Cobalt's best-known product was a small blue cube called the Qube. Plug it in, answer a few questions, and a small office had a web server, email and file sharing, all running on Linux. Its rack-mounted cousin, the RaQ, let hosting companies stack hundreds of cheap servers. When Cobalt went public in November 1999, Linux was the newest darling of Wall Street, and every company with a website needed somewhere to run it.

Linux Before It Was Safe

Vivek Mehra co-founded the company in 1996 as Cobalt Microserver and renamed it Cobalt Networks in June 1998. The Qube came out that March, and the RaQ followed in September. The bet was that most businesses did not want a general-purpose server and a full-time administrator. They wanted an appliance that did a few jobs well and cost little. Cobalt built its machines on free Linux software, which kept prices low.

A 618 Percent Day

Cobalt priced its shares at $22 on November 5, 1999. On its first day the stock rose as much as 618 percent above that price. Ten months later, in September 2000, Sun Microsystems agreed to buy Cobalt for $2 billion in stock, and the deal closed that December. Many of Cobalt's engineers left soon after. Sun shut down the Cobalt product line in December 2003. The RaQ 550 was the last of the blue boxes.

Cover: Nocturne, James McNeill Whistler. Art Institute of Chicago, public domain. Chosen for a blue nocturne (cobalt).