IBM's own history site, with pages on many of their significant systems (see especially the "Exhibits" and "Documents" sections).

Summary of Columbia University's dense, more than 50-year-long history of academic use of IBM systems. Includes links to descriptions of most of the systems they have used.

A condensed history of IBM mainframes and their operating systems from System/360 through System/390.

A description of the first superscalar computer system - the IBM ACS project in the 1960s.

A brief description of the hardware parallelism of the IBM Stretch computer (also known as the IBM 7030).