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Hercules is a computer emulator allowing software written for IBM mainframe computers (System/370, System/390, and zSeries/System z) and for plug compatible mainframes (such as Amdahl machines) to run on other types of computer hardware, notably on low-cost personal computers. Although there are other mainframe emulators performing a similar function, Hercules is significant in enabling private individuals to run mainframe computer software on their own personal computers. Hercules runs under multiple parent operating systems including GNU/Linux, MS Windows, FreeBSD, Oracle Solaris, and Apple Mac OS X and is released under the open source software license QPL.〔.〕 It is analogous to Bochs and QEMU in that it emulates CPU instructions and select peripheral devices only. A vendor (or distributor) must still provide an operating system, and the user must install it. Hercules was notably the first mainframe emulator to incorporate 64-bit z/Architecture support, beating out commercial offerings. Roger Bowler, a mainframe systems programmer, started development of the Hercules emulator in 1999. == Design == The emulator is written almost entirely in C. Its developers ruled out using machine-specific assembly code to avoid problems with portability even though such code could significantly improve performance. There are two exceptions: Hercules uses hardware assists to provide inter-processor consistency when emulating multiple CPUs on SMP host systems, and Hercules uses assembler assists to convert between little-endian and big-endian data on platforms where the operating system provides such services and on x86/x86-64 processors. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Hercules (emulator)」の詳細全文を読む スポンサード リンク
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