IBM didn't invent the PC (that distinction is generally attributed to Apple). But when IBM debuted its first PC in 1981, it paved the way for a host of "IBM-compatible" computers and, eventually, the world's most popular operating system, Microsoft Windows.
The PC allowed consumers to have access to a computer in their homes for the first time. They were marketed as small and inexpensive, which is why they eventually became a dime a dozen.
IBM grew into one of the world's largest PC sellers. But IBM saw the business commoditizing, and decided to bail out. In 2004, it sold its PC division to Lenovo for $1.8 billion.
