Why do you have computer keyboards?

The QWERTY layout was created in the early 1870s by Christopher Sholes, a Milwaukee newspaper editor and printer, who, with the help of his friends Carlos Glidden and Samuel Soule, built an early typewriter and filed a patent for it in 1867.

The first model used a piano like keyboard with 2 rows of keys arranged in alphabetical order like this:

3 5 7 9 N O P Q R S T U V W X Y Z

2 4 6 8 . A B C D E F G H I J K L M

However, it had 2 problems - 1: the keys were mounted on metal arms, which would clash and jam if neighboring arms were pressed simultaneously or one after the other, and 2: the user had to open the paper carriage to fix the jam.

Sholes tried to perfect the invention over the next 6 years, and eventually came up with a layout similar to the modern QWERTY:

2 3 4 5 6 7 8 9 - ,

Q W E . T Y I U O P

Z S D F G H J K L M

A X & C V B N ? ; R

Shole's backer, James Densmore, sold manufacturing rights to E. Remington and Sons, who modified it further. The layout became popular with the Remington No. 2 typewriter, the first one to include a shift key for both upper and lower case letters, and later with the advent of personal computers.

Part of the reason why the QWERTY layout works is also because the letters are arranged in diagonal columns. The idea that the QWERTY layout is meant to slow typists down is incorrect - it's instead meant to prevent jams when the typist is typing rapidly.