What do you mean by an online OS, exactly? What features do you want it to have? If you mean a sort of meta-webapp, then you'll need client-side components (built with Javascript and HTML) and server-side components (built with Perl, PHP, or Python).

Ok picture this, you go online say at school... get home turn on the laptop, and boom in a cloud-like website your files are there... also it runs other things (possibly) like a email service, calendars, and IM.
Take a look at http://glidesociety.com/ it has most of these features but it looks strange I hope to make a better one. you do have to sign-up but its free and you get 30GB of memory.

Ok, this will be fun. Use google.

Google DriveGMailGoogle CalendarGoogle Talk

What you want still isn't an OS, it's google

Noooo .... groan... I want to have some site that is a mix of it all, something that you can do things with like.... make a program that works online but .... its hard to say what it will have. And if its not and online OS then what would one be? example of components please?

i think i understand. take mirage OS, for the calc. it isnt a real OS, but a shell. diggery is saying that he wants to make a shell that runs in a browser. 2 options: limited upload size of programs to be run and streamed to the client, or do as Kerm did for jsTIfied and have everything local. from the sound of it, you'd want to use the 1st one. and, i dont see how this would be incredibly useful. but cool.

did i hit anywhere near what your saying diggery?

Yes, you did and its going to be a very slow process, I have figured out if I make a batch that sets it up it can be like a download of some sort that you "log on" to and its just run in your browser but not online!
The files I would need is several pages that complete my tasks. Fonts that can be installed and sound/.gifs/photos and more. basically it would become a real shell over time with minimum options to begin with.