B may refer to any of the following:
1. B: is a floppy disk drive letter used on MS-DOS and Windows-based computers most associated with the 5.25-inch floppy disk drive, and sometimes the 3.5-inch floppy formats. Today, it's rare for a computer to be using a B: drive, as both floppy formats are obsolete. Also, the hard drive defaults to the C: drive. However, it is still possible to assign any drive as the B: drive.
2. The B programming language is a programming language developed at Bell Labs in 1969 by Ken Thomson and Dennis Ritchie. The language was based on BCPL, and "B" is likely a shortening of that name. Although the B language is no longer used, it led to the development of the C programming language, which is still widely used today.
4. The letter "b" is also chat slang for "be" or "bee."
5. With a regular expression, \b is word boundary in most languages or a backspace. When capitalized, \B is a non word boundary.
If the "B" key is not working on the keyboard, see: Some of the keys on my computer keyboard aren't working.