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  • generating maps

    - by gardian06
    This is a conglomeration question when answering please specify which part you are addressing. I am looking at creating a maze type game that utilizes elevation. I have a few features I would like to have, but am unsure as to some of the implementation. I have done work doing fileIO maze generation (using a key to read the file, and then generate the level based on that file), but I am unsure how to think about this with elevation in the mix. I think height maps might be a good approach, but don't know how to represent them effectively. for a height map which is more beneficial XML(containing h[u,v] data and key definition), CSV (item1 is key reference, item2 is elevation), or another approach that I have not thought of yet? When it comes to placing the elevation values themselves what kind of deltah values are appropriate to have it noticeable at about a 60degree angle while not really effecting gravity driven physics (assuming some effect while moving up/down hill)? I am thinking of maybe going to procedural generation at some point, but am wondering if it is practical to have a procedurally generated grid (wall squares possibly same dimensions as the open space squares), or if designing to a thin wall open spaces is better? this decision will effect the amount of work need on the graphics end for uniform vs. irregular walls. EDIT: game will be a elevation maze shooter. levels/maps will be mazes with elevation the player has to negotiate. elevations will have effects on "combat" vision, and movement

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  • Need alternative to Accessibility's "Locate Pointer" to visually highlight the mouse.

    - by fred.bear
    Update: See end of quetion: A black-on-white cross-hair/I-bar mouse-pointer is soemtimes hard foe me to spot in amongst black-on-white text. I've tried "Accessibility / Mouse Accessibility / Locate Pointer" .. which will: Show pointer position when Control is presssed It works (to a point), but it does have a notable problem, which renders it inpractical. It has the uncanny side-effect of disallowing all Control key navigation while editing a file/dir name in Nautilus (F2).. Just touching the Control key drops it out of edit mode, which means I can't keyboard paste, move-L/R word etc... So, I'm looking for an alternative. I've tried Compiz's Water Effect, but I need something which is sharper, faster, and localized to the pointer. Compiz's Show Mouse (with fire) is no suitable. I'm really lookingf for an analog of "Accessibility / Locate Pointer": * ie. I hit Control (only).. and it blips a quick visual pulse. UPDATE: I've just realized why I can't find my mouse so often! ... It's because it is isn't there !!! ... Two apps I use a lot, Gedit and Konsole (KDE Terminal; it renders unicode better), ... dissolve the mouse-pointer to invisible after the first key is typed ... and Konsole does it after a few seconds of idle-time... like a video-player option: "hide the mouse".. Well I don't use the mouse much, and I thought it was juse my eyesight (which does rely a lot on Compiz's zoom)... I discovered it when I installed a "novelty" app, called Geyes from gnome-applets ("A goofy set of eyes for the GNOME panel. They follow your mouse.") ... It could follow the mouse better than me! :)

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  • Slap the App on the VM for every private cloud solution! Really ?

    - by Anand Akela
    One of the key attractions of the general session "Managing Enterprise Private Cloud" at Oracle OpenWorld 2012 was an interactive role play depicting how to address some of the key challenges of planning, deploying and managing an enterprise private cloud. It was a face-off between Don DeVM, IT manager at a fictitious enterprise 'Vulcan' and Ed Muntz, the Enterprise Manager hero .   Don DeVM is really excited about the efficiency and cost savings from virtualization. The success he enjoyed from the infrastructure virtualization made him believe that for all cloud service delivery models ( database, testing or applications as-a-service ), he has a single solution - slap the app on the VM and here you go . However, Ed Muntz believes in delivering cloud services that allows the business units and enterprise users to manage the complete lifecycle of the cloud services they are providing, for example, setting up cloud, provisioning it to users through a self-service portal ,  managing and tuning the performance, monitoring and applying patches for database or applications. Watch the video of the face-off , see how Don and Ed address some of the key challenges of planning, deploying and managing an enterprise private cloud and be the judge ! ?

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  • Stop animation playing automatically

    - by Starkers
    I've created an animation to animate a swinging mace. To do this I select the mace object in the scene pane, open the animation pane, and key it at a certain position at 0:00. I'm prompted to save this animation in my assets folder, which I do, as maceswing I then rotate the mace, move the slider through time and key it in a different position. I move the slider through time again, move the object to the original position and key it. There are now three things in my assets folder: maceswing appears to be my animation, but I have no idea what Mace Mace 1 and Mace 2 are. (I've been mucking around trying to get this working so it's possible Mace 1 and Mace 2 are just duplicates of Mace. I still want to know what they are though) When I play my game, the mace is constantly swinging, even though I didn't apply maceswing to it. I can't stop it. People say there's some kind of tick box to stop it constantly animating but I can't find it. My mace object only has an Animator component: Unticking this component doesn't stop the animation playing so I have no idea where the animation is coming from. Or what the Animator component actually does. I don't want this animation constantly playing. I only want it to play once when someone clicks a certain button: var Mace : Transform; if(Input.GetButtonDown('Fire1')){ Mace.animation.Play('maceswing'); }; Upon clicking the 'Fire1' button, I get this error: MissingComponentException: There is no 'Animation' attached to the "Mace" game object, but a script is trying to access it. You probably need to add a Animation to the game object "Mace". Or your script needs to check if the component is attached before using it. There is no 'Animation' attached to the "Mace" game object, and yet I can see it swinging away constantly. Infact I can't stop it! So what's causing the animation if the game object doesn't have an 'Animation' attached to it?

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  • VirtualBox Port Fowarding to Connect to PostgreSQL Database

    - by kliao
    I'm trying to connect to a PostgreSQL database hosted on a Win7 guest from a Win7 host. I've configured security in pg_hba.conf host all all 127.0.0.1/32 md5 host all all 10.0.2.15/32 md5 host all all 192.168.1.6/32 md5 and set the listen_addresses setting in postgresql.conf to '*'. I think I've set up port forwarding correctly as I see: Key: VBoxInternal/Devices/e1000/0/LUN#0/Config/win7_vm1/GuestPort, Value: 5432 Key: VBoxInternal/Devices/e1000/0/LUN#0/Config/win7_vm1/HostPort, Value: 5432 Key: VBoxInternal/Devices/e1000/0/LUN#0/Config/win7_vm1/Protocol, Value: TCP when I call getextradata. This is similar to http://serverfault.com/questions/106168/cant-connect-to-postgresql-on-virtualbox-guest but I'm not sure what I'm doing wrong. In the vbox.log file I see: 00:00:01.019 NAT: set redirect TCP host port 5432 = guest port 5432 @ 10.0.2.15 00:00:01.033 NAT: failed to redirect TCP 5432 = 5432 but I'm not sure how to fix that. Any ideas? Thanks.

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  • What did Emolator do with My Laptop?

    - by Garry
    I played SEGA with my KEGA.exe (Sega Emulator) and it made my right key to be malfunctioned. Befor that day, I had played it, too in my notebook with fullscreen mode, and suddenly my ACER Aspire One notebook restarted during that emulator was running and before the screen was black (boot), my screen was blue with many words but I couldn't read them, but I remember that there was a word like 000000 x 0000000 x 000000 and bla bla bla. And when I played without fullscreen mode, It didn't happened but it made my right key to be malfunctioned until when I went to Bot setup, my right key doesn't work. Do U know what is the problem of my emulator? Can U explain me for that?

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  • Test tomcat for ssl renegotiation vulnerability

    - by Jim
    How can I test if my server is vulnerable for SSL renegotiation? I tried the following (using OpenSSL 0.9.8j-fips 07 Jan 2009: openssl s_client -connect 10.2.10.54:443 I see it connects, it brings the certificate chain, it shows the server certificate, and last: SSL handshake has read 2275 bytes and written 465 bytes --- New, TLSv1/SSLv3, Cipher is DHE-RSA-AES256-SHA Server public key is 1024 bit Secure Renegotiation IS supported Compression: NONE Expansion: NONE SSL-Session: Protocol : TLSv1 Cipher : DHE-RSA-AES256-SHA Session-ID: 50B4839724D2A1E7C515EB056FF4C0E57211B1D35253412053534C4A20202020 Session-ID-ctx: Master-Key: 7BC673D771D05599272E120D66477D44A2AF4CC83490CB3FDDCF62CB3FE67ECD051D6A3E9F143AE7C1BA39D0BF3510D4 Key-Arg : None Start Time: 1354008417 Timeout : 300 (sec) Verify return code: 21 (unable to verify the first certificate) What does Secure Renegotiation IS supported mean? That SSL renegotiation is allowed? Then I did but did not get an exception or get the certificate again: verify error:num=20:unable to get local issuer certificate verify return:1 verify error:num=27:certificate not trusted verify return:1 verify error:num=21:unable to verify the first certificate verify return:1 HTTP/1.1 200 OK Server: Apache-Coyote/1.1 Content-Type: text/html;charset=ISO-8859-1 Content-Length: 174 Date: Tue, 27 Nov 2012 09:13:14 GMT Connection: close So is the server vulnerable to SSL renegotiation or not?

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  • xmodmap modifications aren't enough - anything else I can do?

    - by Codemonkey
    I'm using an Apple keyboard which has some annoyances compared to other keyboards. Namely, the Alt_L and Super_L keys are swapped, and the bar and less keys are swapped ("|" and "<"). I've written an Xmodmap file to swap the keys back: keycode 49 = less greater less greater onehalf threequarters keycode 64 = Super_L NoSymbol Super_L keycode 94 = bar section bar section brokenbar paragraph keycode 108 = Super_R NoSymbol Super_R keycode 133 = Alt_L Meta_L Alt_L Meta_L keycode 134 = Alt_R Meta_R Alt_R Meta_R I did this by identifying the keys using xev and the default modmap xmodmap -pke and swapping the keycodes. xev now identifies all my keys as correct, which is awesome! I can also use the correct keys to type the bar and less than symbols. (I followed this answer on askubuntu: How do I remap certain keys?) But it seems the change isn't very deep. For instance, the Super key is now broken in the Compiz Settings Manager. No shortcuts involving the Super key works (but the Alt key does). Also the settings dialog for Gnome Do doesn't heed the changes in xmodmap, and I can't open the Gnome Do window anymore if I use any of the remapped keys. So to summarize, everything broke. I would like a deeper way of telling Ubuntu (or any other Linux distro for that matter) which keys are which on the keyboard. Is there a way to edit the Keyboard Layout directly? I'm using the Norwegian Bokmål keyboard layout. Does it reside in a file somewhere I could edit? Any comments, previous experiences or relevant stray thoughts would be greatly appreciated - Thanks

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  • Rendering transparent textures in directX

    - by Vibhore Tanwer
    I am working with a directX application with WPF, I am facing a problem with videos and images that contains transparent pixels, I have to draw a color in background an then a video/image over it. What I expect is background color should be visible while playing video only non transparent pixels should be visible but what I get is a black background behind the video. I am using following settings on device to achieve alpha blending : device.RenderState.SourceBlend = Blend.SourceAlpha; device.RenderState.DestinationBlend = Blend.InvSourceAlpha; device.RenderState.AlphaBlendEnable = true; What am I missing here? What is the best approach to handle transparent videos? Any help will be of great value to me.

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  • Kubuntu 12.04: Change login screen background?

    - by drezabek
    I am having trouble changing my login screen background. I can select the default wall paper, the Kde-default one, but when ever I select my own custom wallpaper, there is no image, just a solid color. Normally, I would just ignore it, but the thing that bugs me is that this is a fresh install of Kubuntu 12.04 64bit, and the OS before this one, the one I overwrote, I had no trouble using the exact same image as the background... Settings In the System Settings application, Login Screen settings, Background tab, enable background, Under "Background", selected Picture, under options, selected Position: Scaled. Colors: Single Color. Blending: No Blending.

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  • How to get rid of the orange highlight in Unity?

    - by user74660
    I've installed Ubuntu 12.04 LTS and I'm using Unity. I also installed Adwaita theme and Elementary icons. Everything is cool. Highlightings are blue, as I want them to be, but there are some places where the default orange color remains: When clicking on Workspace Switcher, the borders of the current or the selected workspace are still orange. When dragging a window to the edges of the screen, the highlight effect for the Snap Window feature is still orange as well. All other highlights are blue, according to the Adwaita theme. So, how can I get rid of those two mentioned orange highlights and turn them into blue, following the Adwaita color theme? Thanks for your attention. brunces

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  • Install Ubuntu in UEFI mode (unable to boot from USB)

    - by Adele
    I recently bought a Dell Inspiron 15R SE with Windows 8 (64 bit) pre-installed (UEFI supported). I want to install Ubuntu in dual boot with Windows 8. I tried to follow all instruction here : https://help.ubuntu.com/community/UEFI And here : Installing Ubuntu on a Pre-Installed Windows 8 (64-bit) System (UEFI Supported) So, I set Secure Boot to "off" into BIOS and I disable Fast Startup as described here : http://www.eightforums.com/tutorials/6320-fast-startup-turn-off-windows-8-a.html I created a bootable USB key for Ubuntu (Ubuntu 13.10 64bits international Edition) with Unetbootin. The problem is I am unable to boot from the USB key. The computer tries to boot into infinite loop. I also tried to boot from USB with "Legacy Boot" option instead of UEFI. In this case, the computer says there are no bootable devices. Of course, I tried to boot from my USB key on an other computer having normal BIOS and it works perfectly. Have you ideas about what I need to do to be able to boot from USB ? Thanks in advance for your help, Adele

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  • Very slow direct3D texture sampling

    - by __dominic
    Hi, So I'm writing a small game using Direct3D 9 and I'm using multitexturing for the terrain. All I'm doing is sampling 3 textures and a blend map and getting the overall color from the three textures based on the color channels from the blend map. Anyway, I am getting a massive frame rate drop when I sample more than 1 texture, I'm going from 120+ fps to just under 50. This is the HLSL code responsible for the slow down: float3 ground = tex2D(GroundTex, multiTex).rgb; float3 stone = tex2D(StoneTex, multiTex).rgb; float3 grass = tex2D(GrassTex, multiTex).rgb; float3 blend = tex2D(BlendMapTex, blendMap).rgb; Am I doing it wrong ? If anyone has any info or tips about texture sampling or anything, that would be nice. Thanks.

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  • Scale DIV with tiles

    - by user15350
    I am trying to create a repeating background. I have a main DIV with a grid of small 16x16 DIVs. I am trying to scale the main DIV in CSS; when the small DIVs simply have a red background color everything works great, but when there is a background image in the small DIVs then borders become visible between the tiles. This image explains the problem: http://cl.ly/FpNW/o Check the HTML in these examples: With BG-COLOR: http://jsfiddle.net/pTLXw/ With BG-IMG: http://jsfiddle.net/vkpuY/ Does anyone know what is causing this problem and how to fix it? If it is not possible to fix while using DIV, is there another way to do this? Thanks you so much!

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  • Can I automatically add a new host to known_hosts ?

    - by gareth_bowles
    Here's my situation; I'm setting up a test harness that will, from a central client, launch a number of virtual machine instances and then execute commands on them via SSH. The virtual machines will have previously unused hostnames and IP addresses, so they won't be in the ~/.ssh/known_hosts file on the central client. The problem I'm having is that the first SSH command run against a new virtual instance always comes up with an interactive prompt: The authenticity of host '[hostname] ([IP address])' can't be established. RSA key fingerprint is [key fingerprint]. Are you sure you want to continue connecting (yes/no)? Is there a way that I can bypass this and get the new host to be already known to the client machine, maybe by using a public key that's already baked into the virtual machine image ? I'd really like to avoid having to use Expect or whatever to answer the interactive prompt if I can.

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  • Some help understanding and modifying a 2D shader

    - by electroflame
    I have a similar question as the one posed here, except that I don't wish to use a 1D Color Palette. I simply wish to have it display 1 color of my choosing (red, for example). I plan to use this as a "shield" effect for a 2D ship. I also wish to understand how it works a little bit better, as I'll be the first to admit that shaders in general are not my strongest suit. I'm not asking for an overview of HLSL (as that is too broad of a subject), just an explanation of how this shader works, and the best way to implement it in a 2D game. Code examples would be ideal (even if they are theoretical) but if the answer is explained well enough, I might be able to manage with plain old text. This is also in XNA 4.0. Thanks in advance.

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  • Uniform not being applied to proper mesh

    - by HaMMeReD
    Ok, I got some code, and you select blocks on a grid. The selection works. I can modify the blocks to be raised when selected and the correct one shows. I set a color which I use in the shader. However, I am trying to change the color before rendering the geometry, and the last rendered geometry (in the sequence) is rendered light. However, to debug logic I decided to move the block up and make it white, in which case one block moves up and another block becomes white. I checked all my logic and it knows the correct one is selected and it is showing in, in the correct place and rendering it correctly. When there is only 1 it works properly. Video Of the bug in action, note how the highlighted and elevated blocks are not the same block, however the code for color and My Renderer is here (For the items being drawn) public void render(Renderer renderer) { mGrid.render(renderer, mGameState); for (Entity e:mGameEntities) { UnitTypes ut = UnitTypes.valueOf((String)e.getObject(D.UNIT_TYPE.ordinal())); if (ut == UnitTypes.Soldier) { renderer.testShader.begin(); renderer.testShader.setUniformMatrix("u_mvpMatrix",mEntityMatrix); renderer.texture_soldier.bind(0); Vector2 pos = (Vector2) e.getObject(D.COORDS.ordinal()); mEntityMatrix.set(renderer.mCamera.combined); if (mSelectedEntities.contains(e)) { mEntityMatrix.translate(pos.x, 1f, pos.y); renderer.testShader.setUniformf("v_color", 0.5f,0.5f,0.5f,1f); } else { mEntityMatrix.translate(pos.x, 0f, pos.y); renderer.testShader.setUniformf("v_color", 1f,1f,1f,1f); } mEntityMatrix.scale(0.2f, 0.2f, 0.2f); renderer.model_soldier.render(renderer.testShader,GL20.GL_TRIANGLES); renderer.testShader.end(); } else if (ut == UnitTypes.Enemy_Infiltrator) { renderer.testShader.begin(); renderer.testShader.setUniformMatrix("u_mvpMatrix",mEntityMatrix); renderer.testShader.setUniformf("v_color", 1.0f,1,1,1.0f); renderer.texture_enemy_infiltrator.bind(0); Vector2 pos = (Vector2) e.getObject(D.COORDS.ordinal()); mEntityMatrix.set(renderer.mCamera.combined); mEntityMatrix.translate(pos.x, 0f, pos.y); mEntityMatrix.scale(0.2f, 0.2f, 0.2f); renderer.model_enemy_infiltrator.render(renderer.testShader,GL20.GL_TRIANGLES); renderer.testShader.end(); } } }

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  • Disaster Recovery Example

    Previously, I use to work for a small internet company that sells dental plans online. Our primary focus concerning disaster prevention and recovery is on our corporate website and private intranet site. We had a multiphase disaster recovery plan that includes data redundancy, load balancing, and off-site monitoring. Data redundancy is a key aspect of our disaster recovery plan. The first phase of this is to replicate our data to multiple database servers and schedule daily backups of the databases that are stored off site. The next phase is the file replication of data amongst our web servers that are also backed up daily by our collocation. In addition to the files located on the server, files are also stored locally on development machines, and again backed up using version control software. Load balancing is another key aspect of our disaster recovery plan. Load balancing offers many benefits for our system, better performance, load distribution and increased availability. With our servers behind a load balancer our system has the ability to accept multiple requests simultaneously because the load is split between multiple servers. Plus if one server is slow or experiencing a failure the traffic is diverted amongst the other servers connected to the load balancer allowing the server to get back online. The final key to our disaster recovery plan is off-site monitoring that notifies all IT staff of any outages or errors on the main website encountered by the monitor. Messages are sent by email, voicemail, and SMS. According to Disasterrecovery.org, disaster recovery planning is the way companies successfully manage crises with minimal cost and effort and maximum speed compared to others that are forced to make decision out of desperation when disasters occur. In addition Sun Guard stated in 2009 that the first step in disaster recovery planning is to analyze company risks and factor in fixed costs for things like hardware, software, staffing and utilities, as well as indirect costs, such as floor space, power protection, physical and information security, and management. Also availability requirements need to be determined per application and system as well as the strategies for recovery.

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  • SpriteBatch.Begin() making my model not render correctly

    - by manning18
    I was trying to output some debug information using DrawString when I noticed my model suddenly was being rendered like it was inside-out (like the culling had been disabled or something) and the texture maps weren't applied I commented out the DrawString method until I only had SpriteBatch.Begin() and .End() and that was enough to cause the model rendering corruption - when I commented those calls out the model rendered correctly What could this be a symptom of? I've stripped it down to the barest of code to isolate the problem and this is what I noticed. Draw code below (as stripped down as possible) GraphicsDevice.Clear(Color.LightGray); foreach (ModelMesh mesh in TIEAdvanced.Meshes) { foreach (Effect effect in mesh.Effects) { if (effect is BasicEffect) ((BasicEffect)effect).EnableDefaultLighting(); effect.CurrentTechnique.Passes[0].Apply(); } } spriteBatch.Begin(); spriteBatch.DrawString(spriteFont, "Camera Position: " + cameraPosition.ToString(), new Vector2(10, 10), Color.Blue); spriteBatch.End(); GraphicsDevice.DepthStencilState = DepthStencilState.Default; TIEAdvanced.Draw(Matrix.CreateScale(0.025f), viewMatrix, projectionMatrix);

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  • Computer suddenly won't boot - stops at a flashing prompt

    - by Dave M G
    I have been running Ubuntu on my computer for a long time, and I have been using 11.10 since it became available in October. Suddenly, this morning, when I rebooted, the computer would not reach the log in screen. I go through the standard POST boot sequence, and I also get a splash screen for my Nvidia graphics card, so at least most of the hardware seems to be working. After that, all I get is a flashing text prompt - one blinking white underline character on a screen that is otherwise completely blank. I don't think it is even reaching GRUB. No key input is possible. I have tried various key combinations to try and initiate some kind of interface, be it command line or anything else. The only key combination that works is [CTRL]+[ALT]+[Delete] to reboot. I realize this is likely to be a hardware problem, but it could be an Ubuntu problem(?), so I'm hoping for a specific set of troubleshooting steps so I can diagnose and repair this issue. My current suspicion is that one of the drives in my 2 disk software RAID has failed (even though they should be too new for that). However, this computer is critical to my work, so I'd like to invite advice on any possibilities so as to waste as little time as possible in fixing this machine.

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  • hd0 out of disk error results to low graphics mode

    - by msPeachy
    Yesterday, I have reinstalled Ubuntu due to a error: hd0 out of disk on boot. Everything went fine, I've installed apps, perform updates and upgraded the kernel. I've even restarted it a few times just to check if I would encounter boot issues and was glad that everything was working perfectly, then powered it down. The next morning when I boot, I got this error: hd0 out of disk error. Press any key to continue... again! After pressing a key, it took 10 minutes for the Ubuntu logo to appear with it's 5 dots. After another 5 minutes, Ubuntu started checking the disk and displayed a message that / has errors, I pressed F to fix the errors. After which Ubuntu tells me that /tmp is not yet ready for mounting so I pressed S to skip mounting it, then Ubuntu restarted. On boot I saw the error: hd0 out of disk error. Press any key to continue... again. This time it took only a minute for the Ubuntu logo to appear and after another minute a dialog box appeared with the following message: The system is running in low-graphics mode. Your screen, graphics card, and input settings could not be detected correctly. You will have to configure these yourself. What would you like to do? Run in low-graphics mode for just one session Reconfigure graphics Troubleshoot the error Exit to console login Whichever option I choose I ended up with a console prompt: grub-editenv: error: cannot read the file /boot/grub/grubenv. _ I can't do anything on this console, whatever I type nothing happens. I've rebooted several times and I get same error every time. I don't quite understand what is wrong with Ubuntu or with my installation. I've encountered this hd0 out of disk error several times already and always ended up reinstalling. I'd really really appreciate it if you guys can help me fix this. Thank you and good day.

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  • Collaborative Whiteboard using WebSocket in GlassFish 4 - Text/JSON and Binary/ArrayBuffer Data Transfer (TOTD #189)

    - by arungupta
    This blog has published a few blogs on using JSR 356 Reference Implementation (Tyrus) as its integrated in GlassFish 4 promoted builds. TOTD #183: Getting Started with WebSocket in GlassFish TOTD #184: Logging WebSocket Frames using Chrome Developer Tools, Net-internals and Wireshark TOTD #185: Processing Text and Binary (Blob, ArrayBuffer, ArrayBufferView) Payload in WebSocket TOTD #186: Custom Text and Binary Payloads using WebSocket One of the typical usecase for WebSocket is online collaborative games. This Tip Of The Day (TOTD) explains a sample that can be used to build such games easily. The application is a collaborative whiteboard where different shapes can be drawn in multiple colors. The shapes drawn on one browser are automatically drawn on all other peer browsers that are connected to the same endpoint. The shape, color, and coordinates of the image are transfered using a JSON structure. A browser may opt-out of sharing the figures. Alternatively any browser can send a snapshot of their existing whiteboard to all other browsers. Take a look at this video to understand how the application work and the underlying code. The complete sample code can be downloaded here. The code behind the application is also explained below. The web page (index.jsp) has a HTML5 Canvas as shown: <canvas id="myCanvas" width="150" height="150" style="border:1px solid #000000;"></canvas> And some radio buttons to choose the color and shape. By default, the shape, color, and coordinates of any figure drawn on the canvas are put in a JSON structure and sent as a message to the WebSocket endpoint. The JSON structure looks like: { "shape": "square", "color": "#FF0000", "coords": { "x": 31.59999942779541, "y": 49.91999053955078 }} The endpoint definition looks like: @WebSocketEndpoint(value = "websocket",encoders = {FigureDecoderEncoder.class},decoders = {FigureDecoderEncoder.class})public class Whiteboard { As you can see, the endpoint has decoder and encoder registered that decodes JSON to a Figure (a POJO class) and vice versa respectively. The decode method looks like: public Figure decode(String string) throws DecodeException { try { JSONObject jsonObject = new JSONObject(string); return new Figure(jsonObject); } catch (JSONException ex) { throw new DecodeException("Error parsing JSON", ex.getMessage(), ex.fillInStackTrace()); }} And the encode method looks like: public String encode(Figure figure) throws EncodeException { return figure.getJson().toString();} FigureDecoderEncoder implements both decoder and encoder functionality but thats purely for convenience. But the recommended design pattern is to keep them in separate classes. In certain cases, you may even need only one of them. On the client-side, the Canvas is initialized as: var canvas = document.getElementById("myCanvas");var context = canvas.getContext("2d");canvas.addEventListener("click", defineImage, false); The defineImage method constructs the JSON structure as shown above and sends it to the endpoint using websocket.send(). An instant snapshot of the canvas is sent using binary transfer with WebSocket. The WebSocket is initialized as: var wsUri = "ws://localhost:8080/whiteboard/websocket";var websocket = new WebSocket(wsUri);websocket.binaryType = "arraybuffer"; The important part is to set the binaryType property of WebSocket to arraybuffer. This ensures that any binary transfers using WebSocket are done using ArrayBuffer as the default type seem to be blob. The actual binary data transfer is done using the following: var image = context.getImageData(0, 0, canvas.width, canvas.height);var buffer = new ArrayBuffer(image.data.length);var bytes = new Uint8Array(buffer);for (var i=0; i<bytes.length; i++) { bytes[i] = image.data[i];}websocket.send(bytes); This comprehensive sample shows the following features of JSR 356 API: Annotation-driven endpoints Send/receive text and binary payload in WebSocket Encoders/decoders for custom text payload In addition, it also shows how images can be captured and drawn using HTML5 Canvas in a JSP. How could this be turned in to an online game ? Imagine drawing a Tic-tac-toe board on the canvas with two players playing and others watching. Then you can build access rights and controls within the application itself. Instead of sending a snapshot of the canvas on demand, a new peer joining the game could be automatically transferred the current state as well. Do you want to build this game ? I built a similar game a few years ago. Do somebody want to rewrite the game using WebSocket APIs ? :-) Many thanks to Jitu and Akshay for helping through the WebSocket internals! Here are some references for you: JSR 356: Java API for WebSocket - Specification (Early Draft) and Implementation (already integrated in GlassFish 4 promoted builds) Subsequent blogs will discuss the following topics (not necessary in that order) ... Error handling Interface-driven WebSocket endpoint Java client API Client and Server configuration Security Subprotocols Extensions Other topics from the API

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  • A Web Service to collect data from local servers every hour

    - by anilerduran
    I'm trying to find a way to collect data from different servers around the world. Here are the details: There is only one single PowerShell script on servers that encrypts data (simple csv file) and sends with preferred method (HTTP/HTTPS Post could be) There is no more control on that servers. Can't install any service, process etc. Just I can configure script to execute every hour. This script also will have encrypted username/password/license key for every server. Script will compress data and send to me with these information. So I need a service (I'm not sure if Web Service is the rigth solution) on the cloud that will help me to: Will get data that is sent from servers using a method. Will authenticate request to recognize sender using license key/username/password and most importantly, Will redirect/send this filecab to my SQL Server on the cloud (Azure). Also it should seperate data according to customer information in license key. So every data for every customer will be stored in dedicated DB/Tables on my SQL All the processes above should be completed automatically. No way for manual steps. Question: A Web Service (SOAP or Restful) is the rigth solution for that?

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  • Loading Entities Dynamically with Entity Framework

    - by Ricardo Peres
    Sometimes we may be faced with the need to load entities dynamically, that is, knowing their Type and the value(s) for the property(ies) representing the primary key. One way to achieve this is by using the following extension methods for ObjectContext (which can be obtained from a DbContext, of course): 1: public static class ObjectContextExtensions 2: { 3: public static Object Load(this ObjectContext ctx, Type type, params Object [] ids) 4: { 5: Object p = null; 6:  7: EntityType ospaceType = ctx.MetadataWorkspace.GetItems<EntityType>(DataSpace.OSpace).SingleOrDefault(x => x.FullName == type.FullName); 8:  9: List<String> idProperties = ospaceType.KeyMembers.Select(k => k.Name).ToList(); 10:  11: List<EntityKeyMember> members = new List<EntityKeyMember>(); 12:  13: EntitySetBase collection = ctx.MetadataWorkspace.GetEntityContainer(ctx.DefaultContainerName, DataSpace.CSpace).BaseEntitySets.Where(x => x.ElementType.FullName == type.FullName).Single(); 14:  15: for (Int32 i = 0; i < ids.Length; ++i) 16: { 17: members.Add(new EntityKeyMember(idProperties[i], ids[i])); 18: } 19:  20: EntityKey key = new EntityKey(String.Concat(ctx.DefaultContainerName, ".", collection.Name), members); 21:  22: if (ctx.TryGetObjectByKey(key, out p) == true) 23: { 24: return (p); 25: } 26:  27: return (p); 28: } 29:  30: public static T Load<T>(this ObjectContext ctx, params Object[] ids) 31: { 32: return ((T)Load(ctx, typeof(T), ids)); 33: } 34: } This will work with both single-property primary keys or with multiple, but you will have to supply each of the corresponding values in the appropriate order. Hope you find this useful!

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  • bash terminal/console strange overlapping behavior

    - by UpKey
    I am using gnome-terminal in Ubuntu 11.10 and seem to get long lines overlapping in the terminal window. When I copy a long command line and paste it into the terminal, the text gets overlapped to the start of the line and often covers the user prompt. If I resize the terminal window, making it wider the overlapping gets undone and everything looks normal. In previous versions of Ubuntu, if a line was too long it would continue on the next line below. Another problem I have noticed that may be related, is when using the up arrow key to show previously typed commands, sometimes instead of the output command line being replaced by the previous command each time the key is pressed, the lines get partially merged. A portion of the old line remains, and the next command gets joined onto the end. This leftover part of a command is persistent and does not get replaced next time the key is pressed, although the insertion point or blinking cursor is at the end of the latest recalled command, and the leftover has no effect if I press enter. Is this problem a bug or some setting that needs fixing? Where do I look for the cause? keyboard? gnome-terminal? bash? Thank you for any help or suggestions offered

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