I've been using Cygwin for years now and it's been a great tool for porting Linux programs to my Windows computer. It's easy to install and configure, and I've been able to get a lot of use out of it. It's also great for running command line programs, which can be a huge help when trying to troubleshoot or debug an issue. Highly recommended!
Our website provides a free download of Cygwin 11.9. Users write reviews stating that it has such a benefit as the software is fast. From the users' point of view, the major disadvantages of this program are: it crashes and it is hard to use. Our antivirus scan shows that this download is clean. The actual developer of the free software is Cygnus Solutions. It is included in Development Tools.
From the developer:
Cygwin is a collection of tools which provide a Linux look and feel environment for Windows. It a DLL (cygwin1.dll) which acts as a Linux API layer providing substantial Linux API functionality. You must know that it is not a way to run native Linux apps on Windows. You must rebuild your application from source if you want it to run on Windows.
You may want to check out more software, such as Cygwin/X, Cygwin Here or Windows Remote Toolkit, which might be related to Cygwin.