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  • SQL SERVER – BI Quiz Hint – Performance Tuning Cubes – Hints

    - by pinaldave
    I earlier wrote about SQL BI Quiz over here and here. The details of the quiz is here: Working with huge data is very common when it is about Data Warehousing. It is necessary to create Cubes on the data to make it meaningful and consumable. There are cases when retrieving the data from cube takes lots of the time. Let us assume that your cube is returning you data very quickly. Suddenly on one day it is returning the data very slowly. What are the three things will you to diagnose this. After diagnose what you will do to resolve performance issue. Participate in my question over here I required BI Expert Jason Thomas to help with few hints to blog readers. He is one of the leading SSAS expert and writes a complicated subject in simple words. If queries were executing properly before but now take a long time to return the data, it means that there has been a change in the environment in which it is running. Some possible changes are listed below:-  1) Data factors:- Compare the data size then and now. Increase in data can result in different execution times. Poorly written queries as well as poor design will not start showing issues till the data grows. How to find it out? (Ans : SQL Server profiler and Perfmon Counters can be used for identifying the issues and performance  tuning the MDX queries)  2) Internal Factors:- Is some slow MDX query / multiple mdx queries running at the same time, which was not running when you had tested it before? Is there any locking happening due to proactive caching or processing operations? Are the measure group caches being cleared by processing operations? (Ans : Again, profiler and perfmon counters will help in finding it out. Load testing can be done using AS Performance Workbench (http://asperfwb.codeplex.com/) by running multiple queries at once)  3) External factors:- Is some other application competing for the same resources?  HINT : Read “Identifying and Resolving MDX Query Performance Bottlenecks in SQL Server 2005 Analysis Services” (http://sqlcat.com/whitepapers/archive/2007/12/16/identifying-and-resolving-mdx-query-performance-bottlenecks-in-sql-server-2005-analysis-services.aspx) Well, these are great tips. Now win big prizes by participate in my question over here. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

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  • Ubuntu 11.04 Broadcom BCM4312 Not Working

    - by ptran221
    I have a HP MINI 210-1010NR and just installed Ubuntu 11.04 and I can't get my wireless to work.I have checked through multiple Q&A's throughout this FAQ and tried them all. When I go over the wireless thing at the top it says "Wireless Networks device not ready(firmware missing)." Okay, now here is my ~$ lspci -vvnn | grep 14e4 02:00.0 Network controller [0280]: Broadcom Corporation BCM4312 802.11b/g LP-PHY [14e4:4315] (rev 01) Also, when I try to open additional drivers it says that "Downloading package indexes failed, please check your network status."

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  • Enterprise MDM: Rationalizing Reference Data in a Fast Changing Environment

    - by Mala Narasimharajan
    By Rahul Kamath Enterprises must move at a rapid pace to establish and retain global market leadership by continuously focusing on operational efficiency, customer intimacy and relentless execution. Reference Data Management    As multi-national companies with a presence in multiple industry categories, market segments, and geographies, their ability to proactively manage changes and harness them to align their front office with back-office operations and performance management initiatives is critical to make the proverbial elephant dance. Managing reference data including types and codes, business taxonomies, complex relationships as well as mappings represent a key component of the broader agenda for enabling flexibility and agility, without sacrificing enterprise-level consistency, regulatory compliance and control. Financial Transformation  Periodically, companies find that processes implemented a decade or more ago no longer mirror the way of doing business and seek to proactively transform how they operate their business and underlying processes. Financial transformation often begins with the redesign of one’s chart of accounts. The ability to model and redesign one’s chart of accounts collaboratively, quickly validate against historical transaction bases and secure business buy-in across multiple line of business stakeholders, while continuing to manage changes within the legacy general ledger systems and downstream analytical applications while piloting the in-flight transformation can mean the difference between controlled success and project failure. Attend the session titled CON8275 - Oracle Hyperion Data Relationship Management: Enabling Enterprise Transformation at Oracle Openworld on Monday, October 1, 2012 at 4:45pm in Ballroom A of the InterContinental Hotel to learn how Oracle’s Data Relationship Management solution can help you stay ahead of the competition and proactively harness master (and reference) data changes to transform your enterprise. Hear in-depth customer testimonials from GE Healthcare and Old Mutual South Africa to learn how others have harnessed this technology effectively to build enduring competitive advantage through business process innovation and investments in master data governance. Hear GE Healthcare discuss how DRM has enabled financial transformation, ERP consolidation, mergers and acquisitions, and the alignment reference data across financial and management reporting applications. Also, learn how Old Mutual SA has upgraded to EBS R12 Financials and is transforming the management of chart of accounts for corporate reporting. Separately, an esteemed panel of DRM customers including Cisco Systems, Nationwide Insurance, Ralcorp Holdings and Mentor Graphics will discuss their perspectives on how DRM has helped them address business challenges associated with enterprise MDM including major change management initiatives including financial transformations, corporate restructuring, mergers & acquisitions, and the rationalization of financial and analytical master reference data to support alternate business perspectives for the alignment of EPM/BI initiatives. Attend the session titled CON9377 - Customer Showcase: Success with Oracle Hyperion Data Relationship Management at Openworld on Thursday, October 4, 2012 at 12:45pm in Ballroom of the InterContinental Hotel to interact with our esteemed speakers first hand.

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  • Designing Mobile SMS text advertising system

    - by Ramraj Edagutti
    Currently, I am working on a product where we have an SMS text advertising system, and using this, we setup advertising campaigns for clients, and later these campaigns are sent to the end users. This is very similar to Google Adwords, but targeted to Mobile users via SMS. Just to give an overview of the system Each Campaign is mapped to an advertiser Campaign has start date and end date Campaign has a filter condition(s) or query to select the target user base from our database (to whom we send Campaigns) Target user base can be fixed, for e.g send campaign to 10000 users Target user base can also be dynamic based on query condition, for e.g send campaign to users who are active and from a particular state, district, town etc. (this way user base will be keep changing on daily basis) Campaign can have multiple campaign messages Each campaign message has start date and end date Each campaign message can have multiple message texts for different locales, for e.g English,Hindi,Telugu etc After creating an advertisement campaign, we run daily night job to provision the target user base for that a particular campaign in a separate table, and another daily job runs on morning times and checks provisioned table for campaigns and targeted users and sends the campaign to users via SMS. Problem is, current UI for creating advertising campaigns is designed in a very technical manner, I mean, normal user or business owner or clients can not use the UI to create a campaign. Below are reasons why the UI is very technical in nature Filter condition(s) or query input filed, takes user ids or mobile numbers or SQL queries. Most of times or almost every time, we use big SQL queries So we end up storing SQL queries in a database for a campaign, later we use this SQL query to fetch targeted user base. For scheduling these campaigns, we have input filed on UI which takes quartz cron expression(s) ( for e.g. send campaign on "0 0 9 1-10 MAR 2012" ), again very technical in nature Normal user or business owner, can not use the UI for creating campaigns for reasons mentioned above, Currently, we ourself (developers) helping clients to setup/create campaigns. we are trying to re-design the UI to make it more user friendly so that any user can go to UI and create an advertisement campaign by himself. I am thinking of re-designing the current UI similar to Google Adwords interface, especially for selecting target users based on user geography like country, state, city etc. I also need to select users based user subscription(s), which might make system even more complex. And also, for campaign scheduling, I am thinking of using weekdays with hours. For example, I will shows Monday to Sunday on UI, and user can select the from hours, to hours etc. Any better ideas or suggestion on how to design UI in very user friendly manner and what design should be followed on server side code (we write backend code on java/jpa/spring/quartz)? And I am looking for ideas or design patterns on how to build SQL queries (using JPA/Hinernate) programmatically on server side, based on varies conditions like based on country, state, town, village, and user subscriptions.

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  • CoolCommands for Visual Studio 2010

    - by ChrisD
    Gaston Milano has just informed me that he has a new version of CoolCommands for Visual Studio 2010.  In addition to all the existing commands, the new release, now called CoolX,  supports Context Explorer shell commands, support for multiple monitors and new features to help tame the Project Reference beast. Check out all the info including a download, available here –>http://visualstudiogallery.msdn.microsoft.com/en-us/53fe63d5-780d-409b-afc3-10d05906e0a6 I’m also hosting a version for download here. Thanks Gaston!

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  • Configuring SQL Server Audit Logging with Powershell

    - by Jonathan Kehayias
    One of the standard configuration options that I set on all SQL Server installs is to log Failed Login Attempts to the SQL Server Error Log.  I recently inherited an environment that this option wasn’t standardized across all of the servers and needed to configure it for multiple servers in a scripted manner.  There are a couple of ways to handle this kind of task.  First I could log on to every server in SSMS, open the Server Properties, and set the option on the Security sheet for...(read more)

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  • PHP `virtual()` with Apache MultiViews not working after upgrade to 12.04

    - by Izzy
    I use PHP's virtual() directive quite a lot on one of my sites, including central elements. This worked fine for the last ~10 years -- but after upgrading to 12.04 it somehow got broken. Example setup (simplified) To make it easier to understand, I simplify some things (contents). So say I need a HTML fragment like <P>For further instructions, please look <A HREF='foobar'>here</P> in multiple pages. 10 years ago, I used SSI for that, so it is put into a file in a central place -- so if e.g. the targeted URL changes, I only need to update it in one place. To serve multiple languages, I have Apache's MultiViews enabled -- and at $DOCUMENT_ROOT/central/ there are the files: foobar.html (English variant, and the default) foobar.html.de (German variant). Now in the PHP code, I simply placed: <? virtual("/central/foobar"); ?> and let Apache take care to deliver the correct language variant. The problem As said, this worked fine for about 10 years: German visitors got the German variant, all others the English (depending on their preferred language). But after upgrading to Ubuntu 12.04, it no longer worked: Either nothing was delivered from the virtual() command, or (in connection with framesets) it even ended up in binary gibberish. Trying to figure out what happens, I played with a lot of things. I first thought MultiViews was (somehow) not available anymore -- but calling http://<server>/central/foobar showed the right variant, depending on the configured language preferences. This also proved there was nothing wrong with file permissions. The error.log gave no clues either (no error message thrown). Finally, just as a "last ressort", I changed the PHP command to <? virtual("central/foobar.html"); ?> -- and that very same file was in fact included. But the language dependend stuff obviously did no longer work. Of course I tried to find some change (most likely in PHP's virtual() command), using Google a lot, and also searching the questions here -- unfortunately to no avail. Finally: The question Putting "design questions" aside (surely today I would design things differently -- but at least currently I miss the time to change that for a quite huge amount of pages): What can be done to make it work again? I surely missed something -- but I cannot figure out what...

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  • Game programming course materials: What should it include?

    - by Esa
    I am tasked to create the course materials for a game programming class, and I’d like your opinion on what aspects and areas of game programming, such as game state management, game object storing or simple AI, should I include in it? The course is intented to be the first step into game programming for students with novice skills in programming. There will be mathematics as well, but I found that there are multiple questions, with good answers, on that subject already.

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  • SilverlightShow for Feb 28 - March 06, 2011

    - by Dave Campbell
    Check out the Top Five most popular news at SilverlightShow for Feb 28 - Mar 06, 2011. While you're at it, check out the ECO Contest site, and vote for your favorites before midnight PST on March 10. Here are the top 5 news on SilverlightShow for last week: SilverlightShow Bookshelf now released as Open Source CRUD Operation on Relational Data (Multiple table) using RIA and Silverlight 4 A Sample Silverlight 4 Application Using MEF, MVVM, and WCF RIA Services - Part 3 Daily News Digest 03/02/2011 RadControls for Windows Phone 7 Q1 2011 Beta 2 released Visit and bookmark SilverlightShow. Stay in the 'Light

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  • small IIS web farm-create an Active Directory domain or no?

    - by brian b
    We have a smallish web farm of < 5 Windows 2008 servers. Some do data, most do IIS hosting. Is it a good/bad idea to set up a domain controller and put all in the same "production" domain? We want to avoid a world where we have to sync multiple admin passwords between the boxes (or share admin credentials among the team). Presumably, the DC would be just another VM, so hardware cost doesn't enter into the discussion.

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  • Split Internet Explorer into Dual-Panes

    - by Asian Angel
    If you have a wide screen monitor then you may want to make better use of Internet Explorer’s browser window area. Now you can split the browser window into dual-panes as needed with the IE Split browser plugin. Note: Requires .NET Framework 2.0 or higher (link provided below). IE Split in Action If you are using an older version of this software here is something to keep in mind before upgrading to the 2.0 release. Once you have installed IE Split you will notice a new toolbar added to your browser. As seen here, you can condense it down tightly and access it using the drop-down bar. A closer look at the drop-down bar. Notice the address bar…this will be for the left pane when you split the browser window. Here is our browser split into dual-panes. There are two address bars and two tab/title bars each corresponding to their appropriate pane. It may look slightly backwards at first but is not hard to get used to. A better view of the left pane with the IE Split navigation & title bars showing. Note: The title bar can be hidden if desired. And the right pane. You can also have multiple “split” tabs open if needed. There is nothing quite like getting double the value for the same amount of space. When you no longer need dual-panes open just click on the “x” to close IE Split down. All back to normal again. Conclusion While might not be for everyone this can still be useful for those who need side-by-side access to websites without using multiple separate windows. Links Download IE-Split Download the Microsoft .NET Framework 4 (Standalone Installer) Similar Articles Productive Geek Tips Set Up Multi-Pane Viewing in FirefoxWhy Can’t I Turn the Details/Preview Panes On or Off in Windows Vista Explorer?Split a text file in half (or any percentage) on Ubuntu LinuxMysticgeek Blog: A Look at Internet Explorer 8 Beta 1 on Windows XPMake Ctrl+Tab in Internet Explorer 7 Use Most Recent Order 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 Filevo is a Cool File Hosting & Sharing Site Get a free copy of WinUtilities Pro 2010 World Cup Schedule Boot Snooze – Reboot and then Standby or Hibernate Customize Everything Related to Dates, Times, Currency and Measurement in Windows 7 Google Earth replacement Icon (Icons we like)

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  • Desktop Fun: Happy New Year Wallpaper Collection [Bonus Edition]

    - by Asian Angel
    As this year draws to a close, it is a time to reflect back on what we have done this year and to look forward to the new one. To help commemorate the event we have put together a bonus size edition of Happy New Year wallpapers for your desktops. Extra Note: We made a special effort to find wallpapers for this collection without the year “printed” on them, thus allowing for reuse as desired and/or needed beyond the 2010 – 2011 holiday. Note: Click on the picture to see the full-size image—these wallpapers vary in size so you may need to crop, stretch, or place them on a colored background in order to best match them to your screen’s resolution. For more New Year’s desktop goodness be sure to check out our Happy New Year icon & font packs collection (link at bottom)! Note: This wallpaper will need to be placed on a larger white background in order to increase the height. Note: This wallpaper will need to be placed on a larger background in order to increase the width and height. Note: This wallpaper comes in multiple sizes and will need to be downloaded as a zip file. Note: This wallpaper comes in multiple sizes and will need to be downloaded as a zip file. Note: The download size for the original version of this wallpaper is 15 MB. Note: The download size for the original version of this wallpaper is 15 MB. More Happy New Year Fun Desktop Fun: Happy New Year Icon and Font Packs For more wallpapers be certain to see our great collections in the Desktop Fun section. Latest Features How-To Geek ETC How to Use the Avira Rescue CD to Clean Your Infected PC The Complete List of iPad Tips, Tricks, and Tutorials Is Your Desktop Printer More Expensive Than Printing Services? 20 OS X Keyboard Shortcuts You Might Not Know HTG Explains: Which Linux File System Should You Choose? HTG Explains: Why Does Photo Paper Improve Print Quality? The Outdoor Lights Scene from National Lampoon’s Christmas Vacation [Video] The Famous Home Alone Pizza Delivery Scene [Classic Video] Chronicles of Narnia: The Voyage of the Dawn Treader Theme for Windows 7 Cardinal and Rabbit Sharing a Tree on a Cold Winter Morning Wallpaper An Alternate Star Wars Christmas Special [Video] Sunset in a Tropical Paradise Wallpaper

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  • Hardware and Software Working Together - What Does LJE say?

    - by Stephen Slade
     IDG News Service - Oracle CEO Larry Ellison said Oracle will continue to bet on selling high-end custom hardware for its software products, even amidst a growing trend toward roomfuls of cheap, generic servers. "You have to be in the hardware business and the software business, to get the best possible system," he said during a keynote speech at Oracle's OpenWorld conference in Tokyo. "We believe it's the right idea, we believe it's the next generation of computing, we believe all the pieces have to fit together." Ellison, as he has often done in the past, repeatedly referred to Apple as his "favorite example" of such tight integration. He was a close friend of Apple's co-founder Steve Jobs and previously served on Apple's board of directors.He said sales of Oracle's advanced servers were booming and generating around a billion dollars a year in revenue for the company, which has until recent years focused almost exclusively on its software offerings. With the explosion of popular online services and the increasing number of mobile devices that access them, demand is high for databases that can quickly respond to high numbers of relatively simple queries. While Oracle is pitching its expensive, finely-tuned machines to meet this requirement, Internet behemoths like Google, Facebook and Microsoft increasingly rely on armies of low-cost, easily replaceable servers. Ellison emphasized the high specifications of Oracle's servers, which come packed with multiple terabytes of RAM and flash-based storage for speed. Such machines are superior to large server farms, he said, because they require far less electricity and floor space, and are also cost competitive. When asked about whether purchasing such products would lock customers in to expensive hardware from Oracle, he promised that the company's software would always run on "multiple hardware sources."  Ellison, who spoke from Kyoto, Japan's ancient capital, was shown live online via webcast. The Oracle founder has a fondness for Japanese architecture and is staying in his large garden residence in the city Source: Ellison: Hardware-software integration key, Apple is best example. Oracle's founder and CEO reaffirmed his commitment to custom hardware for its software products  LINK to Computerworld article Apr 5, 2012 http://www.computerworld.com/s/article/9225858/Ellison_Hardware_software_integration_key_Apple_is_best_example?source=CTWNLE_nlt_entsoft_2012-04-09&utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+computerworld%2Fs%2Ffeed%2Ftopic%2F173+%28Computerworld+Databases+News%29#disqus_thread

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  • Patterns for Handling Changing Property Sets in C++

    - by Bhargav Bhat
    I have a bunch "Property Sets" (which are simple structs containing POD members). I'd like to modify these property sets (eg: add a new member) at run time so that the definition of the property sets can be externalized and the code itself can be re-used with multiple versions/types of property sets with minimal/no changes. For example, a property set could look like this: struct PropSetA { bool activeFlag; int processingCount; /* snip few other such fields*/ }; But instead of setting its definition in stone at compile time, I'd like to create it dynamically at run time. Something like: class PropSet propSetA; propSetA("activeFlag",true); //overloading the function call operator propSetA("processingCount",0); And the code dependent on the property sets (possibly in some other library) will use the data like so: bool actvFlag = propSet["activeFlag"]; if(actvFlag == true) { //Do Stuff } The current implementation behind all of this is as follows: class PropValue { public: // Variant like class for holding multiple data-types // overloaded Conversion operator. Eg: operator bool() { return (baseType == BOOLEAN) ? this->ToBoolean() : false; } // And a method to create PropValues various base datatypes static FromBool(bool baseValue); }; class PropSet { public: // overloaded[] operator for adding properties void operator()(std::string propName, bool propVal) { propMap.insert(std::make_pair(propName, PropVal::FromBool(propVal))); } protected: // the property map std::map<std::string, PropValue> propMap; }; This problem at hand is similar to this question on SO and the current approach (described above) is based on this answer. But as noted over at SO this is more of a hack than a proper solution. The fundamental issues that I have with this approach are as follows: Extending this for supporting new types will require significant code change. At the bare minimum overloaded operators need to be extended to support the new type. Supporting complex properties (eg: struct containing struct) is tricky. Supporting a reference mechanism (needed for an optimization of not duplicating identical property sets) is tricky. This also applies to supporting pointers and multi-dimensional arrays in general. Are there any known patterns for dealing with this scenario? Essentially, I'm looking for the equivalent of the visitor pattern, but for extending class properties rather than methods. Edit: Modified problem statement for clarity and added some more code from current implementation.

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  • How do search engines segment against locale?

    - by Hope I Helped
    Assume I run a website with multiple language modes. If I had a Spanish section, it should be included in Spanish-segmented search engines such as Google Spain, Google Peru, Google El Salvador, etc. and excluded in the others. Likewise, even though the website would have content in Chinese, multilingual countries such as Singapore should feature content in their main language (English in this case). What is the best approach to ensure the appropriate language is associated with the various geographically segmented search engines?

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  • Is there a better term than "smoothness" or "granularity" to describe this language feature?

    - by Chris
    One of the best things about programming is the abundance of different languages. There are general purpose languages like C++ and Java, as well as little languages like XSLT and AWK. When comparing languages, people often use things like speed, power, expressiveness, and portability as the important distinguishing features. There is one characteristic of languages I consider to be important that, so far, I haven't heard [or been able to come up with] a good term for: how well a language scales from writing tiny programs to writing huge programs. Some languages make it easy and painless to write programs that only require a few lines of code, e.g. task automation. But those languages often don't have enough power to solve large problems, e.g. GUI programming. Conversely, languages that are powerful enough for big problems often require far too much overhead for small problems. This characteristic is important because problems that look small at first frequently grow in scope in unexpected ways. If a programmer chooses a language appropriate only for small tasks, scope changes can require rewriting code from scratch in a new language. And if the programmer chooses a language with lots of overhead and friction to solve a problem that stays small, it will be harder for other people to use and understand than necessary. Rewriting code that works fine is the single most wasteful thing a programmer can do with their time, but using a bazooka to kill a mosquito instead of a flyswatter isn't good either. Here are some of the ways this characteristic presents itself. Can be used interactively - there is some environment where programmers can enter commands one by one Requires no more than one file - neither project files nor makefiles are required for running in batch mode Can easily split code across multiple files - files can refeence each other, or there is some support for modules Has good support for data structures - supports structures like arrays, lists, and especially classes Supports a wide variety of features - features like networking, serialization, XML, and database connectivity are supported by standard libraries Here's my take on how C#, Python, and shell scripting measure up. Python scores highest. Feature C# Python shell scripting --------------- --------- --------- --------------- Interactive poor strong strong One file poor strong strong Multiple files strong strong moderate Data structures strong strong poor Features strong strong strong Is there a term that captures this idea? If not, what term should I use? Here are some candidates. Scalability - already used to decribe language performance, so it's not a good idea to overload it in the context of language syntax Granularity - expresses the idea of being good just for big tasks versus being good for big and small tasks, but doesn't express anything about data structures Smoothness - expresses the idea of low friction, but doesn't express anything about strength of data structures or features Note: Some of these properties are more correctly described as belonging to a compiler or IDE than the language itself. Please consider these tools collectively as the language environment. My question is about how easy or difficult languages are to use, which depends on the environment as well as the language.

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  • Broadcom BCM4312 Not Working

    - by ptran221
    I have a HP MINI 210-1010NR and just installed Ubuntu 11.04 and I can't get my wireless to work.I have checked through multiple Q&A's throughout this FAQ and tried them all. When I go over the wireless thing at the top it says "Wireless Networks device not ready(firmware missing)." Okay, now here is my lspci -vvnn | grep 14e4 02:00.0 Network controller [0280]: Broadcom Corporation BCM4312 802.11b/g LP-PHY [14e4:4315] (rev 01) Also, when I try to open additional drivers it says that "Downloading package indexes failed, please check your network status."

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  • Using lookahead assertions in regular expressions

    - by Greg Jackson
    I use regular expressions on a daily basis, as my daily work is 90% in Perl (legacy codebase, but that's a different issue). Despite this, I still find lookahead and lookbehind to be terribly confusing and often unreadable. Right now, if I were to get a code review with a lookahead or lookbehind, I would immediately send it back to see if the problem can be solved by using multiple regular expressions or a different approach. The following are the main reasons I tend not to like them: They can be terribly unreadable. Lookahead assertions, for example, start from the beginning of the string no matter where they are placed. That, among other things, can cause some very "interesting" and non-obvious behaviors. It used to be the case that many languages didn't support lookahead/lookbehind (or supported them as "experimental features"). This isn't the case quite as much, but there's still always the question as to how well it's supported. Quite frankly, they feel like a dirty hack. Regexps often already are, but they can also be quite elegant, and have gained widespread acceptance. I've gotten by without any need for them at all... sometimes I think that they're extraneous. Now, I'll freely admit that especially the last two reasons aren't really good ones, but I felt that I should enumerate what goes through my mind when I see one. I'm more than willing to change my mind about them, but I feel that they violate some of my core tenets of programming, including: Code should be as readable as possible without sacrificing functionality -- this may include doing something in a less efficient, but clearer was as long as the difference is negligible or unimportant to the application as a whole. Code should be maintainable -- if another programmer comes along to fix my code, non-obvious behavior can hide bugs or make functional code appear buggy (see readability) "The right tool for the right job" -- I'm sure you can come up with contrived examples that could use lookahead, but I've never come across something that really needs them in my real-world development work. Is there anything that they're really the best tool for, as opposed to, say, multiple regexps (or, alternatively, are they the best tool for most cases they're used for today). My question is this: Is it good practice to use lookahead/lookbehind in regular expressions, or are they simply a hack that have found their way into modern production code? I'd be perfectly happy to be convinced that I'm wrong about this, and simple examples are useful for examples or illustration, but by themselves, won't be enough to convince me.

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  • Are there deprecated practices for multithread and multiprocessor programming that I should no longer use?

    - by DeveloperDon
    In the early days of FORTRAN and BASIC, essentially all programs were written with GOTO statements. The result was spaghetti code and the solution was structured programming. Similarly, pointers can have difficult to control characteristics in our programs. C++ started with plenty of pointers, but use of references are recommended. Libraries like STL can reduce some of our dependency. There are also idioms to create smart pointers that have better characteristics, and some version of C++ permit references and managed code. Programming practices like inheritance and polymorphism use a lot of pointers behind the scenes (just as for, while, do structured programming generates code filled with branch instructions). Languages like Java eliminate pointers and use garbage collection to manage dynamically allocated data instead of depending on programmers to match all their new and delete statements. In my reading, I have seen examples of multi-process and multi-thread programming that don't seem to use semaphores. Do they use the same thing with different names or do they have new ways of structuring protection of resources from concurrent use? For example, a specific example of a system for multithread programming with multicore processors is OpenMP. It represents a critical region as follows, without the use of semaphores, which seem not to be included in the environment. th_id = omp_get_thread_num(); #pragma omp critical { cout << "Hello World from thread " << th_id << '\n'; } This example is an excerpt from: http://en.wikipedia.org/wiki/OpenMP Alternatively, similar protection of threads from each other using semaphores with functions wait() and signal() might look like this: wait(sem); th_id = get_thread_num(); cout << "Hello World from thread " << th_id << '\n'; signal(sem); In this example, things are pretty simple, and just a simple review is enough to show the wait() and signal() calls are matched and even with a lot of concurrency, thread safety is provided. But other algorithms are more complicated and use multiple semaphores (both binary and counting) spread across multiple functions with complex conditions that can be called by many threads. The consequences of creating deadlock or failing to make things thread safe can be hard to manage. Do these systems like OpenMP eliminate the problems with semaphores? Do they move the problem somewhere else? How do I transform my favorite semaphore using algorithm to not use semaphores anymore?

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  • Windows Azure Diagnostics: Next to Useless?

    - by Your DisplayName here!
    To quote my good friend Christian: “Tracing is probably one of the most discussed topics in the Windows Azure world. Not because it is freaking cool – but because it can be very tedious and partly massively counter-intuitive.” <rant> The .NET Framework has this wonderful facility called TraceSource. You define a named trace and route that to a configurable listener. This gives you a lot of flexibility – you can create a single trace file – or multiple ones. There is even nice tooling around that. SvcTraceViewer from the SDK let’s you open the XML trace files – you can filter and sort by trace source and event type, aggreate multiple files…blablabla. Just what you would expect from a decent tracing infrastructure. Now comes Windows Azure. I was already were grateful that starting with the SDK 1.2 we finally had a way to do tracing and diagnostics in the cloud (kudos!). But the way the Azure DiagnosticMonitor is currently implemented – could be called flawed. The Azure SDK provides a DiagnosticsMonitorTraceListener – which is the right way to go. The only problem is, that way this works is, that all traces (from all sources) get written to an ETW trace. Then the DiagMon listens to these traces and copies them periodically to your storage account. So far so good. But guess what happens to your nice trace files: the trace source names get “lost”. They appear in your message text at the end. So much for filtering and sorting and aggregating (regex #fail or #win??). Every trace line becomes an entry in a Azure Storage Table – the svclog format is gone. So much for the existing tooling. To solve that problem, one workaround was to write your own trace listener (!) that creates svclog files inside of local storage and use the DiagMon to copy those. Christian has a blog post about that. OK done that. Now it turns out that this mechanism does not work anymore in 1.3 with FullIIS (see here). Quoting: “Some IIS 7.0 logs not collected due to permissions issues...The root cause to both of these issues is the permissions on the log files.” And the workaround: “To read the files yourself, log on to the instance with a remote desktop connection.” Now then have fun with your multi-instance deployments…. </rant>

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