Notices

I'm a little late to this game but I am fascinated by what you have done so far and I would greatly appreciate you continuing to share your knowledge...

I ran your xeyes demo on my N770 and on my powerbook (just for grins). I even tried the xeyes demo over GPRS and it was laggy but not unreasonable. Very cool stuff.

My company builds some linux based telemetry and data acquisition systems. We do all our GUI's in java because that lets us have a single GUI that looks the same on a local display as it does on a web browser.

But you have just shown me a third way to get there, X forwarding.

So let me ask you this... What are the pros / cons of X forwarding versus something like VNC? Both accomplish very similar things.

If you wanted to make a fairly feature rich GUI but not necessarily graphically intensive, what techniques / platforms would you employ to get the most out of a mobile terminal like the 770?

David

http://blog.eikke.com/index.php/real...s_on_nokia_770
Thanks to this blog, I've been able to use x11 forwarding and yes, it is pretty amazing. I was able to use firefox, with extensions, right on my 770, with a little lag. I don't have a keyboard, so no text input yet, heh.

I have been wondering about the VNC issue, also. It seems that if you were to use VNC for the same purpose, you would tie that computer down to that one task. With X forwarding, I could use the app on the 770, and do something different on the computer. I'm sure that VNC also uses more bandwidth.

With the WWW issue, is the fact that by not using the http protocol, and rather going with an internet protocol, that there would be less lag/latency?

Nope to the VNC thing.... At least under *nix I can set up any number of "virtual desktops" as VNC servers and the host machine can go either way, it can observe the VNC client or it can be running its own desktop. Why do are you sure VNC uses more bandwidth? (Not arguing, I don't know). I would assume VNC would allow bandwidth savings by using compression.

Latency is a physical issue, not really a protocol issue. It is affected purely by the physical route you have to take to get from point A to point B. What physical media you pass through and how many hops over what machines determines your latency.

David

"X" is the X Windows System but, frankly, if it were called the X Protocol System then perhaps we would have a significantly different perception of what it is and what it can be used for. A certain Keith Packard has been involved with X virtually from the beginning and is at the center of the X Renaissance (my description) that is taking place today. Here's one of Keith's papers discussing the latencies of the X Network Performance wherein he discusses the latencies of the X protocol. If you have a bookmark Folder for Interesting People then keithp.com should be in it. He's kind of like Richard Stevens to me, a prodigious, intelligent, prolific individual, the kind of person who is out beyond the ocean's horizon somewhere, creating giant waves that touch us all.

If the 770 stands alone as being able to use the X protocol, then that alone makes it a revolutionary device. As this potential is exploited it will become obvious that no matter how badly commercial interests subvert other Protocols, including the WWW protocols, they likely aren't going to bother subverting the X protocol. The X protocol is an efficient, versatile protocol and its development continues today, after more than 20 years. It contains the tools and features that allow displays to be driven over the network without the need for PCs where users are located, to feature efficient GUIs and to allow large numbers of people to work together in real time.

Things I like about X:

I can have applications running on all sorts of different hardware sharing a single desktop, and that desktop can have whatever style and whatever complexity or simplicity I choose.

Things I like about VNC:

If I lose a connection to a machine, accidently or on purpose, I can reconnect and nothing is lost.

But the models are very, very different, so you need to actually use both, perhaps at the same time, to get an idea of what each can do for you.

The POS app I've been speaking of here for the longest time was written several years before Keith Packard decided to invent the Xft and fontconfig libraries to make use of things like FreeType. It has always been happy using the X core fonts. These are not supported, however, on the subset of X that is used on the 770 - the Maemo platform. Matthew Allum's advice (which we have accepted) is that we replace our use of the X core fonts with the Xft and fontconfig libraries. It's turned out to not be such an easy task.

We've made some progress on this but it's been frustrating and we haven't succeeded yet. I'd like to put out a call to anyone who has experience with Xft and fontconfig to step forward and help us out. There is money attached to this, by the way, for anyone who can help.

Any app using the X core fonts will have to make this same change to the way it uses fonts, by the way. It is such an obstacle that people will have to overcome again and again so when we eventually have nailed this we will document it and provide the source to all. It isn't a walk in the park but it is necessary.

It may be that the GTK+ work is directly applicable here - we haven't looked into that yet. GTK+ also solves the X input method problem, I believe. For any who care, Keith Packard developed the Xft and fontconfig libraries along with a lot of other parts of X to make it a better windowing and protocol system for today's requirements. The 770's implementation of X by Matthew has the effect of requiring X apps to be rewritten to use these libraries and to reject X apps that use the X core fonts. My email is embedded in the ITT user area for anyone who is interested.

Is there nothing out there like GNU screen, but for X? I'd be really interested in something that had that "reconnect" facility for X apps ...

Jonathan

Sorry for the late reply. I was ignoring my own thread here because the move from X core fonts to Xft fonts was frustrating me and I am embarrased about that. I'm glad to say that we've finally made the transition and things will change around here soon because of that.

VNC gives you a static image - the whole thing has to be sent over the network. X gives you a dynamic GUI that is 100% data-driven and, in our case, network-driven. If you manipulate the GUI (something you can't do withVNC because it's just a picture) then you can directly manipulate the data behind the GUI, even if it's on the other side of the planet, and even if other people are viewing the same GUI you are viewing. All that's sent over the network is the information about the GUI that the remote display and graphics processor needs to construct the remote user's GUI.

The extra element in this is the GUI toolkit - that's what we had to add to the mix. We built our GUI out of 'X Primitives'. Most people think of X as a windowing system, which it is, but it's also a transparent network protocol. It allows users, their displays and their input devices to be physically separate from where the programs are running and the data storage. It also allows GUIs to represent virtually any kind of resource on any kind of network. That's a long way from what a Desktop GUI is all about.

GUI, by the way, doesn't always mean pictures. It can mean, as it does in our case, use of 'textures' (aka background tiles) and special use of fonts. We add 'frosting' and 'shadowing' to our text to make it easier to read - we increase the contrast. The bottom line of all this is that much in the same way someone can watch TV without needing a PC, someone can be a user of software without needing a PC. In both cases all they need is a display terminal that attaches to a network with rich content. In the case of software the user also needs a rich array of input devices to be available. When the IPTV experience arrives it will also require a rich array of user input devices.

To all, then, we have finally put the X core font limitation (aka the roadblock) behind us and will soon have the POS demo running. Thanks for being patient.

Milhouse just alerted me to this thread-- cool stuff! No updates in some time though?

I tested xeyes on the N800-- VERY responsive on my home broadband! Nice!

EDIT: I overlooked that the password was 'demo'. Corrected.