A
A may refer to any of the following:
1. A: is a physical drive on older PC or IBM compatible computers. The A: drive denotes the 3.5-inch or 5.25-inch floppy disk drive and is often configured in BIOS setup as the first bootable drive on IBM-compatible computers.
By having the drive as the first boot device, the computer can boot from a bootable floppy diskette to install an operating system and fix and repair a computer.
Today, the A: drive is obsolete and has been replaced by the CD-ROM (compact disc read-only memory) and USB (universal serial bus) flash drives.
2. In gaming, when using the WASD keys to control a character or another object, the "A" is the same as the left arrow key.
3. A* (pronounced "A-star") is an algorithm for pathfinding and traversing a graph data structure. It was developed in 1968 by researchers at Stanford University and is widely used today―notably in computer games. When a video game character moves and navigates around obstacles or terrain, the A* algorithm was likely used to calculate the path.
4. A is a keyboard key used with the keyboard shortcuts Alt+A, Command+A, Ctrl+A, and Ctrl+Shift+A.
5. With Perl, \a is a bell or alarm. With a regular expression, \A matches the start of a multiline string.
6. With HTML (hypertext markup language), the <a> tag creates an anchor (hyperlink). See our <a> tag page for further information on this tag.
7. On the keyboard LEDs, a square with the letter "A" indicates the Caps Lock on some keyboards.
8. With Microsoft Excel and other spreadsheet programs, "A" is the first column of a spreadsheet. To reference the first cell in the column, you'd use "A1."
9. When discussing Alexa, it may be called the "A word" to help prevent it from being triggered.
10. In Adobe Photoshop, A is a shortcut to select the Path Selection tool. Pressing Shift+A cycles through related tools, including the Direct Selection tool.
11. With a measurement, an "A" is short for amp or ampere, the measurement for electrical current.
12. With a measurement, "A" is short for angstrom, a measurement that is one 10-billionth of a meter.
13. A lowercase a is the SI-derived symbol of the atto- prefix.
14. In the phonetic alphabet, "A" is often pronounced as "alfa."
15. A is the first letter of the English alphabet, followed by the letter "B." To create a capitalized "A," press Shift and A at the same time.
With U.S. QWERTY keyboards, the "A" key is on the home row, to the right of the Caps Lock key, and left of the "S" key. See our keyboard page for a visual example of all keyboard keys.
If the "A" key is not working on the keyboard, see: Some keys on my computer keyboard aren't working.
In ASCII (American Standard Code for Information Interchange), the uppercase "A" is "065" in decimal (01000001 in binary). The lowercase "a" is "097" in decimal (01100001 in binary).
The number 2 on a phone keypad creates an "A" on a US phone.
AA, AAA, B:, C:, Computer abbreviations, D:, Drive letter, Floppy drive, Floppy drive terms, Letter