[yarvin9]

When I say "the browser for the server side," what I mainly mean is the isolation layer between the browser and the OS.

For example, suppose someone designing the first JS environment at Netscape had suggested that since JS is so great, you should be able to make POSIX system calls from it. Or link to locally stored libraries. Or use a language someone had heard of before. I think you'll agree that if this decision had been made, most people would never have heard of JS.

The browser is a second-level OS which provides a service no first-level OS offers; it loads applications almost instantly and sandboxes them securely.

Now, in theory, you could modify a Unix to solve this problem. Arguably, it's a problem any OS ought to be able to solve. We are certainly much closer with containers. But still, imagine what it would take to replace webpages with Dockerfiles. (sandstorm.io is the closest to something like this; definitely check them out as well.)

Urbit's semantics are isolated from the platform in just the same way. The job of a general-purpose personal server is very different from the job of a general-purpose client -- they have almost nothing in common. But the isolation layer over the current systems platform is the crucial element.