Ubuntu moving away from X

[richard.pieri-Re5JQEeQqe8AvxtiuMwx3w at public.gmane.org (Richard Pieri)]

On Nov 8, 2010, at 12:44 PM, Mark Woodward wrote:
> 
> This is absolutely false. VNC does not even compare. If I have a 1280x1024 display on the target machine, and a 1280x800 display on my laptop. Using VNC to connect to the target machine is unusable, you can scale it, at which point you can't read it, or scroll at which point you can't use it.

I'd say that this is pilot error or sour grapes more than anything.

First, we've had X11 window managers that manage desktops larger than the display size for 20 years, now.  I never used swm but I used tvtwm extensively through the early 1990s.  It was quite usable and probably still is.

Second, if the scaling you use for VNC makes the display unreadable then you are doing it wrong.

> Remoting specific applications is a very powerful feature. People should really try to understand it before disregarding it.

I understand it perfectly well, thank you very much.


> Over the internet or a slow connection, sure, on a local lan, its fine and a lot better than trying to maintain

... what?

Anyway, I choose the tool that works equally well in all situations.  This ensures that managing the servers in the machine room next door is the same as managing the servers in the redundant data center on the other side of the country.


> This is exactly the problem. People don't understand how powerful the feature is. Take my home entertainment system, I use this feature to control rythmbox from my laptop without having to turn on the TV. I can even control the music from my office down the hall.

Like I said, I full-well understand how powerful it is.  What I'm saying is that it isn't necessary and there are frequently better ways.  iTunes in particular uses a standard protocol called DACP which provides for a variety of non-desktop control options.

http://en.wikipedia.org/wiki/Digital_Audio_Control_Protocol

> VNC is a dog. It is slow compared to X remoting. VNC uses raw bitmap, X uses X protocol primitives which are much faster, and compress better using ssh 

"VNC uses raw bitmap".  VNC does not just use raw bitmap and most of the time it doesn't use raw bitmaps at all.  It uses a variety of encoding algorithms depending on the detected network speed or user override.  The most commonly used are CopyRect, Hextile and ZRLE.  You can find more information here:

http://www.realvnc.com/docs/rfbproto.pdf

"X protocol primitives which are much faster".  While true on the surface it ignores the nature of the client-server model that X11 uses.  For every primitive the client makes a drawing request of the server then waits for the server to return a success code.  While faster and more efficient, the latency is grossly higher than VNC which can lead to sluggish UIs.

"and compresses better using ssh".  This is a big "it depends".  For a textual application like an Xterm then sure.  For an application displaying and manipulating bitmaps like the GIMP it can be the same or even slower than VNC depending on the encoding used.

And while I'm on the subject, I suggest that you take a look at NoMachine.  It's a virtual frame buffer X server that uses some VNC-inspired techniques.  It is extremely fast even over slow networks.

--Rich P.