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 your UNIX 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 Telnet client) available for download on the Microsoft Web site (, provides a complete UNIX 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 any emulation.

Features in this release

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 (

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