I'm full of keys but can't open any door. I have a space bar but I'm not a pub. What am I?

The riddle cleverly plays on the multiple meanings of words. When one thinks of "keys" in this context, they are the individual buttons on an input device, each typically corresponding to a character, number, or symbol used for typing, rather than physical objects used to unlock things. Similarly, the "space bar" refers to the long, horizontal key at the bottom of the device, primarily used to insert spaces between words and sentences, not a social establishment for drinks. This makes a computer keyboard the perfect solution.

The lineage of the modern computer keyboard can be traced back to the invention of typewriters in the 19th century. American inventor Christopher Latham Sholes is credited with developing the first practical typewriter in 1868, and crucially, he introduced the now-ubiquitous QWERTY layout in 1873. This arrangement was not arbitrary; it was designed to prevent the mechanical arms of early typewriters from jamming when typists worked too quickly, by separating frequently used letter combinations.

As computing evolved, keyboards transitioned from mechanical typewriters and teletype machines into electronic input devices for computers in the 1950s. The IBM PC keyboard, released in the early 1980s, further standardized the layout, including function keys and a numeric keypad, forming the foundation (Review) for most modern keyboards we use today. Today, keyboards remain an indispensable tool, vital for everything from professional work and coding to gaming and general interaction with digital systems.