Re:A Question (Score 3, Insightful)

What changed, specifically?

IBM lost the OS wars, so selling OS's became a minor part of IBM's business. Sure, there is still a niche market for AIX, but it is pennies for an outfit like IBM.

So, IBM had nothing to lose if it jumped on the Linux bandwagon. In fact, it has been a boon because they've been able to market one OS for their entire server range from the i386s, to the PPCs to the mainframes. And they've been able to pitch a single unified vision around Linux, in particular, IBM hardware running Linux, Apache, and WebSphere.

Also, IBM has understood that the commodity OS market is not the place to be, rather they have a very profitable consulting division (IBM Global Services) that loses nothing and gains everything by promoting Linux.

All in all, hitching its fortunes to Linux has been a very, very smart move on IBM's part. The alternative might have been to end up like Sun!