Re: x11vnc and vncviewer for classroom
On Tue, Nov 25, 2008 at 12:39 PM, Anna ascho...@gmail.com wrote: Another option to accomplish this is to stream the screen of the Ubuntu machine as ogg and then the XOs can simply play the stream via totem. The src of the video is a conventional ubuntu machine - - how powerful is the source machine? - how do you grab the screen? - what bandwidth does the stream take? Setting things up so this is easy to do is something I hope to get to at some point -- cheers, m -- martin.langh...@gmail.com mar...@laptop.org -- School Server Architect - ask interesting questions - don't get distracted with shiny stuff - working code first - http://wiki.laptop.org/go/User:Martinlanghoff ___ Devel mailing list Devel@lists.laptop.org http://lists.laptop.org/listinfo/devel
Re: x11vnc and vncviewer for classroom
Is this Anna Schoolfield from Central Alabama Mensa? Remember me? Gene Geist. Its been a long time so I wouldn't blame you. Anna-2 wrote: *My previous post turned up blank for some reason. Sorry about that. Hopefully this works* From the original email by Arjun Sarwal: The idea is that in a classroom, teacher wants to have these intermediate sessions where he just wants to explain to kids by doing things on his screen - mainly go through specific pages of a pdf while simultaneously explaining something orally. There are ~30 kids in the classroom. Another option to accomplish this is to stream the screen of the Ubuntu machine as ogg and then the XOs can simply play the stream via totem. On my Ubuntu box, I installed Istanbul, changed my screen resolution to 800x600, then did this to stream my entire desktop to the icecast server on my XS 0.4 test box: gst-launch-0.10 oggmux name=mux ! shout2send ip=myip port=port password=secret mount=ubuntu.ogg istximagesrc name=videosource use-damage=false endx=800 endy=600 ! video/x-raw-rgb,framerate=5/1 ! videorate ! ffmpegcolorspace ! videoscale method=1 ! video/x-raw-yuv,width=800,height=600,framerate=5/1 ! theoraenc ! queue ! mux. The stream looked really good on the XO - very clear and legible. The settings probably need tweaking, though, to scale up to ~30 users. I haven't tried setting up icecast on Ubuntu, but it should be possible to stream and broadcast on the same machine. At any rate, this doesn't require anything extra to be installed on the XOs themselves. Anna Schoolfield Birmingham ___ Devel mailing list Devel@lists.laptop.org http://lists.laptop.org/listinfo/devel -- View this message in context: http://n2.nabble.com/x11vnc-and-vncviewer-for-classroom-tp1574311p2265499.html Sent from the Software development mailing list archive at Nabble.com. ___ Devel mailing list Devel@lists.laptop.org http://lists.laptop.org/listinfo/devel
Re: x11vnc and vncviewer for classroom
Hi Mitch, On Sun, 23 Nov 2008, Mitch Bradley wrote: [discussion about LTSP and PXE and Etherboot and wired ethernet adapters] Why is PXE necessary for LTSP? Its not, but if one wants to boot some of the time as a thin client, and some of the time as as a standalone computer, then it becomes very handy. It also allows thin-clientness without altering the filesystem on the XO, preserving all the good work done on that software environment. What I was thinking of with the original question was the following scenario: An XO user runs the stock onboard software stack most of the time. The same user visits a location with an LTSP server. He wants to take advantage of the additional computing power available on that LTSP server, so he plugs into the ethernet, and boots disklessly as a LTSP thin client, w/o any reconfiguration necessary on his part, or any reconfiguration of the LTSP server. I happen to make solar powered LTSP servers that are being deployed in many of the same areas as the XO. I want to know what I need to support on the server side to allow this functionality. PXE requires no alteration to either system... hence my original question. From the LTSP web site, I get the impression that it can run inside several distros, including Fedora and Debian. There are Fedora- and Debian- derived distros for XO. There are LTSP packages for many distros. One could build from source for others. XO's OFW firmware can load kernels and initramfs's over either USB Ethernet adapters or the built-in wireless, using TFTP or HTTP or NFS. OK, but that requires some user interaction with OFW, correct? You are saying that OFW can behave like PXE, by pulling a dhcp address via wireless then TFTPing a kernel/initrd? If so, that probably solves my problem, enumerated above. It's also possible to boot diskless with root on NFS. In fact that's how the manufacturer runs their Linux-based burn-in diagnostics. LTSP uses a NBD for root filesystem in recent releases, iirc. What you can't do is run an absolutely stock distro, because you need a kernel that supports the OLPC-specific hardware. Which devices in particular? Can these device drivers be merged into the upstream kernel tree, or are we still dealing with a binary blob somewhere? Enjoy, Scott ___ Devel mailing list Devel@lists.laptop.org http://lists.laptop.org/listinfo/devel ___ Devel mailing list Devel@lists.laptop.org http://lists.laptop.org/listinfo/devel
Re: x11vnc and vncviewer for classroom
[EMAIL PROTECTED] wrote: Its not, but if one wants to boot some of the time as a thin client, and some of the time as as a standalone computer, then it becomes very handy. It also allows thin-clientness without altering the filesystem on the XO, preserving all the good work done on that software environment. What I was thinking of with the original question was the following scenario: An XO user runs the stock onboard software stack most of the time. The same user visits a location with an LTSP server. He wants to take advantage of the additional computing power available on that LTSP server, so he plugs into the ethernet, and boots disklessly as a LTSP thin client, w/o any reconfiguration necessary on his part, or any reconfiguration of the LTSP server. I happen to make solar powered LTSP servers that are being deployed in many of the same areas as the XO. I want to know what I need to support on the server side to allow this functionality. PXE requires no alteration to either system... hence my original question. Network boot is part of the normal sequence but it's after the other choices. The order is USB, then SD, then NAND, then USB wired ethernet, and finally wireless LAN. The reason for that order is because net boot is rarely used in our target customer scenario and the act of checking for network connectivity is time consuming. On most OFW systems, you could change that order simply by changing a configuration variable in non-volatile storage, but on OLPC, that ability is disabled, because I wanted the machine to really be like a toaster as far as the firmware is concerned - no knobs to turn to the wrong setting, and therefore no support calls resulting from incorrect settings. But there is a solution. OFW boots by loading a Forth script name /boot/olpc.fth . That script can be as short as a single boot command, but normally it does a few other things such as setting the Linux cmdline arguments to device-specific values (e.g. NAND booting requires root=mtd0 rootfstype=jffs2) and perhaps checking for firmware updates. That script can contain arbitrary Forth/OFW commands, so in the general case it can do anything that you want. You could modify /boot/olpc.fth on the NAND to perform some network operation to determine whether to go the network boot route, and if that operation fails, proceed with the normal boot Linux from NAND code. One quick test would be to see if a wired USB ethernet adapter is present; that can be done rather quickly, whereas actually going out onto the network and doing a DHCP operation can take several seconds, especially in the failing case where it has to retry several times. As an alternative to TFTP, you could also load the file via HTTP. That has advantages over TFTP in some network environments. XO's OFW firmware can load kernels and initramfs's over either USB Ethernet adapters or the built-in wireless, using TFTP or HTTP or NFS. OK, but that requires some user interaction with OFW, correct? As indicated above, that interaction can be automated by adding it to the /boot/olpc.fth script . You are saying that OFW can behave like PXE, by pulling a dhcp address via wireless then TFTPing a kernel/initrd? If so, that probably solves my problem, enumerated above. It could be as simple as changing the boot-device configuration variable in olpc.fth, the re-executing boot . But that would slow down the boot in the non-network case. It would be better if you could find some quick way to check. Wireless net boot has several steps that are reasonably quick in the success case, but rather long (due to timeouts and retries) in the fail case, including: * Downloading the wireless firmware to the WLAN chip (no timeout, but takes a second or two) * Scanning for and associating with an access point * Interacting with a DHCP server * Interactingn with a TFTP server It's also possible to boot diskless with root on NFS. In fact that's how the manufacturer runs their Linux-based burn-in diagnostics. LTSP uses a NBD for root filesystem in recent releases, iirc. That would be up to the Linux kernel to take care of that. You might have to set the cmdline properly or something in the olpc.fth script. OFW can load from an NFS server, but that ability is not necessary. The kernel and initramfs can be loaded from anywhere, then it can worry about the root fs for itself. What you can't do is run an absolutely stock distro, because you need a kernel that supports the OLPC-specific hardware. Which devices in particular? Can these device drivers be merged into the upstream kernel tree, or are we still dealing with a binary blob somewhere? There is an effort to get everything upstream, but I'm not sure about the status of that. There are several OLPC-specific devices - DCON, CaFe NAND, some audio GPIO tweaks - plus startup tweaks for interacting
x11vnc and vncviewer for classroom
From the original email by Arjun Sarwal: The idea is that in a classroom, teacher wants to have these intermediate sessions where he just wants to explain to kids by doing things on his screen - mainly go through specific pages of a pdf while simultaneously explaining something orally. There are ~30 kids in the classroom. Another option to accomplish this is to stream the screen of the Ubuntu machine as ogg and then the XOs can simply play the stream via totem. On my Ubuntu box, I installed Istanbul, changed my screen resolution to 800x600, then did this to stream my entire desktop to the icecast server on my XS 0.4 test box: gst-launch-0.10 oggmux name=mux ! shout2send ip=myip port=port password=secret mount=ubuntu.ogg istximagesrc name=videosource use-damage=false endx=800 endy=600 ! video/x-raw-rgb,framerate=5/1 ! videorate ! ffmpegcolorspace ! videoscale method=1 ! video/x-raw-yuv,width=800,height=600,framerate=5/1 ! theoraenc ! queue ! mux. The stream looked really good on the XO - very clear and legible. The settings probably need tweaking, though, to scale up to ~30 users. I haven't tried setting up icecast on Ubuntu, but it should be possible to stream and broadcast on the same machine. At any rate, this doesn't require anything extra to be installed on the XOs themselves. Anna Schoolfield Birmingham ___ Devel mailing list Devel@lists.laptop.org http://lists.laptop.org/listinfo/devel
Re: x11vnc and vncviewer for classroom
*My previous post turned up blank for some reason. Sorry about that. Hopefully this works* From the original email by Arjun Sarwal: The idea is that in a classroom, teacher wants to have these intermediate sessions where he just wants to explain to kids by doing things on his screen - mainly go through specific pages of a pdf while simultaneously explaining something orally. There are ~30 kids in the classroom. Another option to accomplish this is to stream the screen of the Ubuntu machine as ogg and then the XOs can simply play the stream via totem. On my Ubuntu box, I installed Istanbul, changed my screen resolution to 800x600, then did this to stream my entire desktop to the icecast server on my XS 0.4 test box: gst-launch-0.10 oggmux name=mux ! shout2send ip=myip port=port password=secret mount=ubuntu.ogg istximagesrc name=videosource use-damage=false endx=800 endy=600 ! video/x-raw-rgb,framerate=5/1 ! videorate ! ffmpegcolorspace ! videoscale method=1 ! video/x-raw-yuv,width=800,height=600,framerate=5/1 ! theoraenc ! queue ! mux. The stream looked really good on the XO - very clear and legible. The settings probably need tweaking, though, to scale up to ~30 users. I haven't tried setting up icecast on Ubuntu, but it should be possible to stream and broadcast on the same machine. At any rate, this doesn't require anything extra to be installed on the XOs themselves. Anna Schoolfield Birmingham ___ Devel mailing list Devel@lists.laptop.org http://lists.laptop.org/listinfo/devel
Re: x11vnc and vncviewer for classroom
Hi Mitch, Thanks for the very complete response. You are saying that OFW can behave like PXE, by pulling a dhcp address via wireless then TFTPing a kernel/initrd? If so, that probably solves my problem, enumerated above. It could be as simple as changing the boot-device configuration variable in olpc.fth, the re-executing boot . But that would slow down the boot in the non-network case. It would be better if you could find some quick way to check. I concur, that is probably the best solution. No need to waste time in the boot sequence. If I had an XO here, I would be coding as we speak. The original G1G1 machine(s) I was supposed to get through a third party got borked with the paypal thing, so I have none, and do not want to bug my donor for another try. There is an effort to get everything upstream, but I'm not sure about the status of that. There are several OLPC-specific devices - DCON, CaFe NAND, some audio GPIO tweaks - plus startup tweaks for interacting with the OFW device tree to get the system configuration, embedded controller interaction for battery status, and fast non-ACPI power management code. ack. The only binary blob component is the firmware for the wireless LAN module. iirc, that is a full SOC device from marvell, correct? any progress on that front? Thanx, Scott ___ Devel mailing list Devel@lists.laptop.org http://lists.laptop.org/listinfo/devel
Re: x11vnc and vncviewer for classroom
On Sat, 2008-11-22 at 20:56 -0500, Ian Daniher wrote: To be honest, I've had the best luck with microsoft terminal services in so far as the thin client area goes - I use my XO day to day with my school's remote desktop server and it works flawlessly - the fonts are a bit tiny, but it works with no noticeable speed difference between it and a desktop. Why wasn't this approach considered instead of putting XP on XOs? Can't take thin clients home, so you are immediately limited to in-school use. - Jim -- Jim Gettys [EMAIL PROTECTED] One Laptop Per Child ___ Devel mailing list Devel@lists.laptop.org http://lists.laptop.org/listinfo/devel
Re: x11vnc and vncviewer for classroom
Hi All, Pardon my lack of experience with the XO... was supposed to get 2 of them with the original G1G1 program, but that apparently did not work out. Does the XO have a standard ethernet interface? If so, and if that interface does PXE, it would make an admirable LTSP terminal when connected to a wired network also. After all, why use terminal services you have to pay licencing fees for... Enjoy, Scott On Sun, 23 Nov 2008, Jim Gettys wrote: On Sat, 2008-11-22 at 20:56 -0500, Ian Daniher wrote: To be honest, I've had the best luck with microsoft terminal services in so far as the thin client area goes - I use my XO day to day with my school's remote desktop server and it works flawlessly - the fonts are a bit tiny, but it works with no noticeable speed difference between it and a desktop. Why wasn't this approach considered instead of putting XP on XOs? Can't take thin clients home, so you are immediately limited to in-school use. - Jim -- Jim Gettys [EMAIL PROTECTED] One Laptop Per Child ___ Devel mailing list Devel@lists.laptop.org http://lists.laptop.org/listinfo/devel ___ Devel mailing list Devel@lists.laptop.org http://lists.laptop.org/listinfo/devel
Re: x11vnc and vncviewer for classroom
On Sun, Nov 23, 2008 at 4:24 PM, [EMAIL PROTECTED] wrote: Hi Peter, On Mon, 24 Nov 2008, Peter Robinson wrote: Hi All, Pardon my lack of experience with the XO... was supposed to get 2 of them with the original G1G1 program, but that apparently did not work out. Does the XO have a standard ethernet interface? If so, and if that interface does PXE, it would make an admirable LTSP terminal when connected to a wired network also. No wired ethernet onboard, although I think it supports some usb ethernet adapters. Doubtful that would work then, although it could do an X -query $X11SERVER where the X11 server is broadcasting XDMCP. Could probably also use LTSP's ldm to connect to a standard LTSP server instead of running a local GUI. That is essentially X compressed and encrypted over a ssh tunnel. Either of these methods would work over either a usb NIC or the wifi. Enjoy, Scott The XO does have 3 USB 2.0 ports and a whole bunch of USB to ethernet adapters work (http://wiki.laptop.org/go/USB_ethernet_adaptors). However, the XO does not have a traditional BIOS, so no PXE boot option. http://wiki.laptop.org/go/Ask_OLPC_a_Question_about_the_Network#XO_and_PXE.2FEtherboot I remember talking to Oliver Grawert (copied here) of Ubuntu/LTSP fame at the first (and only) UbuntuLive and he said he had an XO in the mix of things that ran LTSP terminals. How he was doing this wasn't clear though. cheers, Sameer -- Dr. Sameer Verma, Ph.D. Associate Professor of Information Systems San Francisco State University San Francisco CA 94132 USA http://verma.sfsu.edu/ http://opensource.sfsu.edu/ ___ Devel mailing list Devel@lists.laptop.org http://lists.laptop.org/listinfo/devel
Re: x11vnc and vncviewer for classroom
[discussion about LTSP and PXE and Etherboot and wired ethernet adapters] Why is PXE necessary for LTSP? From the LTSP web site, I get the impression that it can run inside several distros, including Fedora and Debian. There are Fedora- and Debian- derived distros for XO. XO's OFW firmware can load kernels and initramfs's over either USB Ethernet adapters or the built-in wireless, using TFTP or HTTP or NFS. It's also possible to boot diskless with root on NFS. In fact that's how the manufacturer runs their Linux-based burn-in diagnostics. What you can't do is run an absolutely stock distro, because you need a kernel that supports the OLPC-specific hardware. ___ Devel mailing list Devel@lists.laptop.org http://lists.laptop.org/listinfo/devel
x11vnc and vncviewer for classroom
I ran x11vnc server on my Ubuntu desktop, used vncviewer from the XOs to connect to the machine. I have two XOs that I am testing it with. The performance seems reasonable. Upon having a look I see that the screen on the XOs refreshes once about every one second. I was wondering if someone could comment on the performance when I have about 30 X0s connected to the same ? The idea is that in a classroom, teacher wants to have these intermediate sessions where he just wants to explain to kids by doing things on his screen - mainly go through specific pages of a pdf while simultaneously explaining something orally. There are ~30 kids in the classroom. Also, any specific tweaks/settings that you could suggest for this scenario ? All XOs and the computer are connected to an AP as of now. Thanks! -- Arjun Sarwal [EMAIL PROTECTED] [EMAIL PROTECTED] ___ Devel mailing list Devel@lists.laptop.org http://lists.laptop.org/listinfo/devel
