Mac OS X Developer Preview 1

Mac OS X Developer Preview 1 is the first Developer Preview of Mac OS X Public Beta. It was introduced and distributed at the Worldwide Developers Conference on 10 May 1999, showcasing the Darwin kernel to Mac OS and the bases for the completed operating system.

This Developer Preview is overall similar to Mac OS X Server 1.x, and thus still includes the Platinum theme. Unlike later Developer Previews, this preview's installation method involves booting to a Mac OS 8.6 pre-installation environment and starting the setup program from there, instead of instantly booting to setup. It is notably the first Mac OS X build to introduce the Carbon API, intended to allow classic Mac OS applications to run under the native kernel.

The xnu build for Beaker1N5 is Mac OS Version 10.0: Fri Apr 30 23:26:14 PDT 1999; root(rcbuilder):Objects/xnu-24.6.obj~2/RELEASE_PPC powerpc. It is the only Developer Preview to include a codename that is often associated with the Rhapsody and Server 1.x builds.

System requirements
According to the installation documentary, this developer preview requires the following: This version of Mac OS X works with Power Macintosh G3 computers ("beige" desktops and "blue and white" tower) with:
 * At least 64 MB of RAM
 * Internal video, or an Apple-supplied ixMicro or ATI video card
 * A hard disk with at least 1 gigabyte (GB) of available space