DCDev Environment Installer
If you are going to compile your sources so you can run them on your Dreamcast, you will need to have a working dcdev environment. First of all, download the following dcdev.exe file.
DCDev Installer
Cygwin setup:
Download the Cygwin setup.exe.
Select a mirror and make sure you keep the same mirror when you resume so that your package directory is kept neat (setup.exe should have it highlighted). The latest default Cygwin installation should work just for compiling DC programs but if you want to use kos-svn or compile for Unix/Windows then please click the symbol between All and Default on the top. This will change everything to Install, insuring you have everything needed to run the kos-svn script or for compiling programs for other platforms than DC.
Install Cygwin and tools:
Now it is just a simple matter of installing Cygwin, and running dcdev.exe. Install Cygwin in the folder C:\cygwin or D:\cygwin , it doesn't much matter as long as it is in a root folder.
Run dcdev.exe and install to C:\cygwin\usr\local\dc , so now you should have C:\cygwin\usr\local\dc\sh-elf , another folder beside that one called C:\cygwin\usr\local\dc\arm-elf , and another folder C:\cygwin\usr\local\dc\kos-1.2.0 all together.
Post Installation:
You will be asked if you wish to have environ-dc.sh setup when you start Cygwin.
Answering yes will install a dcdev.sh file to C:\cygwin\etc\profile.d which will run environ-dc.sh when you start Cygwin.
Answering no will complete the installation. You will have to run the environ-dc.sh file each time you wish to compile for DC. Either by typing . environ-dc.sh in the kos-1.2.0 folder or typing . /usr/local/dc/kos-1.2.0/environ-dc.sh and remember it's a . with a space between the filename.
Please look at the KOS Subversion article to learn about getting the latest KOS version.