IBM did not invent personal computing but their “PC” became synonymous with the category. Having entered the market in 1981, the IBM PC quickly became the top selling brand. From 1984 to 1993 IBM sold more PCs than any other vendor, conceding the spot to Compaq which remained on top only until 2000. No PC vendor remained at the top of the sales leagues longer than IBM. HP had the second longest run but that run was broken last year as Lenovo (who acquired IBM’s PC business) surged.
As the graph above shows, the period of time when IBM was dominant was characterized by far lower volumes. In 2004, the year IBM exited, they sold about 10 million units. ((as the graph shows, if we consider Lenovo as taking over from there, they did a very good job extending the legacy.)) It was a decent performance but one that did not keep up with the Dell and HP/Compaq race to the bottom in pricing and subsequent rise in volumes.
However, throughout its position of strength, IBM was a reluctant PC maker.