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• Why are most websites optimized for viewing in portrait mode?

  - by NVM

  I simply cannot figure this out. Almost all monitors have an aspect ratio where width is much bigger than the height and yet almost all websites are designed exactly for the other way round? I am not really a web developer and am just experimenting stuff at the moment but this madness baffles me!!! Edit: The point is not that I would like to limit the height of a website. The point is that I'd wat it to somehow fill all available space when I have my 1920x1080 in landscape mode. Edit 2: See this to understand what I am saying

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• PHP developer wanting to learn python

  - by dclowd9901

  I'm pretty familiar at this point with PHP (Javascript, too), up to the point of OOP in PHP, and am looking to branch out my knowledge. I'm looking at Python next, but a lot of it is a bit alien to me as a PHP developer. I'm less concerned about learning the language itself. I'm positive there's plenty of good resources, documentation and libraries to help me get the code down. I'm less sure about the technical aspects of how to set up a dev environment, unit testing and other more mundane details that are very important, aid in rapid development, but aren't as widely covered. Are there any good resources out there for this?

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• Physics in carrom like game using cocos2d + Box2D

  - by Raj

  I am working on carrom like game using cocos2d + Box2D. I set world gravity(0,0), want gravity in z-axis. I set following values for coin and striker body: Coin body (circle with radius - 15/PTM_RATIO): density = 20.0f; friction = 0.4f; restitution = 0.6f; Striker body (circle with radius - 15/PTM_RATIO): density = 25.0f; friction = 0.6f; restitution = 0.3f; Output is not smooth. When I apply ApplyLinearImpulse(force,position) the coin movement looks like floating in the air - takes too much time to stop. What values for coin and striker make it look like real carrom?

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• Object-Oriented Operating System

  - by nmagerko

  As I thought about writing an operating system, I came across a point that I really couldn't figure out on my own: Can an operating system truly be written in an Object-Oriented Programming (OOP) Language? Being that these types of languages do not allow for direct accessing of memory, wouldn't this make it impossible for a developer to write an entire operating system using only an OOP Language? Take, for example, the Android Operating System that runs many phones and some tablets in use around the world. I believe that this operating system uses only Java, an Object-Oriented language. In Java, I have been unsuccessful in trying to point at and manipulate a specific memory address that the run-time environment (JRE) has not assigned to my program implicitly. In C, C++, and other non-OOP languages, I can do this in a few lines. So this makes me question whether or not an operating system can be written in an OOP, especially Java. Any counterexamples or other information is appreciated.

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• New channels for Exadata 11.2.3.1.1

  - by Rene Kundersma

  With the release of Exadata 11.2.3.1.0 back in April 2012 Oracle has deprecated the minimal pack for the Exadata Database Servers (compute nodes). From that release the Linux Database Server updates will be done using ULN and YUM. For the 11.2.3.1.0 release the ULN exadata_dbserver_11.2.3.1.0_x86_64_base channel was made available and Exadata operators could subscribe their system to it via linux.oracle.com. With the new 11.2.3.1.1 release two additional channels are added: a 'latest' channel (exadata_dbserver_11.2_x86_64_latest) a 'patch' channel (exadata_dbserver_11.2_x86_64_patch) The patch channel has the new or updated packages updated in 11.2.3.1.1 from the base channel. The latest channel has all the packages from 11.2.3.1.0 base and patch channels combined.  From here there are three possible situations a Database Server can be in before it can be updated to 11.2.3.1.1: Database Server is on Exadata release < 11.2.3.1.0 Database Server is patched to 11.2.3.1.0 Database Server is freshly imaged to 11.2.3.1.0 In order to bring a Database Server to 11.2.3.1.1 for all three cases the same approach for updating can be used (using YUM), but there are some minor differences: For Database Servers on a release < 11.2.3.1.0 the following high-level steps need to be performed: Subscribe to el5_x86_64_addons, ol5_x86_64_latest and  exadata_dbserver_11.2_x86_64_latest Create local repository Point Database Server to the local repository* install the update * during this process a one-time action needs to be done (details in the README) For Database Servers patched to 11.2.3.1.0: Subscribe to patch channel  exadata_dbserver_11.2_x86_64_patch Create local repository Point Database Server to the local repository Update the system For Database Servers freshly imaged to 11.2.3.1.0: Subscribe to patch channel  exadata_dbserver_11.2_x86_64_patch Create local  repository Point Database Server to the local repository Update the system The difference between 'situation 2' (Database Server is patched to 11.2.3.1.0) and 'situation 3' (Database Server is freshly imaged to 11.2.3.1.0) is that in situation 2 the existing Exadata-computenode.repo file needs to be edited while in situation 3 this file is not existing  and needs to be created or copied. Another difference is that you will end up with more OFA packages installed in situation 2. This is because none are removed during the updating process.  The YUM update functionality with the new channels is a great enhancements to the Database Server update procedure. As usual, the updates can be done in a rolling fashion so no database service downtime is required.  For detailed and up-to-date instructions always see the patch README's 1466459.1 patch 13998727 888828.1 Rene Kundersma

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• The Infinite Jukebox Creates Seamless Loops from Your Favorite Songs

  - by Jason Fitzpatrick

  Why limit yourself to simply listening to a song on repeat when The Infinite Jukebox can use algorithms to turn your song into a seamless and never ending tune? Unlike simply looping a song from the start to the end over and over, The Infinite Jukebox analyzes the song and looks for spots where it can seamlessly transition from one point in the song to a previous point to create a sense of never-ending music. Some songs worked better than others in our testing–Superstition by Stevie Wonder, for example, worked flawlessly but Gangnam Style by Psy got stuck in a short loop that sounded unnatural. Hit up the link below to play with already uploaded MP3s or upload your own to take it for a spin. The Infinite Jukebox How To Use USB Drives With the Nexus 7 and Other Android Devices Why Does 64-Bit Windows Need a Separate “Program Files (x86)” Folder? Why Your Android Phone Isn’t Getting Operating System Updates and What You Can Do About It

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• Benchmarking CPU processing power

  - by Federico Zancan

  Provided that many tools for computers benchmarking are available already, I'd like to write my own, starting with processing power measurement. I'd like to write it in C under Linux, but other language alternatives are welcome. I thought starting from floating point operations per second, but it is just a hint. I also thought it'd be correct to keep track of CPU number of cores, RAM amount and the like, to more consistently associate results with CPU architecture. How would you proceed to the task of measuring CPU computing power? And on top of that: I would worry about a properly minimum workload induced by concurrently running services; is it correct to run benchmarking as a standalone (and possibly avulsed from the OS environment) process?

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• What terminal emulators are available for heavy terminal users?

  - by Noah Goodrich

  I spend a lot of time at the command-line during the workday and at home too since I run Ubuntu exclusively. I've been using the default gnome terminal but I've reached a point where I'd really like to get my terminal tricked out so that my common tasks are as easy as possible. Specifically, I find that I spend of lot of time browsing code in the terminal and working in config files. On my wish list would be: Ability to have multiple screens, tabs, windows (I don't have a preference at this point) that I can easily switch between. Color coding for everything Easy to modify the aesthetics of the terminal (is it vain to want my terminal to look nice?) such as transparency, borders, etc.

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• links worth clicking&hellip;

  - by Chris Williams

  Scanning my Twitter feed almost always proves to be fruitful when looking for cool/interesting links to share. Here are a few of the highlights: I read this blog post from Justin Angel today, pretty interesting stuff: Windows Phone 7 – Unlocked ROMs  Looks like there’s a lot of good stuff floating just under the surface in the latest build of the WP7 Emulator. (Courtesy of @JustinAngel) Next up is this video titled Game Design Tutorials: From Seconds to Hours of Gameplay. If you’re into Indie Game Development, or just like watching videos… this one is pretty short at 5 minutes, but contains some good information about increasing the duration of fun gameplay in your game. (Courtesy of @Kei_tchan) If you are a Firefly (or Castle, or Dr. Horrible’s Singalong Blog) fan, check out this Facebook campaign to get Nathan Fillion to host SNL: http://tinyurl.com/2dh5m67  It worked for Betty White, so why not, right? (Courtesy of @DGalloway42)

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• Move website from host a to host b without down time dns change

  - by grigione

  I would like to move my website from host A to host B I have uploaded a copy of my site to the new host, while keeping the old copy in place with the old host I will need to update the nameservers to point to the new nameservers. I'll want to change the DNS settings of domain name to point to new host b To avoid down time for the DNS change to propagate through the net, can I add the old nameservers and new nameservers together without causing problems, or must I delete the old nameservers first? What happens to my website when it points to two different nameservers?

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• ArchBeat Link-o-Rama for 2012-09-19

  - by Bob Rhubart

  BPM Process Accelerator Packs – Update | Pat Shepherd Architect Pat Shepherd shares several resources relevant to the new Oracle Process Accelerators for Oracle Business Process Management. Oracle BI EE Management Pack Now Available for Oracle Enterprise Manager 12cR2 | Mark Rittman A handy and informative overview from Oracle ACE Director Mark Rittman. WebSockets on WebLogic Server | Steve Button "As there's no standard WebSocket Java API at this point, we've chosen to model the API on the Grizzly WebSocket API with some minor changes where necessary," says James "Buttso" Buttons. "Once the results of JSR-356 (Java API for WebSocket) becomes public, we'll look to implement and support that." Oracle Reference Architecture: Software Engineering This document from the IT Strategies from Oracle library focuses on integrated asset management and the need for efffective asset metadata management to insure that assets are properly tracked and reused in a manner that provides a holistic functional view of the enterprise. The tipping point for cloud management is nigh | Cloud Computing - InfoWorld "Businesses typically don't think too much about managing IT resources until they become too numerous and cumbersome to deal with on an ad hoc basis—a point many companies will soon hit in their adoption of cloud computing." — David Linthicum DevOps Basics: Track Down High CPU Thread with ps, top and the new JDK7 jcmd Tool | Frank Munz "The approach is very generic and works for WebLogic, Glassfish or any other Java application," say Frank Munz. "UNIX commands in the example are run on CentOS, so they will work without changes for Oracle Enterprise Linux or RedHat. Creating the thread dump at the end of the video is done with the jcmd tool from JDK7." Frank has captured the process in the posted video. OIM 11g R2 UI customization | Daniel Gralewski "OIM user interface customizations are easier now, and they survive patch applications--there is no need to reapply them after patching," says Fusion Middleware A-Team member Daniel Gralewski. "Adding new artifacts, new skins, and plugging code directly into the user interface components became an easier task." Daniel shows just how easy in this post. Thought for the Day "I have yet to see any problem, however complicated, which, when looked at in the right way, did not become still more complicated." — Poul Anderson (November 25, 1926 – July 31, 2001) Source: SoftwareQuotes.com

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• Minimum brightness level is brighter than the levels just above it

  - by greggory.hz

  I'm using a macbook pro 8,1. When I use the brightness keys on the keyboard, decreasing the brightness works until it reaches the lowest brightness level. At that point (when on the lowest level), the brightness is something like 70 or 80% instead of 0-10% (or whatever it usually is). All the other levels are fine. How can I adjust/calibrate these brightness controls? PS: I'm currently using 12.04 but I've had the same issue no later than 11.10 (and I'm fairly confident it was present in 11.04 as well). UPDATE: If I go to System Settings and select "Brightness and Lock" the exact same thing happens, but there is more fine grained control of the brightness. It goes to completely black when the dial is about 10% from the left edge. When it passes that point, anywhere inside that left 10% appears to be about 70 - 80% brightness (there's no change regardless of where the dial is in this section).

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• Absorbtion 2d image effect

  - by Ed.

  I want to create a specyfic 2d image effect. It consists in modifying a sprite so it looks like it is being zoomed to a point or "absorbed" by that point. I'm not really sure what is the technical name of this effect so I cannot explain it correctly. Here you can see a video of what I'm talking about, it is the effect when the character absorbs the three glyphs. http://www.youtube.com/watch?v=PIo-GddsMcU&t=4m45s What is the name of this effect? How can I implement it with XNA for 2D textures/sprites?

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• Ubuntu server 13 hangs on boot

  - by Slava Fomin II

  I formatted my WD30EFRX 3TB SATA HDD as GPT with the following layout: 200 MB FAT32 (BOOTABLE) 50GB EXT4 (Mount point: /) 4 GB SWAP SPACE ~2.9 TB EXT4 (with no mount point) Then i created a Flash USB using Rufus 1.3.3 and the following ISO-image: ubuntu-13.04-server-amd64.iso. I used following configuration to create the USB: GPT partition scheme for UEFI computer FAT32 (16KB) I successfully booted from this USB on my Intel D510MO motherboard in UEFI mode (there were a black and white boot loader menu instead of a colorful GUI) and installed the OS. During the boot loader installation i saw it was grub-efi-amd64 as it must be. After installation i removed the flash drive and tried to boot the system, but just after a BIOS POST it hangs (there is a white blinking cursor at the left top corner of the black screen) and nothing happens. UEFI Mode is enabled in the BIOS configuration and i've updated the BIOS to the latest firmware. What went wrong, how i can confirm that system was installed properly? How can i boot the OS?

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• How to tackle a boss who thinks everybody in this world is wrong except him?

  - by anon

  I mean seriously, how do you tackle a guy who even changes our variable names (even though they are reasonable) and sends back the code (after review) like 4 times? I know for sure I'm not that bad a developer! So many times, he enforces his ideals, which are not even best practices in the industry! I point out to him whatever link I can find on the internet trying to prove my point, but in the end he uses his authority to shut us out. Sick and tired. Frustrated. Do I have any way out other than quitting the job?

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• XNA RTS A* pathfinding issues

  - by Slayter

  I'm starting to develop an RTS game using the XNA framework in C# and am still in the very early prototyping stage. I'm working on the basics. I've got unit selection down and am currently working on moving multiple units. I've implemented an A* pathfinding algorithm which works fine for moving a single unit. However when moving multiple units they stack on top of each other. I tried fixing this with a variation of the boids flocking algorithm but this has caused units to sometimes freeze and get stuck trying to move but going no where. Ill post the related methods for moving the units below but ill only post a link to the pathfinding class because its really long and i don't want to clutter up the page. These parts of the code are in the update method for the main controlling class: if (selectedUnits.Count > 0) { int indexOfLeader = 0; for (int i = 0; i < selectedUnits.Count; i++) { if (i == 0) { indexOfLeader = 0; } else { if (Vector2.Distance(selectedUnits[i].position, destination) < Vector2.Distance(selectedUnits[indexOfLeader].position, destination)) indexOfLeader = i; } selectedUnits[i].leader = false; } selectedUnits[indexOfLeader].leader = true; foreach (Unit unit in selectedUnits) unit.FindPath(destination); } foreach (Unit unit in units) { unit.Update(gameTime, selectedUnits); } These three methods control movement in the Unit class: public void FindPath(Vector2 destination) { if (path != null) path.Clear(); Point startPoint = new Point((int)position.X / 32, (int)position.Y / 32); Point endPoint = new Point((int)destination.X / 32, (int)destination.Y / 32); path = pathfinder.FindPath(startPoint, endPoint); pointCounter = 0; if (path != null) nextPoint = path[pointCounter]; dX = 0.0f; dY = 0.0f; stop = false; } private void Move(List<Unit> units) { if (nextPoint == position && !stop) { pointCounter++; if (pointCounter <= path.Count - 1) { nextPoint = path[pointCounter]; if (nextPoint == position) stop = true; } else if (pointCounter >= path.Count) { path.Clear(); pointCounter = 0; stop = true; } } else { if (!stop) { map.occupiedPoints.Remove(this); Flock(units); // Move in X ********* TOOK OUT SPEED ********** if ((int)nextPoint.X > (int)position.X) { position.X += dX; } else if ((int)nextPoint.X < (int)position.X) { position.X -= dX; } // Move in Y if ((int)nextPoint.Y > (int)position.Y) { position.Y += dY; } else if ((int)nextPoint.Y < (int)position.Y) { position.Y -= dY; } if (position == nextPoint && pointCounter >= path.Count - 1) stop = true; map.occupiedPoints.Add(this, position); } if (stop) { path.Clear(); pointCounter = 0; } } } private void Flock(List<Unit> units) { float distanceToNextPoint = Vector2.Distance(position, nextPoint); foreach (Unit unit in units) { float distance = Vector2.Distance(position, unit.position); if (unit != this) { if (distance < space && !leader && (nextPoint != position)) { // create space dX += (position.X - unit.position.X) * 0.1f; dY += (position.Y - unit.position.Y) * 0.1f; if (dX > .05f) nextPoint.X = nextPoint.X - dX; else if (dX < -.05f) nextPoint.X = nextPoint.X + dX; if (dY > .05f) nextPoint.Y = nextPoint.Y - dY; else if (dY < -.05f) nextPoint.Y = nextPoint.Y + dY; if ((dX < .05f && dX > -.05f) && (dY < .05f && dY > -.05f)) stop = true; path[pointCounter] = nextPoint; Console.WriteLine("Make Space: " + dX + ", " + dY); } else if (nextPoint != position && !stop) { dX = speed; dY = speed; Console.WriteLine(dX + ", " + dY); } } } } And here's the link to the pathfinder: https://docs.google.com/open?id=0B_Cqt6txUDkddU40QXBMeTR1djA I hope this post wasn't too long. Also please excuse the messiness of the code. As I said before this is early prototyping. Any help would be appreciated. Thanks!

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• Samsung Series 5 overheating

  - by Sean Brad

  I bought a Samsung Series 5 Ultra 2 weeks ago and installed Ubuntu 12.04 LTS. I am experiencing problems with overheating. When streaming, watching a movie or when having several programms/actions going on at the same time the CPU temperature rises to 95 degrees and the computer freezes. This happens sometimes when the computer is on battery and always when it is recharging. When I am using the computer on battery the CPU temperature is floating from around 75-95 degrees depending what it's doing. When the battery is recharging the CPU temperature is ranging from 88-95 degrees no matter what tasks it performs. Have anyone experienced this and how may the problem be solved? Best regards

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• Coordinate based travel through multi-line path over elapsed time

  - by Chris

  I have implemented A* Path finding to decide the course of a sprite through multiple waypoints. I have done this for point A to point B locations but am having trouble with multiple waypoints, because on slower devices when the FPS slows and the sprite travels PAST a waypoint I am lost as to the math to switch directions at the proper place. EDIT: To clarify my path finding code is separate in a game thread, this onUpdate method lives in a sprite like class which happens in the UI thread for sprite updating. To be even more clear the path is only updated when objects block the map, at any given point the current path could change but that should not affect the design of the algorithm if I am not mistaken. I do believe all components involved are well designed and accurate, aside from this piece :- ) Here is the scenario: public void onUpdate(float pSecondsElapsed) { // this could be 4x speed, so on slow devices the travel moved between // frames could be very large. What happens with my original algorithm // is it will start actually doing circles around the next waypoint.. pSecondsElapsed *= SomeSpeedModificationValue; final int spriteCurrentX = this.getX(); final int spriteCurrentY = this.getY(); // getCoords contains a large array of the coordinates to each waypoint. // A waypoint is a destination on the map, defined by tile column/row. The // path finder converts these waypoints to X,Y coords. // // I.E: // Given a set of waypoints of 0,0 to 12,23 to 23, 0 on a 23x23 tile map, each tile // being 32x32 pixels. This would translate in the path finder to this: // -> 0,0 to 12,23 // Coord : x=16 y=16 // Coord : x=16 y=48 // Coord : x=16 y=80 // ... // Coord : x=336 y=688 // Coord : x=336 y=720 // Coord : x=368 y=720 // // -> 12,23 to 23,0 -NOTE This direction change gives me trouble specifically // Coord : x=400 y=752 // Coord : x=400 y=720 // Coord : x=400 y=688 // ... // Coord : x=688 y=16 // Coord : x=688 y=0 // Coord : x=720 y=0 // // The current update index, the index specifies the coordinate that you see above // I.E. final int[] coords = getCoords( 2 ); -> x=16 y=80 final int[] coords = getCoords( ... ); // now I have the coords, how do I detect where to set the position? The tricky part // for me is when a direction changes, how do I calculate based on the elapsed time // how far to go up the new direction... I just can't wrap my head around this. this.setPosition(newX, newY); }

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• Unit testing - getting started

  - by higgenkreuz

  I am just getting started with unit testing but I am not sure if I really understand the point of it all. I read tutorials and books on it all, but I just have two quick questions: I thought the purpose of unit testing is to test code we actually wrote. However, to me it seems that in order to just be able to run the test, we have to alter the original code, at which point we are not really testing the code we wrote but rather the code we wrote for testing. Most of our codes rely on external sources. Upon refactoring our code however, even it would break the original code, our tests still would run just fine, since the external sources are just muck-ups inside our test cases. Doesn't it defeat the purpose of unit testing? Sorry if I sound dumb here, but I thought someone could enlighten me a bit. Thanks in advance.

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• Why don't Normal maps in tangent space have a single blue color?

  - by seahorse

  Normal maps are predominantly blue in color because the z component maps to Blue and since normals point out of the surface in the z direction we see Blue as the predominant component. If the above is true then why are normal maps just of one color i.e. blue and they should not be having any other shades(not even shades of blue) Since by definition tangent space is perpendicular to normal at any point we should have the normal always pointing in the Z (Blue direction) with no X(Red component) and Y(Green component). Thus the normal map(since it is a "normal map") should have had color of normals which is just the Blue(Z =Blue compoennt = 1, R=0, G=0) and the normal map should have been of only Blue color with no shades in between. But even then normal maps are not so, and they have gradients of shades in them, why is this so?

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• Isometric Screen View to World View

  - by Sleepy Rhino

  I am having trouble working out the math to transform the screen coordinates to the Grid coordinates. The code below is how far I have got but it is totally wrong any help or resources to fix this issue would be great, had a complete mind block with this for some reason. private Point ScreenToIso(int mouseX, int mouseY) { int offsetX = WorldBuilder.STARTX; int offsetY = WorldBuilder.STARTY; Vector2 startV = new Vector2(offsetX, offsetY); int mapX = offsetX - mouseX; int mapY = offsetY - mouseY + (WorldBuilder.tileHeight / 2); mapY = -1 * (mapY / WorldBuilder.tileHeight); mapX = (mapX / WorldBuilder.tileHeight) + mapY; return new Point(mapX, mapY); }

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• Oracle Standard Installation (OSI) Services – Service für Hardware-Upgrades

  - by swalker

  In diesem Update erfahren Sie alles über die Services der Oracle Standard Installation (OSI) von Oracle Advanced Customer Support (ACS). Oracle imformiert Sie außerdem über die Einführung weiterer OSI-Teile für die Bestellung von Komplettservices zur Installation von Upgrades bei bereits installierten Systemen. Darunter fallen auch zusätzliche Upgrades für Serverprozessoren (CPUs), Arbeitsspeicher, Netzwerkkarten, Speicher-Appliances und Bandbibliotheken. Die OSI Installationsservices für Hardware-Upgrades können wie folgt bestellt werden: beim Hardware Point of Sale (POS) – über den Offline-Prozess für Hardware im Oracle PartnerNetwork (OPN) unabhängige Bestellungen „After Point of Sale (APOS)“ – über den Offline-OSI-Prozess des ACS Services Order Desk. Diese Prozesse sowie die aktualisierten Dateien für die OSI-Teilezuordnung finden Sie auf der Website des Oracle Partner Stores (OPS). Die OSI-Teile für Hardware-Upgrades können im OPS ab Ende 2011 bestellt werden. Wenn Sie Fragen zu diesem Update haben, wenden Sie sich an das Global Partner Support Team unter [email protected].

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• OpenGraph tags and HTML5 validity

  - by netmano

  I have a HTML5 based page, and I inculded the OpenGraph tags according to it's documentation. Also I checked with Facebook Debug, and it can parse the metadata. But when I use W3C Validator, it reports the OG tags as error: Attribute content not allowed on element meta at this point. <meta property="fb:admins" content="...." /> Attribute content not allowed on element meta at this point. <meta property="og:url" content="http://www...."> They are all in the <head>. I would need my page be "valid" HTML5 and OG tags, as well. Could you help me giving a hint how can it be achieved? UPDATE: The name version also invalid: <meta name='fb:admins' content=''>

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• Session Report - Java on the Raspberry Pi

  - by Janice J. Heiss

  On mid-day Wednesday, the always colorful Oracle Evangelist Simon Ritter demonstrated Java on the Raspberry Pi at his session, “Do You Like Coffee with Your Dessert?”. The Raspberry Pi consists of a credit card-sized single-board computer developed in the UK with the intention of stimulating the teaching of basic computer science in schools. “I don't think there is a single feature that makes the Raspberry Pi significant,” observed Ritter, “but a combination of things really makes it stand out. First, it's $35 for what is effectively a completely usable computer. You do have to add a power supply, SD card for storage and maybe a screen, keyboard and mouse, but this is still way cheaper than a typical PC. The choice of an ARM (Advanced RISC Machine and Acorn RISC Machine) processor is noteworthy, because it avoids problems like cooling (no heat sink or fan) and can use a USB power brick. When you add in the enormous community support, it offers a great platform for teaching everyone about computing.”Some 200 enthusiastic attendees were present at the session which had the feel of Simon Ritter sharing a fun toy with friends. The main point of the session was to show what Oracle was doing to support Java on the Raspberry Pi in a way that is entertaining and fun. Ritter pointed out that, in addition to being great for teaching, it’s an excellent introduction to the ARM architecture, and runs well with Java and will get better once it has official hard float support. The possibilities are vast.Ritter explained that the Raspberry Pi Project started in 2006 with the goal of devising a computer to inspire children; it drew inspiration from the BBC Micro literacy project of 1981 that produced a series of microcomputers created by the Acorn Computer company. It was officially launched on February 29, 2012, with a first production of 10,000 boards. There were 100,000 pre-orders in one day; currently about 4,000 boards are produced a day. Ritter described the specification as follows:* CPU: ARM 11 core running at 700MHz Broadcom SoC package Can now be overclocked to 1GHz (without breaking the warranty!) * Memory: 256Mb* I/O: HDMI and composite video 2 x USB ports (Model B only) Ethernet (Model B only) Header pins for GPIO, UART, SPI and I2C He took attendees through a brief history of ARM Architecture:* Acorn BBC Micro (6502 based) Not powerful enough for Acorn’s plans for a business computer * Berkeley RISC Project UNIX kernel only used 30% of instruction set of Motorola 68000 More registers, less instructions (Register windows) One chip architecture to come from this was… SPARC * Acorn RISC Machine (ARM) 32-bit data, 26-bit address space, 27 registers First machine was Acorn Archimedes * Spin off from Acorn, Advanced RISC MachinesNext he presented its features:* 32-bit RISC Architecture–  ARM accounts for 75% of embedded 32-bit CPUs today– 6.1 Billion chips sold last year (zero manufactured by ARM)* Abstract architecture and microprocessor core designs– Raspberry Pi is ARM11 using ARMv6 instruction set* Low power consumption– Good for mobile devices– Raspberry Pi can be powered from 700mA 5V only PSU– Raspberry Pi does not require heatsink or fanHe described the current ARM Technology:* ARMv6– ARM 11, ARM Cortex-M* ARMv7– ARM Cortex-A, ARM Cortex-M, ARM Cortex-R* ARMv8 (Announced)– Will support 64-bit data and addressingHe next gave the Java Specifics for ARM: Floating point operations* Despite being an ARMv6 processor it does include an FPU– FPU only became standard as of ARMv7* FPU (Hard Float, or HF) is much faster than a software library* Linux distros and Oracle JVM for ARM assume no HF on ARMv6– Need special build of both– Raspbian distro build now available– Oracle JVM is in the works, release date TBDNot So RISCPerformance Improvements* DSP Enhancements* Jazelle* Thumb / Thumb2 / ThumbEE* Floating Point (VFP)* NEON* Security Enhancements (TrustZone)He spent a few minutes going over the challenges of using Java on the Raspberry Pi and covered:* Sound* Vision * Serial (TTL UART)* USB* GPIOTo implement sound with Java he pointed out:* Sound drivers are now included in new distros* Java Sound API– Remember to add audio to user’s groups– Some bits work, others not so much* Playing (the right format) WAV file works* Using MIDI hangs trying to open a synthesizer* FreeTTS text-to-speech– Should work once sound works properlyHe turned to JavaFX on the Raspberry Pi:* Currently internal builds only– Will be released as technology preview soon* Work involves optimal implementation of Prism graphics engine– X11?* Once the JavaFX implementation is completed there will be little of concern to developers-- It’s just Java (WORA). He explained the basis of the Serial Port:* UART provides TTL level signals (3.3V)* RS-232 uses 12V signals* Use MAX3232 chip to convert* Use this for access to serial consoleHe summarized his key points. The Raspberry Pi is a very cool (and cheap) computer that is great for teaching, a great introduction to ARM that works very well with Java and will work better in the future. The opportunities are limitless. For further info, check out, Raspberry Pi User Guide by Eben Upton and Gareth Halfacree. From there, Ritter tried out several fun demos, some of which worked better than others, but all of which were greeted with considerable enthusiasm and support and good humor (even when he ran into some glitches).  All in all, this was a fun and lively session.

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• Moving in a diamond - enemy gets stuck

  - by Fibericon

  I have an enemy that I would like to move as follows: Start at (0, 200, 0) Move to (200, 0, 0) Move to (0, -200, 0) Move to (-200, 0, 0) Move to start point, repeat as long as it remains active. This is what I've done to achieve that: if (position.X < 200 && position.Y > 0) { Velocity = new Vector3(1, -1, 0) * speed; } else if (position.X >= 200 && position.Y <= 0 && position.Y > -200) { Velocity = new Vector3(-1, -1, 0) * speed; } else if (position.X <= 0 && position.Y <= -200) { Velocity = new Vector3(-1, 1, 0) * speed; } else { Velocity = new Vector3(1, 1, 0) * speed; } It moves to the second point, but then gets stuck and appears to vibrate in place. How should I be doing this?

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