PearPC
Encyclopedia
PearPC is an architecture-independent PowerPC
platform emulator
capable of running many PowerPC operating system
s, including Mac OS X
, Darwin
and Linux
. It is released under the terms of the GNU General Public License
(GPL). It can be executed on Microsoft Windows
, Linux
, FreeBSD
and other systems based on POSIX
-X11. The first official release was made on May 10, 2004.
The emulator features a just-in-time
(JIT) processor emulation core which dynamically translates PPC code into x86 code, caching the results. Despite running only on x86 host architectures, the JIT emulation core runs at least 10 times as fast as the architecture-independent generic processor emulation core. However, according to the man pages supplied with Debian
's packages of PearPC, even the JIT core runs around 40 times slower than the host machine would if executing native code.
Until December 2005 PearPC advanced quickly in speed, stability and features. After that time, however, there was no new release until July 2011 - five and a half years later. Individuals had also been working on builds with more features such as native CD-ROM support and even progress in emulating sound had begun. Builds including AltiVec
emulation to run applications that require a PowerPC G4
processor were also produced, although there were numerous problems (mainly interface glitches) with running Mac OS X Tiger using such builds which were not resolved. Support for graphics acceleration was also worked on, which in theory should provide a major performance boost due to OS X's hardware-accelerated GUI known as Quartz-Extreme
which is currently not supported in PearPC.
On June 6, 2005, Apple's CEO, Steve Jobs, announced that Apple would begin switching their computers' architectures from IBM's PowerPC to Intel's x86 platform. The transition was completed in August 2006. The news raised a lot of questions about the future of the PearPC project, because although the project itself is a PowerPC emulator, it is used primarily to run Mac OS X on x86 machines. As Mac OS X can now be run natively on the x86 platform, including on non-Apple computers (albeit in contravention of the Mac OS X license agreement), interest in PearPC has waned since and attention now largely centers on running Mac OS X natively on x86 hardware or in virtualization software such as VMware Workstation
.
— the 'Change CD' button found in early versions has been eliminated because it rarely functioned correctly. However, developers have made frontends for the program. Two of these are PearGUI, which looks like a Mac OS X application but is incompatible with current versions of PearPC, and PearPCCP (short for "PearPC Control Panel"), which is compatible with PearPC 0.3 and newer. PearGUI's incompleteness annoys many users and its 'Create Disk Image' feature is not yet complete (a severe shortcoming), but many users have praised its GUI. PearPCCP has a built-in configuration wizard in addition to other advanced features, but is hindered by what many users believe to be an inferior interface and several bugs. Some users also report that PearPCCP removes comments from configuration files, while PearGUI does not. The PearPC.net website also released its own Java-based PearPC-GUI, called APE, which is part of the PearPC.net Package. CherryOS
is alleged to be simply a front-end for PearPC. Its website was shut down in May 2005.
appeared, claiming to offer more features and greater speed. However, within hours of its announcement, questions were raised about the claims, with many experts and open-source advocates suggesting that CherryOS was nothing more than a repackaging of PearPC. The CherryOS Emulator was re-released in March 2005 as a commercial product. According to Cassondra Foesch, a principal author of PearPC, it still contained all or part of the code written for the PearPC Project. CherryOS also created questions regarding the legality of commercial software developed and marketed specifically for the purpose of running Mac OS on the x86 architecture, since Apple's license agreement specifically states that the operating system may only be installed on Apple-labeled computers (this was before Apple shipped x86 machines). Eventually, the distribution of CherryOS ceased due to the very high amount of criticism that had been directed at it.
In addition, although CherryOS supports native CD-ROM installation, the emulator itself runs a bit slower than PearPC does, even though it claims to run three times faster than PearPC.
PowerPC
PowerPC is a RISC architecture created by the 1991 Apple–IBM–Motorola alliance, known as AIM...
platform emulator
Emulator
In computing, an emulator is hardware or software or both that duplicates the functions of a first computer system in a different second computer system, so that the behavior of the second system closely resembles the behavior of the first system...
capable of running many PowerPC operating system
Operating system
An operating system is a set of programs that manage computer hardware resources and provide common services for application software. The operating system is the most important type of system software in a computer system...
s, including Mac OS X
Mac OS X
Mac OS X is a series of Unix-based operating systems and graphical user interfaces developed, marketed, and sold by Apple Inc. Since 2002, has been included with all new Macintosh computer systems...
, Darwin
Darwin (operating system)
Darwin is an open source POSIX-compliant computer operating system released by Apple Inc. in 2000. It is composed of code developed by Apple, as well as code derived from NeXTSTEP, BSD, and other free software projects....
and Linux
Linux
Linux is a Unix-like computer operating system assembled under the model of free and open source software development and distribution. The defining component of any Linux system is the Linux kernel, an operating system kernel first released October 5, 1991 by Linus Torvalds...
. It is released under the terms of the GNU General Public License
GNU General Public License
The GNU General Public License is the most widely used free software license, originally written by Richard Stallman for the GNU Project....
(GPL). It can be executed on Microsoft Windows
Microsoft Windows
Microsoft Windows is a series of operating systems produced by Microsoft.Microsoft introduced an operating environment named Windows on November 20, 1985 as an add-on to MS-DOS in response to the growing interest in graphical user interfaces . Microsoft Windows came to dominate the world's personal...
, Linux
Linux
Linux is a Unix-like computer operating system assembled under the model of free and open source software development and distribution. The defining component of any Linux system is the Linux kernel, an operating system kernel first released October 5, 1991 by Linus Torvalds...
, FreeBSD
FreeBSD
FreeBSD is a free Unix-like operating system descended from AT&T UNIX via BSD UNIX. Although for legal reasons FreeBSD cannot be called “UNIX”, as the direct descendant of BSD UNIX , FreeBSD’s internals and system APIs are UNIX-compliant...
and other systems based on POSIX
POSIX
POSIX , an acronym for "Portable Operating System Interface", is a family of standards specified by the IEEE for maintaining compatibility between operating systems...
-X11. The first official release was made on May 10, 2004.
The emulator features a just-in-time
Just-in-time compilation
In computing, just-in-time compilation , also known as dynamic translation, is a method to improve the runtime performance of computer programs. Historically, computer programs had two modes of runtime operation, either interpreted or static compilation...
(JIT) processor emulation core which dynamically translates PPC code into x86 code, caching the results. Despite running only on x86 host architectures, the JIT emulation core runs at least 10 times as fast as the architecture-independent generic processor emulation core. However, according to the man pages supplied with Debian
Debian
Debian is a computer operating system composed of software packages released as free and open source software primarily under the GNU General Public License along with other free software licenses. Debian GNU/Linux, which includes the GNU OS tools and Linux kernel, is a popular and influential...
's packages of PearPC, even the JIT core runs around 40 times slower than the host machine would if executing native code.
Until December 2005 PearPC advanced quickly in speed, stability and features. After that time, however, there was no new release until July 2011 - five and a half years later. Individuals had also been working on builds with more features such as native CD-ROM support and even progress in emulating sound had begun. Builds including AltiVec
AltiVec
AltiVec is a floating point and integer SIMD instruction set designed and owned by Apple, IBM and Freescale Semiconductor, formerly the Semiconductor Products Sector of Motorola, , and implemented on versions of the PowerPC including Motorola's G4, IBM's G5 and POWER6 processors, and P.A. Semi's...
emulation to run applications that require a PowerPC G4
PowerPC G4
PowerPC G4 is a designation used by Apple Computer to describe a fourth generation of 32-bit PowerPC microprocessors. Apple has applied this name to various processor models from Freescale, a former part of Motorola....
processor were also produced, although there were numerous problems (mainly interface glitches) with running Mac OS X Tiger using such builds which were not resolved. Support for graphics acceleration was also worked on, which in theory should provide a major performance boost due to OS X's hardware-accelerated GUI known as Quartz-Extreme
Quartz Compositor
Quartz Compositor is the windowing system in Mac OS X. It is responsible for presenting and maintaining rasterized, rendered graphics from the rest of the Core Graphics framework and other renderers in the Quartz technologies family...
which is currently not supported in PearPC.
Shortcomings
The current official version of PearPC is 0.5.0 (released July 13, 2011). While its PowerPC emulation handles most applications and the emulator already has an impressive feature set, the project still lacks features needed for a complete emulation of the PowerPC experience:- Sound emulation (there are PearPC sound-test builds on the web, usually called ppc-snd)
- G5 (64-bit64-bit64-bit is a word size that defines certain classes of computer architecture, buses, memory and CPUs, and by extension the software that runs on them. 64-bit CPUs have existed in supercomputers since the 1970s and in RISC-based workstations and servers since the early 1990s...
PowerPC) emulation - Apple Disk ImageApple Disk ImageApple Disk Image is a proprietary disk image format commonly used with the Mac OS X operating system. The format allows secure password protection as well as file compression and hence serves both security and file distribution functions; it is most commonly used to distribute software over the...
(.dmg) support for use as an image (currently, to use a .dmg image the file must be converted into an ISO imageISO imageAn ISO image is an archive file of an optical disc, composed of the data contents of every written sector of an optical disc, including the optical disc file system...
(.iso) (probably with dmg2iso)) - Mac OS X LeopardMac OS X v10.5Mac OS X Leopard is the sixth major release of Mac OS X, Apple's desktop and server operating system for Macintosh computers. Leopard was released on 26 October 2007 as the successor of Tiger , and is available in two variants: a desktop version suitable for personal computers, and a...
support (meanwhile, try using OSX86OSx86OSx86 is a collaborative hacking project to run the Mac OS X computer operating system on non-Apple personal computers with x86 architecture and x86-64 compatible processors...
)
On June 6, 2005, Apple's CEO, Steve Jobs, announced that Apple would begin switching their computers' architectures from IBM's PowerPC to Intel's x86 platform. The transition was completed in August 2006. The news raised a lot of questions about the future of the PearPC project, because although the project itself is a PowerPC emulator, it is used primarily to run Mac OS X on x86 machines. As Mac OS X can now be run natively on the x86 platform, including on non-Apple computers (albeit in contravention of the Mac OS X license agreement), interest in PearPC has waned since and attention now largely centers on running Mac OS X natively on x86 hardware or in virtualization software such as VMware Workstation
VMware Workstation
VMware Workstation is a virtual machine software suite for x86 and x86-64 computers from VMware, a division of EMC Corporation, which allows users to set up multiple x86 and x86-64 virtual machines and use one or more of these virtual machines simultaneously with the hosting operating system...
.
Frontends
PearPC currently lacks its own GUIGraphical user interface
In computing, a graphical user interface is a type of user interface that allows users to interact with electronic devices with images rather than text commands. GUIs can be used in computers, hand-held devices such as MP3 players, portable media players or gaming devices, household appliances and...
— the 'Change CD' button found in early versions has been eliminated because it rarely functioned correctly. However, developers have made frontends for the program. Two of these are PearGUI, which looks like a Mac OS X application but is incompatible with current versions of PearPC, and PearPCCP (short for "PearPC Control Panel"), which is compatible with PearPC 0.3 and newer. PearGUI's incompleteness annoys many users and its 'Create Disk Image' feature is not yet complete (a severe shortcoming), but many users have praised its GUI. PearPCCP has a built-in configuration wizard in addition to other advanced features, but is hindered by what many users believe to be an inferior interface and several bugs. Some users also report that PearPCCP removes comments from configuration files, while PearGUI does not. The PearPC.net website also released its own Java-based PearPC-GUI, called APE, which is part of the PearPC.net Package. CherryOS
CherryOS
CherryOS was a PearPC based PowerPC G4 processor emulator for x86 Microsoft Windows platforms, announced on October 12, 2004. It was released to the public on March 9, 2005 and development stopped on May 6, 2005...
is alleged to be simply a front-end for PearPC. Its website was shut down in May 2005.
CherryOS controversy
Within five months of PearPC's release, another PowerPC emulator called CherryOSCherryOS
CherryOS was a PearPC based PowerPC G4 processor emulator for x86 Microsoft Windows platforms, announced on October 12, 2004. It was released to the public on March 9, 2005 and development stopped on May 6, 2005...
appeared, claiming to offer more features and greater speed. However, within hours of its announcement, questions were raised about the claims, with many experts and open-source advocates suggesting that CherryOS was nothing more than a repackaging of PearPC. The CherryOS Emulator was re-released in March 2005 as a commercial product. According to Cassondra Foesch, a principal author of PearPC, it still contained all or part of the code written for the PearPC Project. CherryOS also created questions regarding the legality of commercial software developed and marketed specifically for the purpose of running Mac OS on the x86 architecture, since Apple's license agreement specifically states that the operating system may only be installed on Apple-labeled computers (this was before Apple shipped x86 machines). Eventually, the distribution of CherryOS ceased due to the very high amount of criticism that had been directed at it.
In addition, although CherryOS supports native CD-ROM installation, the emulator itself runs a bit slower than PearPC does, even though it claims to run three times faster than PearPC.
See also
- Comparison of platform virtual machines
- SheepShaverSheepShaverSheepShaver is an open source PowerPC Apple Macintosh emulator originally designed for BeOS and Linux. The name is a play on ShapeShifter, a Macintosh II emulator for AmigaOS , which is in turn not to be confused with a third-party preference pane for Mac OS X with the same name...