21 November 2010

Windows 7: Subsystem for Unix-based applications (SUA)

Yesterday I was trying to telnet from my new Windows 7 PC and... telnet was not there anymore. I had to go to "Control panel>Programs and Features>Turn Windows features on or off" to activate it.
While being in turn features on/off there was some other interesting stuff:

  • NFS client (!)
  • Subsystem for Unix-based applications
Subsystem for Unix-based applications (SUA) is the new name for Windows Services for UNIX (SFU),which in its turn is an evolution of the Interix system that Microsoft acquired. It is a set of utilities that make Windows POSIX compliant and eligible for tenders that require POSIX. Compliance is a very different goal then features and usability, so don't expect too much. The option is only present on Ultimate/Enterprise editions (Vista or later).

After rebooting  I could go to All Programs > Subsystem for Unix-based applications and... download utilities for Subsystem for Unix-based applications. That's right, it just enables the possibility to run POSIX programs, but Unix utilities themselves were not bundled, not even a shell.


Going to the download page you get these choices:
  1. Utilities and SDK for UNIX-based Applications_AMD64.exe
    • use for 64 bit Windows on Intel or AMD x86 processors
  2. Utilities and SDK for UNIX-based Applications_IA64.exe 
    • Use for Intel itanium
  3. Utilities and SDK for UNIX-based Applications_X86.exe
    •  use for 32bit Windows on Intel or AMD x86 processors
Take special care, to download the AMD64 file for Intel 64bit x86 architecture. Microsoft supposes unix heads know that AMD did not follow Intel on the 64bit Itanium path and made a 64 bit x86 (pentium) architecture version. Afterwards Intel followed the AMD strategy and started producing 64bit x86 processors as well.

When installing, choose custom installation if you want to include GNU stuff.  When installation is done, Windows prompts for another reboot.

Your system is by default installed with a root directory mapped to c:\Windows\SUA. You can now start a shell from the SUA menu. You can also run commands from windows by passing them as arguments  to c:\Windows\posix.exe. From a SUA shell you can access your windows drives from /dev/fs (e.g. /dev/fs/C is your C  drive).