Peter Cohen for iMore:

It was a long road to OS X 10.9 Mavericks. Mac OS X was first introduced as a public beta (codenamed Kodiak) in September of 2000, and beta it was – a radical departure from Mac OS 9, both in look (introducing the “Aqua” interface) and in operation. Mac OS X was built on a UNIX foundation, and was more closely related to the NextStep operating system that had been developed by NeXT, the computing company Steve Jobs founded between stints running Apple.

This brought back some memories.