other minor actions. That little arm is a fast bugger — it can move back and forth over the surface of the platter up to 50 times per second, so fast that if you could watch it in action, the arm would just look like a little blur.

Remember that everything in your hard disk drive moves very fast, so the arm and the drive head never actually touch the memory platters. They skip over the surface of the platter like a hovercraft, supported by a bit of fast-moving air created by the spinning of the platter. Most people are really surprised to learn how much work their computer is doing when they save a file — there’s so much kinetic energy in there its no wonder that we need heat sinks and fans.

What Can Cause a Hard Drive Crash?

Electrical problems with the logic board can cause a hard drive to crash, as can simple shock to drives that are made of glass or other weak material. Luckily, most manufacturers have switched to a material that is not as easily broken.

Another common hard drive failure happens when there are tiny imperfections on the magnetic media on the platters. If a single sector on the hard disk fails to hold alignment, the data will become inaccessible to the user. Most hard drives have these tiny flaws, but the manufacturer marks them in such a way as to prevent the computer from accessing them. You can have your flawed platters fixed in a similar way after-market, but that process will wipe your memory.

The most dramatic example of a hard drive crash is called a “head crash”. This happens when the rapidly moving paltters cause the “heads” holding the arms to literally crash into the memory platters. This is usually caused by dirt or dust in your hard drive that settles on the platters and causes them to bounce and wobble. Remember that the recording medium on the platters is really fragile and is usually totally ruined when the heads crash into it.