But typical desktops only run a few user-mode processes at a time
No. Run ps -A goddamit. A "typical" desktop, especially a UNIX-derived variant, runs a lot of processes. And servers in the near future will do too.
and wouldn't be able to share much code
No, there are a ton of userspace code which is being shared between processes. The code that allocates memory, the code that draws lines and buttons on your screen, the code that sorts strings, the code that implements threading, the code that renders bitmaps out of TTF glyphs, reads files and opens sockets, each process needs megabytes of code you seem to have no idea about: it's not even about libraries, it's about everything not drivers, do you understand now? There are good reasons why JVM programs are memory pigs: they are, essentially, running their own OS in complete isolation.
Disruptive OS innovation will have to wait until someone comes up with a killer app that requires fundamental capabilities which current OS designs can't support.
The problem is that programmers are cheap. There is no market pressure to evolve and leave technology from the 70s in the past. Armies of incubated Java code monkeys cost less in the short run as opposed to going against the stream of mediocrity. This is why new platforms (iPhone) are so exciting and refreshing: they let us leave obsoleted/inherited junk behind: iPhone doesn't have JVM nor Flash/AIR for very good reasons: OS is your VM. Has always been. It's just the right thing to do.
The OS has largely ceased to be an obstacle and quietly faded into the background.
You have demonstrated enough ignorance regarding what OS actually is to allow me to safely ignore this comment. There are a few folks at Apple and Microsoft who are still capable of understanding these issues, this is why Java, despite of 10+ years of availability, with all its beautiful promises, still lives in the obscurity of server rooms.
This is silly. The "typical" desktop runs MS Windows, with only a few user processes running at a time. Some of those processes may have a bunch of threads going, but the process count is small. Of course all of those processes share the low-level OS libraries. And guess what: each JVM process shares those OS libraries, too.
The Java standard library does duplicate some of the higher-level OS features, which is the only practical way to achieve cross-platform compatibility. Any cross-platform solution is going to impose some overhead. Of course you can write native iPhone apps with no extra overhead, but then they can't be used by the 95% of mobile device users who have other platforms.
I'm not sure what you mean about code running in server rooms being obscure. That's what drives web applications and network services which are more visible and critical to many of us than our desktop applications.
By the way, anyone who wants to use the JVM for writing desktop applications should take a look at the Eclipse RCP. I haven't had a need to develop for that platform myself, but the results I've seen from other companies look pretty good.
No. Run ps -A goddamit. A "typical" desktop, especially a UNIX-derived variant, runs a lot of processes. And servers in the near future will do too.
and wouldn't be able to share much code
No, there are a ton of userspace code which is being shared between processes. The code that allocates memory, the code that draws lines and buttons on your screen, the code that sorts strings, the code that implements threading, the code that renders bitmaps out of TTF glyphs, reads files and opens sockets, each process needs megabytes of code you seem to have no idea about: it's not even about libraries, it's about everything not drivers, do you understand now? There are good reasons why JVM programs are memory pigs: they are, essentially, running their own OS in complete isolation.
Disruptive OS innovation will have to wait until someone comes up with a killer app that requires fundamental capabilities which current OS designs can't support.
The problem is that programmers are cheap. There is no market pressure to evolve and leave technology from the 70s in the past. Armies of incubated Java code monkeys cost less in the short run as opposed to going against the stream of mediocrity. This is why new platforms (iPhone) are so exciting and refreshing: they let us leave obsoleted/inherited junk behind: iPhone doesn't have JVM nor Flash/AIR for very good reasons: OS is your VM. Has always been. It's just the right thing to do.
The OS has largely ceased to be an obstacle and quietly faded into the background.
You have demonstrated enough ignorance regarding what OS actually is to allow me to safely ignore this comment. There are a few folks at Apple and Microsoft who are still capable of understanding these issues, this is why Java, despite of 10+ years of availability, with all its beautiful promises, still lives in the obscurity of server rooms.