It's no secret that OS X
is based on BSD Unix, and it looks like Apple
let a little more of those roots shine through with Leopard -- The Open Group has just awarded OS X 10.5 Leopard
UNIX 03 certification, meaning that Apple joins Sun, HP, and IBM as the only certified vendors. The spec covers libraries, system calls, terminal interfaces, commands and utilities, internationalization and the C language, meaning that software vendors can easily port server and non-GUI apps to and from OS X with minimal effort. Although this was already mostly the case, it's
always nice to see the circle complete, isn't it?