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.

The Developer Preview is overall similar to Mac OS X Server 1.0 in appearance and functionality, and still utilizes 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.

Much like in PowerPC builds of Rhapsody and Server 1.x, it includes the Blue Box emulation layer, which runs a copy of Mac OS 8.6 inside the emulator.

The XNU version string for Beaker1N5 is. It is the only Developer Preview to use a codename that is often associated with the Rhapsody and Server 1.x builds.

Web Update
An update was also available online, which updates the system to Beaker1P2, with a version string of.

System requirements
According to the installation documentation, 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

Differences from Server 1.0

 * This is the first build of Mac OS X to be running under the Darwin kernel, and its effects can be seen under a verbose boot, which now displays the debug messages in a full-screen black command line interface instead of inside the NeXTSTEP boot screen. Likewise, this build internally identifies the kernel as "Mac OS 10.0" instead of Rhapsody, although Darwin wouldn't get the official naming in the kernel (via ) until Developer Preview 4.
 * It is 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 SDK for Carbon is contained in the installation media for this build.
 * Updated boot screen to move the progress bar underneath the Mac OS X window.
 * Updated Blue Box default operating system to Mac OS 8.6 from Mac OS 8.5.1.
 * Removed the icons on User Preferences, Computer Settings, and Server Administration in the Apple menu.
 * Removed Sound preference applet and QuickTimeStreamingAdmin on Apple menu.
 * Workspace Manager is updated to v521, and the About dialog no longer shows the PostScript version, as the disk size is displayed instead.
 * Added the current time on the menu bar. It would later be removed in Developer Preview 3 before being readded in the final Cheetah release.

Bugs and quirks

 * Most settings that are changed in the preference applets such as Appearance and Mouse will not take effect until restarting the system.
 * Logging off hangs the system at a purple screen.