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  • The Three Laws of Robotics; As Told by Asimov Himself

    - by Jason Fitzpatrick
    Many Sci-Fi fans and certainly most Isaac Asimov fans are familiar with the Three Laws of Robotics–but how many of us have heard the man himself explain them? In this archival clip a young Isaac Asimov explains the Three Laws of Robotics–the organizing principle behind his robot-based short stories and novels. [via Neatorama] 6 Start Menu Replacements for Windows 8 What Is the Purpose of the “Do Not Cover This Hole” Hole on Hard Drives? How To Log Into The Desktop, Add a Start Menu, and Disable Hot Corners in Windows 8

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  • Dynamic Bursting ... no really!

    - by Tim Dexter
    If any of you have seen me or my colleagues present BI Publisher to you then we have hopefully mentioned 'bursting.' You may have even seen a demo where we talk about being able to take a batch of data, say invoices. Then split them by some criteria, say customer id; format them with a template; generate the output and then deliver the documents to the recipients with a click. We and especially I, always say this can be completely dynamic! By this I mean, that you could store customer preferences in a database. What layout would each customer like; what output format they would like and how they would like the document delivered. We (I) talk a good talk, but typically don't do the walk in a demo. We hard code everything in the bursting query or bursting control file to get the concept across. But no more peeps! I have finally put together a dynamic bursting demo! Its been minutes in the making but its been tough to find those minutes! Read on ... It's nothing amazing in terms of making the burst dynamic. I created a CUSTOMER_PREFS table with some simple UI in an APEX application so that I can maintain their requirements. In EBS you have descriptive flexfields that could do the same thing or probably even 'contact' fields to store most of the info. Here's my table structure: Name                           Type ------------------------------ -------- CUSTOMER_ID                    NUMBER(6) TEMPLATE_TYPE                  VARCHAR2(20) TEMPLATE_NAME                  VARCHAR2(120) OUTPUT_FORMAT                  VARCHAR2(20) DELIVERY_CHANNEL               VARCHAR2(50) EMAIL                          VARCHAR2(255) FAX                            VARCHAR2(20) ATTACH                         VARCHAR2(20) FILE_LOC                       VARCHAR2(255) Simple enough right? Just need CUSTOMER_ID as the key for the bursting engine to join it to the customer data at burst time. I have not covered the full delivery options, just email, fax and file location. Remember, its a demo people :0) However the principal is exactly the same for each delivery type. They each have a set of attributes that need to be provided and you will need to handle that in your bursting query. On a side note, in EBS, you use a bursting control file, you can apply the same principals that I'm laying out here you just need to get the customer bursting info into the XML data stream so that you can refer to it in the control file using XPATH expressions. Next, we need to look up what attributes or parameters are required for each delivery method. that can be found in the documentation here.  Now we know the combinations of parameters and delivery methods we can construct the query using a series a decode statements: select distinct cp.customer_id "KEY", cp.template_name TEMPLATE, cp.template_type TEMPLATE_FORMAT, 'en-US' LOCALE, cp.output_format OUTPUT_FORMAT, 'false' SAVE_FORMAT, cp.delivery_channel DEL_CHANNEL, decode(cp.delivery_channel,'FILE', cp.file_loc , 'EMAIL', cp.email , 'FAX', cp.fax) PARAMETER1, decode(cp.delivery_channel,'FILE', c.cust_last_name||'_orders.pdf' ,'EMAIL','[email protected]' ,'FAX', 'faxserver.com') PARAMETER2, decode(cp.delivery_channel,'FILE',NULL ,'EMAIL','[email protected]' ,'FAX', null) PARAMETER3, decode(cp.delivery_channel,'FILE',NULL ,'EMAIL','Your current orders' ,'FAX',NULL) PARAMETER4, decode(cp.delivery_channel,'FILE',NULL ,'EMAIL','Please find attached a copy of your current orders with BI Publisher, Inc' ,'FAX',NULL) PARAMETER5, decode(cp.delivery_channel,'FILE',NULL ,'EMAIL','false' ,'FAX',NULL) PARAMETER6, decode(cp.delivery_channel,'FILE',NULL ,'EMAIL','[email protected]' ,'FAX',NULL) PARAMETER7 from cust_prefs cp, customers c, orders_view ov where cp.customer_id = c.customer_id and cp.customer_id = ov.customer_id order by cp.customer_id Pretty straightforward, just need to test, test, test, the query and ensure it's bringing back the correct data based on each customers preferences. Notice the NULL values for parameters that are not relevant for a given delivery channel. You should end up with bursting control data that the bursting engine can use:  Now, your users can run the burst and documents will be formatted, generated and delivered based on the customer prefs. If you're interested in the example, I have used the sample OE schema data for the base report. The report files and CUST_PREFS table are zipped up here. The zip contains the data model (.xdmz), the report and templates (.xdoz) and the sql scripts to create and load data to the CUST_PREFS table.  Once you load the report into the catalog, you'll need to create the OE data connection and point the data model at it. You'll probably need to re-point the report to the data model too. Happy Bursting!

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  • Accessing SharePoint 2010 Data with REST/OData on Windows Phone 7

    Consuming SharePoint 2010 data in Windows Phone 7 applications using the CTP version of the developer tools is quite a challenge. The issue is that the SharePoint 2010 data is not anonymously available; users need to authenticate to be able to access the data. When I first tried to access SharePoint 2010 data from my first Hello-World-type Windows Phone 7 application I thought Hey, this should be easy! because Windows Phone 7 development based on Silverlight and SharePoint 2010 has a Client Object...Did you know that DotNetSlackers also publishes .net articles written by top known .net Authors? We already have over 80 articles in several categories including Silverlight. Take a look: here.

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  • I need to develop a parser. Can I use Lex and Yacc for the purpose?

    - by Scrooge
    I need to extract very particular data from log files(of different types and formats). Since I am a recent college passout; my mind ran to using Lex and Yacc for the purpose. Now I have the following Questions 1. Will it be legal to do so ? (This product I am working for belongs to one of the biggest tech companies in the world.) 2. Also ; I would like to know if I am being too afraid to write my own parser? 3. How can I use Lex and Yacc if my product is Windows based? Please tell me if you need any clarification or extra information.

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  • Working with Reporting Services Filters–Part 1

    - by smisner
    There are two ways that you can filter data in Reporting Services. The first way, which usually provides a faster performance, is to use query parameters to apply a filter using the WHERE clause in a SQL statement. In that case, the structure of the filter depends upon the syntax recognized by the source database. Another way to filter data in Reporting Services is to apply a filter to a dataset, data region, or a group. Using this latter method, you can even apply multiple filters. However, the use of filter operators or the setup of multiple filters is not always obvious, so in this series of posts, I'll provide some more information about the configuration of filters. First, why not use query parameters exclusively for filtering? Here are a few reasons: You might want to apply a filter to part of the report, but not all of the report. Your dataset might retrieve data from a stored procedure, and doesn't allow you to pass a query parameter for filtering purposes. Your report might be set up as a snapshot on the report server and, in that case, cannot be dynamically filtered based on a query parameter. Next, let's look at how to set up a report filter in general. The process is the same whether you are applying the filter to a dataset, data region, or a group. When you go to the Filters page in the Properties dialog box for whichever of these items you selected (dataset, data region, group), you click the Add button to create a new filter. The interface looks like this: The Expression field is usually a field in the dataset, so to make it easier for you to make a selection,the drop-down list displays all of the current dataset fields. But notice the expression button to the right, which means that you can set up any type of expression-not just a dataset field. To the right of the expression button, you'll find a data type drop-down list. It's important to specify the correct data type for the field or expression you're using. Now for the operators. Here's a list of the options that you have: This Operator Performs This Action =, <>, >, >=, <, <=, Like Compares expression to value Top N, Bottom N Compares expression to Top (Bottom) set of N values (N = integer) Top %, Bottom % Compares expression to Top (Bottom) N percent of values (N = integer or float) Between Determines whether expression is between two values, inclusive In Determines whether expression is found in list of values Last, the Value is what you're comparing to the expression using the operator. The construction of a filter using some operators (=, <>, >, etc.) is fairly simple. If my dataset (for AdventureWorks data) has a Category field, and I have a parameter that prompts the user for a single category, I can set up a filter like this: Expression Data Type Operator Value [Category] Text = [@Category] But if I set the parameter to accept multiple values, I need to change the operator from = to In, just as I would have to do if I were using a query parameter. The parameter expression, [@Category], which translates to =Parameters!Category.Value, doesn’t need to change because it represents an array as soon as I change the parameter to allow multiple values. The “In” operator requires an array. With that in mind, let’s consider a variation on Value. Let’s say that I have a parameter that prompts the user for a particular year – and for simplicity’s sake, this parameter only allows a single value, and I have an expression that evaluates the previous year based on the user’s selection. Then I want to use these two values in two separate filters with an OR condition. That is, I want to filter either by the year selected OR by the year that was computed. If I create two filters, one for each year (as shown below), then the report will only display results if BOTH filter conditions are met – which would never be true. Expression Data Type Operator Value [CalendarYear] Integer = [@Year] [CalendarYear] Integer = =Parameters!Year.Value-1 To handle this scenario, we need to create a single filter that uses the “In” operator, and then set up the Value expression as an array. To create an array, we use the Split function after creating a string that concatenates the two values (highlighted in yellow) as shown below. Expression Data Type Operator Value =Cstr(Fields!CalendarYear.Value) Text In =Split( CStr(Parameters!Year.Value) + ”,” + CStr(Parameters!Year.Value-1) , “,”) Note that in this case, I had to apply a string conversion on the year integer so that I could concatenate the parameter selection with the calculated year. Pay attention to the second argument of the Split function—you must use a comma delimiter for the result to work correctly with the In operator. I also had to change the Expression value from [CalendarYear] (or =Fields!CalendarYear.Value) so that the expression would return a string that I could compare with the values in the string array. More fun with filter expressions in future posts!

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  • problem connecting to magento connect

    - by amir
    hi, I'm using magento 1.4.0 and when I try to get to magento connect and download a plugin the page will say Error: Please check for sufficient write file permissions Your Magento folder does not have sufficient write permissions, which this web based downloader requires. If you wish to proceed downloading Magento packages online, please set all Magento folders to have writable permission for the web server user (example: apache) and press the "Refresh" button to try again. does anyone know how I can fix this problem, thanks Update: the plugin I'm trying to use is MagentoPycho light box so I unpacked the folder into the app/code/local but it still doesn't show in the admin area

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  • USB mouse disconnecting and reconnecting in windows and linux

    - by Kalak
    I have a problem similar to what is described at "Why is my USB mouse disconnecting and reconnecting randomly and often?" except is is happening in both Windows 7 and Linux (Ubuntu 12/04TLS, fully patched), multiple mice, multiple OSs. It stops responding to input for about 3-5 seconds, then starts responding again. It's more frequent and lasts longer when running games (TF2, L4D, Dishonored, Borderlands 2, and more), but happens when just running the OS as well. I was hoping it was the motherboard so I bought a USB 2.0 PCI card to try that, but it's still happening. I've stripped it down to just the keyboard and mouse (different keyboard too just in case the keyboard was the problem), but it's still happening. All the hardware (mice and keyboards) work fine on other computers. I have literally pulled the mouse and keyboard out and plugged them into another computer (laptop) and re-joined the online game and had no problem with the keyboard and mouse combo that just failed on my gaming rig. Please no driver / Windows or Linux only suggestions, as that wouldn't effect both OSs. edit: known good mice I've brought home are now going bad. I suspect the hardware is messed up (voltage?) and has been frying the mice.

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  • How can an experienced web developer transition to desktop development?

    - by Craige
    I'm a web developer, first and foremost. I've been programming for 5 or 6 years now, all of which has been web-based. I'm good at my job, both specifically as a web developer and as a programmer in general. I have decided recently that I would like to learn some desktop programming to to beef up my skill-set. My question is this: How can an experienced web developer transition to desktop development? To elaborate: I have always been a web-developer, and I can design and build web-applications without any problem. When it comes to sitting down with a to learn some desktop oriented programming, my problem isn't with any of the technical matters, but rather coming up with an idea to program. I draw a blank.

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  • How to install iodbc in Ubuntu 12.10

    - by Hanynowsky
    I need to install the library iodbc (depends on libodbc2) in my Quantal machine. Yet there is creepy dependency problem. This was replaced somehow by unixodbc which I don't have, installed. Here is what I get when I try to install : sudo apt-get install libiodbc2-dev Reading package lists... Done Building dependency tree Reading state information... Done Some packages could not be installed. This may mean that you have requested an impossible situation or if you are using the unstable distribution that some required packages have not yet been created or been moved out of Incoming. The following information may help to resolve the situation: The following packages have unmet dependencies: libiodbc2-dev : Depends: libiodbc2 (= 3.52.7-2build2) but it is not going to be installed Depends: iodbc (= 3.52.7-2build2) but it is not going to be installed E: Unable to correct problems, you have held broken packages. I can tell that iodbc conflicts with odbcinst. Yet, I cannot remove it due to the following: sudo apt-get remove odbcinst Reading package lists... Done Building dependency tree Reading state information... Done The following packages were automatically installed and are no longer required: akonadi-backend-mysql calligra-l10n-engb kde-l10n-engb kdevelop-l10n kdevelop-php-docs-l10n kdevelop-php-l10n libakonadi-kabc4 libakonadi-notes4 libakonadiprotocolinternals1 libboost-thread1.49.0 libdmtx0a libgpgme++2 libkcalcore4 libkdgantt2 libkholidays4 libkimap4 libkldap4 libkmbox4 libkmime4 libkolabxml0 libkpgp4 libkresources4 libksieve4 libprison0 libqgpgme1 libqrencode3 libxerces-c3.1 Use 'apt-get autoremove' to remove them. The following packages will be REMOVED: akonadi-server k3b k3b-i18n katepart kde-runtime kdelibs-bin kdelibs5-plugins kdepim-runtime kdepim-strigi-plugins kdepimlibs-kio-plugins kdoctools kget kmag kmail kmix kmousetool ksystemlog kubuntu-debug-installer language-pack-kde-ar language-pack-kde-en libakonadi-calendar4 libakonadi-contact4 libakonadi-kcal4 libakonadi-kde4 libakonadi-kmime4 libcalendarsupport4 libincidenceeditorsng4 libk3b6 libkabc4 libkactivities-bin libkactivities6 libkalarmcal2 libkatepartinterfaces4 libkcal4 libkcalutils4 libkcddb4 libkde3support4 libkdepim4 libkdepimdbusinterfaces4 libkdewebkit5 libkemoticons4 libkfile4 libkgapi0 libkhtml5 libkio5 libkleo4 libkmanagesieve4 libkmediaplayer4 libknewstuff3-4 libknotifyconfig4 libkolab0 libkonq-common libkonq5abi1 libkontactinterface4 libkparts4 libkpimidentities4 libkpimtextedit4 libkpimutils4 libkprintutils4 libksieveui4 libktexteditor4 libktnef4 libktorrent4 libkworkspace4abi2 libkxmlrpcclient4 libmailcommon4 libmailimporter4 libmailtransport4 libmessagecomposer4 libmessagecore4 libmessagelist4 libmessageviewer4 libmicroblog4 libnepomuk4 libnepomukcore4abi1 libnepomukquery4a libnepomuksync4 libnepomukutils4 libplasma3 libsoprano4 libtemplateparser4 libvirtodbc0 nepomuk-core odbcinst odbcinst1debian2 plasma-scriptengine-javascript qapt-batch soprano-daemon virtuoso-minimal 0 upgraded, 0 newly installed, 89 to remove and 0 not upgraded. After this operation, 126 MB disk space will be freed. Do you want to continue [Y/n]? Other info: Why do the "iodbc" and "libmyodbc" packages conflict with each other? The root problem is that I need to use a new feature introduced in the latest MySQL Workbench builds (DB Migration) which uses odbc for that matter. Here is what Mysql doc says about it : Linux The Migration Wizard uses iODBC as a driver manager for all of its ODBC connections in Linux. This may give you some troubles because most Linux distributions provide ODBC drivers compiled against unixODBC. This is another driver manager not supported by MySQL Workbench so you won’t be able to use those drivers unless you compile them against iODBC. Here’s what you should do. Make sure that you have iODBC installed. If you are using Debian, Ubuntu or another Debian based distro, type this command in your terminal: $ sudo apt-get install iodbc libiodbc2-dev libpq-dev libssl-dev For RPM based distros (RedHat, Fedora, etc.) type this command instead of the previous one: $ sudo yum install iodbc iodbc-dev libpqxx-devel openssl-devel Now we need to install the PostgreSQL ODBC drivers. Download the psqlODBC source tarball from here. Use the latest version available for download. As of this writing the latest version corresponds to the file psqlodbc-09.01.0200.tar.gz. Extract this tarball to a directory in your hard drive and open a terminal and cd into that directory. Type this in the terminal window: $ ./configure --with-iodbc --enable-pthreads $ make $ sudo make install Verify that you have the file psqlodbcw.so in the /usr/local/lib directory. This package seems to pose the problem probably: dpkg -s odbcinst1debian2 Package: odbcinst1debian2 Status: install ok installed Priority: optional Section: libs Installed-Size: 241 Maintainer: Ubuntu Developers <[email protected]> Architecture: amd64 Multi-Arch: same Source: unixodbc Version: 2.2.14p2-5ubuntu4 Replaces: unixodbc (<< 2.1.1-2) Depends: libc6 (>= 2.14), libltdl7 (>= 2.4.2), odbcinst Pre-Depends: multiarch-support Breaks: libiodbc2, libmyodbc (<< 5.1.6-2), odbc-postgresql (<< 1:09.00.0310-1.1), tdsodbc (<< 0.82-8) Conflicts: odbcinst1, odbcinst1debian1 Description: Support library for accessing odbc ini files This package contains the libodbcinst library from unixodbc, a library used by ODBC drivers for reading their configuration settings from /etc/odbc.ini and ~/.odbc.ini. . Also contained in this package are the driver setup plugins, which describe the features supported by individual ODBC drivers. Homepage: http://www.unixodbc.org/ Original-Maintainer: Steve Langasek <[email protected]> I have no broken packages:

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  • Getting overwhelmed after starting a new project

    - by Kian Mayne
    I started a project (a Windows based timetable program that helps you stay organised with your subjects and assignments). The problem is that I'm not sure how I should manage this project and what order to build things. I.e. Should I build all the different interface elements then write the code or should I make an interface, code it, make another interface then code that? So my question is; how do I split up this longish project into small, ordered pieces to complete; and how should I order this?

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  • Email Service or CRM

    - by MG1
    I am creating a process for a client who is a chapel. They have people who sign up to receive notifications of a death anniversary. I exported a CSV from the db, imported it into Mailchimp and I was about to launch a Mailchimp automation based on a date. Not I realized that are many instances where the same person singed up for multiple death reminders. Mailchimp doesn't allow for duplicate email addresses in one list. Is there another service or application that I can use for this?

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  • Unlock the full potential of Oracle Retail with Oracle Retail Consulting

    - by user801960
    In this video, Maria Porretta, Engagement Director, introduces Oracle Retail Consulting which supports Oracle Retail customers by unlocking the potential of the software solutions they are utilising. Oracle Retail Consulting comprises of a global team of over 300 consultants, 70 of which are EMEA based. 90% of the team have a retail background in either IT or business, ensuring true industry expertise and maximum business benefit. Oracle Retail Consulting offers two primary streams of service; design authority which looks at analysis and design to ensure a guided process through to implementation, and delivery ownership which runs throughout the implementation process. Further information is available on our website regarding Oracle Retail Consulting.

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  • Turbo C++ to Visual Studio 2010 migration [closed]

    - by BigGenius
    OK, based on my previous questions and your help., I have gone to install Visual Studio Express. But now problem is, the programs which I successfully code at home on Visual Studio don't run on Turbo C++ compiler at school (assuming I type the program instead of exporting code). Is there anything I can do? Also I am just learning basic syntax and data handling, loops, structures, arrays and all. But Visual Studio has auto completion and pretty typing (which may be advantageous) but crap for a beginner getting hold on to language. Sorry, if I have been unclear. But what should I do? This will make me lazy programmer and will reflect in my grades. Is there any other IDE, which I can use, very similar to Turbo C++ and able to run in Windows 7 in fullsreen mode.

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  • Google webmaster tools: parameters that only apply on one page

    - by Imagine digital
    I'm trying to get my e-commerce website on google and still figuring out how it all works. Now, I have seen this feature named URL-parameters, allowing me to set different parameters that affect page content to be indexed (one can also set parameters that do not affect the page, but for me that does not apply..). The question I have about this is whether and how I should add parameters that I only have on some pages of my site. example: The homepage of my site is www.mysite.nl. no parameters at all. But when a user clicks the navigation bar, it links to www.mysite.nl/itemList.php?category=&....subCategory=.... The parameters category and subCategory define whether there is content on my itemList page and what content that is. It gets matching products out of my database based on those 2 variables. The question: How do I make sure that I apply the google URL Parameters function decently for my website?

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  • Performance: recursion vs. iteration in Javascript

    - by mastazi
    I have read recently some articles (e.g. http://dailyjs.com/2012/09/14/functional-programming/) about the functional aspects of Javascript and the relationship between Scheme and Javascript (the latter was influenced by the first, which is a functional language, while the O-O aspects are inherited from Self which is a prototyping-based language). However my question is more specific: I was wondering if there are metrics about the performance of recursion vs. iteration in Javascript. I know that in some languages (where by design iteration performs better) the difference is minimal because the interpreter / compiler converts recursion into iteration, however I guess that probably this is not the case of Javascript since it is, at least partially, a functional language.

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  • frame lock networking

    - by kochol
    I'm developing an RTS game and I want to add multiplayer support to my game. I picked the easiest technique to implement for start frame locking technique. I used server client networking architecture (I think it's my first mistake I think using peer to peer is a better one for this) On game update every clients send their commands and maybe receive some command then render the frame and wait for all clients to send their update complete message then all of them can go for the next frame. I send commands and all logic is calculated on the clients based on commands but the clients can go out of sync easily. Every AI controlled units make different decisions on each clients What I have to do to sync my game? Do you suggest me a better network architecture or technique?

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  • Scripting a sophisticated RTS AI with Lua

    - by T. Webster
    I'm planning to develop a somewhat sophisticated RTS AI (eg see BWAPI). have experience programming, but none in game development, so it seems easiest to start by scripting the AI of an existing game I've played, Warhammer 40k: Dawn of War (2004). As far as I can tell, the game AI is scripted with some variant of Lua (by the file extension .ai or .scar). The online documentation is sparse and the community isn't active anymore. I'd like to get some idea of the difficulty of this undertaking. Is it practical with a scripting language like Lua to develop a RTS AI that includes FSMs, decision trees, case-based reasoning, and transposition tables? If someone has any experience scripting Dawn of War, that would also help.

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  • Announcement Oracle Solaris Cluster 4.1 Availability!

    - by uwes
    On 26th of October Oracle announced the availability of Oracle Solaris Cluster 4.1. Highlights include: New Oracle Solaris 10 Zone Clusters: customers can now consolidate mission critical Oracle Solaris 10 applications on Oracle Solaris 11 virtualized systems in a virtual cluster Expanded disaster recovery operations: Oracle Solaris Cluster now offers managed switchover and disaster-recovery takeover of applications and data using ZFS Storage Appliance replication services in a multi-site, multi-custer configuration Faster application recovery with improved storage failure detection and resource dependencies management New labeled security environment for mission-critical deployments in Oracle Solaris Zone Clusters with Oracle Solaris 11 Trusted Extensions Learn more about Oracle Solaris Cluster 4.1: What's New in Oracle Solaris 4.1 Oracle Solaris Cluster 4.1 FAQ Oracle.com Oracle Solaris Cluster page Oracle Technology Network Oracle Solaris Cluster page Resouces for downloading: Oracle Solaris Cluster 4.1 download or order a media kit Existing Oracle Solaris Cluster 4.0 customers can quickly and simply update by using the network based repository.   Note: This repository requires keys and certificates which can be obtained here.

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  • PTLQueue : a scalable bounded-capacity MPMC queue

    - by Dave
    Title: Fast concurrent MPMC queue -- I've used the following concurrent queue algorithm enough that it warrants a blog entry. I'll sketch out the design of a fast and scalable multiple-producer multiple-consumer (MPSC) concurrent queue called PTLQueue. The queue has bounded capacity and is implemented via a circular array. Bounded capacity can be a useful property if there's a mismatch between producer rates and consumer rates where an unbounded queue might otherwise result in excessive memory consumption by virtue of the container nodes that -- in some queue implementations -- are used to hold values. A bounded-capacity queue can provide flow control between components. Beware, however, that bounded collections can also result in resource deadlock if abused. The put() and take() operators are partial and wait for the collection to become non-full or non-empty, respectively. Put() and take() do not allocate memory, and are not vulnerable to the ABA pathologies. The PTLQueue algorithm can be implemented equally well in C/C++ and Java. Partial operators are often more convenient than total methods. In many use cases if the preconditions aren't met, there's nothing else useful the thread can do, so it may as well wait via a partial method. An exception is in the case of work-stealing queues where a thief might scan a set of queues from which it could potentially steal. Total methods return ASAP with a success-failure indication. (It's tempting to describe a queue or API as blocking or non-blocking instead of partial or total, but non-blocking is already an overloaded concurrency term. Perhaps waiting/non-waiting or patient/impatient might be better terms). It's also trivial to construct partial operators by busy-waiting via total operators, but such constructs may be less efficient than an operator explicitly and intentionally designed to wait. A PTLQueue instance contains an array of slots, where each slot has volatile Turn and MailBox fields. The array has power-of-two length allowing mod/div operations to be replaced by masking. We assume sensible padding and alignment to reduce the impact of false sharing. (On x86 I recommend 128-byte alignment and padding because of the adjacent-sector prefetch facility). Each queue also has PutCursor and TakeCursor cursor variables, each of which should be sequestered as the sole occupant of a cache line or sector. You can opt to use 64-bit integers if concerned about wrap-around aliasing in the cursor variables. Put(null) is considered illegal, but the caller or implementation can easily check for and convert null to a distinguished non-null proxy value if null happens to be a value you'd like to pass. Take() will accordingly convert the proxy value back to null. An advantage of PTLQueue is that you can use atomic fetch-and-increment for the partial methods. We initialize each slot at index I with (Turn=I, MailBox=null). Both cursors are initially 0. All shared variables are considered "volatile" and atomics such as CAS and AtomicFetchAndIncrement are presumed to have bidirectional fence semantics. Finally T is the templated type. I've sketched out a total tryTake() method below that allows the caller to poll the queue. tryPut() has an analogous construction. Zebra stripping : alternating row colors for nice-looking code listings. See also google code "prettify" : https://code.google.com/p/google-code-prettify/ Prettify is a javascript module that yields the HTML/CSS/JS equivalent of pretty-print. -- pre:nth-child(odd) { background-color:#ff0000; } pre:nth-child(even) { background-color:#0000ff; } border-left: 11px solid #ccc; margin: 1.7em 0 1.7em 0.3em; background-color:#BFB; font-size:12px; line-height:65%; " // PTLQueue : Put(v) : // producer : partial method - waits as necessary assert v != null assert Mask = 1 && (Mask & (Mask+1)) == 0 // Document invariants // doorway step // Obtain a sequence number -- ticket // As a practical concern the ticket value is temporally unique // The ticket also identifies and selects a slot auto tkt = AtomicFetchIncrement (&PutCursor, 1) slot * s = &Slots[tkt & Mask] // waiting phase : // wait for slot's generation to match the tkt value assigned to this put() invocation. // The "generation" is implicitly encoded as the upper bits in the cursor // above those used to specify the index : tkt div (Mask+1) // The generation serves as an epoch number to identify a cohort of threads // accessing disjoint slots while s-Turn != tkt : Pause assert s-MailBox == null s-MailBox = v // deposit and pass message Take() : // consumer : partial method - waits as necessary auto tkt = AtomicFetchIncrement (&TakeCursor,1) slot * s = &Slots[tkt & Mask] // 2-stage waiting : // First wait for turn for our generation // Acquire exclusive "take" access to slot's MailBox field // Then wait for the slot to become occupied while s-Turn != tkt : Pause // Concurrency in this section of code is now reduced to just 1 producer thread // vs 1 consumer thread. // For a given queue and slot, there will be most one Take() operation running // in this section. // Consumer waits for producer to arrive and make slot non-empty // Extract message; clear mailbox; advance Turn indicator // We have an obvious happens-before relation : // Put(m) happens-before corresponding Take() that returns that same "m" for T v = s-MailBox if v != null : s-MailBox = null ST-ST barrier s-Turn = tkt + Mask + 1 // unlock slot to admit next producer and consumer return v Pause tryTake() : // total method - returns ASAP with failure indication for auto tkt = TakeCursor slot * s = &Slots[tkt & Mask] if s-Turn != tkt : return null T v = s-MailBox // presumptive return value if v == null : return null // ratify tkt and v values and commit by advancing cursor if CAS (&TakeCursor, tkt, tkt+1) != tkt : continue s-MailBox = null ST-ST barrier s-Turn = tkt + Mask + 1 return v The basic idea derives from the Partitioned Ticket Lock "PTL" (US20120240126-A1) and the MultiLane Concurrent Bag (US8689237). The latter is essentially a circular ring-buffer where the elements themselves are queues or concurrent collections. You can think of the PTLQueue as a partitioned ticket lock "PTL" augmented to pass values from lock to unlock via the slots. Alternatively, you could conceptualize of PTLQueue as a degenerate MultiLane bag where each slot or "lane" consists of a simple single-word MailBox instead of a general queue. Each lane in PTLQueue also has a private Turn field which acts like the Turn (Grant) variables found in PTL. Turn enforces strict FIFO ordering and restricts concurrency on the slot mailbox field to at most one simultaneous put() and take() operation. PTL uses a single "ticket" variable and per-slot Turn (grant) fields while MultiLane has distinct PutCursor and TakeCursor cursors and abstract per-slot sub-queues. Both PTL and MultiLane advance their cursor and ticket variables with atomic fetch-and-increment. PTLQueue borrows from both PTL and MultiLane and has distinct put and take cursors and per-slot Turn fields. Instead of a per-slot queues, PTLQueue uses a simple single-word MailBox field. PutCursor and TakeCursor act like a pair of ticket locks, conferring "put" and "take" access to a given slot. PutCursor, for instance, assigns an incoming put() request to a slot and serves as a PTL "Ticket" to acquire "put" permission to that slot's MailBox field. To better explain the operation of PTLQueue we deconstruct the operation of put() and take() as follows. Put() first increments PutCursor obtaining a new unique ticket. That ticket value also identifies a slot. Put() next waits for that slot's Turn field to match that ticket value. This is tantamount to using a PTL to acquire "put" permission on the slot's MailBox field. Finally, having obtained exclusive "put" permission on the slot, put() stores the message value into the slot's MailBox. Take() similarly advances TakeCursor, identifying a slot, and then acquires and secures "take" permission on a slot by waiting for Turn. Take() then waits for the slot's MailBox to become non-empty, extracts the message, and clears MailBox. Finally, take() advances the slot's Turn field, which releases both "put" and "take" access to the slot's MailBox. Note the asymmetry : put() acquires "put" access to the slot, but take() releases that lock. At any given time, for a given slot in a PTLQueue, at most one thread has "put" access and at most one thread has "take" access. This restricts concurrency from general MPMC to 1-vs-1. We have 2 ticket locks -- one for put() and one for take() -- each with its own "ticket" variable in the form of the corresponding cursor, but they share a single "Grant" egress variable in the form of the slot's Turn variable. Advancing the PutCursor, for instance, serves two purposes. First, we obtain a unique ticket which identifies a slot. Second, incrementing the cursor is the doorway protocol step to acquire the per-slot mutual exclusion "put" lock. The cursors and operations to increment those cursors serve double-duty : slot-selection and ticket assignment for locking the slot's MailBox field. At any given time a slot MailBox field can be in one of the following states: empty with no pending operations -- neutral state; empty with one or more waiting take() operations pending -- deficit; occupied with no pending operations; occupied with one or more waiting put() operations -- surplus; empty with a pending put() or pending put() and take() operations -- transitional; or occupied with a pending take() or pending put() and take() operations -- transitional. The partial put() and take() operators can be implemented with an atomic fetch-and-increment operation, which may confer a performance advantage over a CAS-based loop. In addition we have independent PutCursor and TakeCursor cursors. Critically, a put() operation modifies PutCursor but does not access the TakeCursor and a take() operation modifies the TakeCursor cursor but does not access the PutCursor. This acts to reduce coherence traffic relative to some other queue designs. It's worth noting that slow threads or obstruction in one slot (or "lane") does not impede or obstruct operations in other slots -- this gives us some degree of obstruction isolation. PTLQueue is not lock-free, however. The implementation above is expressed with polite busy-waiting (Pause) but it's trivial to implement per-slot parking and unparking to deschedule waiting threads. It's also easy to convert the queue to a more general deque by replacing the PutCursor and TakeCursor cursors with Left/Front and Right/Back cursors that can move either direction. Specifically, to push and pop from the "left" side of the deque we would decrement and increment the Left cursor, respectively, and to push and pop from the "right" side of the deque we would increment and decrement the Right cursor, respectively. We used a variation of PTLQueue for message passing in our recent OPODIS 2013 paper. ul { list-style:none; padding-left:0; padding:0; margin:0; margin-left:0; } ul#myTagID { padding: 0px; margin: 0px; list-style:none; margin-left:0;} -- -- There's quite a bit of related literature in this area. I'll call out a few relevant references: Wilson's NYU Courant Institute UltraComputer dissertation from 1988 is classic and the canonical starting point : Operating System Data Structures for Shared-Memory MIMD Machines with Fetch-and-Add. Regarding provenance and priority, I think PTLQueue or queues effectively equivalent to PTLQueue have been independently rediscovered a number of times. See CB-Queue and BNPBV, below, for instance. But Wilson's dissertation anticipates the basic idea and seems to predate all the others. Gottlieb et al : Basic Techniques for the Efficient Coordination of Very Large Numbers of Cooperating Sequential Processors Orozco et al : CB-Queue in Toward high-throughput algorithms on many-core architectures which appeared in TACO 2012. Meneghin et al : BNPVB family in Performance evaluation of inter-thread communication mechanisms on multicore/multithreaded architecture Dmitry Vyukov : bounded MPMC queue (highly recommended) Alex Otenko : US8607249 (highly related). John Mellor-Crummey : Concurrent queues: Practical fetch-and-phi algorithms. Technical Report 229, Department of Computer Science, University of Rochester Thomasson : FIFO Distributed Bakery Algorithm (very similar to PTLQueue). Scott and Scherer : Dual Data Structures I'll propose an optimization left as an exercise for the reader. Say we wanted to reduce memory usage by eliminating inter-slot padding. Such padding is usually "dark" memory and otherwise unused and wasted. But eliminating the padding leaves us at risk of increased false sharing. Furthermore lets say it was usually the case that the PutCursor and TakeCursor were numerically close to each other. (That's true in some use cases). We might still reduce false sharing by incrementing the cursors by some value other than 1 that is not trivially small and is coprime with the number of slots. Alternatively, we might increment the cursor by one and mask as usual, resulting in a logical index. We then use that logical index value to index into a permutation table, yielding an effective index for use in the slot array. The permutation table would be constructed so that nearby logical indices would map to more distant effective indices. (Open question: what should that permutation look like? Possibly some perversion of a Gray code or De Bruijn sequence might be suitable). As an aside, say we need to busy-wait for some condition as follows : "while C == 0 : Pause". Lets say that C is usually non-zero, so we typically don't wait. But when C happens to be 0 we'll have to spin for some period, possibly brief. We can arrange for the code to be more machine-friendly with respect to the branch predictors by transforming the loop into : "if C == 0 : for { Pause; if C != 0 : break; }". Critically, we want to restructure the loop so there's one branch that controls entry and another that controls loop exit. A concern is that your compiler or JIT might be clever enough to transform this back to "while C == 0 : Pause". You can sometimes avoid this by inserting a call to a some type of very cheap "opaque" method that the compiler can't elide or reorder. On Solaris, for instance, you could use :"if C == 0 : { gethrtime(); for { Pause; if C != 0 : break; }}". It's worth noting the obvious duality between locks and queues. If you have strict FIFO lock implementation with local spinning and succession by direct handoff such as MCS or CLH,then you can usually transform that lock into a queue. Hidden commentary and annotations - invisible : * And of course there's a well-known duality between queues and locks, but I'll leave that topic for another blog post. * Compare and contrast : PTLQ vs PTL and MultiLane * Equivalent : Turn; seq; sequence; pos; position; ticket * Put = Lock; Deposit Take = identify and reserve slot; wait; extract & clear; unlock * conceptualize : Distinct PutLock and TakeLock implemented as ticket lock or PTL Distinct arrival cursors but share per-slot "Turn" variable provides exclusive role-based access to slot's mailbox field put() acquires exclusive access to a slot for purposes of "deposit" assigns slot round-robin and then acquires deposit access rights/perms to that slot take() acquires exclusive access to slot for purposes of "withdrawal" assigns slot round-robin and then acquires withdrawal access rights/perms to that slot At any given time, only one thread can have withdrawal access to a slot at any given time, only one thread can have deposit access to a slot Permissible for T1 to have deposit access and T2 to simultaneously have withdrawal access * round-robin for the purposes of; role-based; access mode; access role mailslot; mailbox; allocate/assign/identify slot rights; permission; license; access permission; * PTL/Ticket hybrid Asymmetric usage ; owner oblivious lock-unlock pairing K-exclusion add Grant cursor pass message m from lock to unlock via Slots[] array Cursor performs 2 functions : + PTL ticket + Assigns request to slot in round-robin fashion Deconstruct protocol : explication put() : allocate slot in round-robin fashion acquire PTL for "put" access store message into slot associated with PTL index take() : Acquire PTL for "take" access // doorway step seq = fetchAdd (&Grant, 1) s = &Slots[seq & Mask] // waiting phase while s-Turn != seq : pause Extract : wait for s-mailbox to be full v = s-mailbox s-mailbox = null Release PTL for both "put" and "take" access s-Turn = seq + Mask + 1 * Slot round-robin assignment and lock "doorway" protocol leverage the same cursor and FetchAdd operation on that cursor FetchAdd (&Cursor,1) + round-robin slot assignment and dispersal + PTL/ticket lock "doorway" step waiting phase is via "Turn" field in slot * PTLQueue uses 2 cursors -- put and take. Acquire "put" access to slot via PTL-like lock Acquire "take" access to slot via PTL-like lock 2 locks : put and take -- at most one thread can access slot's mailbox Both locks use same "turn" field Like multilane : 2 cursors : put and take slot is simple 1-capacity mailbox instead of queue Borrow per-slot turn/grant from PTL Provides strict FIFO Lock slot : put-vs-put take-vs-take at most one put accesses slot at any one time at most one put accesses take at any one time reduction to 1-vs-1 instead of N-vs-M concurrency Per slot locks for put/take Release put/take by advancing turn * is instrumental in ... * P-V Semaphore vs lock vs K-exclusion * See also : FastQueues-excerpt.java dice-etc/queue-mpmc-bounded-blocking-circular-xadd/ * PTLQueue is the same as PTLQB - identical * Expedient return; ASAP; prompt; immediately * Lamport's Bakery algorithm : doorway step then waiting phase Threads arriving at doorway obtain a unique ticket number Threads enter in ticket order * In the terminology of Reed and Kanodia a ticket lock corresponds to the busy-wait implementation of a semaphore using an eventcount and a sequencer It can also be thought of as an optimization of Lamport's bakery lock was designed for fault-tolerance rather than performance Instead of spinning on the release counter, processors using a bakery lock repeatedly examine the tickets of their peers --

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  • Merck Serono Gains Deep Understanding of Product Portfolio Value-Drivers, Risks, and Sales Expectations Through Forecasting Solution

    - by Melissa Centurio Lopes
    Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin-top:0in; mso-para-margin-right:0in; mso-para-margin-bottom:10.0pt; mso-para-margin-left:0in; line-height:115%; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;} Merck Serono S.A. is the biopharmaceutical division of Merck KGaA. It offers leading brands in 150 countries to help patients with cancer, multiple sclerosis, infertility, endocrine and metabolic disorders, as well as cardiovascular diseases. Challenges: Establish a better decision-making framework for its complex, development portfolio of pharmaceutical products, where single-point estimates or expected averages of portfolio values, portfolio risks, and sales forecasts are insufficient and can be misleading Enable the company to be aware at all times of the range of possible outcomes of technical and market risks and uncertainties, such as the technical uncertainty of whether a product will produce the desired clinical outcomes, or the market-related uncertainty of whether a product will be outperformed by its competitors Solutions to Overcome the Challenges: Used Oracle Crystal Ball to devise a Monte-Carlo-based approach to better analyze and define the values and risks of the company’s development portfolio, laying the groundwork for optimized decision-making Enabled a better understanding of the range of potential values and risks to improve portfolio planning Enabled detailed analysis of the likelihood of favorable or unfavorable outcomes, such as the likelihood of whether Merck Serono can meet its sales targets planned for the next ten years with its existing product portfolio Gained the ability to take into account correlative risks, synergies and project interactions, enabling Merck Serono to better forecast what the company may achieve—for example, that there is a 70% probability of a particular sales target being met Established Monte-Carlo-based analysis using Oracle Crystal Ball as a useful element in decision-making at the board level, as the approach provides a better analysis of values and risks associated with the company’s product portfolio “Oracle Crystal Ball enables us to make Monte Carlo simulations of the potential value and sales of our development portfolio. It is a very powerful tool for gaining a thorough understanding and improved awareness of value drivers, uncertainties, and risks, along with associated probabilities.” – Riccardo Lampariello, Associate Director, Merck Serono S.A Why Oracle “We chose Oracle Crystal Ball to enable us to perform Monte Carlo analysis, which gives us a deeper understanding and improved awareness of the value drivers, uncertainties and risks of our portfolio of development projects,” said Kimber Hardy, head of valuation and analysis, Merck Serono S.A. Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin-top:0in; mso-para-margin-right:0in; mso-para-margin-bottom:10.0pt; mso-para-margin-left:0in; line-height:115%; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;} Click here to read the full version of the customer success story Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin-top:0in; mso-para-margin-right:0in; mso-para-margin-bottom:10.0pt; mso-para-margin-left:0in; line-height:115%; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;}

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  • Beyond Syntax Highlighting - What other code representations are possible today?

    - by Mathieu Hélie
    Despite GUI applications having been around for 30ish years, software is still written as lines of text instructions, for various valid reasons. But we've also found that manipulating these text instructions is mind-blowingly difficult unless we apply a layer of coloring on different words to represent their syntax, thus allowing us to quickly parse through these text files without having to read the whole words. But besides the Sublime Text minimap feature, I've yet to see any innovation in visual representation of code since colors came around on CRT monitors. I can think of one obviously essential representation that modern graphics technology allows: visual hierarchies for nested structures. If we make nested text slightly smaller than its outer context, and zoom on it when the cursor is focused on the line, then we will be able to browse huge files of nested statements very quickly. This becomes even more essential as languages based on closures and anonymous functions become filled with deep statements. Has anyone attempted to implement this in a text editor? Do you know of any otherwise useful improvements in representing code text graphically?

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  • SilverlightShow for Jan 3-9, 2011

    - by Dave Campbell
    Check out the Top Five most popular news at SilverlightShow for Jan 3-9, 2011. SilverlightShow's review of their top 10 visited articles in 2010 got most hits last week. MicrosoftFeed's review of the Facebook application Picturize.me got the second place. Among the top5 is also an interesting review of the top Silverlight books for 2010 by Michael Crump. Here is SilverlightShow's weekly top 5: Top 10 SilverlightShow Articles for Year 2010 Picturize.me - a Silverlight Based Facebook application Face detection in Windows Phone 7 MVVM Navigation with MEF What is the best book on Silverlight 4 Visit and bookmark SilverlightShow. Stay in the 'Light

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  • Create .deb form gambas2 project

    - by Mauricio Andrés
    I have been working with Gambas 2 (the one in the software center), Actially I took the source code of other program and create a new program basen on that. But now that I finished, I can't create .deb files, gambas show me this error: La creación del paquete ha fallado. Package.MakeDebPackage.368: File or directory does not exist So I dont know what to do now, I really need this program. I tried with Gambas 3, but is too much work to do that the program based in Gmabas 2 works in Gambas 3, also I tried creating a .deb package and gambas get frozen. Please some help

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  • Collision Detection Game Design and Architecture

    - by Chompas
    I've reading some articles about collision detection. My question here is about ideas on the design for it. Baically I have a C++ game that has a main loop with entities with an update method. Based on keyboard input, these characters updates their positions. My question is not about how to detect collisions, it's about getting ideas in which is the best way to implement this. The game has a main character but also enemies that have to collide between them, so I'm not sure where to make all the iterations for checking collisions and if the right way is to check everything against everything. Thanks in advance.

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  • Setting environment variables when executing Eclipse via Unity launcher icon

    - by Nullptr
    My question is a followup for the following: How to pin Eclipse to the Unity launcher? I created Eclipse's icon to the Unity launcher based on the selected answer at the above link. However, when I launch Eclipse via this icon, the environment variables are not properly set. I need to call . /opt/intel/bin/compilervars.sh intel64 to use Intel compiler tools in Eclipse. However, launching via the icon can't do it. Of course, running manually Eclipse on the terminal is okay. I tried to place . /opt/intel/bin/compilervars.sh intel64 on several places such as /etc/profile and /etc/bash.bashrc. But, still not working. Where is the best and correct place to call such environment setup?

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