1971: Watson, Jr., steps down and is succeeded by Frank Cary. The floppy disk is introduced; it later becomes the PC data storage standard.
1975: The IBM 5100 Portable Computer enters the market, weighing 50 pounds and priced at $9,000 to $20,000.
1981: The IBM Personal Computer becomes the smallest, and -- at $1,565, -- the lowest-priced PC to date. IBM's deal for Microsoft to supply the operating system and allow competitors to buy it for "IBM-compatible" clones fuels a growing industry and paves the way for competitors such as Dell and Compaq.
1982: A U.S. antitrust suit filed in 1969 is dismissed, but arguably pushes IBM to further separate hardware from software, allowing customers to increasingly mix and match products from different companies, a trend that takes off during the PC era.
1984: The Personal Computer/AT, IBM's second-generation PC, runs on a 6MHz Intel 80286 processor.
1987: The IBM Personal System/2 (PS/2) is launched along with the OS/2 operating system, jointly developed by Microsoft and IBM. OS/2 offers multitasking capabilities and in six months 1 million PS/2s are shipped. But although IBM PC chief James Cannavino wants OS/2 to maintain compatibility with the AT going forward, Microsoft CEO Bill Gates wants to move on to machines built around the Intel 80386 chip. Windows 3.0, released in 1990, offers crude multitasking features but makes use of 80386 memory management and becomes a hit, leaving OS/2 in the dust.
1990: IBM releases the System/390 family, comprising midrange machines and supercomputers, calling it the company's biggest product development in 25 years. New technology includes high-speed fiber-optic channels, ultradense circuits, and extended supercomputer capabilities.
1991: As Microsoft and PC clone makers rake in profits, client/server architecture takes off and IBM shocks long-time industry insiders by announcing an annual loss of $2.8 billion, the first of three annual losses in a row. Under CEO John Akers, IBM considers breaking up into smaller, nimbler companies.
1993: Louis Gerstner, former chief executive of RJR Nabisco, takes the reins as chairman and CEO. At his inaugural press conference, Gerstner plainly states his intention to keep IBM together as an integrated company and his belief that there is a need for a broad-based IT company that can serve as both supplier and systems integrator to customers.
1995: IBM acquires Lotus Development and its Notes collaboration software, making IBM the world's largest software company.
1995: IBM introduces the ThinkPad 701cm laptop, which runs on the Intel 133MHz Pentium processor. The sleek black design is a departure for IBM and wins accolades.
1996: IBM's launch of the DB2 Universal Database -- capable of querying alphanumeric data as well as images, audio, and video -- marks IBM's firm embrace of the Internet.
1997: Deep Blue, an IBM RS/6000 SP supercomputer able to calculate 200 million chess positions per second, defeats grandmaster Garry Kasparov.
2001: The publication of Edwin Black's "IBM and the Holocaust" coincides with an Alien Tort Claims Act claim, later dismissed, against IBM for allegedly suppling punched card technology that enabled the Holocaust. IBM's response points out that along with hundreds of foreign-owned companies in Germany at that time, its affiliate came under the control of Nazi authorities before World War II.
2002: Sam Palmisano becomes CEO in March, and in July IBM signals it is further strengthening its services business with a $3.5 billion acquisition of the PricewaterhouseCoopers global business and consulting technology unit.
2005: Although IBM has sold more than 20 million ThinkPads, it announces the sale of its PC business to Lenovo in an effort to further focus on software and services.
2011: Watson, a system comprising 90 IBM Power 750 servers, shows off IBM's artificial intelligence and systems architecture expertise by defeating two "Jeopardy" game show champions in a two-game match.
Sources: IBM; interview with James Birkenstock, interviewed in 1980 by Roger Stuewer and Erwin Tomash for the Charles Babbage Institute; "Big Blues: The Unmaking of IBM," by Paul Carroll (Crown Publishers, 1993); and IDG News Service archives