pseudo device

Well I would like to start learning some kernel level programming and try my hands at devices. I want to know what is a pseudo device (yeah.. the name suggests something vaguely :), how does the pseudo device actually get marked in the kernel and is there a way to connect o pseudo device externally also. TIA -- Best Regards, Srinidhi. ============================================== The true delight is in the finding out rather than in the knowing. -- Isaac Asimov ==============================================