Cygwin

As a software review, the Cygwin project is highly regarded for providing a DLL that emulates a Unix environment on Windows. It comes with a complete port of development utilities such as gcc, binutils, gdb, make, and many other useful tools commonly found on a Linux-like environment.

The Cygwin project is a powerful tool in creating an environment that feels and works like Linux on Windows. It consists of two parts: a DLL (cygwin1.dll) acting as a Linux API emulation layer that provides Linux API functionality, and a collection of tools that create the Linux look and feel.

Cygwin is highly compatible as it currently works with all recent, commercially released 32-bit and 64-bit versions of Windows. However, Windows CE is an exception. It's important to note that the official support for Windows 95, Windows 98, and Windows Me is about to be discontinued with the next major release of Cygwin version 1.7.0.

It's essential to understand that Cygwin is not a way to run native Linux apps on Windows. To run an app on Windows, you have to rebuild the application from the source. Additionally, if you want to use Unix functionality, like signals and ptys, you have to rebuild your apps from source to take advantage of Cygwin functionality.

All in all, Cygwin is a powerful tool that provides Unix emulation on Windows, which is highly customizable, and is easy to use. However, it's not a way to run native Linux apps on Windows. The Cygwin project is an excellent software tool for those who need to bring the experience of Linux to Windows.