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• Street-Fighting Mathematics

  Sanjoy Mahajan's new book lays out practical tools for educated guessing and down-and-dirty problem-solving Problem solving - Math - Recreations - Competitions - Methods and Theories

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• Make the Firefox Awesome Bar Semi-Transparent Like Google Chrome

  - by Matthew Guay

  Would you like to make the Firefox Awesome Bar drop-down menu semi-transparent like in Google Chrome?  Here’s a quick trick that can make your Firefox Awesome Bar a bit more awesome. When you type an address or search query into the address bar in Google Chrome, the drop-down list of history and search suggestions that appears is slightly transparent.  Nothing extreme, but it adds a nice touch. Firefox’s Awesome bar, on the other hand, is fully opaque by default. We can change that with a simple change.  Exit Firefox, then open your Firefox profile folder by entering the following in the address bar in Explorer or in the Run command: %appdata%\Mozilla\Firefox\Profiles\ Open the default folder, and then open the Chrome folder in it. Now, open the userChrome.css file in an editor such as Notepad.  If you do not have a userChrome.css file, open the userChrome-example.css file instead. Now, add the following to the end of the file: #PopupAutoCompleteRichResult[type="autocomplete-richlistbox"]{    opacity: 0.9 !important;} You can change the opacity value, but 0.9 seemed the closest to Chrome’s transparency while keeping the text readable. Save the file as userChrome.css in that same folder.  If you’re editing with Notepad, make sure to select to save as All Files so the file won’t be saved with a .txt extension. Open Firefox, and now your Awesome Bar’s drop-down list will be transparent.  Actually, it may look even more awesome than Google Chrome’s address bar! Conclusion With this simple trick, you can make your Firefox Awesome bar a bit more awesome.  With tweaks like this, it’s no wonder Firefox is still so popular. Special thanks to Daniel Spiewak for the tip! Similar Articles Productive Geek Tips Stupid Geek Tricks: Compare Your Browser’s Memory Usage with Google ChromeHow to Make Google Chrome Your Default BrowserEnable Vista Black Style Theme for Google Chrome in XPMake your Gnome Terminal Background (mostly)Transparent on UbuntuStop YouTube Videos from Automatically Playing in Chrome TouchFreeze Alternative in AutoHotkey The Icy Undertow Desktop Windows Home Server – Backup to LAN The Clear & Clean Desktop Use This Bookmarklet to Easily Get Albums Use AutoHotkey to Assign a Hotkey to a Specific Window Latest Software Reviews Tinyhacker Random Tips Xobni Plus for Outlook All My Movies 5.9 CloudBerry Online Backup 1.5 for Windows Home Server Snagit 10 Use ILovePDF To Split and Merge PDF Files TimeToMeet is a Simple Online Meeting Planning Tool Easily Create More Bookmark Toolbars in Firefox Filevo is a Cool File Hosting & Sharing Site Get a free copy of WinUtilities Pro 2010 World Cup Schedule

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• Giving a Bomberman AI intelligent bomb placement

  - by Paul Manta

  I'm trying to implement an AI algorithm for Bomberman. Currently I have a working but not very smart rudimentary implementation (the current AI is overzealous in placing bombs). This is the first AI I've ever tried implementing and I'm a bit stuck. The more sophisticated algorithms I have in mind (the ones that I expect to make better decisions) are too convoluted to be good solutions. What general tips do you have for implementing a Bomberman AI? Are there radically different approaches for making the bot either more defensive or offensive? Edit: Current algorithm My current algorithm goes something like this (pseudo-code): 1) Try to place a bomb and then find a cell that is safe from all the bombs, including the one that you just placed. To find that cell, iterate over the four directions; if you can find any safe divergent cell and reach it in time (eg. if the direction is up or down, look for a cell that is found to the left or right of this path), then it's safe to place a bomb and move in that direction. 2) If you can't find and safe divergent cells, try NOT placing a bomb and look again. This time you'll only need to look for a safe cell in only one direction (you don't have to diverge from it). 3) If you still can't find a safe cell, don't do anything. for $(direction) in (up, down, left, right): place bomb at current location if (can find and reach divergent safe cell in current $(direction)): bomb = true move = $(direction) return for $(direction) in (up, down, left, right): do not place bomb at current location if (any safe cell in the current $(direction)): bomb = false move = $(direction) return else: bomb = false move = stay_put This algorithm makes the bot very trigger-happy (it'll place bombs very frequently). It doesn't kill itself, but it does have a habit of making itself vulnerable by going into dead ends where it can be blocked and killed by the other players. Do you have any suggestions on how I might improve this algorithm? Or maybe I should try something completely different? One of the problems with this algorithm is that it tends to leave the bot with very few (frequently just one) safe cells on which it can stand. This is because the bot leaves a trail of bombs behind it, as long as it doesn't kill itself. However, leaving a trail of bombs behind leaves few places where you can hide. If one of the other players or bots decide to place a bomb somewhere near you, it often happens that you have no place to hide and you die. I need a better way to decide when to place bombs.

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• HTG Explains: Do Non-Windows Platforms Like Mac, Android, iOS, and Linux Get Viruses?

  - by Chris Hoffman

  Viruses and other types of malware seem largely confined to Windows in the real world. Even on a Windows 8 PC, you can still get infected with malware. But how vulnerable are other operating systems to malware? When we say “viruses,” we’re actually talking about malware in general. There’s more to malware than just viruses, although the word virus is often used to talk about malware in general. Why Are All the Viruses For Windows? Not all of the malware out there is for Windows, but most of it is. We’ve tried to cover why Windows has the most viruses in the past. Windows’ popularity is definitely a big factor, but there are other reasons, too. Historically, Windows was never designed for security in the way that UNIX-like platforms were — and every popular operating system that’s not Windows is based on UNIX. Windows also has a culture of installing software by searching the web and downloading it from websites, whereas other platforms have app stores and Linux has centralized software installation from a secure source in the form of its package managers. Do Macs Get Viruses? The vast majority of malware is designed for Windows systems and Macs don’t get Windows malware. While Mac malware is much more rare, Macs are definitely not immune to malware. They can be infected by malware written specifically for Macs, and such malware does exist. At one point, over 650,000 Macs were infected with the Flashback Trojan. [Source] It infected Macs through the Java browser plugin, which is a security nightmare on every platform. Macs no longer include Java by default. Apple also has locked down Macs in other ways. Three things in particular help: Mac App Store: Rather than getting desktop programs from the web and possibly downloading malware, as inexperienced users might on Windows, they can get their applications from a secure place. It’s similar to a smartphone app store or even a Linux package manager. Gatekeeper: Current releases of Mac OS X use Gatekeeper, which only allows programs to run if they’re signed by an approved developer or if they’re from the Mac App Store. This can be disabled by geeks who need to run unsigned software, but it acts as additional protection for typical users. XProtect: Macs also have a built-in technology known as XProtect, or File Quarantine. This feature acts as a blacklist, preventing known-malicious programs from running. It functions similarly to Windows antivirus programs, but works in the background and checks applications you download. Mac malware isn’t coming out nearly as quick as Windows malware, so it’s easier for Apple to keep up. Macs are certainly not immune to all malware, and someone going out of their way to download pirated applications and disable security features may find themselves infected. But Macs are much less at risk of malware in the real world. Android is Vulnerable to Malware, Right? Android malware does exist and companies that produce Android security software would love to sell you their Android antivirus apps. But that isn’t the full picture. By default, Android devices are configured to only install apps from Google Play. They also benefit from antimalware scanning — Google Play itself scans apps for malware. You could disable this protection and go outside Google Play, getting apps from elsewhere (“sideloading”). Google will still help you if you do this, asking if you want to scan your sideloaded apps for malware when you try to install them. In China, where many, many Android devices are in use, there is no Google Play Store. Chinese Android users don’t benefit from Google’s antimalware scanning and have to get their apps from third-party app stores, which may contain infected copies of apps. The majority of Android malware comes from outside Google Play. The scary malware statistics you see primarily include users who get apps from outside Google Play, whether it’s pirating infected apps or acquiring them from untrustworthy app stores. As long as you get your apps from Google Play — or even another secure source, like the Amazon App Store — your Android phone or tablet should be secure. What About iPads and iPhones? Apple’s iOS operating system, used on its iPads, iPhones, and iPod Touches, is more locked down than even Macs and Android devices. iPad and iPhone users are forced to get their apps from Apple’s App Store. Apple is more demanding of developers than Google is — while anyone can upload an app to Google Play and have it available instantly while Google does some automated scanning, getting an app onto Apple’s App Store involves a manual review of that app by an Apple employee. The locked-down environment makes it much more difficult for malware to exist. Even if a malicious application could be installed, it wouldn’t be able to monitor what you typed into your browser and capture your online-banking information without exploiting a deeper system vulnerability. Of course, iOS devices aren’t perfect either. Researchers have proven it’s possible to create malicious apps and sneak them past the app store review process. [Source] However, if a malicious app was discovered, Apple could pull it from the store and immediately uninstall it from all devices. Google and Microsoft have this same ability with Android’s Google Play and Windows Store for new Windows 8-style apps. Does Linux Get Viruses? Malware authors don’t tend to target Linux desktops, as so few average users use them. Linux desktop users are more likely to be geeks that won’t fall for obvious tricks. As with Macs, Linux users get most of their programs from a single place — the package manager — rather than downloading them from websites. Linux also can’t run Windows software natively, so Windows viruses just can’t run. Linux desktop malware is extremely rare, but it does exist. The recent “Hand of Thief” Trojan supports a variety of Linux distributions and desktop environments, running in the background and stealing online banking information. It doesn’t have a good way if infecting Linux systems, though — you’d have to download it from a website or receive it as an email attachment and run the Trojan. [Source] This just confirms how important it is to only run trusted software on any platform, even supposedly secure ones. What About Chromebooks? Chromebooks are locked down laptops that only run the Chrome web browser and some bits around it. We’re not really aware of any form of Chrome OS malware. A Chromebook’s sandbox helps protect it against malware, but it also helps that Chromebooks aren’t very common yet. It would still be possible to infect a Chromebook, if only by tricking a user into installing a malicious browser extension from outside the Chrome web store. The malicious browser extension could run in the background, steal your passwords and online banking credentials, and send it over the web. Such malware could even run on Windows, Mac, and Linux versions of Chrome, but it would appear in the Extensions list, would require the appropriate permissions, and you’d have to agree to install it manually. And Windows RT? Microsoft’s Windows RT only runs desktop programs written by Microsoft. Users can only install “Windows 8-style apps” from the Windows Store. This means that Windows RT devices are as locked down as an iPad — an attacker would have to get a malicious app into the store and trick users into installing it or possibly find a security vulnerability that allowed them to bypass the protection. Malware is definitely at its worst on Windows. This would probably be true even if Windows had a shining security record and a history of being as secure as other operating systems, but you can definitely avoid a lot of malware just by not using Windows. Of course, no platform is a perfect malware-free environment. You should exercise some basic precautions everywhere. Even if malware was eliminated, we’d have to deal with social-engineering attacks like phishing emails asking for credit card numbers. Image Credit: stuartpilbrow on Flickr, Kansir on Flickr     

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• Item 2, Scott Myers Effective C++ question

  - by user619818

  In Item2 on page 16, (Prefer consts, enums, and inlines to #defines), Scott says: 'Also, though good compilers won't set aside storage for const objects of integer types'. I don't understand this. If I define a const object, eg const int myval = 5; then surely the compiler must set aside some memory (of int size) to store the value 5? Or is const data stored in some special way? This is more a question of computer storage I suppose. Basically, how does the computer store const objects so that no storage is set aside?

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• Windows CE: Newsgroups Shutdown

  - by Bruce Eitman

  As of June 1, 2010 many of the Windows CE newsgroups have been shut down by Microsoft, and the rest will be shut down by October 1, 2010.  This is part of an overall Microsoft strategy to move community from newsgroups to web based forums. The newsgroups have been indexed by Google, so the existing content can and should be searched for answers using http://groups.google.com/advanced_search Microsoft has replaced the newsgroups with http://social.msdn.microsoft.com/Forums/en-US/category/windowsembeddedcompact which has forums for OS Development, Managed Application Development and Native Application Development. Note that with the planned release for Q4 2010, Microsoft is renaming Windows Embedded CE to Windows Embedded Compact.  This name change is reflected in the forum naming. Copyright © 2010 – Bruce Eitman All Rights Reserved

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• Dual booting 12.10 and Win 7 - boots directly to Win 7

  - by user110174

  and thank you kindly for you help! I'll preface this with saying that I realize this is a common problem, with lots of trouble-shooting guides available online; however, after multiple attempts with different guides, I've made zero progress and am hoping to someone could help me with my specific scenario. First, my story: -Initially, I installed Ubuntu 12.10 with the "Something Else" option with no problems. Used 4 GB Swap Logical Partition, 26 GB Primary Root Partition. Wanting to trying out Mint 13, I booted into Windows from GRUB2, used the latest version of EasyBCD (v2.2) to restore the Windows 7 bootloader to the MBR, deleted the Ubuntu partitions, reformatted them in NTFS. I then created a 30 GB partition of free space for Mint. I installed Mint using the same partitioning described above for Ubuntu 12.10, using /dev/sda for the boot installation files, and everything seemed to go well, until I re-booted my computer and it went straight to Windows - I could find no way to get into Mint. So I went into windows, restored windows bootloader to the MBR w/ EasyBCD, deleted partitions, etc., as I figured I'd done enough messing around and would go with Ubuntu 12.10. Now the problem: I restarted my computer booting from the same Ubuntu USB key I originally used. Briefly, "error: "prefix" is not set" flashed on screen, and instead of being greeted with the GUI menu of "try vs. install Ubuntu", there was a menu with minimal graphics (like a BIOS menu) where I could select install, run from USB, etc. After selecting "Install Ubuntu", the familiar install wizard with a GUI came up, I partitioned my drive as described, /dev/sda for the boot installation files, install went well, rebooted and...straight to Windows. This is where I'm at. Fixes I've tried: -This guide: How can I repair grub? (How to get Ubuntu back after installing Windows?) to ensure Grub is on the MBR. I followed all steps, but still when I reboot, I go directly into Windows. -Installing 12.04 instead of 12.10 - same issue -Re-installed Ubuntu, writing the boot files to their own partition, then using EasyBCD to to add a boot option for Ubuntu using the Windows bootloader, ensuring I instruct EasyBCD to look at the partition I created with the Ubuntu installer (instructions here http://neosmart.net/wiki/display/EBCD/Ubuntu). When I reboot, I select the Ubuntu option, and it puts me in GRUB4DOS, with a cursor waiting for input. I have no idea what to put here, so I would just type "reboot" to exit out. And this is where I am now. Any clue as to why I can't boot into Ubuntu? My computer specs are: ASUS UX31A Core i7, Win 7 64 Pro, 256 GB SSD, Intel HM76 Chipset and Integrated Intel HD 4000 Graphics, 4 GB memory I've tried to be as clear as possible, but I'd be happy to provide any info that would help anyone along. Thanks for your patience in reading this! Sincerely, -MN

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• What Is the Purpose of the “Do Not Cover This Hole” Hole on Hard Drives?

  - by Jason Fitzpatrick

  From tiny laptop hard drives to beefier desktop models, traditional disk-based hard drives have a very bold warning on them: DO NOT COVER THIS HOLE. What exactly is the hole and what terrible fate would befall you if you covered it? Today’s Question & Answer session comes to us courtesy of SuperUser—a subdivision of Stack Exchange, a community-drive grouping of Q&A web sites. How Hackers Can Disguise Malicious Programs With Fake File Extensions Can Dust Actually Damage My Computer? What To Do If You Get a Virus on Your Computer

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• How to ‘Bounce’ Drops of Water on Top of a Pool of Water Indefinitely [Physics Video]

  - by Asian Angel

  Normally drops of water are automatically ‘absorbed’ into a larger pool of water when contact is made, but there is one way to stop those water drops from coalescing with the rest: vibration. This awesome video shows the process in action as drops of water remain on top of the pool of water and even form groups of drops! Drops on Drops on Drops Article [Physics Buzz Blog] Drops on Drops on Drops Video [YouTube] [via Neatorama] How Hackers Can Disguise Malicious Programs With Fake File Extensions Can Dust Actually Damage My Computer? What To Do If You Get a Virus on Your Computer

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• How John Got 15x Improvement Without Really Trying

  - by rchrd

  The following article was published on a Sun Microsystems website a number of years ago by John Feo. It is still useful and worth preserving. So I'm republishing it here.  How I Got 15x Improvement Without Really Trying John Feo, Sun Microsystems Taking ten "personal" program codes used in scientific and engineering research, the author was able to get from 2 to 15 times performance improvement easily by applying some simple general optimization techniques. Introduction Scientific research based on computer simulation depends on the simulation for advancement. The research can advance only as fast as the computational codes can execute. The codes' efficiency determines both the rate and quality of results. In the same amount of time, a faster program can generate more results and can carry out a more detailed simulation of physical phenomena than a slower program. Highly optimized programs help science advance quickly and insure that monies supporting scientific research are used as effectively as possible. Scientific computer codes divide into three broad categories: ISV, community, and personal. ISV codes are large, mature production codes developed and sold commercially. The codes improve slowly over time both in methods and capabilities, and they are well tuned for most vendor platforms. Since the codes are mature and complex, there are few opportunities to improve their performance solely through code optimization. Improvements of 10% to 15% are typical. Examples of ISV codes are DYNA3D, Gaussian, and Nastran. Community codes are non-commercial production codes used by a particular research field. Generally, they are developed and distributed by a single academic or research institution with assistance from the community. Most users just run the codes, but some develop new methods and extensions that feed back into the general release. The codes are available on most vendor platforms. Since these codes are younger than ISV codes, there are more opportunities to optimize the source code. Improvements of 50% are not unusual. Examples of community codes are AMBER, CHARM, BLAST, and FASTA. Personal codes are those written by single users or small research groups for their own use. These codes are not distributed, but may be passed from professor-to-student or student-to-student over several years. They form the primordial ocean of applications from which community and ISV codes emerge. Government research grants pay for the development of most personal codes. This paper reports on the nature and performance of this class of codes. Over the last year, I have looked at over two dozen personal codes from more than a dozen research institutions. The codes cover a variety of scientific fields, including astronomy, atmospheric sciences, bioinformatics, biology, chemistry, geology, and physics. The sources range from a few hundred lines to more than ten thousand lines, and are written in Fortran, Fortran 90, C, and C++. For the most part, the codes are modular, documented, and written in a clear, straightforward manner. They do not use complex language features, advanced data structures, programming tricks, or libraries. I had little trouble understanding what the codes did or how data structures were used. Most came with a makefile. Surprisingly, only one of the applications is parallel. All developers have access to parallel machines, so availability is not an issue. Several tried to parallelize their applications, but stopped after encountering difficulties. Lack of education and a perception that parallelism is difficult prevented most from trying. I parallelized several of the codes using OpenMP, and did not judge any of the codes as difficult to parallelize. Even more surprising than the lack of parallelism is the inefficiency of the codes. I was able to get large improvements in performance in a matter of a few days applying simple optimization techniques. Table 1 lists ten representative codes [names and affiliation are omitted to preserve anonymity]. Improvements on one processor range from 2x to 15.5x with a simple average of 4.75x. I did not use sophisticated performance tools or drill deep into the program's execution character as one would do when tuning ISV or community codes. Using only a profiler and source line timers, I identified inefficient sections of code and improved their performance by inspection. The changes were at a high level. I am sure there is another factor of 2 or 3 in each code, and more if the codes are parallelized. The study’s results show that personal scientific codes are running many times slower than they should and that the problem is pervasive. Computational scientists are not sloppy programmers; however, few are trained in the art of computer programming or code optimization. I found that most have a working knowledge of some programming language and standard software engineering practices; but they do not know, or think about, how to make their programs run faster. They simply do not know the standard techniques used to make codes run faster. In fact, they do not even perceive that such techniques exist. The case studies described in this paper show that applying simple, well known techniques can significantly increase the performance of personal codes. It is important that the scientific community and the Government agencies that support scientific research find ways to better educate academic scientific programmers. The inefficiency of their codes is so bad that it is retarding both the quality and progress of scientific research. # cacheperformance redundantoperations loopstructures performanceimprovement 1 x x 15.5 2 x 2.8 3 x x 2.5 4 x 2.1 5 x x 2.0 6 x 5.0 7 x 5.8 8 x 6.3 9 2.2 10 x x 3.3 Table 1 — Area of improvement and performance gains of 10 codes The remainder of the paper is organized as follows: sections 2, 3, and 4 discuss the three most common sources of inefficiencies in the codes studied. These are cache performance, redundant operations, and loop structures. Each section includes several examples. The last section summaries the work and suggests a possible solution to the issues raised. Optimizing cache performance Commodity microprocessor systems use caches to increase memory bandwidth and reduce memory latencies. Typical latencies from processor to L1, L2, local, and remote memory are 3, 10, 50, and 200 cycles, respectively. Moreover, bandwidth falls off dramatically as memory distances increase. Programs that do not use cache effectively run many times slower than programs that do. When optimizing for cache, the biggest performance gains are achieved by accessing data in cache order and reusing data to amortize the overhead of cache misses. Secondary considerations are prefetching, associativity, and replacement; however, the understanding and analysis required to optimize for the latter are probably beyond the capabilities of the non-expert. Much can be gained simply by accessing data in the correct order and maximizing data reuse. 6 out of the 10 codes studied here benefited from such high level optimizations. Array Accesses The most important cache optimization is the most basic: accessing Fortran array elements in column order and C array elements in row order. Four of the ten codes—1, 2, 4, and 10—got it wrong. Compilers will restructure nested loops to optimize cache performance, but may not do so if the loop structure is too complex, or the loop body includes conditionals, complex addressing, or function calls. In code 1, the compiler failed to invert a key loop because of complex addressing do I = 0, 1010, delta_x IM = I - delta_x IP = I + delta_x do J = 5, 995, delta_x JM = J - delta_x JP = J + delta_x T1 = CA1(IP, J) + CA1(I, JP) T2 = CA1(IM, J) + CA1(I, JM) S1 = T1 + T2 - 4 * CA1(I, J) CA(I, J) = CA1(I, J) + D * S1 end do end do In code 2, the culprit is conditionals do I = 1, N do J = 1, N If (IFLAG(I,J) .EQ. 0) then T1 = Value(I, J-1) T2 = Value(I-1, J) T3 = Value(I, J) T4 = Value(I+1, J) T5 = Value(I, J+1) Value(I,J) = 0.25 * (T1 + T2 + T5 + T4) Delta = ABS(T3 - Value(I,J)) If (Delta .GT. MaxDelta) MaxDelta = Delta endif enddo enddo I fixed both programs by inverting the loops by hand. Code 10 has three-dimensional arrays and triply nested loops. The structure of the most computationally intensive loops is too complex to invert automatically or by hand. The only practical solution is to transpose the arrays so that the dimension accessed by the innermost loop is in cache order. The arrays can be transposed at construction or prior to entering a computationally intensive section of code. The former requires all array references to be modified, while the latter is cost effective only if the cost of the transpose is amortized over many accesses. I used the second approach to optimize code 10. Code 5 has four-dimensional arrays and loops are nested four deep. For all of the reasons cited above the compiler is not able to restructure three key loops. Assume C arrays and let the four dimensions of the arrays be i, j, k, and l. In the original code, the index structure of the three loops is L1: for i L2: for i L3: for i for l for l for j for k for j for k for j for k for l So only L3 accesses array elements in cache order. L1 is a very complex loop—much too complex to invert. I brought the loop into cache alignment by transposing the second and fourth dimensions of the arrays. Since the code uses a macro to compute all array indexes, I effected the transpose at construction and changed the macro appropriately. The dimensions of the new arrays are now: i, l, k, and j. L3 is a simple loop and easily inverted. L2 has a loop-carried scalar dependence in k. By promoting the scalar name that carries the dependence to an array, I was able to invert the third and fourth subloops aligning the loop with cache. Code 5 is by far the most difficult of the four codes to optimize for array accesses; but the knowledge required to fix the problems is no more than that required for the other codes. I would judge this code at the limits of, but not beyond, the capabilities of appropriately trained computational scientists. Array Strides When a cache miss occurs, a line (64 bytes) rather than just one word is loaded into the cache. If data is accessed stride 1, than the cost of the miss is amortized over 8 words. Any stride other than one reduces the cost savings. Two of the ten codes studied suffered from non-unit strides. The codes represent two important classes of "strided" codes. Code 1 employs a multi-grid algorithm to reduce time to convergence. The grids are every tenth, fifth, second, and unit element. Since time to convergence is inversely proportional to the distance between elements, coarse grids converge quickly providing good starting values for finer grids. The better starting values further reduce the time to convergence. The downside is that grids of every nth element, n > 1, introduce non-unit strides into the computation. In the original code, much of the savings of the multi-grid algorithm were lost due to this problem. I eliminated the problem by compressing (copying) coarse grids into continuous memory, and rewriting the computation as a function of the compressed grid. On convergence, I copied the final values of the compressed grid back to the original grid. The savings gained from unit stride access of the compressed grid more than paid for the cost of copying. Using compressed grids, the loop from code 1 included in the previous section becomes do j = 1, GZ do i = 1, GZ T1 = CA(i+0, j-1) + CA(i-1, j+0) T4 = CA1(i+1, j+0) + CA1(i+0, j+1) S1 = T1 + T4 - 4 * CA1(i+0, j+0) CA(i+0, j+0) = CA1(i+0, j+0) + DD * S1 enddo enddo where CA and CA1 are compressed arrays of size GZ. Code 7 traverses a list of objects selecting objects for later processing. The labels of the selected objects are stored in an array. The selection step has unit stride, but the processing steps have irregular stride. A fix is to save the parameters of the selected objects in temporary arrays as they are selected, and pass the temporary arrays to the processing functions. The fix is practical if the same parameters are used in selection as in processing, or if processing comprises a series of distinct steps which use overlapping subsets of the parameters. Both conditions are true for code 7, so I achieved significant improvement by copying parameters to temporary arrays during selection. Data reuse In the previous sections, we optimized for spatial locality. It is also important to optimize for temporal locality. Once read, a datum should be used as much as possible before it is forced from cache. Loop fusion and loop unrolling are two techniques that increase temporal locality. Unfortunately, both techniques increase register pressure—as loop bodies become larger, the number of registers required to hold temporary values grows. Once register spilling occurs, any gains evaporate quickly. For multiprocessors with small register sets or small caches, the sweet spot can be very small. In the ten codes presented here, I found no opportunities for loop fusion and only two opportunities for loop unrolling (codes 1 and 3). In code 1, unrolling the outer and inner loop one iteration increases the number of result values computed by the loop body from 1 to 4, do J = 1, GZ-2, 2 do I = 1, GZ-2, 2 T1 = CA1(i+0, j-1) + CA1(i-1, j+0) T2 = CA1(i+1, j-1) + CA1(i+0, j+0) T3 = CA1(i+0, j+0) + CA1(i-1, j+1) T4 = CA1(i+1, j+0) + CA1(i+0, j+1) T5 = CA1(i+2, j+0) + CA1(i+1, j+1) T6 = CA1(i+1, j+1) + CA1(i+0, j+2) T7 = CA1(i+2, j+1) + CA1(i+1, j+2) S1 = T1 + T4 - 4 * CA1(i+0, j+0) S2 = T2 + T5 - 4 * CA1(i+1, j+0) S3 = T3 + T6 - 4 * CA1(i+0, j+1) S4 = T4 + T7 - 4 * CA1(i+1, j+1) CA(i+0, j+0) = CA1(i+0, j+0) + DD * S1 CA(i+1, j+0) = CA1(i+1, j+0) + DD * S2 CA(i+0, j+1) = CA1(i+0, j+1) + DD * S3 CA(i+1, j+1) = CA1(i+1, j+1) + DD * S4 enddo enddo The loop body executes 12 reads, whereas as the rolled loop shown in the previous section executes 20 reads to compute the same four values. In code 3, two loops are unrolled 8 times and one loop is unrolled 4 times. Here is the before for (k = 0; k < NK[u]; k++) { sum = 0.0; for (y = 0; y < NY; y++) { sum += W[y][u][k] * delta[y]; } backprop[i++]=sum; } and after code for (k = 0; k < KK - 8; k+=8) { sum0 = 0.0; sum1 = 0.0; sum2 = 0.0; sum3 = 0.0; sum4 = 0.0; sum5 = 0.0; sum6 = 0.0; sum7 = 0.0; for (y = 0; y < NY; y++) { sum0 += W[y][0][k+0] * delta[y]; sum1 += W[y][0][k+1] * delta[y]; sum2 += W[y][0][k+2] * delta[y]; sum3 += W[y][0][k+3] * delta[y]; sum4 += W[y][0][k+4] * delta[y]; sum5 += W[y][0][k+5] * delta[y]; sum6 += W[y][0][k+6] * delta[y]; sum7 += W[y][0][k+7] * delta[y]; } backprop[k+0] = sum0; backprop[k+1] = sum1; backprop[k+2] = sum2; backprop[k+3] = sum3; backprop[k+4] = sum4; backprop[k+5] = sum5; backprop[k+6] = sum6; backprop[k+7] = sum7; } for one of the loops unrolled 8 times. Optimizing for temporal locality is the most difficult optimization considered in this paper. The concepts are not difficult, but the sweet spot is small. Identifying where the program can benefit from loop unrolling or loop fusion is not trivial. Moreover, it takes some effort to get it right. Still, educating scientific programmers about temporal locality and teaching them how to optimize for it will pay dividends. Reducing instruction count Execution time is a function of instruction count. Reduce the count and you usually reduce the time. The best solution is to use a more efficient algorithm; that is, an algorithm whose order of complexity is smaller, that converges quicker, or is more accurate. Optimizing source code without changing the algorithm yields smaller, but still significant, gains. This paper considers only the latter because the intent is to study how much better codes can run if written by programmers schooled in basic code optimization techniques. The ten codes studied benefited from three types of "instruction reducing" optimizations. The two most prevalent were hoisting invariant memory and data operations out of inner loops. The third was eliminating unnecessary data copying. The nature of these inefficiencies is language dependent. Memory operations The semantics of C make it difficult for the compiler to determine all the invariant memory operations in a loop. The problem is particularly acute for loops in functions since the compiler may not know the values of the function's parameters at every call site when compiling the function. Most compilers support pragmas to help resolve ambiguities; however, these pragmas are not comprehensive and there is no standard syntax. To guarantee that invariant memory operations are not executed repetitively, the user has little choice but to hoist the operations by hand. The problem is not as severe in Fortran programs because in the absence of equivalence statements, it is a violation of the language's semantics for two names to share memory. Codes 3 and 5 are C programs. In both cases, the compiler did not hoist all invariant memory operations from inner loops. Consider the following loop from code 3 for (y = 0; y < NY; y++) { i = 0; for (u = 0; u < NU; u++) { for (k = 0; k < NK[u]; k++) { dW[y][u][k] += delta[y] * I1[i++]; } } } Since dW[y][u] can point to the same memory space as delta for one or more values of y and u, assignment to dW[y][u][k] may change the value of delta[y]. In reality, dW and delta do not overlap in memory, so I rewrote the loop as for (y = 0; y < NY; y++) { i = 0; Dy = delta[y]; for (u = 0; u < NU; u++) { for (k = 0; k < NK[u]; k++) { dW[y][u][k] += Dy * I1[i++]; } } } Failure to hoist invariant memory operations may be due to complex address calculations. If the compiler can not determine that the address calculation is invariant, then it can hoist neither the calculation nor the associated memory operations. As noted above, code 5 uses a macro to address four-dimensional arrays #define MAT4D(a,q,i,j,k) (double *)((a)->data + (q)*(a)->strides[0] + (i)*(a)->strides[3] + (j)*(a)->strides[2] + (k)*(a)->strides[1]) The macro is too complex for the compiler to understand and so, it does not identify any subexpressions as loop invariant. The simplest way to eliminate the address calculation from the innermost loop (over i) is to define a0 = MAT4D(a,q,0,j,k) before the loop and then replace all instances of *MAT4D(a,q,i,j,k) in the loop with a0[i] A similar problem appears in code 6, a Fortran program. The key loop in this program is do n1 = 1, nh nx1 = (n1 - 1) / nz + 1 nz1 = n1 - nz * (nx1 - 1) do n2 = 1, nh nx2 = (n2 - 1) / nz + 1 nz2 = n2 - nz * (nx2 - 1) ndx = nx2 - nx1 ndy = nz2 - nz1 gxx = grn(1,ndx,ndy) gyy = grn(2,ndx,ndy) gxy = grn(3,ndx,ndy) balance(n1,1) = balance(n1,1) + (force(n2,1) * gxx + force(n2,2) * gxy) * h1 balance(n1,2) = balance(n1,2) + (force(n2,1) * gxy + force(n2,2) * gyy)*h1 end do end do The programmer has written this loop well—there are no loop invariant operations with respect to n1 and n2. However, the loop resides within an iterative loop over time and the index calculations are independent with respect to time. Trading space for time, I precomputed the index values prior to the entering the time loop and stored the values in two arrays. I then replaced the index calculations with reads of the arrays. Data operations Ways to reduce data operations can appear in many forms. Implementing a more efficient algorithm produces the biggest gains. The closest I came to an algorithm change was in code 4. This code computes the inner product of K-vectors A(i) and B(j), 0 = i < N, 0 = j < M, for most values of i and j. Since the program computes most of the NM possible inner products, it is more efficient to compute all the inner products in one triply-nested loop rather than one at a time when needed. The savings accrue from reading A(i) once for all B(j) vectors and from loop unrolling. for (i = 0; i < N; i+=8) { for (j = 0; j < M; j++) { sum0 = 0.0; sum1 = 0.0; sum2 = 0.0; sum3 = 0.0; sum4 = 0.0; sum5 = 0.0; sum6 = 0.0; sum7 = 0.0; for (k = 0; k < K; k++) { sum0 += A[i+0][k] * B[j][k]; sum1 += A[i+1][k] * B[j][k]; sum2 += A[i+2][k] * B[j][k]; sum3 += A[i+3][k] * B[j][k]; sum4 += A[i+4][k] * B[j][k]; sum5 += A[i+5][k] * B[j][k]; sum6 += A[i+6][k] * B[j][k]; sum7 += A[i+7][k] * B[j][k]; } C[i+0][j] = sum0; C[i+1][j] = sum1; C[i+2][j] = sum2; C[i+3][j] = sum3; C[i+4][j] = sum4; C[i+5][j] = sum5; C[i+6][j] = sum6; C[i+7][j] = sum7; }} This change requires knowledge of a typical run; i.e., that most inner products are computed. The reasons for the change, however, derive from basic optimization concepts. It is the type of change easily made at development time by a knowledgeable programmer. In code 5, we have the data version of the index optimization in code 6. Here a very expensive computation is a function of the loop indices and so cannot be hoisted out of the loop; however, the computation is invariant with respect to an outer iterative loop over time. We can compute its value for each iteration of the computation loop prior to entering the time loop and save the values in an array. The increase in memory required to store the values is small in comparison to the large savings in time. The main loop in Code 8 is doubly nested. The inner loop includes a series of guarded computations; some are a function of the inner loop index but not the outer loop index while others are a function of the outer loop index but not the inner loop index for (j = 0; j < N; j++) { for (i = 0; i < M; i++) { r = i * hrmax; R = A[j]; temp = (PRM[3] == 0.0) ? 1.0 : pow(r, PRM[3]); high = temp * kcoeff * B[j] * PRM[2] * PRM[4]; low = high * PRM[6] * PRM[6] / (1.0 + pow(PRM[4] * PRM[6], 2.0)); kap = (R > PRM[6]) ? high * R * R / (1.0 + pow(PRM[4]*r, 2.0) : low * pow(R/PRM[6], PRM[5]); < rest of loop omitted > }} Note that the value of temp is invariant to j. Thus, we can hoist the computation for temp out of the loop and save its values in an array. for (i = 0; i < M; i++) { r = i * hrmax; TEMP[i] = pow(r, PRM[3]); } [N.B. – the case for PRM[3] = 0 is omitted and will be reintroduced later.] We now hoist out of the inner loop the computations invariant to i. Since the conditional guarding the value of kap is invariant to i, it behooves us to hoist the computation out of the inner loop, thereby executing the guard once rather than M times. The final version of the code is for (j = 0; j < N; j++) { R = rig[j] / 1000.; tmp1 = kcoeff * par[2] * beta[j] * par[4]; tmp2 = 1.0 + (par[4] * par[4] * par[6] * par[6]); tmp3 = 1.0 + (par[4] * par[4] * R * R); tmp4 = par[6] * par[6] / tmp2; tmp5 = R * R / tmp3; tmp6 = pow(R / par[6], par[5]); if ((par[3] == 0.0) && (R > par[6])) { for (i = 1; i <= imax1; i++) KAP[i] = tmp1 * tmp5; } else if ((par[3] == 0.0) && (R <= par[6])) { for (i = 1; i <= imax1; i++) KAP[i] = tmp1 * tmp4 * tmp6; } else if ((par[3] != 0.0) && (R > par[6])) { for (i = 1; i <= imax1; i++) KAP[i] = tmp1 * TEMP[i] * tmp5; } else if ((par[3] != 0.0) && (R <= par[6])) { for (i = 1; i <= imax1; i++) KAP[i] = tmp1 * TEMP[i] * tmp4 * tmp6; } for (i = 0; i < M; i++) { kap = KAP[i]; r = i * hrmax; < rest of loop omitted > } } Maybe not the prettiest piece of code, but certainly much more efficient than the original loop, Copy operations Several programs unnecessarily copy data from one data structure to another. This problem occurs in both Fortran and C programs, although it manifests itself differently in the two languages. Code 1 declares two arrays—one for old values and one for new values. At the end of each iteration, the array of new values is copied to the array of old values to reset the data structures for the next iteration. This problem occurs in Fortran programs not included in this study and in both Fortran 77 and Fortran 90 code. Introducing pointers to the arrays and swapping pointer values is an obvious way to eliminate the copying; but pointers is not a feature that many Fortran programmers know well or are comfortable using. An easy solution not involving pointers is to extend the dimension of the value array by 1 and use the last dimension to differentiate between arrays at different times. For example, if the data space is N x N, declare the array (N, N, 2). Then store the problem’s initial values in (_, _, 2) and define the scalar names new = 2 and old = 1. At the start of each iteration, swap old and new to reset the arrays. The old–new copy problem did not appear in any C program. In programs that had new and old values, the code swapped pointers to reset data structures. Where unnecessary coping did occur is in structure assignment and parameter passing. Structures in C are handled much like scalars. Assignment causes the data space of the right-hand name to be copied to the data space of the left-hand name. Similarly, when a structure is passed to a function, the data space of the actual parameter is copied to the data space of the formal parameter. If the structure is large and the assignment or function call is in an inner loop, then copying costs can grow quite large. While none of the ten programs considered here manifested this problem, it did occur in programs not included in the study. A simple fix is always to refer to structures via pointers. Optimizing loop structures Since scientific programs spend almost all their time in loops, efficient loops are the key to good performance. Conditionals, function calls, little instruction level parallelism, and large numbers of temporary values make it difficult for the compiler to generate tightly packed, highly efficient code. Conditionals and function calls introduce jumps that disrupt code flow. Users should eliminate or isolate conditionls to their own loops as much as possible. Often logical expressions can be substituted for if-then-else statements. For example, code 2 includes the following snippet MaxDelta = 0.0 do J = 1, N do I = 1, M < code omitted > Delta = abs(OldValue ? NewValue) if (Delta > MaxDelta) MaxDelta = Delta enddo enddo if (MaxDelta .gt. 0.001) goto 200 Since the only use of MaxDelta is to control the jump to 200 and all that matters is whether or not it is greater than 0.001, I made MaxDelta a boolean and rewrote the snippet as MaxDelta = .false. do J = 1, N do I = 1, M < code omitted > Delta = abs(OldValue ? NewValue) MaxDelta = MaxDelta .or. (Delta .gt. 0.001) enddo enddo if (MaxDelta) goto 200 thereby, eliminating the conditional expression from the inner loop. A microprocessor can execute many instructions per instruction cycle. Typically, it can execute one or more memory, floating point, integer, and jump operations. To be executed simultaneously, the operations must be independent. Thick loops tend to have more instruction level parallelism than thin loops. Moreover, they reduce memory traffice by maximizing data reuse. Loop unrolling and loop fusion are two techniques to increase the size of loop bodies. Several of the codes studied benefitted from loop unrolling, but none benefitted from loop fusion. This observation is not too surpising since it is the general tendency of programmers to write thick loops. As loops become thicker, the number of temporary values grows, increasing register pressure. If registers spill, then memory traffic increases and code flow is disrupted. A thick loop with many temporary values may execute slower than an equivalent series of thin loops. The biggest gain will be achieved if the thick loop can be split into a series of independent loops eliminating the need to write and read temporary arrays. I found such an occasion in code 10 where I split the loop do i = 1, n do j = 1, m A24(j,i)= S24(j,i) * T24(j,i) + S25(j,i) * U25(j,i) B24(j,i)= S24(j,i) * T25(j,i) + S25(j,i) * U24(j,i) A25(j,i)= S24(j,i) * C24(j,i) + S25(j,i) * V24(j,i) B25(j,i)= S24(j,i) * U25(j,i) + S25(j,i) * V25(j,i) C24(j,i)= S26(j,i) * T26(j,i) + S27(j,i) * U26(j,i) D24(j,i)= S26(j,i) * T27(j,i) + S27(j,i) * V26(j,i) C25(j,i)= S27(j,i) * S28(j,i) + S26(j,i) * U28(j,i) D25(j,i)= S27(j,i) * T28(j,i) + S26(j,i) * V28(j,i) end do end do into two disjoint loops do i = 1, n do j = 1, m A24(j,i)= S24(j,i) * T24(j,i) + S25(j,i) * U25(j,i) B24(j,i)= S24(j,i) * T25(j,i) + S25(j,i) * U24(j,i) A25(j,i)= S24(j,i) * C24(j,i) + S25(j,i) * V24(j,i) B25(j,i)= S24(j,i) * U25(j,i) + S25(j,i) * V25(j,i) end do end do do i = 1, n do j = 1, m C24(j,i)= S26(j,i) * T26(j,i) + S27(j,i) * U26(j,i) D24(j,i)= S26(j,i) * T27(j,i) + S27(j,i) * V26(j,i) C25(j,i)= S27(j,i) * S28(j,i) + S26(j,i) * U28(j,i) D25(j,i)= S27(j,i) * T28(j,i) + S26(j,i) * V28(j,i) end do end do Conclusions Over the course of the last year, I have had the opportunity to work with over two dozen academic scientific programmers at leading research universities. Their research interests span a broad range of scientific fields. Except for two programs that relied almost exclusively on library routines (matrix multiply and fast Fourier transform), I was able to improve significantly the single processor performance of all codes. Improvements range from 2x to 15.5x with a simple average of 4.75x. Changes to the source code were at a very high level. I did not use sophisticated techniques or programming tools to discover inefficiencies or effect the changes. Only one code was parallel despite the availability of parallel systems to all developers. Clearly, we have a problem—personal scientific research codes are highly inefficient and not running parallel. The developers are unaware of simple optimization techniques to make programs run faster. They lack education in the art of code optimization and parallel programming. I do not believe we can fix the problem by publishing additional books or training manuals. To date, the developers in questions have not studied the books or manual available, and are unlikely to do so in the future. Short courses are a possible solution, but I believe they are too concentrated to be much use. The general concepts can be taught in a three or four day course, but that is not enough time for students to practice what they learn and acquire the experience to apply and extend the concepts to their codes. Practice is the key to becoming proficient at optimization. I recommend that graduate students be required to take a semester length course in optimization and parallel programming. We would never give someone access to state-of-the-art scientific equipment costing hundreds of thousands of dollars without first requiring them to demonstrate that they know how to use the equipment. Yet the criterion for time on state-of-the-art supercomputers is at most an interesting project. Requestors are never asked to demonstrate that they know how to use the system, or can use the system effectively. A semester course would teach them the required skills. Government agencies that fund academic scientific research pay for most of the computer systems supporting scientific research as well as the development of most personal scientific codes. These agencies should require graduate schools to offer a course in optimization and parallel programming as a requirement for funding. About the Author John Feo received his Ph.D. in Computer Science from The University of Texas at Austin in 1986. After graduate school, Dr. Feo worked at Lawrence Livermore National Laboratory where he was the Group Leader of the Computer Research Group and principal investigator of the Sisal Language Project. In 1997, Dr. Feo joined Tera Computer Company where he was project manager for the MTA, and oversaw the programming and evaluation of the MTA at the San Diego Supercomputer Center. In 2000, Dr. Feo joined Sun Microsystems as an HPC application specialist. He works with university research groups to optimize and parallelize scientific codes. Dr. Feo has published over two dozen research articles in the areas of parallel parallel programming, parallel programming languages, and application performance.

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• How to create a "shutdown user" or "shutdown account"

  - by pcapademic

  Red Hat had a feature useful to me at the present time. There was an account, generally called "shutdown", and when you logged in with the account, the system shut down. In my specific case, I have Ubuntu Server running in a VM on my local system. The VM is running a web app, and when I'm done doing work, I want to shut down the VM. Unfortunately, I can't install VMware tools to get the "power button" based shutdown. Currently I login then sudo shutdown -h now, then type my password again, and things shutdown. Really, it's getting annoying all that waiting around and typing things. How do I replicate the "shutdown account" functionality in Ubuntu? A related question, were there any security gotchas that motivated people to stop using this kind of account?

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• HTG Explains: Why You Shouldn’t Disable UAC

  - by Chris Hoffman

  User Account Control is an important security feature in the latest versions of Windows. While we’ve explained how to disable UAC in the past, you shouldn’t disable it – it helps keep your computer secure. If you reflexively disable UAC when setting up a computer, you should give it another try – UAC and the Windows software ecosystem have come a long way from when UAC was introduced with Windows Vista. How To Create a Customized Windows 7 Installation Disc With Integrated Updates How to Get Pro Features in Windows Home Versions with Third Party Tools HTG Explains: Is ReadyBoost Worth Using?

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• keyboard layout switching on restart

  - by zidarsk8

  I have two keyboard layouts that I use, My default keyboard is an USA layout, with a secondary Slovenian layout. I use the Slovenian layout only when I need some special characters when writing emails and such. But my problem is this: Every time I reboot my computer, the layout indicator shows I am on the USA layout, but the actual keyboard layout is Slovenian. Then I normally have to switch from USA to Slovenian and back, to get the layout I want. Is there anything I can do about this? I don't restart my computer often, but when I do I forget about that, and typing the passwords like that doesn't work.

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• Changing enum in a different class for screen

  - by user2434321

  I'm trying to make a start menu for my game and my code uses Enum's to moniter the screen state. Now i want to change the screenstate declared in the main class, in my Background class Screen screen = new Screen(); is declared in the Game1 class Background(ref screen); This is in the update method for the Background Class KeyboardState keystate = Keyboard.GetState(); switch (screen) { case Screen.Start: if (isPressed && keystate.IsKeyUp(Keys.Up) && keystate.IsKeyUp(Keys.Down) && keystate.IsKeyUp(Keys.Enter)) { isPressed = false; } if (keystate.IsKeyDown(Keys.Down) && isPressed != true) { if (menuState == MenuState.Options) menuState = MenuState.Credits; if (menuState == MenuState.Play) menuState = MenuState.Options; isPressed = true; } if (keystate.IsKeyDown(Keys.Up) && isPressed != true) { if (menuState == MenuState.Options) menuState = MenuState.Play; if (menuState == MenuState.Credits) menuState = MenuState.Options; isPressed = true; } switch (menuState) { case MenuState.Play: arrowRect.X = 450; arrowRect.Y = 220; if (keystate.IsKeyDown(Keys.Enter) && isPressed != true) screen = Screen.Play; break; case MenuState.Options: arrowRect.X = 419; arrowRect.Y = 340; if (keystate.IsKeyDown(Keys.Enter) && isPressed != true) screen = Screen.Options; break; case MenuState.Credits: arrowRect.X = 425; arrowRect.Y = 460; if (keystate.IsKeyDown(Keys.Enter) && isPressed != true) screen = Screen.Credits; break; } break; } } For some reason when I play this and I hit the enter button the Background class's screen is changed but the main class's screen isn't how can i change this? EDIT 1* class Background { private Texture2D background; private Rectangle backgroundRect; private Texture2D arrow; private Rectangle arrowRect; private Screen screen; private MenuState menuState; private bool isPressed = false; public Screen getScreenState(ref Screen screen) { this.screen = screen; return this.screen; } public Background(ref Screen screen) { this.screen = screen; } public void Update() { KeyboardState keystate = Keyboard.GetState(); switch (screen) { case Screen.Start: if (isPressed && keystate.IsKeyUp(Keys.Up) && keystate.IsKeyUp(Keys.Down) && keystate.IsKeyUp(Keys.Enter)) { isPressed = false; } if (keystate.IsKeyDown(Keys.Down) && isPressed != true) { if (menuState == MenuState.Options) menuState = MenuState.Credits; if (menuState == MenuState.Play) menuState = MenuState.Options; isPressed = true; } if (keystate.IsKeyDown(Keys.Up) && isPressed != true) { if (menuState == MenuState.Options) menuState = MenuState.Play; if (menuState == MenuState.Credits) menuState = MenuState.Options; isPressed = true; } switch (menuState) { case MenuState.Play: arrowRect.X = 450; arrowRect.Y = 220; if (keystate.IsKeyDown(Keys.Enter) && isPressed != true) screen = Screen.Play; break; case MenuState.Options: arrowRect.X = 419; arrowRect.Y = 340; if (keystate.IsKeyDown(Keys.Enter) && isPressed != true) screen = Screen.Options; break; case MenuState.Credits: arrowRect.X = 425; arrowRect.Y = 460; if (keystate.IsKeyDown(Keys.Enter) && isPressed != true) screen = Screen.Credits; break; } break; case Screen.Pause: break; case Screen.Over: break; } } public void LoadStartContent(ContentManager Content, GraphicsDeviceManager graphics) { background = Content.Load<Texture2D>("startBackground"); arrow = Content.Load<Texture2D>("arrow"); backgroundRect = new Rectangle(0, 0, graphics.GraphicsDevice.Viewport.Width, graphics.GraphicsDevice.Viewport.Height); arrowRect = new Rectangle(450, 225, arrow.Width, arrow.Height); screen = Screen.Start; } public void LoadPlayContent(ContentManager Content, GraphicsDeviceManager graphics) { background = Content.Load<Texture2D>("Background"); backgroundRect = new Rectangle(0, 0, graphics.GraphicsDevice.Viewport.Width, graphics.GraphicsDevice.Viewport.Height); screen = Screen.Play; } public void LoadOverContent(ContentManager Content, GraphicsDeviceManager graphics) { } public void Draw(SpriteBatch spritebatch) { if (screen == Screen.Start) { spritebatch.Draw(background, backgroundRect, Color.White); spritebatch.Draw(arrow, arrowRect, Color.White); } else spritebatch.Draw(background, backgroundRect, Color.White); } } Thats my background class!

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• Clockwork: A 40,000 Piece K’Nex Ball Machine [Video]

  - by Jason Fitzpatrick

  You may have built a simple marble raceway out of construction toys like LEGO or K’Nex at some point in your life. No matter how grand a raceway it was, we can assure you it had nothing on this 40,000 piece room-sized monster. The creator, Austron, writes: This is Clockwork, my fifth major K’nex ball machine, and my largest and most complex K’nex structure to date. It took 8 months to build, has over 40,000 pieces, over 450 feet of track, 21 different paths, 8 motors, 5 lifts, and a one-of-a-kind computer-controlled crane, as well as two computer-controlled illuminated K’nex balls. For a more in-depth look at the construction we suggest checking out both his YouTube channel and his build blog. [via Make] How to Get Pro Features in Windows Home Versions with Third Party Tools HTG Explains: Is ReadyBoost Worth Using? HTG Explains: What The Windows Event Viewer Is and How You Can Use It

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• Choose Your Ubuntu: 8 Ubuntu Derivatives with Different Desktop Environments

  - by Chris Hoffman

  There are a wide variety of Linux distributions, but there are also a wide variety of distributions based on other Linux distributions. The official Ubuntu release with the Unity desktop is only one of many possible ways to use Ubuntu. Most of these Ubuntu derivatives are officially supported by Ubuntu. Some, like the Ubuntu GNOME Remix and Linux Mint, aren’t official. Each includes different desktop environments with different software, but the base system is the same (except with Linux Mint.) You can try each of these derivatives by downloading its appropriate live CD, burning it to a disc, and booting from it – no installation required. Testing desktop environments is probably the best way to find the one you’re most comfortable with. How Hackers Can Disguise Malicious Programs With Fake File Extensions Can Dust Actually Damage My Computer? What To Do If You Get a Virus on Your Computer

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• Regardless of battery charge, when unplugged Ubuntu displays critical battery message and hibernates

  - by Chesc

  Regardless of battery charge, when unplugged Ubuntu displays critical battery message and hibernates. I can only seem to change it to either shutdown or hibernate. This does not happen when using windows 7 on the same computer. Windows 7 gives a good few hours on a full charge indicating that it is not a battery problem. Any help? I really don't want to have to use windows but its kinda pointless having a netbook that doesn't work when not plugged in! I'm using a toshiba nb250 and the most up to date 11.10 ubuntu distro. I use to get the critical battery message before on the previous ubuntu but it never shut down or hibernated my computer.

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• Why does my domain not show up in Google anymore?

  - by Earlz

  So I have had a website since about 2006. It's http://earlz.biz.tm . Recently I've noticed that no results will show up for it in google. I do have a secondary domain(that I plan on getting rid of) pointing to it but I don't understand why google would suddenly not show my site. I believe it was showing up a few months ago and my website is hardly ever down, like one or two days I believe has been the most it's been down in a row in this time period. Is there something wrong with my DNS or other configuration that would make google not index me? For reference I've tried: earlz.biz.tm site:earlz.biz.tm and the heading from my site "Earlz.biz.tm -- The reasoning is bacon" A few show up with the therusticstone.com domain(the one I plan to point somewhere else) but none show up directly linking to earlz.biz.tm.

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• Ask the Readers: What’s the First Thing You Do After Installing a New OS?

  - by Jason Fitzpatrick

  You’ve just booted up your new OS for the first time after a fresh install. What’s the first thing you do? Install specific apps? Tweak settings? Bask in the new-computer-smell of an uncluttered OS? Once a week we put a question before the How-To Geek readership to give you all a chance to share your knowledge and tips with your fellow readers. This week we want to hear about your tips and tricks for whipping a new OS installation into shape. Whether you’ve just installed Windows, Mac OS X, or Linux, we’re curious what kind of computer-warming rituals you visit upon your new OS. Sound off in the comments below and then check back in on Friday for the What Your Said roundup.  How to Enable Google Chrome’s Secret Gold IconHow to Create an Easy Pixel Art Avatar in Photoshop or GIMPInternet Explorer 9 Released: Here’s What You Need To Know

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• ANTS Memory Profiler 7.0 Review

  - by Michael B. McLaughlin

  (This is my first review as a part of the GeeksWithBlogs.net Influencers program. It’s a program in which I (and the others who have been selected for it) get the opportunity to check out new products and services and write reviews about them. We don’t get paid for this, but we do generally get to keep a copy of the software or retain an account for some period of time on the service that we review. In this case I received a copy of Red Gate Software’s ANTS Memory Profiler 7.0, which was released in January. I don’t have any upgrade rights nor is my review guided, restrained, influenced, or otherwise controlled by Red Gate or anyone else. But I do get to keep the software license. I will always be clear about what I received whenever I do a review – I leave it up to you to decide whether you believe I can be objective. I believe I can be. If I used something and really didn’t like it, keeping a copy of it wouldn’t be worth anything to me. In that case though, I would simply uninstall/deactivate/whatever the software or service and tell the company what I didn’t like about it so they could (hopefully) make it better in the future. I don’t think it’d be polite to write up a terrible review, nor do I think it would be a particularly good use of my time. There are people who get paid for a living to review things, so I leave it to them to tell you what they think is bad and why. I’ll only spend my time telling you about things I think are good.) Overview of Common .NET Memory Problems When coming to land of managed memory from the wilds of unmanaged code, it’s easy to say to one’s self, “Wow! Now I never have to worry about memory problems again!” But this simply isn’t true. Managed code environments, such as .NET, make many, many things easier. You will never have to worry about memory corruption due to a bad pointer, for example (unless you’re working with unsafe code, of course). But managed code has its own set of memory concerns. For example, failing to unsubscribe from events when you are done with them leaves the publisher of an event with a reference to the subscriber. If you eliminate all your own references to the subscriber, then that memory is effectively lost since the GC won’t delete it because of the publishing object’s reference. When the publishing object itself becomes subject to garbage collection then you’ll get that memory back finally, but that could take a very long time depending of the life of the publisher. Another common source of resource leaks is failing to properly release unmanaged resources. When writing a class that contains members that hold unmanaged resources (e.g. any of the Stream-derived classes, IsolatedStorageFile, most classes ending in “Reader” or “Writer”), you should always implement IDisposable, making sure to use a properly written Dispose method. And when you are using an instance of a class that implements IDisposable, you should always make sure to use a 'using' statement in order to ensure that the object’s unmanaged resources are disposed of properly. (A ‘using’ statement is a nicer, cleaner looking, and easier to use version of a try-finally block. The compiler actually translates it as though it were a try-finally block. Note that Code Analysis warning 2202 (CA2202) will often be triggered by nested using blocks. A properly written dispose method ensures that it only runs once such that calling dispose multiple times should not be a problem. Nonetheless, CA2202 exists and if you want to avoid triggering it then you should write your code such that only the innermost IDisposable object uses a ‘using’ statement, with any outer code making use of appropriate try-finally blocks instead). Then, of course, there are situations where you are operating in a memory-constrained environment or else you want to limit or even eliminate allocations within a certain part of your program (e.g. within the main game loop of an XNA game) in order to avoid having the GC run. On the Xbox 360 and Windows Phone 7, for example, for every 1 MB of heap allocations you make, the GC runs; the added time of a GC collection can cause a game to drop frames or run slowly thereby making it look bad. Eliminating allocations (or else minimizing them and calling an explicit Collect at an appropriate time) is a common way of avoiding this (the other way is to simplify your heap so that the GC’s latency is low enough not to cause performance issues). ANTS Memory Profiler 7.0 When the opportunity to review Red Gate’s recently released ANTS Memory Profiler 7.0 arose, I jumped at it. In order to review it, I was given a free copy (which does not include upgrade rights for future versions) which I am allowed to keep. For those of you who are familiar with ANTS Memory Profiler, you can find a list of new features and enhancements here. If you are an experienced .NET developer who is familiar with .NET memory management issues, ANTS Memory Profiler is great. More importantly still, if you are new to .NET development or you have no experience or limited experience with memory profiling, ANTS Memory Profiler is awesome. From the very beginning, it guides you through the process of memory profiling. If you’re experienced and just want dive in however, it doesn’t get in your way. The help items GAHSFLASHDAJLDJA are well designed and located right next to the UI controls so that they are easy to find without being intrusive. When you first launch it, it presents you with a “Getting Started” screen that contains links to “Memory profiling video tutorials”, “Strategies for memory profiling”, and the “ANTS Memory Profiler forum”. I’m normally the kind of person who looks at a screen like that only to find the “Don’t show this again” checkbox. Since I was doing a review, though, I decided I should examine them. I was pleasantly surprised. The overview video clocks in at three minutes and fifty seconds. It begins by showing you how to get started profiling an application. It explains that profiling is done by taking memory snapshots periodically while your program is running and then comparing them. ANTS Memory Profiler (I’m just going to call it “ANTS MP” from here) analyzes these snapshots in the background while your application is running. It briefly mentions a new feature in Version 7, a new API that give you the ability to trigger snapshots from within your application’s source code (more about this below). You can also, and this is the more common way you would do it, take a memory snapshot at any time from within the ANTS MP window by clicking the “Take Memory Snapshot” button in the upper right corner. The overview video goes on to demonstrate a basic profiling session on an application that pulls information from a database and displays it. It shows how to switch which snapshots you are comparing, explains the different sections of the Summary view and what they are showing, and proceeds to show you how to investigate memory problems using the “Instance Categorizer” to track the path from an object (or set of objects) to the GC’s root in order to find what things along the path are holding a reference to it/them. For a set of objects, you can then click on it and get the “Instance List” view. This displays all of the individual objects (including their individual sizes, values, etc.) of that type which share the same path to the GC root. You can then click on one of the objects to generate an “Instance Retention Graph” view. This lets you track directly up to see the reference chain for that individual object. In the overview video, it turned out that there was an event handler which was holding on to a reference, thereby keeping a large number of strings that should have been freed in memory. Lastly the video shows the “Class List” view, which lets you dig in deeply to find problems that might not have been clear when following the previous workflow. Once you have at least one memory snapshot you can begin analyzing. The main interface is in the “Analysis” tab. You can also switch to the “Session Overview” tab, which gives you several bar charts highlighting basic memory data about the snapshots you’ve taken. If you hover over the individual bars (and the individual colors in bars that have more than one), you will see a detailed text description of what the bar is representing visually. The Session Overview is good for a quick summary of memory usage and information about the different heaps. You are going to spend most of your time in the Analysis tab, but it’s good to remember that the Session Overview is there to give you some quick feedback on basic memory usage stats. As described above in the summary of the overview video, there is a certain natural workflow to the Analysis tab. You’ll spin up your application and take some snapshots at various times such as before and after clicking a button to open a window or before and after closing a window. Taking these snapshots lets you examine what is happening with memory. You would normally expect that a lot of memory would be freed up when closing a window or exiting a document. By taking snapshots before and after performing an action like that you can see whether or not the memory is really being freed. If you already know an area that’s giving you trouble, you can run your application just like normal until just before getting to that part and then you can take a few strategic snapshots that should help you pin down the problem. Something the overview didn’t go into is how to use the “Filters” section at the bottom of ANTS MP together with the Class List view in order to narrow things down. The video tutorials page has a nice 3 minute intro video called “How to use the filters”. It’s a nice introduction and covers some of the basics. I’m going to cover a bit more because I think they’re a really neat, really helpful feature. Large programs can bring up thousands of classes. Even simple programs can instantiate far more classes than you might realize. In a basic .NET 4 WPF application for example (and when I say basic, I mean just MainWindow.xaml with a button added to it), the unfiltered Class List view will have in excess of 1000 classes (my simple test app had anywhere from 1066 to 1148 classes depending on which snapshot I was using as the “Current” snapshot). This is amazing in some ways as it shows you how in stark detail just how immensely powerful the WPF framework is. But hunting through 1100 classes isn’t productive, no matter how cool it is that there are that many classes instantiated and doing all sorts of awesome things. Let’s say you wanted to examine just the classes your application contains source code for (in my simple example, that would be the MainWindow and App). Under “Basic Filters”, click on “Classes with source” under “Show only…”. Voilà. Down from 1070 classes in the snapshot I was using as “Current” to 2 classes. If you then click on a class’s name, it will show you (to the right of the class name) two little icon buttons. Hover over them and you will see that you can click one to view the Instance Categorizer for the class and another to view the Instance List for the class. You can also show classes based on which heap they live on. If you chose both a Baseline snapshot and a Current snapshot then you can use the “Comparing snapshots” filters to show only: “New objects”; “Surviving objects”; “Survivors in growing classes”; or “Zombie objects” (if you aren’t sure what one of these means, you can click the helpful “?” in a green circle icon to bring up a popup that explains them and provides context). Remember that your selection(s) under the “Show only…” heading will still apply, so you should update those selections to make sure you are seeing the view you want. There are also links under the “What is my memory problem?” heading that can help you diagnose the problems you are seeing including one for “I don’t know which kind I have” for situations where you know generally that your application has some problems but aren’t sure what the behavior you have been seeing (OutOfMemoryExceptions, continually growing memory usage, larger memory use than expected at certain points in the program). The Basic Filters are not the only filters there are. “Filter by Object Type” gives you the ability to filter by: “Objects that are disposable”; “Objects that are/are not disposed”; “Objects that are/are not GC roots” (GC roots are things like static variables); and “Objects that implement _______”. “Objects that implement” is particularly neat. Once you check the box, you can then add one or more classes and interfaces that an object must implement in order to survive the filtering. Lastly there is “Filter by Reference”, which gives you the option to pare down the list based on whether an object is “Kept in memory exclusively by” a particular item, a class/interface, or a namespace; whether an object is “Referenced by” one or more of those choices; and whether an object is “Never referenced by” one or more of those choices. Remember that filtering is cumulative, so anything you had set in one of the filter sections still remains in effect unless and until you go back and change it. There’s quite a bit more to ANTS MP – it’s a very full featured product – but I think I touched on all of the most significant pieces. You can use it to debug: a .NET executable; an ASP.NET web application (running on IIS); an ASP.NET web application (running on Visual Studio’s built-in web development server); a Silverlight 4 browser application; a Windows service; a COM+ server; and even something called an XBAP (local XAML browser application). You can also attach to a .NET 4 process to profile an application that’s already running. The startup screen also has a large number of “Charting Options” that let you adjust which statistics ANTS MP should collect. The default selection is a good, minimal set. It’s worth your time to browse through the charting options to examine other statistics that may also help you diagnose a particular problem. The more statistics ANTS MP collects, the longer it will take to collect statistics. So just turning everything on is probably a bad idea. But the option to selectively add in additional performance counters from the extensive list could be a very helpful thing for your memory profiling as it lets you see additional data that might provide clues about a particular problem that has been bothering you. ANTS MP integrates very nicely with all versions of Visual Studio that support plugins (i.e. all of the non-Express versions). Just note that if you choose “Profile Memory” from the “ANTS” menu that it will launch profiling for whichever project you have set as the Startup project. One quick tip from my experience so far using ANTS MP: if you want to properly understand your memory usage in an application you’ve written, first create an “empty” version of the type of project you are going to profile (a WPF application, an XNA game, etc.) and do a quick profiling session on that so that you know the baseline memory usage of the framework itself. By “empty” I mean just create a new project of that type in Visual Studio then compile it and run it with profiling – don’t do anything special or add in anything (except perhaps for any external libraries you’re planning to use). The first thing I tried ANTS MP out on was a demo XNA project of an editor that I’ve been working on for quite some time that involves a custom extension to XNA’s content pipeline. The first time I ran it and saw the unmanaged memory usage I was convinced I had some horrible bug that was creating extra copies of texture data (the demo project didn’t have a lot of texture data so when I saw a lot of unmanaged memory I instantly figured I was doing something wrong). Then I thought to run an empty project through and when I saw that the amount of unmanaged memory was virtually identical, it dawned on me that the CLR itself sits in unmanaged memory and that (thankfully) there was nothing wrong with my code! Quite a relief. Earlier, when discussing the overview video, I mentioned the API that lets you take snapshots from within your application. I gave it a quick trial and it’s very easy to integrate and make use of and is a really nice addition (especially for projects where you want to know what, if any, allocations there are in a specific, complicated section of code). The only concern I had was that if I hadn’t watched the overview video I might never have known it existed. Even then it took me five minutes of hunting around Red Gate’s website before I found the “Taking snapshots from your code" article that explains what DLL you need to add as a reference and what method of what class you should call in order to take an automatic snapshot (including the helpful warning to wrap it in a try-catch block since, under certain circumstances, it can raise an exception, such as trying to call it more than 5 times in 30 seconds. The difficulty in discovering and then finding information about the automatic snapshots API was one thing I thought could use improvement. Another thing I think would make it even better would be local copies of the webpages it links to. Although I’m generally always connected to the internet, I imagine there are more than a few developers who aren’t or who are behind very restrictive firewalls. For them (and for me, too, if my internet connection happens to be down), it would be nice to have those documents installed locally or to have the option to download an additional “documentation” package that would add local copies. Another thing that I wish could be easier to manage is the Filters area. Finding and setting individual filters is very easy as is understanding what those filter do. And breaking it up into three sections (basic, by object, and by reference) makes sense. But I could easily see myself running a long profiling session and forgetting that I had set some filter a long while earlier in a different filter section and then spending quite a bit of time trying to figure out why some problem that was clearly visible in the data wasn’t showing up in, e.g. the instance list before remembering to check all the filters for that one setting that was only culling a few things from view. Some sort of indicator icon next to the filter section names that appears you have at least one filter set in that area would be a nice visual clue to remind me that “oh yeah, I told it to only show objects on the Gen 2 heap! That’s why I’m not seeing those instances of the SuperMagic class!” Something that would be nice (but that Red Gate cannot really do anything about) would be if this could be used in Windows Phone 7 development. If Microsoft and Red Gate could work together to make this happen (even if just on the WP7 emulator), that would be amazing. Especially given the memory constraints that apps and games running on mobile devices need to work within, a good memory profiler would be a phenomenally helpful tool. If anyone at Microsoft reads this, it’d be really great if you could make something like that happen. Perhaps even a (subsidized) custom version just for WP7 development. (For XNA games, of course, you can create a Windows version of the game and use ANTS MP on the Windows version in order to get a better picture of your memory situation. For Silverlight on WP7, though, there’s quite a bit of educated guess work and WeakReference creation followed by forced collections in order to find the source of a memory problem.) The only other thing I found myself wanting was a “Back” button. Between my Windows Phone 7, Zune, and other things, I’ve grown very used to having a “back stack” that lets me just navigate back to where I came from. The ANTS MP interface is surprisingly easy to use given how much it lets you do, and once you start using it for any amount of time, you learn all of the different areas such that you know where to go. And it does remember the state of the areas you were previously in, of course. So if you go to, e.g., the Instance Retention Graph from the Class List and then return back to the Class List, it will remember which class you had selected and all that other state information. Still, a “Back” button would be a welcome addition to a future release. Bottom Line ANTS Memory Profiler is not an inexpensive tool. But my time is valuable. I can easily see ANTS MP saving me enough time tracking down memory problems to justify it on a cost basis. More importantly to me, knowing what is happening memory-wise in my programs and having the confidence that my code doesn’t have any hidden time bombs in it that will cause it to OOM if I leave it running for longer than I do when I spin it up real quickly for debugging or just to see how a new feature looks and feels is a good feeling. It’s a feeling that I like having and want to continue to have. I got the current version for free in order to review it. Having done so, I’ve now added it to my must-have tools and will gladly lay out the money for the next version when it comes out. It has a 14 day free trial, so if you aren’t sure if it’s right for you or if you think it seems interesting but aren’t really sure if it’s worth shelling out the money for it, give it a try.

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• How do I make my purchased music be synchronized on Rhythmbox and in ~./ubuntuone/Purchased from Ubuntu One?

  - by dln9

  I am signed up for the Ubuntu One service, and have my computer added. Under System ? Preferences ? Ubuntu One, I have enabled all synchronizations, including for music. System ? Prefereneces ? Ubuntu One, it shows this message: "Synchronization Complete". But, when (via Rhythmbox) I purchase a song, no synchronization occurs. I can see the purchased song on the Ubuntu One web page, but the "Purchased Music" folder in Rhythmbox is empty, and the folder ~/.ubuntuone/Purchased from Ubuntu One is also empty. (So, the only way I can get at the song is to manually download it from the Ubuntu One web site to my computer.) I thought that these synchronizations should just happen automatically, but it appears that is not the case for me, and I can't figure out why. Thanks in advance for any help.

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• Wireless Drivers for Broadcom BCM 4321 (14e4:4329) will not stay connected to a wireless network

  - by Eugene

  So, I'm not necessary new to Linux, I just never took the time to learn it, so please, bare with me. I just swapped out one of my wireless cards from one computer to another. This wireless card in question would be a "Broadcom BCM4321 (14e4:4329)" or actually a "Netgear WN311B Rangemax Next 270 Mbps Wireless PCI Adapter", but that's not important. I've tried (but probably screwed up in the process) installing the "wl" , "b43" and "brcmsmac" drivers, or at least I think I did. Currently I have only the following drivers loaded: eugene@EugeneS-PCu:~$ lsmod | grep "brcmsmac\|b43\|ssb\|bcma\|wl" b43 387371 0 bcma 52096 1 b43 mac80211 630653 1 b43 cfg80211 484040 2 b43,mac80211 ssb_hcd 12869 0 ssb 62379 2 b43,ssb_hcd The main issue is that with most of the drivers available that I've installed, they will find my wireless network but, they will only stay connected for about a minute with abnormally slow speed and then all of a sudden disconnect. Currently, the computer is hooked into another to share it's connect so that I can install drivers from the internet instead of loading them on to a flash drive and doing it offline. If anyone has any insight to the problem, that would be awesome. If not, I'll probably just look up how to install the Windows closed source driver. Edit 1: Even when I try the method here, as suggested when this was marked as a duplicate, I still can't stay connected to a wireless network. Edit 2: After discussing my issue with @Luis, he opened my question back up and told me to include the tests/procedures in the comments. Basically I did this: Read the first answer of the link above when this question was marked as duplicate which involved installing removing bcmwl-kernel-source and instead install firmware-b43-installer and b43-fwcutter. No change of result and contacted Luis in the comments, who then told me to try the second answer which involved removing my previous mistake and installing bcmwl-kernel-source Now the Network Manger (this has happend before, but usally I fixed it by using a different driver) even recognizes WiFi exist (both non-literal and literal). Luis who then suggested sudo rfkill unblock all rfkill unblock all didn't return anything, so I decide to try sudo rfkill list all. Returns nothing (no wonder rfkill unblock all did nothing). I enter lsmod | grep "brcmsmac\|b43\|ssb\|bcma\|wl" and that returns nothing. Try loading the driver by entering sudo modprobe b43 and try lsmod | grep "brcmsmac\|b43\|ssb\|bcma\|wl" again. Returns this: eugene@Eugenes-uPC:~$ sudo modprobe b43 eugene@Eugenes-uPC:~$ lsmod | grep "brcmsmac\|b43\|ssb\|bcma\|wl" b43 387371 0 bcma 52096 1 b43 mac80211 630653 1 b43 cfg80211 484040 2 b43,mac80211 ssb_hcd 12869 0 ssb 62379 2 b43,ssb_hcd So to recap: Currently Network Manager doesn't recognize Wireless exists, b43 drivers are loaded and I've currently hardwired a connect from my laptop to the computer that's causing this.

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• Dell Inspiron 1120 Ubuntu Light -> Desktop and now I'm having problems with wifi and suspend

  - by David N. Welton

  I got a Dell Inspiron 1120 which ships with Ubuntu Light, as well as Windows. My wife prefers Ubuntu, but obviously outside of web stuff, you can't do a lot with Light, so I went ahead and installed the Desktop version of Ubuntu (10.10 / maverick). Whereas before it suspended beautifully and connected to wifi networks flawlessly, it now displays the following problems: It seems to suspend ok, but on resume, the screen remains blank, even though the computer appears to wake up again. Wifi doesn't connect. I tried using the suggested proprietary drivers, and those don't seem to change the situation. All in all, a bit frustrating to run into these sorts of "regressions" - does anyone know what sort of drivers and such Ubuntu Light might have shipped with for this computer that made it work so well? Unfortunately, I wiped the disk in order to install the Desktop version of Ubuntu.

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• Set Custom Reload Times for Individual Webpages in Chrome

  - by Asian Angel

  Do you have a webpage that needs to be reloaded every so often or perhaps you have multiple webpages that each need their own individual reload time? Now you can have the best of both with the AutoReloader extension for Google Chrome. Using AutoReloader When you first look at the drop-down window everything will be in a neutral “waiting” state. You can start using the extension immediately by simply entering the desired “time frame” for reloading a webpage. Notice for the “Repeat Option” that “0 = Continuous”… You may want to have a quick look through the “Options” to see if there are any “operational changes” that you would like to make. Once you enter a time click on the “Set Link” to start the timer. Notice that you can view the time remaining on the “Toolbar Button” unless you disabled the feature in the “Options”. Clicking on the “Toolbar Button” will show a larger version of the timer in the drop-down window along with a “Cancel Current Timer Link”. Here is the best part of all with AutoReloader…you can set up your own customized list of “Reload Times” and then access them through the drop-down window. Using the two times shown here we were able to set the “Productive Geek Webpage” up for 30 second reloads and the “TinyHacker Webpage” up for 1 minute reloads at the same time. There was no conflict whatsoever in running both “reload times” simultaneously. This is a really terrific feature! Conclusion Whether you have only one webpage or multiple pages that need periodic reloading (such as tracking a Woot-Off or an Ebay auction) the AutoReloader extension is the perfect tool for the job. Running custom reload times simultaneously have never been easier. Links Download the AutoReloader extension (Google Chrome Extensions) Similar Articles Productive Geek Tips Set Up Automatic Timed Page Reloading on Your Webpages in FirefoxRemove Custom about:config Entries the Easy WayEnable Vista Black Style Theme for Google Chrome in XPActivate the Redesigned New-Tab Interface in Google ChromeModify Tab Ordering in Google Chrome TouchFreeze Alternative in AutoHotkey The Icy Undertow Desktop Windows Home Server – Backup to LAN The Clear & Clean Desktop Use This Bookmarklet to Easily Get Albums Use AutoHotkey to Assign a Hotkey to a Specific Window Latest Software Reviews Tinyhacker Random Tips Revo Uninstaller Pro Registry Mechanic 9 for Windows PC Tools Internet Security Suite 2010 PCmover Professional The Growth of Citibank Quickly Switch between Tabs in IE Windows Media Player 12: Tweak Video & Sound with Playback Enhancements Own a cell phone, or does a cell phone own you? Make your Joomla & Drupal Sites Mobile with OSMOBI Integrate Twitter and Delicious and Make Life Easier

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• How to Restore Uninstalled Modern UI Apps that Ship with Windows 8

  - by Lori Kaufman

  Windows 8 ships with built-in apps available on the Modern UI screen (formerly the Metro or Start screen), such as Mail, Calendar, Photos, Music, Maps, and Weather. Installing additional Modern UI apps is easy using the Windows Store, and uninstalling apps is just as easy. What if you accidentally uninstall a built-in app? It can be easily restored with a few clicks of your mouse. To begin, access the Modern UI screen by moving your mouse to the extreme, lower, left corner of the screen and click the Start screen button that displays. NOTE: You can also press the Windows key to access the Modern UI screen. How Hackers Can Disguise Malicious Programs With Fake File Extensions Can Dust Actually Damage My Computer? What To Do If You Get a Virus on Your Computer

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