A Technical History of Apple's Operating Systems - Mac OS X Internals

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114 Chapter 1 A Technical History of Apple’s Operating Systems FIGURE 1–31 Rhapsody Rhapsody consisted of the following primary components. • The kernel and related subsystems that were based on Mach and BSD • A Mac OS compatibility subsystem (the Blue Box) • An extended OpenStep API implementation (the Yellow Box) • A Java virtual machine • A Display PostScript-based windowing system • A user interface that was Mac OS-like, but also had features from OPENSTEP
Mac OS X Internals (www.osxbook.com) 115 Apple had plans to port to Rhapsody most key Mac OS frameworks, for example, QuickTime, QuickDraw 3D, QuickDraw GX, and ColorSync. Rhapsody was also to support numerous file systems such as Apple Filing Protocol (AFP), FAT, HFS, HFS Plus, ISO9660, and UFS. There were two developer releases of Rhapsody, dubbed DR1 and DR2. These were released both for the PowerPC and the x86 platforms. 1.9.2.1. Blue Box Shortly after Rhapsody DR1 was released, Apple extended the PowerPC version with a Mac OS compatibility environment called the Blue Box. Implemented by a Rhapsody application (MacOS.app), Blue Box was a virtual environment that ap- peared as a new Macintosh hardware model. MacOS.app loaded a Macintosh ROM file from disk and created an environment within which Mac OS ran mostly un- changed. Blue Box initially ran Mac OS 8.x, full-screen, with the ability to switch between Rhapsody and Mac OS using the key combination. It placed certain restrictions on the applications that ran within it. For example, an application could neither access the hardware directly, nor could use undocumented Mac OS APIs. The implementers’ initial goal was to achieve 90% to 115% of native Mac OS performance. Blue Box beta 1.0 used Open Transport—rather than BSD sockets—for networking. Support for newer versions of Mac OS, as well as for running the Blue Box windowed, was added later. The Blue Box environment would be known as the Classic environment in Mac OS X, provided by an application named “Classic Startup.app”. 61 The Blue Box environment is a virtualization layer, and not an emulation layer. “Harmless” instructions execute natively on the processor, whereas “harmful” instructions, such as those that can affect the hardware, are trapped and handled appropriately. 61 The application was called Classic.app in earlier versions of Mac OS X.
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A Technical History of Apple’s Op
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Dear Reader This is a supplementary
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About Mac OS X Internals Mac OS X w
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A Technical History of Apple’s Op
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Mac OS X Internals (www.osxbook.com
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C H A P T E R 1 A Technical History
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A Technical History of Apple's Operating Systems - Mac OS X Internals

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