WSL1

WSL1, or the original Windows Subsystem for Linux, is a feature of Windows that enables running Linux userland applications directly on Windows without a full Linux kernel or virtual machine. It was introduced for Windows 10 in 2016 and was initially known as LXSS, the Linux Subsystem for Windows. It provides a way to run common Linux tools and utilities alongside Windows.

WSL1 uses a Linux-compatible translation layer that runs in user mode on the Windows NT kernel. It does not include a real Linux kernel; instead, Linux system calls are translated into Windows kernel calls by the subsystem. Each Linux distribution provides its root filesystem, typically stored as a virtual disk image managed by the Windows subsystem.

Interoperability between Windows and Linux is a key feature: you can invoke Windows executables from within Linux and run Linux tools from Windows. File access is supported across environments, with drives and Windows paths accessible from Linux, and Linux files visible to Windows through integration features. However, WSL1 omits capabilities that depend on a Linux kernel, such as loading kernel modules, and it supports a subset of Linux system calls. Kernel-dependent workloads, including native Docker containers, are not natively supported inside WSL1.

To use WSL1, users enable the Windows Subsystem for Linux feature, install a Linux distribution from the Microsoft Store, and then run Linux commands, shells, and package managers. It supports common tools such as bash, Python, and git, and operates on Windows 10 and Windows 11, though Microsoft’s emphasis has shifted toward WSL2 for new development.

WSL2, released in 2020, provides a real Linux kernel running in a lightweight virtual machine, offering improved compatibility and performance. Microsoft recommends WSL2 for new workloads, while WSL1 remains available for compatibility with older workflows and tools that do not require a kernel. Users can upgrade existing distributions to WSL2.