the binary locks during their execution. All Linux processes invoked by a particular user go into a "Linux Instance" (usually, the first invoked process is init). Once all the applications are closed, the instance is closed. WSL 1's design featured no hardware emulation / virtualization (unlike other projects such as coLinux) and makes direct use of the host file system (through and ) and some parts of the hardware, such as the network, which guarantees interoperability. Web servers for example, can be accessed through the same interfaces and IP addresses configured on the host, and shares the same restrictions on the use of ports that require administrative permissions, or ports already occupied by other applications. There are certain locations (such as system folders) and configurations whose access/modification is restricted, even when running as root, with sudo from the shell. An instance with elevated privileges must be launched in order to get "sudo" to give real root privileges, and allow such access. WSL 1 is not capable of running all Linux software, such as 32-bit binaries, or those that require specific Linux kernel services not implemented in WSL. Due to a lack of any "real" Linux kernel in WSL 1, kernel modules, such as device drivers, cannot be run. WSL 2, however, makes use of live virtualized Linux kernel instances. It is possible to run some graphical (GUI) applications (such as Mozilla Firefox) by installing an X11 server within the Windows (host) environment (such as VcXsrv or Xming), although not without caveats, such as the lack of audio support (though this can be remedied by installing PulseAudio in Windows in a similar manner to X11) or hardware acceleration (resulting in poor graphics performance). Support for OpenCL and CUDA is also not being implemented currently, although planned for future releases. Microsoft stated WSL was designed for the development of applications, and not for desktop computers or production servers, recommending the use of virtual machines (Hyper-V), Kubernetes, and Azure for those purposes. In benchmarks WSL 1's performance is often near native Linux Ubuntu, Debian, Intel Clear Linux or other Linux distributions. I/O is in some tests a bottleneck for WSL. The redesigned WSL 2 backend is claimed by Microsoft to offer twenty-fold increases in speed on certain operations compared to that of WSL 1. In June 2020, a benchmark with 173 tests with an AMD Threadripper 3970x shows good performance with WSL 2