Computer keyboard Computer keyboard is the set of typewriter-like keys that enables you to enter data into a computer. Computer keyboards are similar to electric-typewriter keyboards but contain additional keys. The keys on computer keyboards are often classified as follows: alphanumeric keys — letters and numbers punctuation keys — comma, period, semicolon, and so on. special keys — function keys, control keys, arrow keys, Caps Lock key, and so on. The standard layout of letters, numbers, and punctuation is called QWERTY keyboard because the first six keys on the top row of letters spell QWERTY. The QWERTY keyboard was designed in the 1800s for mechanical typewriters. There is no standard computer keyboard, although many manufacturers imitate the keyboards of PCs. There are actually three different PC keyboards: the original PC keyboard, with 84 keys; the AT keyboard, also With 84 keys; and the enhanced keyboard, with 101 keys. The three differ somewhat in the placement of function keys, the Control key, the Return key, and the Shift keys. In addition to these keys, IBM keyboards contain the following keys: Page Up, Page Down, Home, End, Insert, Pause, Num Lock, Scroll Lock, Break, Caps Lock, Print Screen. What is a Hard Disk Drive (HDD)? Hard disk drive is the mechanism that reads and writes data on a hard disk. Hard disk drive has many inflexible platters (discs) coated with magnetic material. Read/write heads can record computer data on these discs. Atypical hard disk rotates at 3, 600 revolutions per minute, and the read/ write heads ride over the surface of the disk on a cushion of air 25 micron deep. Hard disk drives (HDDs) for PCs generally have seek times of about 12 milliseconds or less. Hard disk drives are sometimes called Winchester drives. Winchester is the name of one of the first popular harddisk drive technologies developed by IBM Questions: 1. How are the keys on computer keyboards classified? 2. How is the standard layout of keys on a keyboard called? 3. How many keys has enhanced keyboard? 4. How are hard disk drives sometimes called? 5. What is hard disk drive?