422 windows subsystems a subsystem is a portion of

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4.2.2 Windows Subsystems A subsystem is a portion of the Windows operating system that provides a service to application programs through a callable API. Subsystems come in two varieties, depending upon the application program that finally handles the request: Environment subsystems. These subsystems run in a user mode and provide functions through a published API. The Windows API subsystem provides an API for operating system services, GUI capabilities, and functions to control all user input and output. The Win32 subsystem and POSIX subsystem are part of the environment subsystems and are described as follows: o Win32 subsystem. The Win32 environment subsystem allows applications to benefit from the complete power of the Windows family of operating systems. The Win32 subsystem has a vast collection of functions, including those required for advanced operating systems, such as security, synchronization, virtual memory management, and threads. You can use Windows APIs to write 32-bit and 64-bit applications that run on all versions of Windows.
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13 o POSIX subsystem and Windows Services for UNIX. To provide more comprehensive support for UNIX programs, Windows uses the Interix subsystem. Interix is a multiuser UNIX environment for a Windows-based computer. Interix conforms to the POSIX.1 and POSIX.2 standards. It provides all features of a traditional UNIX operating system, including pipes, hard links, symbolic links, UNIX networking, and UNIX graphical support through the X Windows system. It also includes case-sensitive file names, job control tools, compilation tools, and more than 300 UNIX commands and tools, such as KornShell, C Shell, awk, and vi. Because it is layered on top of the Windows kernel, the Interix subsystem is not an emulation. Instead, it is a native environment subsystem that integrates with the Windows kernel, just as the Win32 subsystem does. Shell scripts and other scripted applications that use UNIX and POSIX.2 tools run under Interix. o Interix is the name of an optional, full-featured POSIX and Unix environment subsystem for Microsoft's Windows NT-based operating systems. Interix is a component of the Services for Unix (SFU). The most recent releases of Interix, 5.2 and 6.0, are components of the Windows Server 2003 R2, Windows Vista Enterprise and Ultimate editions and Windows Server 2008 under the name SUA (Subsystem for Unix-based Applications). Version 6.1 is included in Windows 7 (Enterprise and Ultimate) and Windows Server 2008 R2 (all editions). Integral subsystems . These subsystems perform key operating system functions and run as a part of the executive or kernel. Examples are the user-mode subsystems, Local Security Authority subsystem (LSASS), and Remote Procedure Call subsystem (RPCSS). 4.2.3 Processes and Threads In addition to being a preemptive multitasking operating system, Windows is also multithreaded, meaning that more than one thread of execution (or thread ) can execute in a single task at once.
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  • Spring '12
  • GwangS.Jung

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