Comment by cturner | Hacker News Reader

Comment by cturner | Hacker News Reader

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More on Raspberry Pi port in case others are interested. Raspberry Pi port is interesting, because it allows us to run plan9 on native hardware (access keyboard, mouse, video and probably audio - haven't checked). It doesn't matter that there isn't much power in it, because plan9 is designed to be distributed. Once you have a terminal, you can set up a cpu server and file server to run under a linux hypervisor in the same network.

You can think of a cpu server as being similar to this scenario: you ssh to a fast box, and run an app on that remote machine. However, due to the elegance of the plan9 architecture, instead of having the app run in the terminal window or over a laborious x-windows protocol, it writes quickly over the network to the window that you invoked the command from.

Unlike the unix experience, cross-compiling is trivial in this environment. Hence, it's fine to run varying architectures in the same system. Setting up a Raspberry Pi terminal is easy and cheap.

Some might ask - why? My motive: I see it as a different approach to software development. Instead of bolting monolithic systems together, I'll be able to implement platforms as devices that are exposed over 9p. Consider how much easier it is to do init for multi-host applications. Convential unix approach is and ugly spaghetti of scripts+ssh. In this design, just mount the apps and script them from one host. The network becomes transparent: you just script against devices.

> However, due to the elegance of the plan9 architecture, instead of having the app run in the terminal window or over a laborious x-windows protocol, it writes quickly over the network to the window that you invoked the command from.

I don't understand the distinction you are trying to make with the phrsase "quickly over the network". SSH and networked X aren't exactly slow. The latter can be a slug with a bad network, but I recently had to do something kind of fringe and ended up running firefox over wifi with ssh -Y, and it was usable.

You can argue that protocols, implementation, API, etc. are better with plan9 (consistent with claims I heard before) but I don't totally understand how that would necessarily translate into performance (if anything I would expect things used by more people over more time would be better tuned).

Thanks for the corrections. There are many reasons to dislike X, but sounds like speed isn't one.

Oh, God. Are you serious? Listen try sitting in Texas some time and opening a X application even over a compressed SSH link from Delaware. It literally takes minutes for a splash screen to paint. And using applications are nearly impossible due to interaction lag. You're better off using a VMware console, RDP heck even Citrix which at one time was itself supposedly X based.

X is simply awful over the WAN, trust me. Please note: I'm not talking about an essentially text-only experience like xterm, which works fine. I mean actually using X as a graphical client.

The problem there is not so much X, as software devs not using X but instead just painting everything into "image" that is then dumped into X. This means you are effectively looking at what amounts of a VNC session, without the benefit of compression.

There are at least one X extension out there that offer compression for long distance connections. But for some reason they never really took off.

I did mention compression of the X session itself by way of compressing the SSH tunnel. The problems run deeper than "software devs just painting everthing into image". X itself has a mix of synchronous and asynchronous calls that are very sensitive to latency. XCB instead Xlib and use of LBX can help but do not eliminate the performance issues with X Window.

See http://keithp.com/~keithp/talks/usenix2003/html/net.html and http://vis.lbl.gov/Events/SC08/RemoteX/index.html for more details.

As it relates to the original topic I'd be interested to see real-world performance comparisons between Plan 9 and X because as the papers state X stinks on ice over the WAN.

Nomachine worked reasonably well for me cities apart. I believe it was adding some compression to X at the time; circa 2011.

Does plan9 works well over a WAN? (Genuine question)

Yes. For remote control, drawterm (a client to "cpu" into a plan9 box from a non-plan9 box) can even make the GUI feel local over poor connections (except if you try to play doom or something).

That's over a LAN. But what about over the distances earlier in the thread - the earlier example was a line across a significant bit of continental US. [More interesting still would be Sydney to London.]

No, I was talking about WAN, not LAN. (Note that 9front's fork of drawterm is a lot faster than the normal version - a regular drawterm can be a bit slow)

I am not located in the US, but hopping borders in europe does not seem to be a problem. It's less of a problem than with X-forwarding or VNC.

As for regular fs mounts (note that a remote control session on plan9 is actually also just a regular fs mount), I mount things from the US every once in a while, and I am located in Sweden. It's obviously not fast due to very high latency and limited bandwidth, but it works just fine within those constraints.

But of course, if the RTT >1 second, then it will take >1 second for a keystroke to show up on screen in a remote control session. You cannot be resistant to this (mosh tries to guess how things would look if the keystrokes had gone through, which is a major hack, and not really an issue).

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