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Subsystem for UNIX-based Applications Overview

Applies To: Windows Server 2008 R2

Subsystem for UNIX-based Applications (SUA) is a source-compatibility subsystem for compiling and running custom UNIX-based applications on a computer running a Microsoft® Windows® server-class operating system. You can make UNIX-based applications fully interoperable with Windows in SUA with little or no change to your original source code.

Subsystem for UNIX-based Applications provides an operating system for Portable Operating System Interface (POSIX) processes. SUA, along with its package of support utilities (such as shells and a Visual Studio® 2005 debugger extension) available for download on the Microsoft Web site (, provides a complete UNIX-based environment. The download package includes a comprehensive set of scripting utilities, and a software development kit (SDK) designed to fully support the development capabilities of SUA and to provide a complete UNIX-based application development experience.

SUA also supports case-sensitive file names, job control, compilation tools, and the use of over 300 UNIX commands, utilities, and shell scripts. Because the subsystem installs separately from the Windows kernel, it offers true UNIX functionality without emulation.

Features in Subsystem for UNIX-based Applications

Features in Subsystem for UNIX-based Applications include the following:

  • **Database (OCI/ODBC) library connectivity   **SUA supports connectivity to Oracle and SQL Server from database applications by using the Oracle Call Interface (OCI) and the Open Database Connectivity (ODBC) standard.

  • **Microsoft Visual Studio® Debugger Extension for debugging POSIX applications   **SUA includes support for debugging your POSIX processes by using the Visual Studio integrated development environment (IDE).

  • **Utilities based on SVR-5 and BSD UNIX environments   **The SUA download package supports two different UNIX environments: SVR-5 and BSD.

  • **Support for 64-bit applications   **By using a process called thunking, SUA provides support not only for 64-bit applications running on a 64-bit operating system, but also default support for 32-bit binaries running on a 64-bit operating system.

For more information, and to download the scripting utilities and the SDK, see the Microsoft Web site (

Installing Subsystem for UNIX-based Applications

Subsystem for UNIX-based Applications (SUA) is a feature included with Microsoft® Windows Server® 2008 R2 and Windows® 7.


Until the download package Utilities and Software Development Kit for Subsystem for UNIX-based Applications (Utilities and SDK for SUA) has been installed on the computer, you cannot run or modify UNIX-based scripts and custom UNIX-based applications. The Utilities and SDK for SUA package is available for download on the Microsoft Web site (

On Windows Server 2008 R2, you can install SUA by using the Add Features Wizard in Server Manager. Although Server Manager opens by default when a member of the Administrators group logs on to the computer, you can also open Server Manager by using commands on the Start menu in Administrative Tools, and by opening Programs in Control Panel. Windows Server 2008 R2 users can also install SUA by using either the Server Manager command line (ServerManagerCmd.exe) or the Server Manager set of Windows PowerShell cmdlets. For more information about the Server Manager command line or installing features by using Windows PowerShell cmdlets, see the Server Manager Help, either by pressing F1 from within the Server Manager console, or by opening the Help file at %windir%\Help\mui\0409\rmt.chm.


Because of security restrictions imposed by User Account Control in Windows Server 2008 R2 and Windows 7, to install or remove features on your computer by using either Windows PowerShell cmdlets or the Server Manager command-line utility, you must run the Windows PowerShell or Command Prompt session as an administrator. To do this, right-click the shortcut for Windows PowerShell or Command Prompt, and then click Run as administrator.

On Windows 7, you can install SUA by opening Control Panel, clicking Programs, and then clicking Turn Windows features on or off.

Opening Subsystem for UNIX-based Applications

Installing the subsystem by using the Add Features Wizard or Turn Windows features on or off adds an SUA object to the Start menu. This object is not a shortcut, however; it does not open any SUA windows as other Start menu shortcuts typically do. The object is a container for the shells and utilities available in the SUA download package. After the download package is installed, you can access SUA by opening and working in UNIX-based command shells, the shortcuts to which populate the SUA object on the Start menu.