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• Pixels - A cry for some insight

  - by CarrotFile

  I'm pretty new to web developing and I'd love some clarification. Although reading more than one book on the topic, I cannot seem to wrap my head around the pixel concept. I encounter problems with this issue when trying to use CSS and pixel units for design that fits different screen sizes. To my understanding a pixel is the most basic unit used by a monitor in order to compose an image on the screen. So if me resolution is 800 by 600, everything on my screen is rendered using those 800*600 basic building blocks. If I were to enlarge my screen resolution, 3 things would accrue: A. The basic image building block(the pixel) would shrink in size B. The pixels would move close together C. Well, more pixels would now be available All these combined lead to a sharper(depending on the viewing distance) and more detail enabling image. Well so far so good. Here is were I start getting lost: To my knowledge a pixel is not a physical, real object. Monitors are not embedded with a few thousand pixels. I am drawn to this conclusion because anyone can change his screen's resolution, making a pixel on his screen bigger or smaller, and adding or subtracting the amount of total pixels on screen. Adding to that, I have herd that different monitors have different pixel densities. For example Apple's retina monitors. Taking all of the above as my knowledge base, These are my questions: If a pixel has no real world constant size, what does comparing different pixel densities matter? Each screen company can define it's own pixel concept and declare the higher density. What does a bigger pixel density mean? Say we take two screens with the same physical dimensions, but with a different pixel density, am I to assert that the main difference would be the larger density screen being able to display a higher max resolution? Or am I to assert that given the same resolution on both monitors, the higher density one would display a sharper, smaller image? If a pixel is not a fixed size within one monitor, is it a fixed size between the same resolution on two different monitors? For example, would two different monitors, set to the same resolution, be comprised of same size, same quantity pixels? I'd love some help (:

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• HTML5 game programming style

  - by fnx

  I am currently trying learn javascript in form of HTML5 games. Stuff that I've done so far isn't too fancy since I'm still a beginner. My biggest concern so far has been that I don't really know what is the best way to code since I don't know the pros and cons of different methods, nor I've found any good explanations about them. So far I've been using the worst (and propably easiest) method of all (I think) since I'm just starting out, for example like this: var canvas = document.getElementById("canvas"); var ctx = canvas.getContext("2d"); var width = 640; var height = 480; var player = new Player("pic.png", 100, 100, ...); also some other global vars... function Player(imgSrc, x, y, ...) { this.sprite = new Image(); this.sprite.src = imgSrc; this.x = x; this.y = y; ... } Player.prototype.update = function() { // blah blah... } Player.prototype.draw = function() { // yada yada... } function GameLoop() { player.update(); player.draw(); setTimeout(GameLoop, 1000/60); } However, I've seen a few examples on the internet that look interesting, but I don't know how to properly code in these styles, nor do I know if there are names for them. These might not be the best examples but hopefully you'll get the point: 1: Game = { variables: { width: 640, height: 480, stuff: value }, init: function(args) { // some stuff here }, update: function(args) { // some stuff here }, draw: function(args) { // some stuff here }, }; // from http://codeincomplete.com/posts/2011/5/14/javascript_pong/ 2: function Game() { this.Initialize = function () { } this.LoadContent = function () { this.GameLoop = setInterval(this.RunGameLoop, this.DrawInterval); } this.RunGameLoop = function (game) { this.Update(); this.Draw(); } this.Update = function () { // update } this.Draw = function () { // draw game frame } } // from http://www.felinesoft.com/blog/index.php/2010/09/accelerated-game-programming-with-html5-and-canvas/ 3: var engine = {}; engine.canvas = document.getElementById('canvas'); engine.ctx = engine.canvas.getContext('2d'); engine.map = {}; engine.map.draw = function() { // draw map } engine.player = {}; engine.player.draw = function() { // draw player } // from http://that-guy.net/articles/ So I guess my questions are: Which is most CPU efficient, is there any difference between these styles at runtime? Which one allows for easy expandability? Which one is the most safe, or at least harder to hack? Are there any good websites where stuff like this is explained? or... Does it all come to just personal preferance? :)

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• Applying DDD principles in a RESTish web service

  - by Andy

  I am developing an RESTish web service. I think I got the idea of the difference between aggregation and composition. Aggregation does not enforce lifecycle/scope on the objects it references. Composition does enforce lifecycle/scope on the objects it contain/own. If I delete a composite object then all the objects it contain/own are deleted as well, while the deleting an aggregate root does not delete referenced objects. 1) If it is true that deleting aggregate roots does not necessary delete referenced objects, what sense does it make to not have a repository for the references objects? Or are aggregate roots as a term referring to what is known as composite object? 2) When you create an web service you will have multiple endpoints, in my case I have one entity Book and another named Comment. It does not make sense to leave the comments in my application if the book is deleted. Therefore, book is a composite object. I guess I should not have a repository for comments since that would break the enforcement of lifecycle and rules that the book class may have. However I have URL such as (examples only): GET /books/1/comments POST /books/1/comments Now, if I do not have a repository for comments, does that mean I have to load the book object and then return the referenced comments? Am I allowed to return a list of Comment entities from the BookRepository, does that make sense? The repository for Book may eventually become rather big with all sorts of methods. Am I allowed to write JPQL (JPA queries) that targets comments and not books inside the repository? What about pagination and filtering of comments. When adding a new comment triggered by the POST endpoint, do you need to load the book, add the comment to the book, and then update the whole book object? What I am currently doing is having a own CommentRepository, even though the comments are deleted with the book. I could need some direction on how to do it correct. Since you are exposing not only root objects in RESTish services I wonder how to handle this at the backend. I am using Hibernate and Spring.

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• Enterprise with eyes on NoSQL

  - by thegreeneman

  Since joining Oracle a few months back, I have had the fortune of being able to interact with a number of large enterprise organizations and discuss their current state of adoption for NoSQL database technology.   It is worth noting that a large percentage of these organizations do have some NoSQL use and have been steadily increasing their understanding of its applicability for certain data management workloads.   Thru those discussions I’ve learned that it seems one of the biggest issues confronting enterprise adoption of NoSQL databases is the lack of standards for access, administration and monitoring.    This was not so much of an issue with the early adopters of NoSQL technology because they employed a highly DevOps centric approach to application deployment leaving a select few highly qualified developers with the task of managing the production of the system that they designed and implemented. However, as NoSQL technology moves out of the startup and into the hands of larger corporate entities, developers with a broad skill set that are capable of both development and I.T. type production management are in short supply and quickly get moved on to do new projects, often moving to different roles within the company.  This difference in the way smaller more agile startups operate as compared to more established companies is revealing a gap in the NoSQL technology segment that needs to get addressed.    This is one of places that a company such as Oracle has a leg up in the NoSQL Database front.  A combination of having gone thru a past database maturization process,  combined with a vast set of corporate relationships that have grown hand in hand to solve these types of issues, Oracle is in a great place to lead the way in closing the requirements gap for NoSQL technology.  Oracle's understanding of the needs specific to mature organizations have already made their way into the Oracle’s NoSQL Database offering with features such as:  One click cluster deployment with visual topology planning,  standards based monitoring protocols such as SNMP, support for data access for reporting via standard SQL  and integration with emerging standards for data access such as MapReduce.  Given the exciting developments we’re driving in the Oracle NoSQL Database group, I will have a lot more to say about this topic as we move into the second half of the year.

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• Nails vs Screws (C# List vs Dictionary)

  - by MarkPearl

  General This may sound like a typical noob statement, but I’m finding out in a very real way that just because you have a solution to a problem, doesn’t necessarily mean it is the best solution. This was reiterated to me when a friend of mine suggested I look at using Dictionaries instead of Lists for a particular problem – he was right, I have always just assumed that because lists solved my problem I did not need to look elsewhere. So my new manifesto to counter this ageless problem is as follows… Look for a solution that will logically work Once you have a solution look for possible alternatives Decide why your current solution is the best approach compared to the alternatives If it is.. use it till something better comes along, if it isnt…. change What’s the difference between Lists & Dictionaries Both lists and dictionaries are used to store collections of data. Assume we had the following declarations… var dic = new Dictionary<string, long>(); var lst = new List<long>(); long data;   With a list, you simply add the item to the list and it will add the item to the end of the list. lst.Add(data); With a dictionary, you need to specify some sort of key and the data you want to add so that it can be uniquely identified. dic.Add(uniquekey, data);   Because with a dictionary you now have unique identifier, in the background they provide all sort’s of optimized algorithms to find your associated data. What this means is that if you are wanting to access your data it is a lot faster than a List. So when is it appropriate to use either class? For me, if I can guarantee that each item in my collection will have a unique identifier, then I will use Dictionaries instead of Lists as there is a considerable performance benefit when accessing each data item. If I cannot make this sort of guarantee, then by default I will use a list. I know this is all really basic, and I hope I haven’t missed some fundamental principle… If anyone would like to add their 2 cents, please feel free to do so…

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• PASS: FY10 Actuals Posted

  - by Bill Graziano

  Earlier this year we published preliminary fiscal year 2010 financials to the Governance page on the PASS web site.  Please remember that FY10 runs from July 1st, 2009 through June 30th, 2010 and includes the November 2009 Summit.  We do our fiscal year this way so that the Summit falls earlier in the fiscal year.  The financials we had posted were P&L numbers at the portfolio level.  Prior to this we had posted our detailed budget but only posted the auditors report at the end of each year.  Today we updated our published financials to include: Pre-audit actuals from FY10 at the same level as our budget.  The document has both actuals and budget for FY10 side by side.  This is over 20 pages of detailed financial information covering hundreds of line-items. A letter describing key differences between our budget and actuals.  I walked through each line item where the difference was greater than $25,000 and explained what happened and why. We updated the financial graph going back to 2003 to include FY10. This update should “close the loop” on our financials.  You can now start with the published budget and compare it to the finished financials at the same level of detail.  We also plan to publish the auditor’s report when that is completed -- as we do every year. Overall I’m very happy with how FY10 turned out.  Keep in mind that this was the November 2009 Summit so we were still facing economic challenges.  With all that we were roughly break-even showing a $15,000 profit on $3.9 million of revenue.  I didn’t find anything shocking in reviewing our actual vs. budget but there were a few things that needed explanation.  You can see those in the letter on the governance page. Please keep in mind that these are the actuals from our operating financials.  The auditor may have us make adjustments for depreciation or other financial transactions.  We may also account for certain transactions differently for tax purposes than we do for financial reporting purposes.  I feel these financial statements give you the clearest picture of how our organization spends its money. We were late publishing these this year.  We were working through some tax issues and that delayed our ability to file our final tax forms which delayed this process.  In hindsight I should have published these documents as soon as we had them and not waited for the tax issues.  We’ll do this better in the future. And on a final note, you don’t need to login to view these documents.  If you have any questions you can post them here.  If we get more than a few questions we may see about creating some forums for financial issues on the PASS web site.

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• POST and PUT requests – is it just the convention?

  - by bckpwrld

  I've read quite a few articles on the difference between POST and PUT and in when the two should be used. But there are still few things confusing me ( hopefully questions will make some sense ): 1) We should use PUT to create resources when we want clients to specify the URI of the newly created resources and we should use POST to create resources when we let service generate the URI of the newly created resources. a) Is it just by convention that POST create request doesn't contain an URI of the newly created resource or POST create request actually can't contain the URI of the newly created resource? b) PUT has idempotent semantics and thus can be safely used for absolute updates ( ie we send entire state of the resource to the server ), but not also for relative updates ( ie we send just changes to the resource state ), since that would violate its semantics. But I assume it's still possible for PUT to send relative updates to the server, it's just that in that case the PUT update won't be idempotent? 2) I've read somewhere that we should "use POST to append a resource to a collection identified by a service-generated URI". a) What exactly does that mean? That if URIs for the resources were generated by a server ( thus the resources were created via POST ), then ALL subsequent resources should also be created via POST? Thus, in such situation no resource should be created via PUT? b) If my assumption under a) is correct, could you elaborate why we shouldn't create some resources via POST and some via PUT ( assuming server already contains a collection of resources created via POST )? REPLY: 1) Please correct me if I'm wrong, but from your post and from the link you've posted, it seems: a) The Request-URI in POST is interpreted by server as the URI of the service. Thus, it could just as easily be interpreted as an URI of a newly created resource, if server code was written to recognize Request-URI as such b) Similarly, PUT is able to send relative updates, it's just that service code is usually written such that it will complain if PUT updates are relative. 2) Usually, create has fallen into the POST camp, because of the idea of "appending to a collection." It's become the way to append a resource to a list of resources. I don't quite understand the reasoning behind the idea of "appending to a collection" and why this idea prefers POST for create. Namely, if we create 10 resources via PUT, then server will contain a collection of 10 resources and if we then create another resource, then server will append this resource to that collection ( which will now contain 11 resources )?! Uh, this is kinda confusing thank you

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• How do you conquer the challenge of designing for large screen real-estate?

  - by Berin Loritsch

  This question is a bit more subjective, but I'm hoping to get some new perspective. I'm so used to designing for a certain screen size (typically 1024x768) that I find that size to not be a problem. Expanding the size to 1280x1024 doesn't buy you enough screen real estate to make an appreciable difference, but will give me a little more breathing room. Basically, I just expand my "grid size" and the same basic design for the slightly smaller screen still works. However, in the last couple of projects my clients were all using 1080p (1920x1080) screens and they wanted solutions to use as much of that real estate as possible. 1920 pixels across provides just under twice the width I am used to, and the wide screen makes some of my old go to design approaches not to work as well. The problem I'm running into is that when presented with so much space, I'm confronted with some major problems. How many columns should I use? The wide format lends itself to a 3 column split with a 2:1:1 split (i.e. the content column bigger than the other two). However, if I go with three columns what do I do with that extra column? How do I make efficient use of the screen real estate? There's a temptation to put everything on the screen at once, but too much information actually makes the application harder to use. White space is important to help make sense of complex information, but too much makes related concepts look too separate. I'm usually working with web applications that have complex data, and visualization and presentation is key to making sense of the raw data. When your user also has a large screen (at least 24"), some information is out of eye sight and you need to move the pointer a long distance. How do you make sure everything that's needed stays within the visual hot points? Simple sites like blogs actually do better when the width is constrained, which results in a lot of wasted real estate. I kind of wonder if having the text box and the text preview side by side would be a big benefit for the admin side of that type of screen? (1:1 two column split). For your answers, I know almost everything in design is "it depends". What I'm looking for is: General principles you use How your approach to design has changed I'm finding that i have to retrain myself how to work with this different format. Every bump in resolution I've worked through to date has been about 25%: 640 to 800 (25% increase), 800 to 1024 (28% increase), and 1024 to 1280 (25% increase). However, the jump from 1280 to 1920 is a good 50% increase in space--the equivalent from jumping from 640 straight to 1024. There was no commonly used middle size to help learn lessons more gradually.

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• How is a switch statement better than a series of if statements? [closed]

  - by user1276078

  Possible Duplicate: Should I use switch statements or long if…else chains? I'm working on a small program that will conduct an Insertion Sort. A number will be inputted through the keyboard and stored in a variable I called "num." I've decided to use a switch statement in order to obtain the number inputted. switch( e.getKeyCode() ) { case KeyEvent.VK_0: num = 0; break; case KeyEvent.VK_1: num = 1; break; case KeyEvent.VK_2: num = 2; break; case KeyEvent.VK_3: num = 3; break; case KeyEvent.VK_4: num = 4; break; case KeyEvent.VK_5: num = 5; break; case KeyEvent.VK_6: num = 6; break; case KeyEvent.VK_7: num = 7; break; case KeyEvent.VK_8: num = 8; break; case KeyEvent.VK_9: num = 9; break; } I realized one other course of action could have been to use a set of if statements. if( e.getKeyCode() == KeyEvent.VK_0 ) num = 0; else if( e.getKeyCode() == KeyEvent.VK_1 ) num = 1; etc. for every number up until 9. I then wondered what the essential difference is between a switch statement and a series of if statements. I know it saves space and time to write, but it's not that much. So, my question is, aside from the space, does a switch statement differ from a series of if statments in any way? Is it faster, less error-prone, etc.? This question really doesn't affect my code that much. I was just wondering. Also, this question pertains to the JAVA language, not any other programming language.

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• Correct permissions for /var/www and wordpress

  - by dpbklyn

  Hello and thank you in advance! I am relatively new to ubuntu, so please excuse the newbie-ness of this question... I have set up a LAMP server (ubuntu server 11.10) and I have access via SSH and to the "it works" page from a web browser from inside my network (via ip address) and from outside using dyndns. I have a couple of projects in development with some outside developers and I want to use this server as a development server for testing and for client approvals. We have some Wordpress projects that sit in subdirectories in /var/www/wordpress1 /var/www/wordpress2, etc. I cannot access these sub directories from a browser in order to set up WP--or (I assume) to see the content on a browser. I get a 403 Forbidden error on my browser. I assume that this is a permissions problem. Can you please tell me the proper settings for the permissions to: 1) Allow the developers and me to read/write. 2) to allow WP set up and do its thing 3) Allow visitors to access the site(s) via the web. I should also mention that the subfolder are actually simlinks to folder on another internal hdd--I don't think this will make a difference, but I thought I should disclose. Since I am a newbie to ubuntu, step-by-step directions are greatly appreciated! Thank you for taking the time! dp total 12 drwxr-xr-x 2 root root 4096 2012-07-12 10:55 . drwxr-xr-x 13 root root 4096 2012-07-11 20:02 .. lrwxrwxrwx 1 root root 43 2012-07-11 20:45 admin_media -> /root/django_src/django/contrib/admin/media -rw-r--r-- 1 root root 177 2012-07-11 17:50 index.html lrwxrwxrwx 1 root root 14 2012-07-11 20:42 media -> /hdd/web/media lrwxrwxrwx 1 root root 18 2012-07-12 10:55 wordpress -> /hdd/web/wordpress Here is the result of using chown -R www-data:www-data /var/www total 12 drwxr-xr-x 2 www-data www-data 4096 2012-07-12 10:55 . drwxr-xr-x 13 root root 4096 2012-07-11 20:02 .. lrwxrwxrwx 1 www-data www-data 43 2012-07-11 20:45 admin_media -> /root/django_src/django/contrib/admin/media -rw-r--r-- 1 www-data www-data 177 2012-07-11 17:50 index.html lrwxrwxrwx 1 www-data www-data 14 2012-07-11 20:42 media -> /hdd/web/media lrwxrwxrwx 1 www-data www-data 18 2012-07-12 10:55 wordpress -> /hdd/web/wordpress I am still unable to access via browser...

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• C Programming arrays, I dont understand how I would go about making this program, If anyone can just guide me through the basic outline please :) [on hold]

  - by Rashmi Kohli

  Problem The temperature of a car engine has been measured, from real-world experiments, as shown in the table and graph below: Time (min) Temperature (oC) 0 20 1 36 2 61 3 68 4 77 5 110 Use linear regression to find the engine’s temperature at 1.5 minutes, 4.3 minutes, and any other time specified by the user. Background In engineering, many times we measure several data points in an experiment, but then we need to predict a value that we have not measured which lies between two measured values, such as the problem statement above. If the relation between the measured parameters seems to be roughly linear, then we can use linear regression to find the relationship between those parameters. In the graph of the problem statement above, the relation seems to be roughly linear. Hence, we can apply linear regression to the above problem. Assuming y {y0, y1, …yn-1} has a linear relation with x {x0, x1, … xn-1}, we can say that: y = mx+b where m and b can be found with linear regression as follows: For the problem in this lab, using linear regression gives us the following line (in blue) compared to the measured curve (in red). As you can see, there is usually a difference between the measured values and the estimated (predicted) values. What linear regression does is to minimize those differences and still give us a straight line (blue). Other methods, such as non-linear regression, are also possible to achieve higher accuracy and better curve fitting. Requirements Your program should first print the table of the temperatures similar to the way it’s printed in the problem statement. It should then calculate the temperature at minute 1.5 and 4.3 and show the answers to the user. Next, it should prompt the user to enter a time in minutes (or -1 to quit), and after reading the user’s specified time it should give the value of the engine’s temperature at that time. It should then go back to the prompt. Hints •Use a one dimensional array to store the temperature values given in the problem statement. •Use functions to separate tasks such as calculating m, calculating b, calculating the temperature at a given time, printing the prompt, etc. You can then give your algorithm as well as you pseudo code per function, as opposed to one large algorithm diagram or one large sequence of pseudo code.

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• Advantages to Multiple Methods over Switch

  - by tandu

  I received a code review from a senior developer today asking "By the way, what is your objection to dispatching functions by way of a switch statement?" I have read in many places about how pumping an argument through switch to call methods is bad OOP, not as extensible, etc. However, I can't really come up with a definitive answer for him. I would like to settle this for myself once and for all. Here are our competing code suggestions (php used as an example, but can apply more universally): class Switch { public function go($arg) { switch ($arg) { case "one": echo "one\n"; break; case "two": echo "two\n"; break; case "three": echo "three\n"; break; default: throw new Exception("Unknown call: $arg"); break; } } } class Oop { public function go_one() { echo "one\n"; } public function go_two() { echo "two\n"; } public function go_three() { echo "three\n"; } public function __call($_, $__) { throw new Exception("Unknown call $_ with arguments: " . print_r($__, true)); } } Part of his argument was "It (switch method) has a much cleaner way of handling default cases than what you have in the generic __call() magic method." I disagree about the cleanliness and in fact prefer call, but I would like to hear what others have to say. Arguments I can come up with in support of Oop scheme: A bit cleaner in terms of the code you have to write (less, easier to read, less keywords to consider) Not all actions delegated to a single method. Not much difference in execution here, but at least the text is more compartmentalized. In the same vein, another method can be added anywhere in the class instead of a specific spot. Methods are namespaced, which is nice. Does not apply here, but consider a case where Switch::go() operated on a member rather than a parameter. You would have to change the member first, then call the method. For Oop you can call the methods independently at any time. Arguments I can come up with in support of Switch scheme: For the sake of argument, cleaner method of dealing with a default (unknown) request Seems less magical, which might make unfamiliar developers feel more comfortable Anyone have anything to add for either side? I'd like to have a good answer for him.

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• WiFi on Ubuntu 12.04 custom: downloading unbearably slow

  - by Mark

  iwconfig reports 11 Mbps, yet I've seen as low as <1 KBps. This is the latest in my laundry list of Ubuntu problems in a dual-boot machine (cyberpowerpc custom, intel i7-3820, nvidia gtx 570). I received it two days ago, Windows 7 running fine, still having problems with Ubuntu. The browsing is intermittent but unacceptable. e.g. I could get to this site last night but I couldn't post this question. The downloading is unbearably slow, I can't download anything or install any packages because the speed is so slow. e.g. I am trying to install vim which is inexplicably missing from my 12.04 install (add another one to the problems list) and my download speed reported in the terminal was 241 B/s. Yes, bytes. iwconfig reports 11 Mbps, which further adds to the confusion. User@ubuntu:~$ iwconfig lo no wireless extensions. wlan0 IEEE 802.11bgn ESSID:"linksys" Mode:Managed Frequency:2.437 GHz Access Point: 00:18:39:76:2C:A1 Bit Rate=11 Mb/s Tx-Power=20 dBm Retry long limit:7 RTS thr:off Fragment thr:off Power Management:off Link Quality=36/70 Signal level=-74 dBm Rx invalid nwid:0 Rx invalid crypt:0 Rx invalid frag:0 Tx excessive retries:54 Invalid misc:18 Missed beacon:0 eth0 no wireless extensions. Any ideas? I see this is a problem a lot of people, but none of the on line solutions have worked for me so far. e.g. one site recommends editing the ath9k.conf file in /etc/modprobe.d, yet this file isn't even in the folder: User@ubuntu:/$ cd etc/modprobe.d User@ubuntu:/etc/modprobe.d$ ls alsa-base.conf blacklist-oss.conf blacklist-ath_pci.conf blacklist-rare-network.conf blacklist.conf blacklist-watchdog.conf blacklist-firewire.conf dkms.conf blacklist-framebuffer.conf nvidia-current_hybrid.conf blacklist-modem.conf nvidia-graphics-drivers.conf I think the nvidia gpu might be mucking things up. I had the "blinking cursor" problem when installing in the first place, and then I had the monitor out of range problem as well. I have my faithful Asus laptop, which is running Ubuntu 12.04 just fine. The only difference is executing host -t SOA local in the terminal gives User@ubuntu:~$ host -t SOA local local has SOA record local. nobody.localhost. 42 86400 43200 604800 10800 in my new machine, and the command reports Host local. not found in the laptop. Help would be most welcome, as I am in danger of reverting back to Windows. I'm seriously considering it. Sorry for the length, trying to show my effort in resolving the issue and include terminal snippets that might be helpful.

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• The term "interface" in C++

  - by Flexo

  Java makes a clear distinction between class and interface. (I believe C# does also, but I have no experience with it). When writing C++ however there is no language enforced distinction between class and interface. Consequently I've always viewed interface as a workaround for the lack of multiple inheritance in Java. Making such a distinction feels arbitrary and meaningless in C++. I've always tended to go with the "write things in the most obvious way" approach, so if in C++ I've got what might be called an interface in Java, e.g.: class Foo { public: virtual void doStuff() = 0; ~Foo() = 0; }; and I then decided that most implementers of Foo wanted to share some common functionality I would probably write: class Foo { public: virtual void doStuff() = 0; ~Foo() {} protected: // If it needs this to do its thing: int internalHelperThing(int); // Or if it doesn't need the this pointer: static int someOtherHelper(int); }; Which then makes this not an interface in the Java sense anymore. Instead C++ has two important concepts, related to the same underlying inheritance problem: virtual inhertiance Classes with no member variables can occupy no extra space when used as a base "Base class subobjects may have zero size" Reference Of those I try to avoid #1 wherever possible - it's rare to encounter a scenario where that genuinely is the "cleanest" design. #2 is however a subtle, but important difference between my understanding of the term "interface" and the C++ language features. As a result of this I currently (almost) never refer to things as "interfaces" in C++ and talk in terms of base classes and their sizes. I would say that in the context of C++ "interface" is a misnomer. It has come to my attention though that not many people make such a distinction. Do I stand to lose anything by allowing (e.g. protected) non-virtual functions to exist within an "interface" in C++? (My feeling is the exactly the opposite - a more natural location for shared code) Is the term "interface" meaningful in C++ - does it imply only pure virtual or would it be fair to call C++ classes with no member variables an interface still?

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• Deleted Myself from Admin Group - Now Getting Error usermod: cannot lock /etc/passwd; try again later

  - by BubbaJ

  I have a laptop with Ubuntu 11.10 that is shared between myself and two other family members. My user id was setup as the only "Administrator" on the laptop. The other users were setup as "Standard" users. In my attempt to try to add myself to the user groups for the other users, I somehow deleted myself from the admin groups. I used the "usermod" command from the terminal. I must have neglected to include the proper switches or syntax for the update. It looks like I successfully added my userid to the group associated with my wife's account. When I use the "groups" command, I can see only my id and my wife's id in the list. I no longer see the "admin" or "adm" groups, and others that used to be listed. When I go into System Settings User Accounts it looks like my ID is now listed as a "Standard" user. I would like to change my account back to "Administrator", but now I can't. I did some searches for solutions and found that I would need to boot into Recovery Mode and execute the usermod command from the root session. I was able to successfully boot into Recovery Mode and get to the root session. I was trying to execute the command "usermod -a -G admin user1" to add my id (user1) back to the admin group. When I execute the command from the root session, I get the error message "usermod: cannot lock /etc/passwd; try again later". I tried preceding the usermod command with "sudo", but it didn't make a difference, same error. I then tried adding a new user using adduser, thinking I would try to create a new userid and make the new userid part of the admin group. I get the same error using the adduser command. I saw some posts that recommend looking for and deleting files that end in ".lock" in the etc directory. The only file I found was .pwd.lock which I haven't touched. I am at a loss as to what to try next. I am relatively inexperienced with Ubuntu and Linux, so alot of this is new to me. Any help you can provide would be much appreciated.

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• How do I render from one render target to another?

  - by Chaotikmind

  I have two render targets: a fake backbuffer; a special render target where I do all my rendering. a light render target; where I render my light fx. I'm sure I'm rendering correctly on both. The problem arises when I overlay the light render target onto the fake backbuffer by drawing a quad covering it: DxEngine.DrawSprite(0.0f, 0.0f, 0.0f, (float)DxEngine.GetWidth(), (float)DxEngine.GetHeight(), 0xFFFFFFFF, LightSurface->GetTexture()); Regardless of what's in the light target, nothing is rendered onto the other target. I tried clearing the light target with full-white or full-black, but still get nothing. Fake backbuffer created with Direct3dDev->CreateTexture(Width, Height, 1, D3DUSAGE_RENDERTARGET, D3DFMT_X8R8G8B8, D3DPOOL_DEFAULT, &Texture, nullptr); Light render target created with Direct3dDev->CreateTexture(Width, Height, 1, D3DUSAGE_RENDERTARGET, D3DFMT_A8R8G8B8, D3DPOOL_DEFAULT, &Texture, nullptr); I also tried to create both with D3DFMT_A8R8G8B8, again without difference. Both targets have the same width and height. Only the fixed pipeline is used DirectX setup for rendering : Direct3dDev->SetSamplerState(0, D3DSAMP_MINFILTER, D3DTEXF_LINEAR ); Direct3dDev->SetSamplerState(0, D3DSAMP_MAGFILTER, D3DTEXF_LINEAR ); Direct3dDev->SetSamplerState(0, D3DSAMP_MIPFILTER, D3DTEXF_NONE ); Direct3dDev->SetSamplerState(0, D3DSAMP_ADDRESSU, D3DTADDRESS_WRAP ); Direct3dDev->SetSamplerState(0, D3DSAMP_ADDRESSV, D3DTADDRESS_WRAP ); Direct3dDev->SetRenderState(D3DRS_CULLMODE, D3DCULL_NONE); Direct3dDev->SetRenderState(D3DRS_LIGHTING, false); Direct3dDev->SetRenderState(D3DRS_ZENABLE, D3DZB_TRUE); Direct3dDev->SetRenderState(D3DRS_ZWRITEENABLE,D3DZB_TRUE); Direct3dDev->SetRenderState(D3DRS_ZFUNC,D3DCMP_LESSEQUAL); Direct3dDev->SetRenderState(D3DRS_ALPHABLENDENABLE, true ); Direct3dDev->SetRenderState(D3DRS_ALPHAREF, 0x00000000ul); Direct3dDev->SetRenderState(D3DRS_ALPHATESTENABLE, true); Direct3dDev->SetRenderState(D3DRS_ALPHAFUNC,D3DCMP_GREATER); Direct3dDev->SetRenderState(D3DRS_SRCBLEND, D3DBLEND_SRCALPHA ); Direct3dDev->SetRenderState(D3DRS_DESTBLEND, D3DBLEND_INVSRCALPHA ); Direct3dDev->SetTextureStageState(0, D3DTSS_COLORARG1, D3DTA_TEXTURE); Direct3dDev->SetTextureStageState(0, D3DTSS_COLORARG2, D3DTA_DIFFUSE); Direct3dDev->SetTextureStageState(0, D3DTSS_COLOROP, D3DTOP_MODULATE); Direct3dDev->SetTextureStageState(0, D3DTSS_ALPHAARG1, D3DTA_TEXTURE); Direct3dDev->SetTextureStageState(0, D3DTSS_ALPHAARG2, D3DTA_DIFFUSE); Direct3dDev->SetTextureStageState(0, D3DTSS_ALPHAOP, D3DTOP_MODULATE); Direct3dDev->SetTextureStageState(0, D3DTSS_RESULTARG, D3DTA_CURRENT); Direct3dDev->SetTextureStageState(0, D3DTSS_TEXCOORDINDEX, D3DTSS_TCI_PASSTHRU); //ensure the first stage is not used for now Direct3dDev->SetTextureStageState(1, D3DTSS_COLOROP, D3DTOP_DISABLE); How can I do this right?

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• Hyper-V Server 2012 - "No Active Network Adapter Found"

  - by Vazgen

  I just installed Hyper-V Server 2012 and first thing I get when logging in to the host is "No Active Network Adapter Found". I know I have to use the following command: pnputil –i –a <inf file> I found the Realtek Network Driver for my MB for Windows 7 here: http://za.asus.com/Motherboards/AMD_AM3Plus/M5A97_PRO/#download But there is not one for Windows 8 so I tried using the Win 7 one with PnPUtil, and I got: Failed to install the driver on any of the devices on the system: No more data is available. Does this really mean I can't use Hyper-V Server 2012 with my motherboard? This is hard to believe because I installed Windows Server 2012 directly (prior to installing Hyper-V Server 2012) on this same computer and I had internet access on that server without even configuring any drivers. Ok so I went to PowerShell from cmd and typed Get-NetIPConfiguration And it said the name of my driver (Realtek) and "Disconnected". I switched the Ethernet wire from my primary computer with my server and everything was fixed. Interestingly, my primary computer connects to the internet just fine with the wire that was previously in the server, just with much slower speed. Does anyone know what could be the difference between these 2 Ethernet wires?

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• Hyper-V Virtual Ethernet Adapter not working probperly - Code 31 on Host

  - by Chris S

  I have a Windows 8.1 machine with Hyper-V installed. From a "clean" Hyper-V configuration I open Virtual Switch Manager, create an External switch with "Allow management operating system to share this network adapter", click OK. Everything seems to work properly but the host loses network connectivity. Opening Device Manager, the "Hyper-V Virtual Ethernet Adapter" is shown under the Network Adapter section with a yellow triangle, and the following message: This device is not working properly because Windows cannot load the drivers required for this device. (Code 31) An object ID was not found in the file. I tried "Uninstalling" the device, seems to work, but the device doesn't actually remove. I tried removing and re-adding the Hyper-V feature completely, no difference. Tried scf /scannow, no problems. System and Application logs show no errors. The Hyper-V-VMMS Networking log shows the following: Log Name: Microsoft-Windows-Hyper-V-VMMS-Networking Source: Microsoft-Windows-Hyper-V-VMMS Date: 10/24/2013 10:53:07 AM Event ID: 26088 Description: Failed to apply static IP settings to internal Ethernet adapter {A813DE9A-BE70-4FAE-AD31-BE4D54505A4B} ('885435B8-BE65-4EE9-826D-AB56035237ED'): Unspecified error (0x80004005). If I try to remove the Virtual Switch in Hyper-V Virtual Switch Manager I get this in that same log: Log Name: Microsoft-Windows-Hyper-V-VMMS-Networking Source: Microsoft-Windows-Hyper-V-VMMS Date: 10/24/2013 11:19:47 AM Event ID: 26142 Description: Failed while removing virtual Ethernet switch. Trying to remove the Virtual Switch leads to an error: Error applying Virtual Switch Properties changes Failed while removing virtual Ethernet switch. VM Networking does work.

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• Kernel panic while loading Mac OS X on VMWare

  - by Vladimir Gritsenko

  I have Mac OS X 10.6.3 and VMWare 7.1. Trying to run the OS X doesn't work - shortly after booting VMWare announces the machine's death with this pop-up message: The CPU has been disabled by the guest operating system. You will need to power off or reset the virtual machine at this point. The console has a more interesting announcement: The real-time clock was not properly initialized on your system! With a dump of the detected CPU speed (~2.9 GHz), FSB (~94 MHz) and bus ratio (31). Somehow, the code that panics is documented in an accidental .diff file here. Apparently, it commits seppuku if the bus ratio is greater than 30. I underclocked my E6500 to a slower speed, but this apparently didn't make any difference. I can think of two possibilities right now: The CPU info being read is constant, and defines the maximum ability of the CPU. In which case it appears I'm screwed. VMWare presents its own CPU info to the machine, which I can perhaps somehow change. If so, how? If these sound completely off, that's because I'm a real newbie in these matters. Here's hoping you guys can show me the light :-)

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• Upgraded AGPM Server cannot connect to relocated archive

  - by thommck

  We were using the Advanced Group Policy Management (AGPM) v3.0 on out Windows Server 2008 DC. It kept the archive on the C: drive. When we upgraded to AGPM v4 we relocated the archive to the D: drive. Now when we try to look at a GPO's hisory in GPMC we get the following error Failed to connect to the AGPM Server. The following error occurred: The server was unable to process the request due to an internal error. For more information about the error, either turn on IncludeExceptionDetailInFaults (either from ServiceBehaviorAttribute or from the configuration behavior) on the server in order to send the exception information back to the client, or turn on tracing as per the Microsoft .NET Framework 3.0 SDK documentation and inspect the server trace logs. System.ServiceModel.FaultException (80131501) You are able to click Retry or Cancel. Retry brings up the same error and Cancel takes you back to GPMC and the History tab displays "Archive not found". I installed the client on a Windows 7 computer (which is a n unsupported set up) and it could read the server archive without any issues. I followed the TechNet article "Move the AGPM Server and the Archive" but that didn't make a difference How can I tell the server where the archive is?

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• Diagnosing permission problems with Cobian Backup to network share

  - by DaveBurns

  I'm running the latest Cobian 11. I have a Synology DS412 NAS. All of my machines (Mac and Windows) access this just fine when I'm logged in and I browse to it manually. I have Cobian installed as a service on two Windows machines: WinXP SP3 and Win7 x64. On both machines, the service is set to log on with my user account which is in the Windows administrator group. Backups on both machines fail with the message "Couldn't create the destination directory "\nas1\backups\foo\bar\": The filename, directory name, or volume label syntax is incorrect". I have tried setting the NAS's share to allow anonymous read/write access but it made no difference. Although I want the backups to run unattended in the middle of the night, I have tested them by running them manually while I'm logged in but no luck. Before starting that, I make sure that I can browse to the NAS with Explorer to ensure that any authentication session with Windows and the NAS has not expired. Still no luck. I have tried creating that destination directory both on the NAS before the backup and deleting it so the backup job could create it with the client's credentials but no luck. The usual answer in the Cobian support forums is that there is a permission problem. I agree. But at this point, what can I do to diagnose this further?

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• HP DL160G6 bios update fails

  - by Bojo

  I tried to update the BIOS from my HP DL160G6's. Unfortunately the Windows update degraded my BIOS version from 243 to 237. But when I try to upgrade both servers to version the update fails. First I got a warning like: CMOS Layout difference between System ROM and ROM file has detected. AFU recommand (sic) adding /C commands of your original input commands. Press "A" to accept AFU's recommendation. Press "F" to keep original input commands. And the update did not do anything. But now I get a message like: Reading flash ........ done Bootblock checksum ... ok Module checksums ..... bad Error: BIOS checksum error And the update stops. I tried some commands form this page: http://www.ami.com/support/downloads/txt/AFU_README.TXT But I don't try to much, the servers are still booting. Does anyone know how to update my servers to BIOS version 245? I used this version http://h20565.www2.hp.com/portal/site/hpsc/template.PAGE/public/psi/swdDetails/?sp4ts.oid=3884344&spf_p.tpst=swdMain&spf_p.prp_swdMain=wsrp-navigationalState%3Didx%253D%257CswItem%253DMTX_7bd12651ab954fdcb0d7ee164a%257CswEnvOID%253D54%257CitemLocale%253D%257CswLang%253D%257Cmode%253D%257Caction%253DdriverDocument&javax.portlet.begCacheTok=com.vignette.cachetoken&javax.portlet.endCacheTok=com.vignette.cachetoken and created a bootable USB stick sith HPQUSB.exe

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• Updating Windows DNS records from a remote windows DNS server

  - by Luckyboy

  Does anyone know if it is possible for a windows 2003 DNS server to update the records for a domain so that it contains all the records of a domain of of a remotely based DNS server? Im almost certain that doesn't quite explain the problem so I shall illustrate with an example: We have two offices, both are based about 100 miles apart. One deals with IT (Intranet development etc.) while the other is a call centre that uses the Intranet systems. Currently each office has its own DNS server, with the IT office's and call centre's DNS servers containing entries for intranet site. The difference is that the IT DNS server records point to the various servers that host the Intranet sites (e.g. intranetsite1 - 192.168.1.10, intranetsite2 - 192.168.1.11) while all of the entries in the call centre's DNS point to the IT office's DNS server (intranetsite1 - [it office ip address], intranetsite2 - [it office ip address]). Is there any way that the call centre's DNS server could automatically add all DNS records hosted by the IT office's DNS, translating the IP addresses to the IP address of the IT office?

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• Windows 7 intermittently drops wired internet/lan connection.

  - by CraigTP

  In a nutshell, my Windows 7 Ultimate PC intermittently drops it's internet connection. Why? Background: My PC is wired to my ADSL modem/router which is directly connected to the phone line. I also have wireless connectivity turned on within the router for a laptop to connect wirelessly. Every few hours or so, when using my PC, I find I cannot access the internet and pages will not load. Eventually, Windows7 will update the network icon in the task-tray to show the exclamation mark symbol on the network icon. Opening up the Network And Sharing Centre will show the red cross between the "Multiple Networks" and "The Internet". Here's a picture of the "Network And Sharing Centre" (grabbed when everything was working!) As you can see, I'm running Sun's VirtualBox on this machine and that creates a Network connection for itself. This doesn't seem to affect the intermittent dropping (i.e. the intermittent drops occur whether the VirtualBox connection is in use or not). When the connection does drop, I cannot access any internet pages, nor can I access the router's web admin page at http://192.168.1.1/, so I'm assuming I've lost all local LAN access too. It's definitely not the router (or the internet connection itself) as my laptop, using the wireless connection (and running Vista Home Premium) continues to be able to access the internet (and the router's web admin pages) just fine. Every time this happens, I can immediately restore all internet and LAN access by opening Network Adapter page, disabling the "Local Area Connection" and then re-enabling it. Give it a few seconds and everything is fine again. I assume this is because, beneath the GUI, it's effectively doing an "ipconfig /release" then "ipconfig /renew". Why does this happen in the first place, though? I've googled for this and seen quite a few other people (even on MSDN/Technet forums) experiencing the same or almost the same problem, but with no clear resolution. Suggestions of turning off IPv6 on the LAN adapter, and ensuring there's no power management "sleeping" the network adapter have been tried but do not cure the problem. There does not seem to be any particular sequence of events that cause it to happen either. I've had it go twice in 20 minutes when just randomly browsing the web with no other traffic, and I've also had it go once then not go again for 2-3 hours with the same sort of usage. Can anyone tell me why this is happening and how to make it stop? EDIT: Additional information based upon the answer provided so far: Firstly, I forgot the mention that this is Windows 7 64 bit if that makes any difference at all. I mentioned that I don't think the VirtualBox network adpater is causing this problem in any way, and I also have VirtualBox installed on two other machines, one running Vista Home Premium and the other running XP. Neither of these machine experience the same network connectivity issues as the Windows 7 machine. The IP assignment for the Windows 7 machine is the same both before and after the "drop". I have a DHCP server on the router issuing IP Addresses, however my Windows 7 machine uses a static address. Here's the output from "ipconfig": Ethernet adapter Local Area Connection: Connection-specific DNS Suffix . : Description . . . . . . . . . . . : Realtek PCIe GBE Family Controller DHCP Enabled. . . . . . . . . . . : No Autoconfiguration Enabled . . . . : Yes IPv4 Address. . . . . . . . . . . : 192.168.1.2(Preferred) Subnet Mask . . . . . . . . . . . : 255.255.255.0 Default Gateway . . . . . . . . . : 192.168.1.1 DNS Servers . . . . . . . . . . . : 192.168.1.1 NetBIOS over Tcpip. . . . . . . . : Enabled Within the system's event logs, the only event that relates to the connection dropping is a "DNS Client Event" and this is generated after the connection has dropped and is an event detailing that DNS information can't be found for whatever website I may be trying to access, just as the connection drops: Log Name: System Source: Microsoft-Windows-DNS-Client Event ID: 1014 Task Category: None Level: Warning Keywords: User: NETWORK SERVICE Description: Name resolution for the name weather.service.msn.com timed out after none of the configured DNS servers responded. The network adapter chipset is Realtek PCIe GBE Family Controller and I have confirmed that this is the correct chipset for the motherboard (Asus M4A77TD PRO), and in fact, Windows Update installed an updated driver for this on 12/Jan/2009. The details of the update say that it's a Realtek software update from December 2009. Incidentally, I was still having the same intermittent problems prior to this update. It seems to have made no difference at all. EDIT 2 (1 Feb 2010): In my quest to solve this problem, I have discovered some more interesting information. On another forum, someone suggested that I should try running Windows in "Safe Mode With Networking" and see if the problem continues to occur. This was a fantastic suggestion and I don't know why I didn't think of it sooner myself. So, I proceeded to run in Safe Mode with Networking for a number of hours, and amazingly, the "drops" didn't occur once. It was a positive discovery, however, due to the intermittent nature of the original problem, I wasn't completely convinced that the problem was cured. One thing I did note is that the fan on my GFX card was running alot louder than normal. This is due to the fact that I have an ASUS ENGTS250 graphics card (http://www.asus.com/product.aspx?P_ID=B6imcoax3MRY42f3) which had a known problem with a noisy fan until a BIOS update fixed the issue. (See the "Manufacturer Response" here: http://www.newegg.com/Product/Product.aspx?Item=N82E16814121334 for details). Well, running in safe mode had the fan running (incorrectly) at full speed (as it did before the BIOS update), but with an (apparently) stable network connection. Obviously some driver was not loaded for the GFX card when in Safe Mode so this got me thinking about the GFX card (since the very noisy fan was quite obvious when running in Safe Mode). I rebooted into normal mode, and found that Nvidia had a very up-to-date new driver for my GFX card (only about 1 week old), so I downloaded the appropriate driver and installed it. After installation and a reboot, I was able to use my PC for an entire day with NO NETWORK DROPS!!! This was on Saturday. However, on the Sunday, I also had my PC for pretty much the entire day and experienced 2 network drops. No other changes have been made to my PC in this time. So, the story seems to be that updating my graphics card drivers seems to have improved (if not completely fixed) the issue, however, I'm still searching for a proper fix for this problem. Hopefully, this information may help anyone who may have additional ideas as to why this problem is occuring in the first place. (And why does new GFX card drivers have anything to do with the network?) I appreciate everyone's feedback so far. However, I'll have to ask once more if anyone has any further ideas of how to fix this particular problem? Thanks in advance.

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• Lotus NotesSQL Driver - cannot install

  - by PowerUser

  Hi all, I need to install Lotus NotesSQL Driver (current version is 8.5) onto a virtual machine running XP. Here's what's I've done so far: I retrieved the file (CZOWFEN.zip) from the IBM website. I ran the exe. I then went to My Computer-Properties-Advanced-Environmental Settings-System Variables-Path and added "; c:\notessql" so the ODBC administrator could find Notes.ini (why the setup file didn't do this in the first place, i don't know). I opened up the ODBC administrator and tried to add a new System DSN to a Lotus DB. "The setup routines for the Lotus Notes SQL Driver (*.nsf) ODBC driver could not be loaded due to system error code 126" I redownloaded and reinstalled the driver (making sure I had the latest version 8.5). No luck. I checked the registry. All the file paths appeared to be correct. Per many, many similar cases on the internet, I tried several different variations of adding the various Lotus Notes folders to my PATH variables. Same error. I've done this setup on 5 different machines now with no problem. The only difference here is that this machine is virtual. Ideas?

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