Happy birthday to IBM, which celebrated its 100th anniversary this week. It's been quite a ride for a company that started out as the Computing-Tabulating-Recording Company before changing to its more familiar moniker in 1924. InformationWeek assembled a fun slide show looking back at IBM's biggest breakthroughs, beginning with its earliest tabulating machines. Those machines led to systems designed to help implement the Social Security system, and from there it was on to the Cold War mainframe development that ultimately revolutionized American business. After that, it was airline reservation systems and midsize systems and eventually a PC renaissance. After a bit of a decline in the '90s as the PC revolution largely passed it by (remember the PS/2 and OS/2? The PCJr?), the company was revivified as a systems and services company with an R&D arm that's still able to come up with things like the Jeopardy-winning Watson supercomputer. For an insightful look back at the company's winning business strategies, check out The Economist's retrospective. IBM may have lost a bit of its uptight gray-suit and white-shirt culture along the way, and employees probably don't jot ideas onto their embossed THINK notepads anymore, but this great American innovator is as healthy as ever with a $200 billion market cap and a near-record-high stock price. Big Blue seems well-positioned to prosper for another 100 years. Graphic: IBM