COSMOS has been rattling around in Chad's brain since about 1995 with a lot of brain cycles spent on deep designs of the system. It was however at the time CHAOS - Chad Hower's Advanced Operating System.
Finally in about 2007 Chad convinced Matthijs to join him in another crazy open source adventure and they named it COSMOS as Chad didn't want the project to be only about him. COSMOS is an Open Source Operating System SDK which allows individuals with very little coding experience to write their own Operating System.
Since then COSMOS has grown into a large open source project with around 60 contributors. In its now teenage years, just approaching adulthood COSMOS has reached a level of maturity that takes it to MS-DOS and Linux stages prior to their introduction of a "Window" based Operating System. You have networking, filesystems, memory management and a rich and growing API for the development of your console based Operating System. However, it does not do everything for you. It can't possibly know what file system you are going to choose to use or if you roll-your-own. It can not possibly know what executable system you are going to use or will you roll-your-own?
Thus, the tool-chain for developing your applications and external commands has not been included, it is something you will have to decide on yourself and create from open source versions of the pre-compiler, compiler, linker and / or assembler. There are a lot of instructions on the internet about building your own tool-chain. Alternatively, if you decide to use a Microsoft .exe format or the Linux .elf program executable format then, simply download the tool-chain appropriate to your coding language and that is you.
However, at this stage in our life-cycle we are really needing many more coders to contribute to the COSMOS SDK, as well as translators, documentation and API writers, a NUGET package developer for the UserKit package and tutorial writers. If you would like to join then talk to us on our Gitter Chat.
We are rapidly coming up to our childhood end and our adulthood beginning; this is the time you and we have all be waiting for.