Windows Services for UNIX (SFU) is a discontinued software package produced by Microsoft which provided a Unix environment on Windows NT and some of its immediate successor operating systems.

SFU 1.0 and 2.0 used the MKS Toolkit; starting with SFU 3.0, SFU included the Interix subsystem, which was acquired by Microsoft in 1999 from US-based Softway Systems as part of an asset acquisition. SFU 3.5 was the last release and was available as a free download from Microsoft. Windows Server 2003 R2 included most of the former SFU components (on Disk 2), naming the Interix subsystem component Subsystem for UNIX-based Applications (SUA). In Windows Server 2008 and high-end versions of both Windows Vista and Windows 7 (Enterprise and Ultimate), a minimal Interix SUA was included, but most of the other SFU utilities had to be downloaded separately from Microsoft's web site. General support continued until 2011; extended support until 2014.

Known problems

Character translation must be used to accommodate filenames which include a colon (:) or other characters that do not comply with the naming conventions of Windows file-systems. Files with the same name but different cases are also not allowed by default, but can be enabled on installation with the side-effect of making the underlying partition's filesystem case-sensitive, even for the Win32 subsystem.

Network authentication for UNIX systems relies on the insecure NIS protocol (LDAP- and Kerberos-based authentication require a third-party solution). Microsoft has released several hotfixes for Windows Services for UNIX, and at least one Security Update (KB939778). The GNU Project utilities are several versions older than the latest ones. A separate port of the up-to-date Debian utilities was started in 2007, but apparently abandoned in 2009. Several of the text processing utilities in SUA (e.g. awk) are not compatible with Unicode or wide character text files.

No version of Windows Services for UNIX is available for Windows XP Professional x64 Edition.

Legacy

Windows Server 2003 R2 contains most SFU components, namely Microsoft Services for Network File System (NFS), Subsystem for UNIX-based Applications (SUA, a.k.a. Interix), and Identity Management for UNIX. The July 2007 SFU 3.5 Security Update updated posix.exe and related files to match the SUA version.

Unlike the SFU, the SUA version included in Windows Server 2003 R2 (and subsequent versions) has 64-bit support and allows linking of Win32 libraries to SUA applications.

Windows Vista and Windows 7 Enterprise and Ultimate Editions also contain the Services for Unix components, now called the Subsystem for UNIX-based applications (SUA), – these are included in Server editions of Windows (i.e. Windows Server 2008).

SUA was deprecated in Windows 8 Enterprise and Windows Server 2012, and completely removed in Windows 8.1 and Windows Server 2012 R2. The NFS server is still supported in Windows Server 2012 R2.

The NFS client feature and server features are separate from the SUA in Windows 7 and 2008, and remained supported until Windows Subsystem for Linux replaced it. On desktop (Windows 7), NFS is only available in the Enterprise and Ultimate editions. The free reference implementation of NFS 4.1 for Windows (by UMICH CITI), the development of which was sponsored by Microsoft, does work on lower-end versions of Windows 7, but requires more involved installation.

In Windows 8, the NFS client gained krb5p (Kerberos 5 with full data encryption) support. In Windows 7, Kerberos 5 was supported for authentication, but only packet integrity checking was available for data. The maximum block/buffer size was also increased from 32 KB to 1 MB in Windows 8.

Windows Server 2012 added support for NFS 4.1 server. The new implementation is kernel-based (RPC/XDR-wise) but many optional features from NFS4 are not implemented, including ACLs, pNFS etc. There is however support in PowerShell for mapping user identities.

See also

  • Cygwin
  • UnxUtils
  • UWIN
  • Windows Subsystem for Linux

Notes

References

  • Microsoft TechNet: Windows Services for UNIX
  • Services for UNIX: Blog