They have, there was a light-gun developed for the original xbox.
Yes. There are currently 3 different console developers; Microsoft, Sony, and Nintendo.
Microsoft XBox
It will be on the Sony PS3 and Microsoft Xbox 360.
You and everyone will know that Nintendo, Microsoft and Sony are battling to be the best console. When Microsoft was creating there Xbox 360, Sony created there PS3, Nintendo created the Wii. When times pass, the graphics in the console gets old and games will suffer badly. So really the main reason why Microsoft created the Xbox 360 is because they wanted more and better games to be played on there console.
There was never any conversation between Microsoft and Sony regarding making Halo available to the PlayStation platform, Sony has never showed interest in it either.
XBox 360 is a Microsoft gaming console. The XBox 360 was originally unveiled in 2005, and competes directly with the Nintendo Wii and the Sony Playstation 3 as part of the seventh generation of gaming consoles.
They require different software to read the discs, and companies such as Sony and Microsoft do not readily give out that software.
There will be no new gaming system in 2008. Nintendo, Sony, or Microsoft are going to probably release their next console in 2012.
Sony
They wanted to make a better game console that could also become more and be used as it has been on the internet and for downloading movies and music
sony
sony invented CD System in 1982