NewWorld

New World ROM computers are Macintosh models that do not use a Macintosh Toolbox ROM on the logic board. Due to Mac OS X not requiring the availability of the Toolbox, this allowed ROM sizes to shrink dramatically (typically from 4 MB to 1 MB), and facilitated the use of Flash memory for system firmware instead of the now more expensive and less flexible Mask ROM that most previous Macs used. A facility for loading the Toolbox from the startup device was, however, made available, allowing the use of Mac OS 8 and Mac OS 9 on New World machines.

The New World architecture was developed for the Macintosh Network Computer, an unrealized project that eventually contributed several key technologies to the first-generation iMac.

All PowerPC Macs from the iMac, the iBook, the Blue and White Power Mac G3 and the Bronze Keyboard PowerBook G3 forward are New World ROM machines, while all previous models (including the Beige Power Mac G3 and all other beige and platinum Macs) are Old World ROM machines. Intel based Macs are incapable of running Mac OS 9, and on these machines EFI is used instead of Open Firmware, which both New World and Old World machines are based on.

New World ROM Macs are the first Macs where direct usage of the Open Firmware (OF) subsystem is encouraged. Previous PCI Power Macs used Open Firmware for booting, but the implementation was not complete; in these machines OF was only expected to probe PCI devices, then immediately hand control over to the Mac OS ROM. Because of this, versions 1.0.5 and 2.x had several serious bugs, as well as missing functionality (such as being able to load files from a HFS partition or a server). Apple also set the default input and output devices to ttya (the modem port on beige Macs), which made it difficult for normal users to get to Open Firmware; to do so it was necessary to either hook up a terminal, or change the Open Firmware settings from inside Mac OS using a tool such as Boot Variables or Apple's System Disk.

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