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  • New Netra SPARC T3 Servers

    - by Ferhat Hatay
    Today at the Mobile World Congress 2011, Oracle announced two new carrier-grade NEBS Level 3- certified servers: Oracle’s Netra SPARC T3-1 rackmount server and Oracle’s Netra SPARC T3-1BA ATCA blade server bringing the performance, scalability and power efficiency of the newest SPARC T3 processor to the communications market.    The Netra SPARC T3-1 server enclosure has a compact 20inch-deep carrier-grade rack-optimized design The new Netra SPARC T3 servers further expand Oracle’s complete portfolio for the communications industry, which includes carrier-grade servers, storage and application software to run operations support systems and service delivery platforms with easy migration capabilities and unmatched investment protection via the binary compatibility guarantee of the Oracle Solaris operating system. With advanced reliability, networking and security features built-in to Oracle Solaris – the most widely deployed carrier-grade OS – the systems announced today are uniquely suited for mission-critical core network infrastructure and service delivery. The world’s first carrier-grade system using the 16-core, 128-thread SPARC T3 processor, the Netra SPARC T3-1 server supports 2x the I/O bandwidth, 2x the memory and is 35 percent faster than the previous generation. With integrated on-chip 10 Gigabit Ethernet, on-chip cryptographic acceleration, and built-in, no-cost Oracle VM Server for SPARC and Oracle Solaris Containers for virtualization, the Netra SPARC T3-1 server is an ideal platform for consolidation, offering 128 virtual systems in a single server. As the next generation Netra SPARC ATCA blade, Netra SPARC T3-1BA ATCA blade server brings the PICMG 3.0 compatibility, NEBS Level 3 Certification, ETSI compliance and the Netra business practices to the customer solution. The Netra SPARC T3-1BA ATCA blade server can be mixed in the Sun Netra CT900 blade chassis with other ATCA UltraSPARC and x86 blades.     The Netra SPARC T3-1BA ATCA blade server   The Netra SPARC T3-1BA ATCA blade server delivers industry-leading scalability, density and cost efficiency with up to 36 SPARC T3 processors (3456 processing threads) in a single rack – a 50 percent increase over the previous generation. The Netra SPARC T3-1BA blade server also offers high-bandwidth and high-capacity I/O, with greater memory capacity to tackle the increasing business demands of the communications industry. For service providers faced with the rapid growth of broadband networks and the dramatic surge in global smartphone adoption, the new Netra SPARC T3 systems deliver continuous availability with massive scalability, tested and certified to run in the harshest conditions. More information Oracle’s Sun Netra Servers Scaling Throughput and Managing TCO with Oracle’s Netra SPARC T3-1 Servers Enabling End-to-End 10 Gigabit Ethernet in Oracle's Sun Netra ATCA Product Family Data Sheet: Netra SPARC T3-1BA ATCA Blade Server Data Sheet: Netra SPARC T3-1 Server Oracle Solaris: The Carrier Grade Operating System

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  • LinqToXML removing empty xmlns attributes &amp; adding attributes like xmlns:xsi, xsi:schemaLocation

    - by Rohit Gupta
    Suppose you need to generate the following XML: 1: <GenevaLoader xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 2: xsi:schemaLocation="http://www.advent.com/SchemaRevLevel401/Geneva masterschema.xsd" 3: xmlns="http://www.advent.com/SchemaRevLevel401/Geneva"> 4: <PriceRecords> 5: <PriceRecord> 6: </PriceRecord> 7: </PriceRecords> 8: </GenevaLoader> Normally you would write the following C# code to accomplish this: 1: const string ns = "http://www.advent.com/SchemaRevLevel401/Geneva"; 2: XNamespace xnsp = ns; 3: XNamespace xsi = XNamespace.Get("http://www.w3.org/2001/XMLSchema-instance"); 4:  5: XElement root = new XElement( xnsp + "GenevaLoader", 6: new XAttribute(XNamespace.Xmlns + "xsi", xsi.NamespaceName), 7: new XAttribute( xsi + "schemaLocation", "http://www.advent.com/SchemaRevLevel401/Geneva masterschema.xsd")); 8:  9: XElement priceRecords = new XElement("PriceRecords"); 10: root.Add(priceRecords); 11:  12: for(int i = 0; i < 3; i++) 13: { 14: XElement price = new XElement("PriceRecord"); 15: priceRecords.Add(price); 16: } 17:  18: doc.Save("geneva.xml"); The problem with this approach is that it adds a additional empty xmlns arrtribute on the “PriceRecords” element, like so : 1: <GenevaLoader xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.advent.com/SchemaRevLevel401/Geneva masterschema.xsd" xmlns="http://www.advent.com/SchemaRevLevel401/Geneva"> 2: <PriceRecords xmlns=""> 3: <PriceRecord> 4: </PriceRecord> 5: </PriceRecords> 6: </GenevaLoader> The solution is to add the xmlns NameSpace in code to each child and grandchild elements of the root element like so : 1: XElement priceRecords = new XElement( xnsp + "PriceRecords"); 2: root.Add(priceRecords); 3:  4: for(int i = 0; i < 3; i++) 5: { 6: XElement price = new XElement(xnsp + "PriceRecord"); 7: priceRecords.Add(price); 8: }

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  • ASP.NET MVC localization DisplayNameAttribute alternatives: a better way

    - by Brian Schroer
    In my last post, I talked bout creating a custom class inheriting from System.ComponentModel.DisplayNameAttribute to retrieve display names from resource files: [LocalizedDisplayName("RememberMe")] public bool RememberMe { get; set; } That’s a lot of work to put an attribute on all of my model properties though. It would be nice if I could intercept the ASP.NET MVC code that analyzes the model metadata to retrieve display names to make it automatically get localized text from my resource files. That way, I could just set up resource file entries where the keys are the property names, and not have to put attributes on all of my properties. That’s done by creating a custom class inheriting from System.Web.Mvc.DataAnnotationsModelMetadataProvider: 1: public class LocalizedDataAnnotationsModelMetadataProvider : 2: DataAnnotationsModelMetadataProvider 3: { 4: protected override ModelMetadata CreateMetadata( 5: IEnumerable<Attribute> attributes, 6: Type containerType, 7: Func<object> modelAccessor, 8: Type modelType, 9: string propertyName) 10: { 11: var meta = base.CreateMetadata 12: (attributes, containerType, modelAccessor, modelType, propertyName); 13:   14: if (string.IsNullOrEmpty(propertyName)) 15: return meta; 16:   17: if (meta.DisplayName == null) 18: GetLocalizedDisplayName(meta, propertyName); 19:   20: if (string.IsNullOrEmpty(meta.DisplayName)) 21: meta.DisplayName = string.Format("[[{0}]]", propertyName); 22:   23: return meta; 24: } 25:   26: private static void GetLocalizedDisplayName(ModelMetadata meta, string propertyName) 27: { 28: ResourceManager resourceManager = MyResource.ResourceManager; 29: CultureInfo culture = Thread.CurrentThread.CurrentUICulture; 30:   31: meta.DisplayName = resourceManager.GetString(propertyName, culture); 32: } 33: } Line 11 calls the base CreateMetadata method. Line 17 checks whether the metadata DisplayName property has already been populated by a DisplayNameAttribute (or my LocalizedDisplayNameAttribute). If so, it respects that and doesn’t use my custom localized text lookup. The GetLocalizedDisplayName method checks for the property name as a resource file key. If found, it uses the localized text from the resource files. If the key is not found in the resource file, as with my LocalizedDisplayNameAttribute, I return a formatted string containing the property name (e.g. “[[RememberMe]]”) so I can tell by looking at my web pages which resource keys I haven’t defined yet. It’s hooked up with this code in the Application_Start method of Global.asax: ModelMetadataProviders.Current = new LocalizedDataAnnotationsModelMetadataProvider();

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  • Why is Excel 2010/2013 taking 10 seconds open any file?

    - by jbkly
    I have a fast Windows 7 PC with two SSDs and 16GB of RAM, so I'm used to programs loading very fast. But recently, for no reason I can figure out, Excel has started taking way too long to open Excel files (of any size--even blank files). This is occurring with Excel 2010 and with Excel 2013 after I upgraded, hoping to solve the problem. Here a couple scenarios: If I start Excel directly, it opens almost instantly. No problem there. If I start Excel directly, and then open any Excel file (.xls or .xlsx), it loads almost instantly. Still no problem BUT if I attempt to open any Excel file directly, with Excel not running, it consistently takes 10-11 seconds for Excel to start. I get no error messages, just a spinning cursor for 10-11 seconds, and then the file opens. During the delay while Excel is trying to start, I'm not really seeing any discernible spike in CPU or memory usage, other than explorer.exe. This problem is only occurring with Excel, not Word or any other program I'm aware of. I've searched around quite a bit on this question and found various others who have experienced it, but the solutions that worked for them are not working for me. For a few people it was a problem with scanning network drives, but my problem is purely with local files; I have no network drives, and the problem persists even with all network connections disabled. Some people suggested worksheets with corrupted formulas or links, but I'm experiencing this with ANY Excel file: even blank worksheets. Others thought it was a problem with add-ins, but I have all Excel add-ins disabled (as far as I can tell). One person solved it by disabling a "clipboard manager" process that was running in the background, but I don't have that. I've disabled as many startup and background processes as I can, but the problem persists. I've run malware scans, disk cleanup, CCleaner, and installed Excel 2013. I've deleted temporary files, enabled SuperFetch, and edited registry keys. Still can't get rid of the problem. Any ideas? My system details: Windows 7 Professional SP1 64-bit, Excel 2013 32-bit, 16GB RAM, all programs installed on SSD.

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  • Windows could not update the computer's boot configuration.

    - by Luke Puplett
    Hello, I am trying to install Windows Web Server 2008 x64 (have tried 32-bit, too) onto an IBM eServer 326m and am getting the following error message some time after the unpacking files section: Windows could not update the computer's boot configuration. Installation cannot proceed. I can repair the boot information using the Repair option in the WinPE bit of the setup, and it reboots into the Windows installation, so it has good boot data on the drive. Just to complicate things, the server does not have a DVD-ROM so I'm installing from HDD to HDD, both SATA, one an SSD. I've tried each drive in isolation, e.g. removing the SSD and installing from spindle onto itself, same error every time. Flashed IBM BIOS, too. Thanks for your help. Luke

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  • Creating a bare bone web-browser: After the html parser, javascript parser, etc have done their work, how do I display the content of the webpage?

    - by aste123
    This is a personal project to learn computer programming. I took a look at this: https://www.udacity.com/course/viewer#!/c-cs262 The following is the approach taken in it: Abstract Syntax Tree is created. But javascript is still not completely broken down in order not to confuse with the html tags. Then the javascript interpreter is called on it. Javascript interpreter stores the text from the write() and document.write() to be used later. Then a graphics library in Python is called which will convert everything to a pdf file and then we convert it into png or jpeg and then display it. My Question: I want to display the actual text in a window (which I will design later) like firefox or chrome does instead of image files so that the data can be selected, copied, etc by the user of the browser. How do I accomplish this? In other words, what are the other elements of a bare bone web browser that I am missing? I would prefer to implement most of the stuff in C++ although if things seem too complicated I might go with Python to save time and create a prototype and later creating another bare bone browser in C++ and add more features. This is a project to learn more. I do realize we already have lots of reliable browsers like firefox, etc. The way I feel it is done: I think after all the broken down contents have been created by the parsers and interpreters, I will need to access them individually from within the window's code (like qt) and then decide upon a good way to display them. I am not sure if it is the way this should be done. Additions after useful comment by Kilian Foth: I found this page: http://friendlybit.com/css/rendering-a-web-page-step-by-step/ 14. A DOM tree is built out of the broken HTML 15. New requests are made to the server for each new resource that is found in the HTML source (typically images, style sheets, and JavaScript files). Go back to step 3 and repeat for each resource. 16. Stylesheets are parsed, and the rendering information in each gets attached to the matching node in the DOM tree 17. Javascript is parsed and executed, and DOM nodes are moved and style information is updated accordingly 18. The browser renders the page on the screen according to the DOM tree and the style information for each node 19. You see the page on the screen I need help with step 18. How do I do that? How much work do Webkit and Gecko do? I want to use a readymade layout renderer for step number 18 and not for anything that comes before that.

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  • Alert visualization recipe: Get out your blender, drop in some sp_send_dbmail, Google Charts API, add your favorite colors and sprinkle with html. Blend till it’s smooth and looks pretty enough to taste.

    - by Maria Zakourdaev
      I really like database monitoring. My email inbox have a constant flow of different types of alerts coming from our production servers with all kinds of information, sometimes more useful and sometimes less useful. Usually database alerts look really simple, it’s usually a plain text email saying “Prod1 Database data file on Server X is 80% used. You’d better grow it manually before some query triggers the AutoGrowth process”. Imagine you could have received email like the one below.  In addition to the alert description it could have also included the the database file growth chart over the past 6 months. Wouldn’t it give you much more information whether the data growth is natural or extreme? That’s truly what data visualization is for. Believe it or not, I have sent the graph below from SQL Server stored procedure without buying any additional data monitoring/visualization tool.   Would you like to visualize your database alerts like I do? Then like myself, you’d love the Google Charts. All you need to know is a little HTML and have a mail profile configured on your SQL Server instance regardless of the SQL Server version. First of all, I hope you know that the sp_send_dbmail procedure has a great parameter @body_format = ‘HTML’, which allows us to send rich and colorful messages instead of boring black and white ones. All that we need is to dynamically create HTML code. This is how, for instance, you can create a table and populate it with some data: DECLARE @html varchar(max) SET @html = '<html>' + '<H3><font id="Text" style='color: Green;'>Top Databases: </H3>' + '<table border="1" bordercolor="#3300FF" style='background-color:#DDF8CC' width='70%' cellpadding='3' cellspacing='3'>' + '<tr><font color="Green"><th>Database Name</th><th>Size</th><th>Physical Name</th></tr>' + CAST( (SELECT TOP 10                             td = name,'',                             td = size * 8/1024 ,'',                             td = physical_name              FROM sys.master_files               ORDER BY size DESC             FOR XML PATH ('tr'),TYPE ) AS VARCHAR(MAX)) + '</table>' EXEC msdb.dbo.sp_send_dbmail @recipients = '[email protected]', @subject ='Top databases', @body = @html, @body_format = 'HTML' This is the result:   If you want to add more visualization effects, you can use Google Charts Tools https://google-developers.appspot.com/chart/interactive/docs/index which is a free and rich library of data visualization charts, they’re also easy to populate and embed. There are two versions of the Google Charts Image based charts: https://google-developers.appspot.com/chart/image/docs/gallery/chart_gall This is an old version, it’s officially deprecated although it will be up for a next few years or so. I really enjoy using this one because it can be viewed within the email body. For mobile devices you need to change the “Load remote images” property in your email application configuration.           Charts based on JavaScript classes: https://google-developers.appspot.com/chart/interactive/docs/gallery This API is newer, with rich and highly interactive charts, and it’s much more easier to understand and configure. The only downside of it is that they cannot be viewed within the email body. Outlook, Gmail and many other email clients, as part of their security policy, do not run any JavaScript that’s placed within the email body. However, you can still enjoy this API by sending the report as an email attachment. Here is an example of the old version of Google Charts API, sending the same top databases report as in the previous example but instead of a simple table, this script is using a pie chart right from  the T-SQL code DECLARE @html  varchar(8000) DECLARE @Series  varchar(800),@Labels  varchar(8000),@Legend  varchar(8000);     SET @Series = ''; SET @Labels = ''; SET @Legend = ''; SELECT TOP 5 @Series = @Series + CAST(size * 8/1024 as varchar) + ',',                         @Labels = @Labels +CAST(size * 8/1024 as varchar) + 'MB'+'|',                         @Legend = @Legend + name + '|' FROM sys.master_files ORDER BY size DESC SELECT @Series = SUBSTRING(@Series,1,LEN(@Series)-1),         @Labels = SUBSTRING(@Labels,1,LEN(@Labels)-1),         @Legend = SUBSTRING(@Legend,1,LEN(@Legend)-1) SET @html =   '<H3><font color="Green"> '+@@ServerName+' top 5 databases : </H3>'+    '<br>'+    '<img src="http://chart.apis.google.com/chart?'+    'chf=bg,s,DDF8CC&'+    'cht=p&'+    'chs=400x200&'+    'chco=3072F3|7777CC|FF9900|FF0000|4A8C26&'+    'chd=t:'+@Series+'&'+    'chl='+@Labels+'&'+    'chma=0,0,0,0&'+    'chdl='+@Legend+'&'+    'chdlp=b"'+    'alt="'+@@ServerName+' top 5 databases" />'              EXEC msdb.dbo.sp_send_dbmail @recipients = '[email protected]',                             @subject = 'Top databases',                             @body = @html,                             @body_format = 'HTML' This is what you get. Isn’t it great? Chart parameters reference: chf     Gradient fill  bg - backgroud ; s- solid cht     chart type  ( p - pie) chs        chart size width/height chco    series colors chd        chart data string        1,2,3,2 chl        pir chart labels        a|b|c|d chma    chart margins chdl    chart legend            a|b|c|d chdlp    chart legend text        b - bottom of chart   Line graph implementation is also really easy and powerful DECLARE @html varchar(max) DECLARE @Series varchar(max) DECLARE @HourList varchar(max) SET @Series = ''; SET @HourList = ''; SELECT @HourList = @HourList + SUBSTRING(CONVERT(varchar(13),last_execution_time,121), 12,2)  + '|' ,              @Series = @Series + CAST( COUNT(1) as varchar) + ',' FROM sys.dm_exec_query_stats s     CROSS APPLY sys.dm_exec_sql_text(plan_handle) t WHERE last_execution_time > = getdate()-1 GROUP BY CONVERT(varchar(13),last_execution_time,121) ORDER BY CONVERT(varchar(13),last_execution_time,121) SET @Series = SUBSTRING(@Series,1,LEN(@Series)-1) SET @html = '<img src="http://chart.apis.google.com/chart?'+ 'chco=CA3D05,87CEEB&'+ 'chd=t:'+@Series+'&'+ 'chds=1,350&'+ 'chdl= Proc executions from cache&'+ 'chf=bg,s,1F1D1D|c,lg,0,363433,1.0,2E2B2A,0.0&'+ 'chg=25.0,25.0,3,2&'+ 'chls=3|3&'+ 'chm=d,CA3D05,0,-1,12,0|d,FFFFFF,0,-1,8,0|d,87CEEB,1,-1,12,0|d,FFFFFF,1,-1,8,0&'+ 'chs=600x450&'+ 'cht=lc&'+ 'chts=FFFFFF,14&'+ 'chtt=Executions for from' +(SELECT CONVERT(varchar(16),min(last_execution_time),121)          FROM sys.dm_exec_query_stats          WHERE last_execution_time > = getdate()-1) +' till '+ +(SELECT CONVERT(varchar(16),max(last_execution_time),121)     FROM sys.dm_exec_query_stats) + '&'+ 'chxp=1,50.0|4,50.0&'+ 'chxs=0,FFFFFF,12,0|1,FFFFFF,12,0|2,FFFFFF,12,0|3,FFFFFF,12,0|4,FFFFFF,14,0&'+ 'chxt=y,y,x,x,x&'+ 'chxl=0:|1|350|1:|N|2:|'+@HourList+'3:|Hour&'+ 'chma=55,120,0,0" alt="" />' EXEC msdb.dbo.sp_send_dbmail @recipients = '[email protected]', @subject ='Daily number of executions', @body = @html, @body_format = 'HTML' Chart parameters reference: chco    series colors chd        series data chds    scale format chdl    chart legend chf        background fills chg        grid line chls    line style chm        line fill chs        chart size cht        chart type chts    chart style chtt    chart title chxp    axis label positions chxs    axis label styles chxt    axis tick mark styles chxl    axis labels chma    chart margins If you don’t mind to get your charts as an email attachment, you can enjoy the Java based Google Charts which are even easier to configure, and have much more advanced graphics. In the example below, the sp_send_email procedure uses the parameter @query which will be executed at the time that sp_send_dbemail is executed and the HTML result of this execution will be attached to the email. DECLARE @html varchar(max),@query varchar(max) DECLARE @SeriesDBusers  varchar(800);     SET @SeriesDBusers = ''; SELECT @SeriesDBusers = @SeriesDBusers +  ' ["'+DB_NAME(r.database_id) +'", ' +cast(count(1) as varchar)+'],' FROM sys.dm_exec_requests r GROUP BY DB_NAME(database_id) ORDER BY count(1) desc; SET @SeriesDBusers = SUBSTRING(@SeriesDBusers,1,LEN(@SeriesDBusers)-1) SET @query = ' PRINT '' <html>   <head>     <script type="text/javascript" src="https://www.google.com/jsapi"></script>     <script type="text/javascript">       google.load("visualization", "1", {packages:["corechart"]});        google.setOnLoadCallback(drawChart);       function drawChart() {                      var data = google.visualization.arrayToDataTable([                        ["Database Name", "Active users"],                        '+@SeriesDBusers+'                      ]);                        var options = {                        title: "Active users",                        pieSliceText: "value"                      };                        var chart = new google.visualization.PieChart(document.getElementById("chart_div"));                      chart.draw(data, options);       };     </script>   </head>   <body>     <table>     <tr><td>         <div id="chart_div" style='width: 800px; height: 300px;'></div>         </td></tr>     </table>   </body> </html> ''' EXEC msdb.dbo.sp_send_dbmail    @recipients = '[email protected]',    @subject ='Active users',    @body = @html,    @body_format = 'HTML',    @query = @Query,     @attach_query_result_as_file = 1,     @query_attachment_filename = 'Results.htm' After opening the email attachment in the browser you are getting this kind of report: In fact, the above is not only for database alerts. It can be used for applicative reports if you need high levels of customization that you cannot achieve using standard methods like SSRS. If you need more information on how to customize the charts, you can try the following: Image Based Charts wizard https://google-developers.appspot.com/chart/image/docs/chart_wizard  Live Image Charts Playground https://google-developers.appspot.com/chart/image/docs/chart_playground Image Based Charts Parameters List https://google-developers.appspot.com/chart/image/docs/chart_params Java Script Charts Playground https://code.google.com/apis/ajax/playground/?type=visualization Use the above examples as a starting point for your procedures and I’d be more than happy to hear of your implementations of the above techniques. Yours, Maria

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  • setting ulimit and ubuntu 8.04

    - by Wizzard
    Hi there, We have two ubuntu 8.04 servers. With the database server I set the table_cache to 1000 however when I restart mysql the status only shows 257 and the open files limit says 1024 I adjusted ulimit by doing ulimit -n 8192 and then restarting mysql; this seemed to do the tick however after a few hours I did ulimit -n and saw it had returned back to 1024 Bit of a worry. I edited the /etc/security/limits.conf and added mysql soft nofile 8192 mysql hard nofile 8192 then rebooted, no change. I then edited and change mysql to * rebooted, no change I then edited and changed it to one line * - nofile 8192 and rebooted, no change. cat /proc/sys/fs/file-max gives me 768730 sysctl fs.file-max gives me fs.file-max = 768730 I am at a bit of a loss to how I can set and keep the ulimit value set so I can increase the table cache properly on mysql.

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  • Machine Check Exception

    - by Karl Entwistle
    When trying to install ubuntu-12.04-desktop-amd64.iso from USB I get one of the following errors http://en.wikipedia.org/wiki/Machine_Check_Exception states the error can occur due to -poorly fitted heatsink/computer fans (the same problem can happen with excessive dust in the CPU fan) -an overloaded internal or external power supply (fixable by upgrading) So I tried the following -Using rubbing alcohol to remove all the thermal paste from the CPU and heatsink, I then reseated the CPU after checking all the pins on the MOBO, everything seems fine. -Boot without the GPU to see if was the PSU that is being over stressed. -Removing all RAM apart from one stick and running a Memtest86 which it passed -Using Ubuntu 10.04.4 Desktop 64 bit (Different USB slots and USB sticks) -Using Ubuntu 12.04 Desktop 64 bit (Different USB slots and USB sticks) -Reset the BIOS using the Clear CMOS jumper -Removing all HD power cables and SATA cables -Updating the BIOS from F2 to F6 My PC is using the following parts. -Gigabyte GA-Z77-DS3H (F6 BIOS) -Intel Core i7 3770K 3.5GHz Socket 1155 -G-Skill 8GB (2x4GB) DDR3 1600Mhz RipjawsX Memory Kit CL9 (9-9-9-24) 1.5V -Be Quiet Shadow Rock Pro -Be Quiet Pure Power 730W Modular PSU -Sapphire HD 6870 1GB GDDR5 DVI HDMI DisplayPort PCI-E Graphics Card Any ideas?

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  • Java Spotlight Episode 138: Paul Perrone on Life Saving Embedded Java

    - by Roger Brinkley
    Interview with Paul Perrone, founder and CEO of Perrone Robotics, on using Java Embedded to test autonomous vehicle operations for the Insurance Institute for Highway Safety that will save lives. Right-click or Control-click to download this MP3 file. You can also subscribe to the Java Spotlight Podcast Feed to get the latest podcast automatically. If you use iTunes you can open iTunes and subscribe with this link: Java Spotlight Podcast in iTunes. Show Notes News JDK 8 is Feature Complete Java SE 7 Update 25 Released What should the JCP be doing? 2013 Duke's Choice Award Nominations Another Quick update to Code Signing Article on OTN Events June 24, Austin JUG, Austin, TX June 25, Virtual Developer Day - Java, EMEA, 10AM CEST Jul 16-19, Uberconf, Denver, USA Jul 22-24, JavaOne Shanghai, China Jul 29-31, JVM Summit Language, Santa Clara Sep 11-12, JavaZone, Oslo, Norway Sep 19-20, Strange Loop, St. Louis Sep 22-26 JavaOne San Francisco 2013, USA Feature Interview Paul J. Perrone is founder/CEO of Perrone Robotics. Paul architected the Java-based general-purpose robotics and automation software platform known as “MAX”. Paul has overseen MAX’s application to rapidly field self-driving robotic cars, unmanned air vehicles, factory and road-side automation applications, and a wide range of advanced robots and automaton applications. He fielded a self-driving autonomous robotic dune buggy in the historic 2005 Grand Challenge race across the Mojave desert and a self-driving autonomous car in the 2007 Urban Challenge through a city landscape. His work has been featured in numerous televised and print media including the Discovery Channel, a theatrical documentary, scientific journals, trade magazines, and international press. Since 2008, Paul has also been working as the chief software engineer, CTO, and roboticist automating rock star Neil Young’s LincVolt, a 1959 Lincoln Continental retro-fitted as a fully autonomous extended range electric vehicle. Paul has been an engineer, author of books and articles on Java, frequent speaker on Java, and entrepreneur in the robotics and software space for over 20 years. He is a member of the Java Champions program, recipient of three Duke Awards including a Gold Duke and Lifetime Achievement Award, has showcased Java-based robots at five JavaOne keynotes, and is a frequent JavaOne speaker and show floor participant. He holds a B.S.E.E. from Rutgers University and an M.S.E.E. from the University of Virginia. What’s Cool Shenandoah: A pauseless GC for OpenJDK

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  • GlassFish will not start when SNMP is enabled

    - by edarc
    I have a GlassFish v3 app server running on 64-bit Debian Lenny. Everything is running fine, except I would like to monitor GF's JVM instance with SNMP. However, every time I try to enable it by adding the following <jvm-options> in domain.xml: -Dcom.sun.management.snmp.port=10161 -Dcom.sun.management.snmp.acl.file=/path/to/snmp.acl -Dcom.sun.management.snmp.interface=127.0.0.1 GlassFish refuses to start: $ asadmin start-domain Waiting for DAS to start .Error starting domain: default. The server exited prematurely with exit code 1. Command start-domain failed. $ There is also nothing illuminating (well, really nothing at all) in jvm.log or server.log. The snmp.acl file contains: acl = { { communities = public access = read-only managers = localhost } } and is chmod 600 (I know this is not the problem because it will actually fail with an error about the permissions if it is set to anything other than 600) $ java -version java version "1.6.0_0" OpenJDK Runtime Environment (build 1.6.0_0-b11) OpenJDK 64-Bit Server VM (build 1.6.0_0-b11, mixed mode)

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  • SQL SERVER – 2011 – Introduction to SEQUENCE – Simple Example of SEQUENCE

    - by pinaldave
    SQL Server 2011 will contain one of the very interesting feature called SEQUENCE. I have waited for this feature for really long time. I am glad it is here finally. SEQUENCE allows you to define a single point of repository where SQL Server will maintain in memory counter. USE AdventureWorks2008R2 GO CREATE SEQUENCE [Seq] AS [int] START WITH 1 INCREMENT BY 1 MAXVALUE 20000 GO SEQUENCE is very interesting concept and I will write few blog post on this subject in future. Today we will see only working example of the same. Let us create a sequence. We can specify various values like start value, increment value as well maxvalue. -- First Run SELECT NEXT VALUE FOR Seq, c.CustomerID FROM Sales.Customer c GO -- Second Run SELECT NEXT VALUE FOR Seq, c.AccountNumber FROM Sales.Customer c GO Once the sequence is defined, it can be fetched using following method. Every single time new incremental value is provided, irrespective of sessions. Sequence will generate values till the max value specified. Once the max value is reached, query will stop and will return error message. Msg 11728, Level 16, State 1, Line 2 The sequence object ‘Seq’ has reached its minimum or maximum value. Restart the sequence object to allow new values to be generated. We can restart the sequence from any particular value and it will work fine. -- Restart the Sequence ALTER SEQUENCE [Seq] RESTART WITH 1 GO -- Sequence Restarted SELECT NEXT VALUE FOR Seq, c.CustomerID FROM Sales.Customer c GO Let us do final clean up. -- Clean Up DROP SEQUENCE [Seq] GO There are lots of things one can find useful about this feature. We will see that in future posts. Here is the complete code for easy reference. USE AdventureWorks2008R2 GO CREATE SEQUENCE [Seq] AS [int] START WITH 1 INCREMENT BY 1 MAXVALUE 20000 GO -- First Run SELECT NEXT VALUE FOR Seq, c.CustomerID FROM Sales.Customer c GO -- Second Run SELECT NEXT VALUE FOR Seq, c.AccountNumber FROM Sales.Customer c GO -- Restart the Sequence ALTER SEQUENCE [Seq] RESTART WITH 1 GO -- Sequence Restarted SELECT NEXT VALUE FOR Seq, c.CustomerID FROM Sales.Customer c GO -- Clean Up DROP SEQUENCE [Seq] GO Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: Pinal Dave, PostADay, SQL, SQL Authority, SQL Query, SQL Scripts, SQL Server, SQL Tips and Tricks, SQLServer, T SQL, Technology

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  • Time based movement Vs Frame rate based movement?

    - by sil3nt
    Hello there, I'm new to Game programmming and SDL, and I have been following Lazyfoo's SDL tutorials. My question is related to time based motion and frame rate based motion, basically which is better or appropriate depending on situations?. Could you give me an example where each of these methods are used?. Another question I have is that, in lazyfoo's two Motion tutorials (FPS based and time based) The time based method showed a much smoother animation while the Frame rate based one was a little hiccupy, meaning you could clearly see the gap between the previous location of the dot and its current position when you compare the two programs. As beginner which method should I stick to?(all I want is smooth animations).

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  • Why are all the tabs except MBeans disabled in JConsole?

    - by Kem Mason
    I'm trying to connect to JConsole on a server running: java version "1.6.0_0" OpenJDK Runtime Environment (IcedTea6 1.4.1) (6b14-1.4.1-0ubuntu12) OpenJDK 64-Bit Server VM (build 14.0-b08, mixed mode) from my local machine, running: java version "1.6.0_24" Java(TM) SE Runtime Environment (build 1.6.0_24-b07-334-10M3326) Java HotSpot(TM) 64-Bit Server VM (build 19.1-b02-334, mixed mode) When I connect to jconsole on the server, all the tabs except the MBeans tab are disabled. If I run the same application on my local machine, and use jconsole to connect to it there (using the remote interface still), all the tabs are enabled just fine. Everything I have seen only suggested the possibility that the server was 1.4 or earlier.

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  • Snort: not logging anything

    - by ethrbunny
    My site seems to be the target of quite a bit of probing over the last few months. In an attempt to get a better handle on this I installed SNORT on one of the machines that has external exposure. Something must not be installed correctly as I see lots of probing in /var/log/messages but snort isn't logging anything. System: CentOS 6.2 (32 bit) Snort: (latest build and rules) Snort configured from this v excellent site: http://nachum234.no-ip.org/security/snort/001-snort-installation-on-centos-6-2/ snort running as daemon: /usr/local/bin/snort -d -D -i bond0 -u snort -g snort -c /etc/snort.d/snort.conf -l /var/log/snort The snort.log file is empty despite hundreds (or more) failed login attempts from individual IP addresses. Maybe Im missing the purpose of SNORT? I was hoping it would log this sort of info.

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  • System crashes/lockups + compiz/cairo/gnome-panel crashing due to cached ram, please help?

    - by Kristian Thomson
    Can someone help me to troubleshoot system crashes and lockups which result in compiz/cairo dock and gnome-panel crashing? I also get no window borders after the crash and a lot of kernel memory errors. Logs are telling me that apps were killed due to not enough memory, but the system is caching like 14GB of my ram so I'm a bit stuck on what/how to stop it. I'm running Ubuntu 12.10 on a 2011 Mac Mini with 16 GB ram. Here's some of the logs that look like they could be causing trouble. I woke up this morning to find chrome/skype/cairo dock and a few others had been killed and here is what the log said. Nov 5 04:00:45 linkandzelda-Macmini kernel: [ 9310.959890] Out of memory: Kill process 12247 (chromium-browse) score 101 or sacrifice child Nov 5 04:00:45 linkandzelda-Macmini kernel: [ 9310.959893] Killed process 12247 (chromium-browse) total-vm:238948kB, anon-rss:17064kB, file-rss:20008kB Nov 5 04:00:45 linkandzelda-Macmini kernel: [ 9310.972283] Out of memory: Kill process 10976 (dropbox) score 3 or sacrifice child Nov 5 04:00:45 linkandzelda-Macmini kernel: [ 9310.972288] Killed process 10976 (dropbox) total-vm:316392kB, anon-rss:115484kB, file-rss:16504kB Nov 5 04:00:45 linkandzelda-Macmini kernel: [ 9310.975890] Out of memory: Kill process 10887 (rhythmbox) score 3 or sacrifice child Nov 5 04:00:45 linkandzelda-Macmini kernel: [ 9310.975895] Killed process 11515 (tray_icon_worke) total-vm:63336kB, anon-rss:15960kB, file-rss:11436kB Nov 5 04:00:45 linkandzelda-Macmini kernel: [ 9311.281535] Out of memory: Kill process 10887 (rhythmbox) score 3 or sacrifice child Nov 5 04:00:45 linkandzelda-Macmini kernel: [ 9311.281539] Killed process 10887 (rhythmbox) total-vm:528980kB, anon-rss:92272kB, file-rss:36520kB Nov 5 04:00:45 linkandzelda-Macmini kernel: [ 9311.283110] Out of memory: Kill process 10889 (skype) score 3 or sacrifice child Nov 5 04:00:45 linkandzelda-Macmini kernel: [ 9311.283113] Killed process 10889 (skype) total-vm:415056kB, anon-rss:84880kB, file-rss:22160kB I went to look deeper into things and saw that the whole time I'm having these kernel errors with out of memory and something mentioning radeon. I have a Radeon HD 6600M graphics card using the open source driver, not the proprietary one. I was wondering if perhaps using the proprietary one would solve the problem. Also, while writing this in Chrome rhythmbox and chrome just got killed while typing this, due to out of memory errors or so it reports, though I have 7 GB of free RAM at the time with 7 GB cached as well. Here is a full copy of my logs that happened in kern.log simply from when I began typing this question. http://pastebin.com/cdxxDktG Thanks in advance, Kris

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  • Unity Plugin DLLNotFoundException

    - by Dewayne
    I am using a plugin DLL that I created in Visual C++ Express 2010 on windows 7 64 bit Ultimate Edition. The DLL functions properly on the machine that it was originally created on. The problem is that the DLL is not functioning in the Unity3d Editor on another machine and giving an error that basically states that the DLL is missing some of its dependencies. The target machine is running Windows 7 Home 64 bit (if this is relevant) Results from the error log of Dependency Walker: Error: The Side-by-Side configuration information for "c:\users\dewayne\desktop\shared\vrpnplugin\unityplugin\build\release\OPTITRACKPLUGIN.DLL" contains errors. The application has failed to start because its side-by-side configuration is incorrect. Please see the application event log or use the command-line sxstrace.exe tool for more detail (14001). Error: At least one module has an unresolved import due to a missing export function in an implicitly dependent module. Error: Modules with different CPU types were found. Warning: At least one delay-load dependency module was not found. Warning: At least one module has an unresolved import due to a missing export function in a delay-load dependent module. The Visual C++ Express 2010 project and solution file can be found here: https://docs.google.com/leaf?id=0B1F4pP7mRSiYMGU2YTJiNTUtOWJiMS00YTYzLThhYWQtMzNiOWJhZDU5M2M0&hl=en&authkey=CJSXhqgH The zip is 79MB and also contains its dependencies. The DLL in question is OptiTrackPlugin.dll

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  • SQL SERVER – Online Index Rebuilding Index Improvement in SQL Server 2012

    - by pinaldave
    Have you ever faced situation when you see something working and you feel it should not be working? Well, I had similar moments few days ago. I know that SQL Server 2008 supports online indexing. However, I also know that I cannot rebuild index ONLINE if I have used VARCHAR(MAX), NVARCHAR(MAX) or few other data types. While I held my belief very strongly I came across situation, where I had to go online and do little bit reading from Book Online. Here is the similar example. First of all – run following code in SQL Server 2008 or SQL Server 2008 R2. USE TempDB GO CREATE TABLE TestTable (ID INT, FirstCol NVARCHAR(10), SecondCol NVARCHAR(MAX)) GO CREATE CLUSTERED INDEX [IX_TestTable] ON TestTable (ID) GO CREATE NONCLUSTERED INDEX [IX_TestTable_Cols] ON TestTable (FirstCol) INCLUDE (SecondCol) GO USE [tempdb] GO ALTER INDEX [IX_TestTable_Cols] ON [dbo].[TestTable] REBUILD WITH (ONLINE = ON) GO DROP TABLE TestTable GO Now run the same code in SQL Server 2012 version. Observe the difference between both of the execution. You will be get following resultset. In SQL Server 2008/R2 it will throw following error: Msg 2725, Level 16, State 2, Line 1 An online operation cannot be performed for index ‘IX_TestTable_Cols’ because the index contains column ‘SecondCol’ of data type text, ntext, image, varchar(max), nvarchar(max), varbinary(max), xml, or large CLR type. For a non-clustered index, the column could be an include column of the index. For a clustered index, the column could be any column of the table. If DROP_EXISTING is used, the column could be part of a new or old index. The operation must be performed offline. In SQL Server 2012 it will run successfully and will not throw any error. Command(s) completed successfully. I always thought it will throw an error if there is VARCHAR(MAX) or NVARCHAR(MAX) used in table schema definition. When I saw this result it was clear to me that it will be for sure not bug enhancement in SQL Server 2012. For matter for the fact, I always wanted this feature to be added in SQL Server Engine as this will enable ONLINE Index Rebuilding for mission critical tables which needs to be always online. I quickly searched online and landed on Jacob Sebastian’s blog where he has blogged about it as well. Well, is there any other new feature in SQL Server 2012 which gave you good surprise? Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Index, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

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  • BOX2D and AS3: Mouse Event not working

    - by Gabriel Meono
    Background: Trying to make a simple "drop the ball" game. The code is located inside the first frame of the timeline. Nothing more is on the stage. Issue: Using QuickBox2D I made a simple If statement that drops and object acording the Mouse-x position: if (MouseEvent.CLICK) { sim.addCircle({x:mouseX, y:1, radius:0.25, density:5}); I imported the MouseEvent library: import flash.events.MouseEvent; Nothing happens if I click, no output errors either. See it in action: http://gabrielmeono.com/download/Lucky_Hit_Alpha.swf http://gabrielmeono.com/download/Lucky_Hit_Alpha.fla Full Code: [SWF(width = 350, height = 600, frameRate = 60)] import com.actionsnippet.qbox.*; import flash.events.MouseEvent; var sim:QuickBox2D = new QuickBox2D(this); sim.createStageWalls(); //var ball:sim.addCircle({x:mouseX, y:1, radius:0.25, density:5}); // // make a heavy circle sim.addCircle({x:3, y:1, radius:0.25, density:5}); sim.addCircle({x:2, y:1, radius:0.25, density:5}); sim.addCircle({x:4, y:1, radius:0.25, density:5}); sim.addCircle({x:5, y:1, radius:0.25, density:5}); sim.addCircle({x:6, y:1, radius:0.25, density:5}); // create a few platforms sim.addBox({x:3, y:2, width:4, height:0.2, density:0, angle:0.1}); // make 26 dominoes for (var i:int = 0; i<7; i++){ //End sim.addCircle({x:1 + i * 1.5, y:16, radius:0.1, density:0}); sim.addCircle({x:2 + i * 1.5, y:15, radius:0.1, density:0}); //Mid end sim.addCircle({x:0 + i * 2, y:14, radius:0.1, density:0}); sim.addCircle({x:0 + i * 2, y:13, radius:0.1, density:0}); sim.addCircle({x:0 + i * 2, y:12, radius:0.1, density:0}); sim.addCircle({x:0 + i * 2, y:11, radius:0.1, density:0}); sim.addCircle({x:0 + i * 2, y:10, radius:0.1, density:0}); //Middle Start sim.addCircle({x:0 + i * 1.5, y:09, radius:0.1, density:0}); sim.addCircle({x:1 + i * 1.5, y:08, radius:0.1, density:0}); sim.addCircle({x:0 + i * 1.5, y:07, radius:0.1, density:0}); sim.addCircle({x:1 + i * 1.5, y:06, radius:0.1, density:0}); } if (MouseEvent.CLICK) { sim.addCircle({x:mouseX, y:1, radius:0.25, density:5}); sim.start(); /*sim.mouseDrag();*/ }

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  • Should I be worried about overengineering programming assignments given during interview process?

    - by DormoTheNord
    I recently had a phone interview with a company. After that phone interview, I was told to complete a short programming assignment (a small program; shouldn't take more than three hours). I'm only directly instructed to complete the assignment and turn in the code. I was given complete freedom to use any language I wished and was not told exactly how to turn in the code. Immediately I planned on throwing it on Github, writing a test suite for it, using Travis-CI (free continuous integration for public Github repositories) to run the test suites, and using CMake to build the Linux makefiles for Travis-CI. That way, not only can I demonstrate that I understand how to use Git, CMake, Travis-CI, and how to write tests, but I can also simply link to the Travis-CI page so they can see the output of the tests. I figured that'd make it a tiny bit more convenient for the interviewer. Since I know those technologies well, it would add essentially no time to the assignment. However, I'm a bit worried that doing all this for a relatively simple task would look bad. Although it wouldn't add much more time at all for me, I don't want them thinking I spend too much time on things that should be simple.

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  • Customer Experience Online Forum

    - by Christie Flanagan
    Missed Oracle’s Customer Experience Online Forum?  Don’t worry. You can still catch the sessions at your convenience. Watch the Customer Experience Online Forum on demand to hear from Bruce Tempkin, a leading expert in customer experience, as well as other thought leaders and they delve into topics such as the ROI of customer experience and strategies for winning over customers.  Simply register to gain access to these sessions and more: The Customer Experience RevolutionCustomer experience has become the most important and defensible differentiator for your business. The customer experience is a journey that transcends all customer touchpoints and stages of the customer lifecycle. Discover where you are in the journey, identify how to begin optimizing the experience you deliver your customers, and join the Revolution.The ROI of Customer ExperienceBruce Temkin, Customer Experience Transformist & Managing Partner, Temkin GroupResearch of US and UK customers demonstrates a high correlation between a positive customer experience and loyalty. A successful customer interaction increases the willingness to buy more and to recommend your company. US companies can gain $380 million over three years by providing an optimized customer experience. This session will help companies determine the business impact that customer experience has on their specific business. Integrating Marketing and Loyalty to Deliver Great Customer ExperiencesNew devices and channels, such as mobile, social and web, are creating radical shifts in the customer buying process and the ways your company can reach and communicate with existing and potential customers. Learn how leading brands are using Oracle's marketing solutions to harness big data and better understand their customers, extend their marketing reach into social channels, and retain their high value customers through more rewarding customer experience.Where to Start Your Organization's RevolutionThe process of crafting a great customer experience starts with understanding customers and their goals. This session helps you to begin mapping a sound customer experience strategy, describing the intended experience and kinds of processes that create differentiation. The ROI of Customer Experience: A Tempkin Group Insight Report Did you know that customer experience leaders have more than a 16 percentage point advantage over customer experience laggards in consumers’ willingness to buy more, their reluctance to switch business away, and their likelihood to recommend? Did you know that even a modest increase in customer experience can translate into millions of dollars gained? Learn more about the ROI of customer experience in this free report.

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  • How to monitor CPU usage and performance on a Hyper-V server with several VM's

    - by Bjørn
    Hello, I have a server that is running Windows 2008 64 bit Hyper-V, with 8 gigs of RAM and Intel Xeon X3440 @ 2.53 Ghz, which gives me 8 logical cores in the performance monitor on the host system. I have set up three Virtual Machines, all running Windows 2008 32 bit. Build server, running Team City Staging server SQL Server, running SQL Server 2005 I have some troubles with the setup in that the host monitor remains responsive at all times, even though the VM's are seemingly working at 100% cpu and are very sluggish and unresponsive. (I have asked a separate question about that.) So the question here is: What is the best way to monitor how the physical CPU's are actually utilized? The reason I am asking is that I am being told that i cannot reliably use the task manager to monitor CPU usage in a VM.

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  • Python PyBluez loses Bluetooth connection after a while

    - by Travis G.
    I am using Python to write a simple serial Bluetooth script that sends information about my computer stats periodically. The receiving device is a Sparkfun BlueSmirf Silver. The problem is that, after the script runs for a few minutes, it stops sending packets to the receiver and fails with the error: (11, 'Resource temporarily unavailable') Noticing that this inevitably happens, I added some code to automatically try to reopen the connection. However, then I get: Could not connect: (16, 'Device or resource busy') Am I doing something wrong with the connection? Do I need to occasionally reopen the socket? I'm not sure how to recover from this type of error. I understand that sometimes the port will be busy and a write operation is deferred to avoid blocking other processes, but I wouldn't expect the connection to fail so regularly. Any thoughts? Here is the script: import psutil import serial import string import time import bluetooth sampleTime = 1 numSamples = 5 lastTemp = 0 TEMP_CHAR = 't' USAGE_CHAR = 'u' SENSOR_NAME = 'TC0D' #gauges = serial.Serial() #gauges.port = '/dev/rfcomm0' #gauges.baudrate = 9600 #gauges.parity = 'N' #gauges.writeTimeout = 0 #gauges.open() filename = '/sys/bus/platform/devices/applesmc.768/temp2_input' def parseSensorsOutputLinux(output): return int(round(float(output) / 1000)) def connect(): while(True): try: gaugeSocket = bluetooth.BluetoothSocket(bluetooth.RFCOMM) gaugeSocket.connect(('00:06:66:42:22:96', 1)) break; except bluetooth.btcommon.BluetoothError as error: print "Could not connect: ", error, "; Retrying in 5s..." time.sleep(5) return gaugeSocket; gaugeSocket = connect() while(1): usage = psutil.cpu_percent(interval=sampleTime) sensorFile = open(filename) temp = parseSensorsOutputLinux(sensorFile.read()) try: #gauges.write(USAGE_CHAR) gaugeSocket.send(USAGE_CHAR) #gauges.write(chr(int(usage))) #write the first byte gaugeSocket.send(chr(int(usage))) #print("Wrote usage: " + str(int(usage))) #gauges.write(TEMP_CHAR) gaugeSocket.send(TEMP_CHAR) #gauges.write(chr(temp)) gaugeSocket.send(chr(temp)) #print("Wrote temp: " + str(temp)) except bluetooth.btcommon.BluetoothError as error: print "Caught BluetoothError: ", error time.sleep(5) gaugeSocket = connect() pass gaugeSocket.close() EDIT: I should add that this code connects fine after I power-cycle the receiver and start the script. However, it fails after the first exception until I restart the receiver. P.S. This is related to my recent question, Why is /dev/rfcomm0 giving PySerial problems?, but that was more about PySerial specifically with rfcomm0. Here I am asking about general rfcomm etiquette.

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  • Scaling-out Your Services by Message Bus based WCF Transport Extension &ndash; Part 1 &ndash; Background

    - by Shaun
    Cloud computing gives us more flexibility on the computing resource, we can provision and deploy an application or service with multiple instances over multiple machines. With the increment of the service instances, how to balance the incoming message and workload would become a new challenge. Currently there are two approaches we can use to pass the incoming messages to the service instances, I would like call them dispatcher mode and pulling mode.   Dispatcher Mode The dispatcher mode introduces a role which takes the responsible to find the best service instance to process the request. The image below describes the sharp of this mode. There are four clients communicate with the service through the underlying transportation. For example, if we are using HTTP the clients might be connecting to the same service URL. On the server side there’s a dispatcher listening on this URL and try to retrieve all messages. When a message came in, the dispatcher will find a proper service instance to process it. There are three mechanism to find the instance: Round-robin: Dispatcher will always send the message to the next instance. For example, if the dispatcher sent the message to instance 2, then the next message will be sent to instance 3, regardless if instance 3 is busy or not at that moment. Random: Dispatcher will find a service instance randomly, and same as the round-robin mode it regardless if the instance is busy or not. Sticky: Dispatcher will send all related messages to the same service instance. This approach always being used if the service methods are state-ful or session-ful. But as you can see, all of these approaches are not really load balanced. The clients will send messages at any time, and each message might take different process duration on the server side. This means in some cases, some of the service instances are very busy while others are almost idle. For example, if we were using round-robin mode, it could be happened that most of the simple task messages were passed to instance 1 while the complex ones were sent to instance 3, even though instance 1 should be idle. This brings some problem in our architecture. The first one is that, the response to the clients might be longer than it should be. As it’s shown in the figure above, message 6 and 9 can be processed by instance 1 or instance 2, but in reality they were dispatched to the busy instance 3 since the dispatcher and round-robin mode. Secondly, if there are many requests came from the clients in a very short period, service instances might be filled by tons of pending tasks and some instances might be crashed. Third, if we are using some cloud platform to host our service instances, for example the Windows Azure, the computing resource is billed by service deployment period instead of the actual CPU usage. This means if any service instance is idle it is wasting our money! Last one, the dispatcher would be the bottleneck of our system since all incoming messages must be routed by the dispatcher. If we are using HTTP or TCP as the transport, the dispatcher would be a network load balance. If we wants more capacity, we have to scale-up, or buy a hardware load balance which is very expensive, as well as scaling-out the service instances. Pulling Mode Pulling mode doesn’t need a dispatcher to route the messages. All service instances are listening to the same transport and try to retrieve the next proper message to process if they are idle. Since there is no dispatcher in pulling mode, it requires some features on the transportation. The transportation must support multiple client connection and server listening. HTTP and TCP doesn’t allow multiple clients are listening on the same address and port, so it cannot be used in pulling mode directly. All messages in the transportation must be FIFO, which means the old message must be received before the new one. Message selection would be a plus on the transportation. This means both service and client can specify some selection criteria and just receive some specified kinds of messages. This feature is not mandatory but would be very useful when implementing the request reply and duplex WCF channel modes. Otherwise we must have a memory dictionary to store the reply messages. I will explain more about this in the following articles. Message bus, or the message queue would be best candidate as the transportation when using the pulling mode. First, it allows multiple application to listen on the same queue, and it’s FIFO. Some of the message bus also support the message selection, such as TIBCO EMS, RabbitMQ. Some others provide in memory dictionary which can store the reply messages, for example the Redis. The principle of pulling mode is to let the service instances self-managed. This means each instance will try to retrieve the next pending incoming message if they finished the current task. This gives us more benefit and can solve the problems we met with in the dispatcher mode. The incoming message will be received to the best instance to process, which means this will be very balanced. And it will not happen that some instances are busy while other are idle, since the idle one will retrieve more tasks to make them busy. Since all instances are try their best to be busy we can use less instances than dispatcher mode, which more cost effective. Since there’s no dispatcher in the system, there is no bottleneck. When we introduced more service instances, in dispatcher mode we have to change something to let the dispatcher know the new instances. But in pulling mode since all service instance are self-managed, there no extra change at all. If there are many incoming messages, since the message bus can queue them in the transportation, service instances would not be crashed. All above are the benefits using the pulling mode, but it will introduce some problem as well. The process tracking and debugging become more difficult. Since the service instances are self-managed, we cannot know which instance will process the message. So we need more information to support debug and track. Real-time response may not be supported. All service instances will process the next message after the current one has done, if we have some real-time request this may not be a good solution. Compare with the Pros and Cons above, the pulling mode would a better solution for the distributed system architecture. Because what we need more is the scalability, cost-effect and the self-management.   WCF and WCF Transport Extensibility Windows Communication Foundation (WCF) is a framework for building service-oriented applications. In the .NET world WCF is the best way to implement the service. In this series I’m going to demonstrate how to implement the pulling mode on top of a message bus by extending the WCF. I don’t want to deep into every related field in WCF but will highlight its transport extensibility. When we implemented an RPC foundation there are many aspects we need to deal with, for example the message encoding, encryption, authentication and message sending and receiving. In WCF, each aspect is represented by a channel. A message will be passed through all necessary channels and finally send to the underlying transportation. And on the other side the message will be received from the transport and though the same channels until the business logic. This mode is called “Channel Stack” in WCF, and the last channel in the channel stack must always be a transport channel, which takes the responsible for sending and receiving the messages. As we are going to implement the WCF over message bus and implement the pulling mode scaling-out solution, we need to create our own transport channel so that the client and service can exchange messages over our bus. Before we deep into the transport channel, let’s have a look on the message exchange patterns that WCF defines. Message exchange pattern (MEP) defines how client and service exchange the messages over the transportation. WCF defines 3 basic MEPs which are datagram, Request-Reply and Duplex. Datagram: Also known as one-way, or fire-forgot mode. The message sent from the client to the service, and no need any reply from the service. The client doesn’t care about the message result at all. Request-Reply: Very common used pattern. The client send the request message to the service and wait until the reply message comes from the service. Duplex: The client sent message to the service, when the service processing the message it can callback to the client. When callback the service would be like a client while the client would be like a service. In WCF, each MEP represent some channels associated. MEP Channels Datagram IInputChannel, IOutputChannel Request-Reply IRequestChannel, IReplyChannel Duplex IDuplexChannel And the channels are created by ChannelListener on the server side, and ChannelFactory on the client side. The ChannelListener and ChannelFactory are created by the TransportBindingElement. The TransportBindingElement is created by the Binding, which can be defined as a new binding or from a custom binding. For more information about the transport channel mode, please refer to the MSDN document. The figure below shows the transport channel objects when using the request-reply MEP. And this is the datagram MEP. And this is the duplex MEP. After investigated the WCF transport architecture, channel mode and MEP, we finally identified what we should do to extend our message bus based transport layer. They are: Binding: (Optional) Defines the channel elements in the channel stack and added our transport binding element at the bottom of the stack. But we can use the build-in CustomBinding as well. TransportBindingElement: Defines which MEP is supported in our transport and create the related ChannelListener and ChannelFactory. This also defines the scheme of the endpoint if using this transport. ChannelListener: Create the server side channel based on the MEP it’s. We can have one ChannelListener to create channels for all supported MEPs, or we can have ChannelListener for each MEP. In this series I will use the second approach. ChannelFactory: Create the client side channel based on the MEP it’s. We can have one ChannelFactory to create channels for all supported MEPs, or we can have ChannelFactory for each MEP. In this series I will use the second approach. Channels: Based on the MEPs we want to support, we need to implement the channels accordingly. For example, if we want our transport support Request-Reply mode we should implement IRequestChannel and IReplyChannel. In this series I will implement all 3 MEPs listed above one by one. Scaffold: In order to make our transport extension works we also need to implement some scaffold stuff. For example we need some classes to send and receive message though out message bus. We also need some codes to read and write the WCF message, etc.. These are not necessary but would be very useful in our example.   Message Bus There is only one thing remained before we can begin to implement our scaling-out support WCF transport, which is the message bus. As I mentioned above, the message bus must have some features to fulfill all the WCF MEPs. In my company we will be using TIBCO EMS, which is an enterprise message bus product. And I have said before we can use any message bus production if it’s satisfied with our requests. Here I would like to introduce an interface to separate the message bus from the WCF. This allows us to implement the bus operations by any kinds bus we are going to use. The interface would be like this. 1: public interface IBus : IDisposable 2: { 3: string SendRequest(string message, bool fromClient, string from, string to = null); 4:  5: void SendReply(string message, bool fromClient, string replyTo); 6:  7: BusMessage Receive(bool fromClient, string replyTo); 8: } There are only three methods for the bus interface. Let me explain one by one. The SendRequest method takes the responsible for sending the request message into the bus. The parameters description are: message: The WCF message content. fromClient: Indicates if this message was came from the client. from: The channel ID that this message was sent from. The channel ID will be generated when any kinds of channel was created, which will be explained in the following articles. to: The channel ID that this message should be received. In Request-Reply and Duplex MEP this is necessary since the reply message must be received by the channel which sent the related request message. The SendReply method takes the responsible for sending the reply message. It’s very similar as the previous one but no “from” parameter. This is because it’s no need to reply a reply message again in any MEPs. The Receive method takes the responsible for waiting for a incoming message, includes the request message and specified reply message. It returned a BusMessage object, which contains some information about the channel information. The code of the BusMessage class is 1: public class BusMessage 2: { 3: public string MessageID { get; private set; } 4: public string From { get; private set; } 5: public string ReplyTo { get; private set; } 6: public string Content { get; private set; } 7:  8: public BusMessage(string messageId, string fromChannelId, string replyToChannelId, string content) 9: { 10: MessageID = messageId; 11: From = fromChannelId; 12: ReplyTo = replyToChannelId; 13: Content = content; 14: } 15: } Now let’s implement a message bus based on the IBus interface. Since I don’t want you to buy and install the TIBCO EMS or any other message bus products, I will implement an in process memory bus. This bus is only for test and sample purpose. It can only be used if the service and client are in the same process. Very straightforward. 1: public class InProcMessageBus : IBus 2: { 3: private readonly ConcurrentDictionary<Guid, InProcMessageEntity> _queue; 4: private readonly object _lock; 5:  6: public InProcMessageBus() 7: { 8: _queue = new ConcurrentDictionary<Guid, InProcMessageEntity>(); 9: _lock = new object(); 10: } 11:  12: public string SendRequest(string message, bool fromClient, string from, string to = null) 13: { 14: var entity = new InProcMessageEntity(message, fromClient, from, to); 15: _queue.TryAdd(entity.ID, entity); 16: return entity.ID.ToString(); 17: } 18:  19: public void SendReply(string message, bool fromClient, string replyTo) 20: { 21: var entity = new InProcMessageEntity(message, fromClient, null, replyTo); 22: _queue.TryAdd(entity.ID, entity); 23: } 24:  25: public BusMessage Receive(bool fromClient, string replyTo) 26: { 27: InProcMessageEntity e = null; 28: while (true) 29: { 30: lock (_lock) 31: { 32: var entity = _queue 33: .Where(kvp => kvp.Value.FromClient == fromClient && (kvp.Value.To == replyTo || string.IsNullOrWhiteSpace(kvp.Value.To))) 34: .FirstOrDefault(); 35: if (entity.Key != Guid.Empty && entity.Value != null) 36: { 37: _queue.TryRemove(entity.Key, out e); 38: } 39: } 40: if (e == null) 41: { 42: Thread.Sleep(100); 43: } 44: else 45: { 46: return new BusMessage(e.ID.ToString(), e.From, e.To, e.Content); 47: } 48: } 49: } 50:  51: public void Dispose() 52: { 53: } 54: } The InProcMessageBus stores the messages in the objects of InProcMessageEntity, which can take some extra information beside the WCF message itself. 1: public class InProcMessageEntity 2: { 3: public Guid ID { get; set; } 4: public string Content { get; set; } 5: public bool FromClient { get; set; } 6: public string From { get; set; } 7: public string To { get; set; } 8:  9: public InProcMessageEntity() 10: : this(string.Empty, false, string.Empty, string.Empty) 11: { 12: } 13:  14: public InProcMessageEntity(string content, bool fromClient, string from, string to) 15: { 16: ID = Guid.NewGuid(); 17: Content = content; 18: FromClient = fromClient; 19: From = from; 20: To = to; 21: } 22: }   Summary OK, now I have all necessary stuff ready. The next step would be implementing our WCF message bus transport extension. In this post I described two scaling-out approaches on the service side especially if we are using the cloud platform: dispatcher mode and pulling mode. And I compared the Pros and Cons of them. Then I introduced the WCF channel stack, channel mode and the transport extension part, and identified what we should do to create our own WCF transport extension, to let our WCF services using pulling mode based on a message bus. And finally I provided some classes that need to be used in the future posts that working against an in process memory message bus, for the demonstration purpose only. In the next post I will begin to implement the transport extension step by step.   Hope this helps, Shaun All documents and related graphics, codes are provided "AS IS" without warranty of any kind. Copyright © Shaun Ziyan Xu. This work is licensed under the Creative Commons License.

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