WHY QWERTY PATTERN ?

• Devised by Christopher Latham Sholes.
• Originally letters were arranged in alphabetic order.
• Alphabetic order causes keyboard stroke become tangled.
• Also leading to staining the document frequently.
• QWERTY arrangement leads to splitting up of commonly used keys to avoid jamming.
• Alphabets which are mostly used are accessed fast following the QWERTY pattern.
• same layout is nearly optimal for pure speed, as it tends to cause the fingers and hands to alternate.

Still used to this day, the QWERTY layout was devised and created in the early 1870s by Christopher Latham Sholes, a newspaper editor and printer who lived in Milwaukee.

The first model constructed by Sholes used a piano-like keyboard with two rows of characters arranged alphabetically.

Originally, the characters on the typewriters he invented were arranged alphabetically, set on the end of a metal bar which struck the paper when its key was pressed. 

the characters on the typewriters were arranged in alphabetical order; Letters that placed close together on the keyboard became tangled with one another as the operator had learned to type at speed, forcing the typist to manually unstick the type bars. This also caused staining the document frequently and jams in typewriter machine.

Initially in 1870s, An associate suggested using nice trick by splitting most commonly keys to speed up typing, so that they also don’t get tangled very often. Rearrangement of keys introduced the word QWERTY, the most commonly used modern-day keyboard layout.

The logic behind such an arrangement is that the alphabets which are most needed can be accessed fast.

QWERTY layout was designed to let people type as quickly as possible, without jamming a mechanical typewriter. As it happens, this same layout is nearly optimal for pure speed, as it tends to cause the fingers and hands to alternate.
A simple A to Z layout, would really slow down people as it would overload some weaker fingers and waste the stronger ones. It would also tend to require more side-to-side motion. Considerable wrist strain is also thought of.

This arrangement is now widely accepted.