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  • Personal search – the future of search

    - by jamiet
    [Four months ago I wrote a meandering blog post on another blogging site entitled Personal search – the future of search. The points I made therein are becoming more relevant to what I'm reading about and hoping to get involved in in the future so I'm re-posting here to a wider audience to hopefully get some more feedback and guage reaction to it. This has been prompted by the book Pull by David Siegel that is forming my current holiday reading (recommended to me by a commenter on my previous post Interesting things – Twitter annotations and your phone as a web server) and in particular by Siegel's notion of us all in the future having a personal online data vault.] My one-time colleague Paul Dawson recently wrote an article called The Future of Search and in it he proposed some interesting ideas. Some choice quotes: The growth of Chinese search giant Baidu is an indicator that fully localised and tailored content and offerings have great traction with local audiences This trend is already driving an increase in the use of specialist searches … Look at how Farecast is now integrated into Bing for example, or how Flightstats is now integrated into Google. Search does not necessarily have to begin with a keyword, but could start instead with a click or a touch. Take a look at Retrievr. Start drawing a picture in the box and see what happens. This is certainly search without the need for typing in keywords search technology has advanced greatly in recent years. The recent launch of Microsoft Live Labs’ Pivot has given us a taste of what we can expect to see in the future This really got me thinking about where search might go in the future and as my mind wandered I realised that as the amount of data that we collect about ourselves increases so too will the need and the desire to search it. The amount of electronic data that exists about each and every person is increasing and in the near future I fully expect that we are going to be able to store personal data such as: A history of our location (in fact Google Latitude already offers this facility) Recordings of all our phone conversations Health information history (weight, blood pressure etc…) Energy usage Spending history What films we watch, what radio stations we listen to Voting history Of course, most of this stuff is already stored somewhere but crucially we don’t have easy access to it. My utilities supplier knows how much electricity I’m using but if I want to know for myself I have to go and dig through my statements (assuming I have kept them). Similarly my doctor probably has ready access to all of my health records, my bank knows exactly what I have spent my money on, my cable supplier knows what I watch on TV and my mobile phone supplier probably knows exactly where I am and where I’ve been for the past few years. Strange then that none of this electronic information is available to me in a way that I can really make use of it; after all, its MY information. Its MY data. I created it. That is set to change. As technologies mature and customers become more technically cognizant they will demand more access to the data that companies hold about them. The companies themselves will realise the benefit that they derive from giving users what they want and will embrace ways of providing it. As a result the amount of data that we store about ourselves is going to increase exponentially and the desire to search and derive value from that data is going to grow with it; we are about to enter the era of the “personal datastore” and we will want, and need, to search through it in order to make sense of it all. Its interesting then that today when we think of search we think of search engines and yet in these personal datastores we’re referring to data that search engines can’t touch because WE own it and we (hopefully) choose to keep it private. Someone, I know not who, is going to lead in this space by making it easy for us to search our data and retrieve information that we have either forgotten or maybe didn’t even know in the first place. We will learn new things about ourselves and about our habits; we will share these findings with whomever we choose; we will compare what we discover with others; we will collaborate for mutual benefit and, most of all, we will educate ourselves as to how to live our lives better. Search will be the means to that end, it will enable us to make sense of the wealth of information that we will collect day in day out. The future of search is personal, why would we be interested in anything else? @Jamiet Share this post: email it! | bookmark it! | digg it! | reddit! | kick it! | live it!

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  • Personal search – the future of search

    - by jamiet
    [Four months ago I wrote a meandering blog post on another blogging site entitled Personal search – the future of search. The points I made therein are becoming more relevant to what I'm reading about and hoping to get involved in in the future so I'm re-posting here to a wider audience to hopefully get some more feedback and guage reaction to it. This has been prompted by the book Pull by David Siegel that is forming my current holiday reading (recommended to me by a commenter on my previous post Interesting things – Twitter annotations and your phone as a web server) and in particular by Siegel's notion of us all in the future having a personal online data vault.] My one-time colleague Paul Dawson recently wrote an article called The Future of Search and in it he proposed some interesting ideas. Some choice quotes: The growth of Chinese search giant Baidu is an indicator that fully localised and tailored content and offerings have great traction with local audiences This trend is already driving an increase in the use of specialist searches … Look at how Farecast is now integrated into Bing for example, or how Flightstats is now integrated into Google. Search does not necessarily have to begin with a keyword, but could start instead with a click or a touch. Take a look at Retrievr. Start drawing a picture in the box and see what happens. This is certainly search without the need for typing in keywords search technology has advanced greatly in recent years. The recent launch of Microsoft Live Labs’ Pivot has given us a taste of what we can expect to see in the future This really got me thinking about where search might go in the future and as my mind wandered I realised that as the amount of data that we collect about ourselves increases so too will the need and the desire to search it. The amount of electronic data that exists about each and every person is increasing and in the near future I fully expect that we are going to be able to store personal data such as: A history of our location (in fact Google Latitude already offers this facility) Recordings of all our phone conversations Health information history (weight, blood pressure etc…) Energy usage Spending history What films we watch, what radio stations we listen to Voting history Of course, most of this stuff is already stored somewhere but crucially we don’t have easy access to it. My utilities supplier knows how much electricity I’m using but if I want to know for myself I have to go and dig through my statements (assuming I have kept them). Similarly my doctor probably has ready access to all of my health records, my bank knows exactly what I have spent my money on, my cable supplier knows what I watch on TV and my mobile phone supplier probably knows exactly where I am and where I’ve been for the past few years. Strange then that none of this electronic information is available to me in a way that I can really make use of it; after all, its MY information. Its MY data. I created it. That is set to change. As technologies mature and customers become more technically cognizant they will demand more access to the data that companies hold about them. The companies themselves will realise the benefit that they derive from giving users what they want and will embrace ways of providing it. As a result the amount of data that we store about ourselves is going to increase exponentially and the desire to search and derive value from that data is going to grow with it; we are about to enter the era of the “personal datastore” and we will want, and need, to search through it in order to make sense of it all. Its interesting then that today when we think of search we think of search engines and yet in these personal datastores we’re referring to data that search engines can’t touch because WE own it and we (hopefully) choose to keep it private. Someone, I know not who, is going to lead in this space by making it easy for us to search our data and retrieve information that we have either forgotten or maybe didn’t even know in the first place. We will learn new things about ourselves and about our habits; we will share these findings with whomever we choose; we will compare what we discover with others; we will collaborate for mutual benefit and, most of all, we will educate ourselves as to how to live our lives better. Search will be the means to that end, it will enable us to make sense of the wealth of information that we will collect day in day out. The future of search is personal, why would we be interested in anything else? @Jamiet Share this post: email it! | bookmark it! | digg it! | reddit! | kick it! | live it!

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  • SQLAuthority News – #TechEDIn – TechEd India 2012 – Things to Do and Explore for SQL Enthusiast

    - by pinaldave
    TechEd India 2012 is just 48 hours away and I have been receiving lots of requests regarding how SQL enthusiasts can maximize their time they’ll be spending at TechEd India 2012. Trust me – TechEd is the biggest Tech Event in India and it is much larger in magnitude than we can imagine. There are plenty of tracks there and lots of things to do. Honestly, we need clone ourselves multiple times to completely cover the event. However, I am going to talk about SQL enthusiasts only right now. In this post, I’ll share a few things they can do in this big event. But before I start talking about specific things, there is one thing which is a must – Keynote. There are amazing Keynotes planned every single day at TechEd India 2012. One should not miss them at all. Social Media I am a big believer of the social media. I am everywhere - Twitter, Facebook, LinkedIn and GPlus. I suggest you follow the tag #TechEdIn as well as contribute at the healthy conversation going on right now. You may want to follow a few of the SQL Server enthusiasts who are also attending events like TechEd India. This way, you will know where they are and you can contribute along with them. For a good start, you can follow all the speakers who are presenting at the event. I have linked all the speakers’ names with their respective Twitter accounts. Networking Do not stop meeting new people. Introduce yourself. Catch the speakers after their sessions. Meet other SQL experts and discuss SQL as well as life aside SQL. The best way to start the communication is to talk about something new. Here are a few lines I usually use when I have to break the ice: SQL Server 2012 is just released and I have installed it. How many SQL Server sessions are you going to attend? I am going to attend _________ I am a big fan of SQL Server. Sessions Agenda Day 1 T-SQL Rediscovered with SQL Server 2012 - Jacob Sebastian Catapult your data with SQL Server 2012 integration services - Praveen Srivatsa Processing Big Data with SQL Server 2012 and Hadoop  - Stephan Forte SQL Server Misconceptions and Resolution – A Practical Perspective – Pinal Dave and Vinod Kumar Securing with ContainedDB in SQL Server 2012  - Pranab Majumdar Agenda Day 2 Hand-on-Lab – Exploring Power View with SQL Server 2012 – Ravi S. Maniam Hand-on-Lab - SQL Server 2012 – AlwaysOn Availability Groups  - Amit Ganguli Agenda Day 3 Peeling SQL Server like an Onion: Internals Debunked  - Vinod Kumar Speed Up! – Parallel Processes and Unparalleled Performance  - Pinal Dave Keeping Your Database Available – ‘AlwaysOn’  - Balmukund Lakhani Lesser Known Facts of SQL Server Backup and Restore  - Amit Banerjee Top five reasons why you want SQL Server 2012 BI - Praveen Srivatsa Product Booth and Event Partners There will be a dedicated SQL Server booth at the event. I suggest you stop by there and do communication with SQL Server Experts. Additionally there will be booths of various event partners. Stop by their booth and see if they have a product which can help your career. I know that Pluralsight has recently released my course on their online learning site and if that interests you, you can talk about the subject with them. Bring Your Camera Make a list of the people you want to meet. Follow them on Twitter or send them an email and know their location. Introduce yourself, meet them and have your conversation. Do not forget to take a photo with them and later on, share the photo on social media. It would be nice to send an email to everyone with attached high resolution images if you have their email address. After-hours parties After-hours parties are not always about eating and meeting friends but sometimes, they are very informative. Last time I ended up meeting an SQL expert, and we end up talking for long hours on various aspects of SQL Server. After 4 hours, we figured out that he stays in the same apartment complex as mine and since we have had an excellent friendship, he has then become our family friend. So, my advice is that you start to seek out who is meeting where in the evening and see if you can get invited to the parties. Make new friends but never lose mutual respect by doing something silly. Meet Me I will be at the event for three days straight. I will be around the SQL tracks. Please stop by and introduce yourself. I would like to meet you and talk to you. Meeting folks from the Community is very important as we all speak the same language at the end of the day – SQL Server. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, SQLAuthority News, SQLServer, T SQL, Technology

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  • IE9, LightSwitch Beta 2 and Zune HD: A Study in Risk Management?

    - by andrewbrust
    Photo by parl, 'Risk.’ Under Creative Commons Attribution-NonCommercial-NoDerivs License This has been a busy week for Microsoft, and for me as well.  On Monday, Microsoft launched Internet Explorer 9 at South by Southwest (SXSW) in Austin, TX.  That evening I flew from New York to Seattle.  On Tuesday morning, Microsoft launched Visual Studio LightSwitch, Beta 2 with a Go-Live license, in Redmond, and I had the privilege of speaking at the keynote presentation where the announcement was made.  Readers of this blog know I‘m a fan of LightSwitch, so I was happy to tell the app dev tools partners in the audience that I thought the LightSwitch extensions ecosystem represented a big opportunity – comparable to the opportunity when Visual Basic 1.0 was entering its final beta roughly 20 years ago.  On Tuesday evening, I flew back to New York (and wrote most of this post in-flight). Two busy, productive days.  But there was a caveat that impacts the accomplishments, because Monday was also the day reports surfaced from credible news agencies that Microsoft was discontinuing its dedicated Zune hardware efforts.  While the Zune brand, technology and service will continue to be a component of Windows Phone and a piece of the Xbox puzzle as well, speculation is that Microsoft will no longer be going toe-to-toe with iPod touch in the portable music player market. If we take all three of these developments together (even if one of them is based on speculation), two interesting conclusions can reasonably be drawn, one good and one less so. Microsoft is doubling down on technologies it finds strategic and de-emphasizing those that it does not.  HTML 5 and the Web are strategic, so here comes IE9, and it’s a very good browser.  Try it and see.  Silverlight is strategic too, as is SQL Server, Windows Azure and SQL Azure, so here comes Visual Studio LightSwitch Beta 2 and a license to deploy its apps to production.  Downloads of that product have exceeded Microsoft’s projections by more than 50%, and the company is even citing analyst firms’ figures covering the number of power-user developers that might use it. (I happen to think the product will be used by full-fledged developers as well, but that’s a separate discussion.) Windows Phone is strategic too…I wasn’t 100% positive of that before, but the Nokia agreement has made me confident.  Xbox as an entertainment appliance is also strategic.  Standalone music players are not strategic – and even if they were, selling them has been a losing battle for Microsoft.  So if Microsoft has consolidated the Zune content story and the ZunePass subscription into Xbox and Windows Phone, it would make sense, and would be a smart allocation of resources.  Essentially, it would be for the greater good. But it’s not all good.  In this scenario, Zune player customers would lose out.  Unless they wanted to switch to Windows Phone, and then use their phone’s battery for the portable media needs, they’re going to need a new platform.  They’re going to feel abandoned.  Even if Zune lives, there have been other such cul de sacs for customers.  Remember SPOT watches?  Live Spaces?  The original Live Mesh?  Microsoft discontinued each of these products.  The company is to be commended for cutting its losses, as admitting a loss isn’t easy.  But Redmond won’t be well-regarded by the victims of those decisions.  Instead, it gets black marks. What’s the answer?  I think it’s a bit like the 1980’s New York City “don’t block the box” gridlock rules: don’t enter an intersection unless you see a clear path through it.  If the light turns red and you’re blocking the perpendicular traffic, that’s your fault in judgment.  You get fined and get points on your license and you don’t get to shrug it off as beyond your control.  Accountability is key.  The same goes for Microsoft.  If it decides to enter a market, it should see a reasonable path through success in that market. Switching analogies, Microsoft shouldn’t make investments haphazardly, and it certainly shouldn’t ask investors to buy into a high-risk fund that is sold as safe and which offers only moderate returns.  People won’t continue to invest with a fund manager with a track record of over-zealous, imprudent, sub-prime investments.  The same is true on the product side for Microsoft, and not just with music players and geeky wrist watches.  It’s true of Web browsers, and line-of-business app dev tools, and smartphones, and cloud platforms and operating systems too.  When Microsoft is casual about its own risk, it raises risk for its customers, and weakens its reputation, market share and credibility.  That doesn’t mean all risk is bad, but it does mean no product team’s risk should be taken lightly. For mutual fund companies, it’s the CEO’s job to give his fund managers autonomy, but to make sure they’re conforming to a standard of rational risk management.  Because all those funds carry the same brand, and many of them serve the same investors. The same goes for Microsoft, its product portfolio, its executive ranks and its product managers.

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  • Issues in Ada Concurrency

    - by Arkapravo
    Hi I need some help and also some insight. This is a program in Ada-2005 which has 3 tasks. The output is 'z'. If the 3 tasks do not happen in the order of their placement in the program then output can vary from z = 2, z = 1 to z = 0 ( That is easy to see in the program, mutual exclusion is attempted to make sure output is z = 2). WITH Ada.Text_IO; USE Ada.Text_IO; WITH Ada.Integer_Text_IO; USE Ada.Integer_Text_IO; WITH System; USE System; procedure xyz is x : Integer := 0; y : Integer := 0; z : Integer := 0; task task1 is pragma Priority(System.Default_Priority + 3); end task1; task task2 is pragma Priority(System.Default_Priority + 2); end task2; task task3 is pragma Priority(System.Default_Priority + 1); end task3; task body task1 is begin x := x + 1; end task1; task body task2 is begin y := x + y; end task2; task body task3 is begin z := x + y + z; end task3; begin Put(" z = "); Put(z); end xyz; I first tried this program (a) without pragmas, the result : In 100 tries, occurence of 2: 86, occurence of 1: 10, occurence of 0: 4. Then (b) with pragmas, the result : In 100 tries, occurence of 2: 84, occurence of 1 : 14, occurence of 0: 2. Which is unexpected as the 2 results are nearly identical. Which means pragmas or no pragmas the output has same behavior. Those who are Ada concurrency Gurus please shed some light on this topic. Alternative solutions with semaphores (if possible) is also invited. Further in my opinion for a critical process (that is what we do with Ada), with pragmas the result should be z = 2, 100% at all times, hence or otherwise this program should be termed as 85% critical !!!! (That should not be so with Ada)

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  • Certificate Trusts Lists in IIS7

    - by BrettRobi
    I am trying to enable mutual authentication for my WebService hosted in IIS7. I have the server side cert setup and working but cannot figure out how to get a Certificate Trust List created and setup in IIS7 so that I can require and validate client side certificates. All of my client side certs are signed by my own root cert so I need to create a CTL that contains just my root cert and then have IIS validate client provided certs against the CTL. Can anyone shed some light on how to do this? IIS6 had a UI for assigning a CTL, but I can find nothing similar in IIS7. Update: I have now successfully used MakeCTL in wizard mode to create a CTL with a Friendly Name. However I don't have adsutil support on my IIS7 box so via other posts elsewhere I am trying to use the 'netsh http add sslcert' command to assign the CTL to my site. Before I could use this command I had to remove the existing SSL cert that was assigned to my site for server authentication. Then in my netsh command I specify the thumbprint of that very same SSL cert I removed, plus a made up appid, plus 'sslctlidentifier=MyCTL sslctlstorename=CA'. The resulting command is: netsh http add sslcert ipport=10.10.10.10:443 certhash=adfdffa988bb50736b8e58a54c1eac26ed005050 appid={ffc3e181-e14b-4a21-b022-59fc669b09ff} sslctlidentifier=MyCTL sslctlstorename=CA (the IP addr is munged), but I am getting this error: SSL Certificate add failed, Error: 1312 A specified logon session does not exist. It may already have been terminated. I am sure the error is related to the CTL options because if I remove them it works (though no CTL is assigned of course). Can anyone help me take this last step and make this work? UPDATE 01-07-2010: I never resolved this with IIS 7.0 and have since migrated our app to IIS 7.5 and am giving this another try. Per the response from Taras Chuhay I installed IIS6 Compatibility on my test server and tried the steps he documented using adsutil.vbs (which can also be found here). I immediately ran into this error: ErrNumber: -2147023584 Error trying to SET the Property: SslCtlIdentifier when running this command: adsutil.vbs set w3svc/1/SslCtlIdentifier MyFriendlyName I then went on to try the next adsutil.vbs command documented and it failed with the same error. I have verified that the CTL I created has a Friendly Name of MyFriendlyName and that it exists in the 'Intermediate Certification Authorities\Certificate Trust List' store of LocalComputer. So once again I am at a dead standstill. I don't know what else to try. Has anyone ever gotten CTL's to work with IIS7 or 7.5? Ever? Am I beating a DEAD horse. Google turns up nothing but my own posts and other similar stories. Update 2/23/10 - I've confirmed with Microsoft that this is a bug with IIS 7.5, but it does work with IIS 7. Check out this link for details: http://viisual.net/configuration/IIS7-CTLs.htm Update 6/08/10 - I can now confirm that KB981506 resolves this issue. There is a patch associated with this KB that must be applied to Server 2008 R2 machines to enable this functionality. Once that is installed all works flawlessly for me.

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  • What can I send back to the browser while I wait for PHP execution?

    - by Matt Malesky
    So....I have a PHP page that involves a lot of backend execution, namely 'exec' calls to run shell commands on the host server. This can take upwards of a few minutes depending on the calls involved. (If you look below, each recursion through the exec calls is mounting a LUN; I'd like to sometimes do upwards of 100 per execution.) I'm curious on what I can do to send content back to the browser (and prevent it from timing out). <!DOCTYPE html> <html> <head> <title>sfvmtk</title> </head> <body> <?php // TEMPORARY VARIABLES FOR TESTING $hba = 'vmhba38'; $svip = '10.10.20.100'; $targets = array ( 0 => array ( 'iqn' => 'iqn.2010-01.com.sf:t5np.esxtest.41', 'account' => 'esx', 'isecret' => 'isecret00000', 'tsecret' => 'tsecret00000' ), 1 => array ( 'iqn' => 'iqn.2010-01.com.sf:t5np.esxtest2.42', 'account' => 'esx2', 'isecret' => 'isecret00001', 'tsecret' => 'tsecret00001' ) ); $hostname = $_REQUEST['hostname']; $username = $_REQUEST['username']; $password = $_REQUEST['password']; foreach ($targets as $ctarget) { exec('esxcli -s '.$hostname.' -u '.$username.' -p '.$password.' iscsi adapter discovery statictarget add -A '.$hba.' -a '.$svip.' -n '.$ctarget['iqn'], $out); exec('esxcli -s '.$hostname.' -u '.$username.' -p '.$password.' iscsi adapter target portal auth chap set -A '.$hba.' -a '.$svip.' -N '.$ctarget['account'].' -d uni -l required -n '.$ctarget['iqn'].' -S '.$ctarget['isecret'], $out); exec('esxcli -s '.$hostname.' -u '.$username.' -p '.$password.' iscsi adapter target portal auth chap set -A '.$hba.' -a '.$svip.' -N '.$ctarget['account'].' -d mutual -l required -n '.$ctarget['iqn'].' -S '.$ctarget['tsecret'], $out); } exec('vicfg-rescan --server '.$hostname.' --username '.$username.' --password '.$password.' '.$hba, $out); ?> </body> </html>

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  • WWDC and Tech Ed: A Tale of Two DevCons

    - by andrewbrust
    Next week marks the first full week of June.  Summer will feel in full swing and it will be a pretty big season for technology.  In seeming acknowledgement of that very fact, both Apple and Microsoft will be holding large developers conferences starting Monday.  Apple will hold its annual Worldwide Developers Conference (WWDC) in lovely San Francisco and Microsoft will hold its Tech Ed conference in muggy, oil-laden yet soulful New Orleans.  A brief survey of each show reveals much about the differences in each company’s offerings, strategy, and approach to customers and partners. In the interest of full disclosure, I must explain that I will be speaking at Microsoft’s Tech Ed show, and have done so, on and off, since 2003.  I have never been to an Apple conference and, as readers of this blog may know, I acquired my first ever Apple product 2 months ago when I bought an iPad on the day of that product’s launch.  I think I have keen insights into Microsoft’s conference.  My ability to comment on Apple’s event ranges somewhere between backseat driver and naive observer.  Just so you know. Although both shows cater to their respective company’s developers, there are a number of differences in the events’ purposes and content approaches.  First off, let’s consider each show as a news and PR vehicle.  WWDC will feature Steve Jobs’ keynote address and most likely will be where Apple officially reveals details of its 4th-generation iPhone. Jobs will likely also provide deep background information on the corresponding iPhone OS release.  These presumed announcements will make the show a magnet for the tech press and tech blogger elite.  Apple’s customers will be interested too, especially since the iPhone OS release will likely be made available to owners of existing iPhone, iPod Touch and iPad devices. Tech Ed, on the other hand, may not be especially newsworthy at all.  The keynote address will be given by Bob Muglia, who is President of the company’s Server and Tools Division, and he’ll likely be reviewing things more than previewing them. That’s because the company has, in the last 6-8 months, already released new versions of a majority of its products, including Windows, Office, SharePoint, SQL Server, Exchange, its Azure cloud platform, its .NET software development layer, its Silverlight Rich Internet Application (RIA) technology and its Visual Studio developer suite.  Redmond’s product pipeline has functioned more like a firehose of late, and the company has a ton of work to do to get developers up to speed on everything that’s new. I know I keep saying “developers,” but in Tech Ed’s case, that’s not really accurate.  In North America, Tech Ed caters to both developers and IT pros (i.e. technologists who work with physical IT infrastructure, as well as security and administration of the server software that runs on it).  This pairing has, since its inception, struck some as anomalous and others, including many exhibitors, as very smart. Certainly, it means Tech Ed ends up being a confab for virtually all professionals in Microsoft’s ecosystem.  And this year, Microsoft’s Business Intelligence (BI) conference will be co-located with Tech Ed, further enhancing that fusion effect. Clearly then, Microsoft’s show will focus on education, as its name assures us.  Apple’s will serve as both a press event and an opportunity to get its own App Store developer channel synced up with its newest technology advances.  For example, we already know that iPhone OS 4.0 will provide for a limited multitasking capability; that will only work well if people know how to code to it in a capable way.  Apple also told us its iAd advertising platform will be part of the new OS, and Steve Jobs insists that’s to provide a revenue opportunity for developers.  This too, then, needs to be explicated and soaked up buy the faithful. A look at each show’s breakout session lineup provides some interesting takeaways.  WWDC will have very few Mac-specific sessions on offer, and virtually no sessions that at are IT- or “Enterprise-“ related.  It’s all about the phone, music players and tablets.  However, WWDC will have plenty of low-level, hardcore tech coverage of such things as Advanced Memory Analysis and Creating Secure Applications, as well as lots of rich media-related content like Core Animation and Game Design and Development.  Beyond Apple’s proprietary platform, WWDC will also feature an array of sessions on HTML 5 and other Web standards.  In all, WWDC offers over 100 technical sessions and hands-on labs. What about Tech Ed’s editorial content?  Like the target audience, it really runs the gamut.  The show has 21 tracks (versus WWDC’s 5) and more than 745 “learning opportunities” which include breakout sessions, demo stations, hands-on labs and BIrds of a Feather discussion sessions.  Topics range from Architecture talks like Patterns of Parallel Programming to cloud computing talks like Building High Capacity Compute Applications with Windows Azure to IT-focused topics like Virtualization of Microsoft SharePoint 2010 Farm Architecture.  I also count 19 sessions on Windows Phone 7.  Unfortunately, with regard to Web standards and HTML 5, only a few sessions are offered, all of them specific to Internet Explorer. All-in-all, Apple’s show looks more exciting and “sexier” than Tech Ed. Microsoft’s show seems a lot more enterprise-focused than WWDC. This is, of course, well in sync with each company’s approach and products.  Microsoft’s content is much wider ranging and bests WWDC in sheer volume of sessions and labs.  I suppose some might argue that less is more; others that Apple’s consumer-focused offerings simply don’t provide for the same depth of coverage to a business audience.  Microsoft has a serious focus on the cloud and  a paucity of coverage on client-side Web standards; Apple has virtually no cloud offering at all.  Again, this reflects each tech titan’s go-to-market strategy. My own take is that employees of each company should attend the other’s event.  The amount of mutual exclusivity in content may make sense in terms of corporate philosophy, but the reality is that each company could stand to diversify into the other’s territory, at least somewhat. My own talk at Tech Ed will focus on competitive analysis around Microsoft’s BI products.  Apple does not today figure into that analysis. Maybe one day it will.

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  • Is Financial Inclusion an Obligation or an Opportunity for Banks?

    - by tushar.chitra
    Why should banks care about financial inclusion? First, the statistics, I think this will set the tone for this blog post. There are close to 2.5 billion people who are excluded from the banking stream and out of this, 2.2 billion people are from the continents of Africa, Latin America and Asia (McKinsey on Society: Global Financial Inclusion). However, this is not just a third-world phenomenon. According to Federal Deposit Insurance Corp (FDIC), in the US, post 2008 financial crisis, one family out of five has either opted out of the banking system or has been moved out (American Banker). Moving this huge unbanked population into mainstream banking is both an opportunity and a challenge for banks. An obvious opportunity is the significant untapped customer base that banks can target, so is the positive brand equity a bank can build by fulfilling its social responsibilities. Also, as banks target the cost-conscious unbanked customer, they will be forced to look at ways to offer cost-effective products and services, necessitating technology upgrades and innovations. However, cost is not the only hurdle in increasing the adoption of banking services. The potential users need to be convinced of the benefits of banking and banks will also face stiff competition from unorganized players. Finally, the banks will have to believe in the viability of this business opportunity, and not treat financial inclusion as an obligation. In what ways can banks target the unbanked For financial inclusion to be a success, banks should adopt innovative business models to develop products that address the stated and unstated needs of the unbanked population and also design delivery channels that are cost effective and viable in the long run. Through business correspondents and facilitators In rural and remote areas, one of the major hurdles in increasing banking penetration is connectivity and accessibility to banking services, which makes last mile inclusion a daunting challenge. To address this, banks can avail the services of business correspondents or facilitators. This model allows banks to establish greater connectivity through a trusted and reliable intermediary. In India, for instance, banks can leverage the local Kirana stores (the mom & pop stores) to service rural and remote areas. With a supportive nudge from the central bank, the commercial banks can enlist these shop owners as business correspondents to increase their reach. Since these neighborhood stores are acquainted with the local population, they can help banks manage the KYC norms, besides serving as a conduit for remittance. Banks also have an opportunity over a period of time to cross-sell other financial products such as micro insurance, mutual funds and pension products through these correspondents. To exercise greater operational control over the business correspondents, banks can also adopt a combination of branch and business correspondent models to deliver financial inclusion. Through mobile devices According to a 2012 world bank report on financial inclusion, out of a world population of 7 billion, over 5 billion or 70% have mobile phones and only 2 billion or 30% have a bank account. What this means for banks is that there is scope for them to leverage this phenomenal growth in mobile usage to serve the unbanked population. Banks can use mobile technology to service the basic banking requirements of their customers with no frills accounts, effectively bringing down the cost per transaction. As I had discussed in my earlier post on mobile payments, though non-traditional players have taken the lead in P2P mobile payments, banks still hold an edge in terms of infrastructure and reliability. Through crowd-funding According to the Crowdfunding Industry Report by Massolution, the global crowdfunding industry raised $2.7 billion in 2012, and is projected to grow to $5.1 billion in 2013. With credit policies becoming tighter and banks becoming more circumspect in terms of loan disbursals, crowdfunding has emerged as an alternative channel for lending. Typically, these initiatives target the unbanked population by offering small loans that are unviable for larger banks. Though a significant proportion of crowdfunding initiatives globally are run by non-banking institutions, banks are also venturing into this space. The next step towards inclusive finance Banks by themselves cannot make financial inclusion a success. There is a need for a whole ecosystem that is supportive of this mission. The policy makers, that include the regulators and government bodies, must be in sync, the IT solution providers must put on their thinking caps to come out with innovative products and solutions, communication channels such as internet and mobile need to expand their reach, and the media and the public need to play an active part. The other challenge for financial inclusion is from the banks themselves. While it is true that financial inclusion will unleash a hitherto hugely untapped market, the normal banking model may be found wanting because of issues such as flexibility, convenience and reliability. The business will be viable only when there is a focus on increasing the usage of existing infrastructure and that is possible when the banks can offer the entire range of products and services to the large number of users of essential banking services. Apart from these challenges, banks will also have to quickly master and replicate the business model to extend their reach to the remotest regions in their respective geographies. They will need to ensure that the transactions deliver a viable business benefit to the bank. For tapping cross-sell opportunities, banks will have to quickly roll-out customized and segment-specific products. The bank staff should be brought in sync with the business plan by convincing them of the viability of the business model and the need for a business correspondent delivery model. Banks, in collaboration with the government and NGOs, will have to run an extensive financial literacy program to educate the unbanked about the benefits of banking. Finally, with the growing importance of retail banking and with many unconventional players eyeing the opportunity in payments and other lucrative areas of banking, banks need to understand the importance of micro and small branches. These micro and small branches can help banks increase their presence without a huge cost burden, provide bankers an opportunity to cross sell micro products and offer a window of opportunity for the large non-banked population to transact without any interference from intermediaries. These branches can also help diminish the role of the unorganized financial sector, such as local moneylenders and unregistered credit societies. This will also help banks build a brand awareness and loyalty among the users, which by itself has a cascading effect on the business operations, especially among the rural and un-banked centers. In conclusion, with the increasingly competitive banking sector facing frequent slowdowns and downturns, the unbanked population presents a huge opportunity for banks to enhance their customer base and fulfill their social responsibility.

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  • DRY and SRP

    - by Timothy Klenke
    Originally posted on: http://geekswithblogs.net/TimothyK/archive/2014/06/11/dry-and-srp.aspxKent Beck’s XP Simplicity Rules (aka Four Rules of Simple Design) are a prioritized list of rules that when applied to your code generally yield a great design.  As you’ll see from the above link the list has slightly evolved over time.  I find today they are usually listed as: All Tests Pass Don’t Repeat Yourself (DRY) Express Intent Minimalistic These are prioritized.  If your code doesn’t work (rule 1) then everything else is forfeit.  Go back to rule one and get the code working before worrying about anything else. Over the years the community have debated whether the priority of rules 2 and 3 should be reversed.  Some say a little duplication in the code is OK as long as it helps express intent.  I’ve debated it myself.  This recent post got me thinking about this again, hence this post.   I don’t think it is fair to compare “Expressing Intent” against “DRY”.  This is a comparison of apples to oranges.  “Expressing Intent” is a principal of code quality.  “Repeating Yourself” is a code smell.  A code smell is merely an indicator that there might be something wrong with the code.  It takes further investigation to determine if a violation of an underlying principal of code quality has actually occurred. For example “using nouns for method names”, “using verbs for property names”, or “using Booleans for parameters” are all code smells that indicate that code probably isn’t doing a good job at expressing intent.  They are usually very good indicators.  But what principle is the code smell of Duplication pointing to and how good of an indicator is it? Duplication in the code base is bad for a couple reasons.  If you need to make a change and that needs to be made in a number of locations it is difficult to know if you have caught all of them.  This can lead to bugs if/when one of those locations is overlooked.  By refactoring the code to remove all duplication there will be left with only one place to change, thereby eliminating this problem. With most projects the code becomes the single source of truth for a project.  If a production code base is inconsistent with a five year old requirements or design document the production code that people are currently living with is usually declared as the current reality (or truth).  Requirement or design documents at this age in a project life cycle are usually of little value. Although comparing production code to external documentation is usually straight forward, duplication within the code base muddles this declaration of truth.  When code is duplicated small discrepancies will creep in between the two copies over time.  The question then becomes which copy is correct?  As different factions debate how the software should work, trust in the software and the team behind it erodes. The code smell of Duplication points to a violation of the “Single Source of Truth” principle.  Let me define that as: A stakeholder’s requirement for a software change should never cause more than one class to change. Violation of the Single Source of Truth principle will always result in duplication in the code.  However, the inverse is not always true.  Duplication in the code does not necessarily indicate that there is a violation of the Single Source of Truth principle. To illustrate this, let’s look at a retail system where the system will (1) send a transaction to a bank and (2) print a receipt for the customer.  Although these are two separate features of the system, they are closely related.  The reason for printing the receipt is usually to provide an audit trail back to the bank transaction.  Both features use the same data:  amount charged, account number, transaction date, customer name, retail store name, and etcetera.  Because both features use much of the same data, there is likely to be a lot of duplication between them.  This duplication can be removed by making both features use the same data access layer. Then start coming the divergent requirements.  The receipt stakeholder wants a change so that the account number has the last few digits masked out to protect the customer’s privacy.  That can be solve with a small IF statement whilst still eliminating all duplication in the system.  Then the bank wants to take a picture of the customer as well as capture their signature and/or PIN number for enhanced security.  Then the receipt owner wants to pull data from a completely different system to report the customer’s loyalty program point total. After a while you realize that the two stakeholders have somewhat similar, but ultimately different responsibilities.  They have their own reasons for pulling the data access layer in different directions.  Then it dawns on you, the Single Responsibility Principle: There should never be more than one reason for a class to change. In this example we have two stakeholders giving two separate reasons for the data access class to change.  It is clear violation of the Single Responsibility Principle.  That’s a problem because it can often lead the project owner pitting the two stakeholders against each other in a vein attempt to get them to work out a mutual single source of truth.  But that doesn’t exist.  There are two completely valid truths that the developers need to support.  How is this to be supported and honour the Single Responsibility Principle?  The solution is to duplicate the data access layer and let each stakeholder control their own copy. The Single Source of Truth and Single Responsibility Principles are very closely related.  SST tells you when to remove duplication; SRP tells you when to introduce it.  They may seem to be fighting each other, but really they are not.  The key is to clearly identify the different responsibilities (or sources of truth) over a system.  Sometimes there is a single person with that responsibility, other times there are many.  This can be especially difficult if the same person has dual responsibilities.  They might not even realize they are wearing multiple hats. In my opinion Single Source of Truth should be listed as the second rule of simple design with Express Intent at number three.  Investigation of the DRY code smell should yield to the proper application SST, without violating SRP.  When necessary leave duplication in the system and let the class names express the different people that are responsible for controlling them.  Knowing all the people with responsibilities over a system is the higher priority because you’ll need to know this before you can express it.  Although it may be a code smell when there is duplication in the code, it does not necessarily mean that the coder has chosen to be expressive over DRY or that the code is bad.

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  • SonicOS Enhanced 5.8.1.2 L2TP VPN Authentication Failed

    - by Dean A. Vassallo
    I have a SonicWall TZ 215 running SonicOS Enhanced 5.8.1.2-6o. I have configured the L2TP VPN using the default crypto suite ESP: 3DES/HMAC SHA1 (IKE). Proposals are as such: IKE (Phase 1) Proposal DH Group: Group 2 Encryption: 3DES Authentication: SHA1 Life Time (seconds): 28800 Ipsec (Phase 2) Proposal Protocol: ESP Encryption: 3DES Authentication: SHA1 Enable Perfect Forward Secrecy DISABLED Life Time (seconds): 28800 When attempting to connect via my Mac OS X client I get an authentication error. It appears to pass the pre-authentication but fails to complete. I am at a complete loss. I reconfigured from scratch multiple times...used simple usernames and passwords to verify this wasn't a miskeyed password issue. I have Here are the logs (noted IP has been removed for privacy): 7/1/13 8:19:05.174 PM pppd[1268]: setup_security_context server port: 0x1503 7/1/13 8:19:05.190 PM pppd[1268]: publish_entry SCDSet() failed: Success! 7/1/13 8:19:05.191 PM pppd[1268]: publish_entry SCDSet() failed: Success! 7/1/13 8:19:05.191 PM pppd[1268]: pppd 2.4.2 (Apple version 727.1.1) started by dean, uid 501 7/1/13 8:19:05.192 PM pppd[1268]: L2TP connecting to server ‘0.0.0.0’ (0.0.0.0)... 7/1/13 8:19:05.193 PM pppd[1268]: IPSec connection started 7/1/13 8:19:05.208 PM racoon[1269]: accepted connection on vpn control socket. 7/1/13 8:19:05.209 PM racoon[1269]: Connecting. 7/1/13 8:19:05.209 PM racoon[1269]: IPSec Phase 1 started (Initiated by me). 7/1/13 8:19:05.209 PM racoon[1269]: IKE Packet: transmit success. (Initiator, Main-Mode message 1). 7/1/13 8:19:05.209 PM racoon[1269]: >>>>> phase change status = Phase 1 started by us 7/1/13 8:19:05.231 PM racoon[1269]: >>>>> phase change status = Phase 1 started by peer 7/1/13 8:19:05.231 PM racoon[1269]: IKE Packet: receive success. (Initiator, Main-Mode message 2). 7/1/13 8:19:05.234 PM racoon[1269]: IKE Packet: transmit success. (Initiator, Main-Mode message 3). 7/1/13 8:19:05.293 PM racoon[1269]: IKE Packet: receive success. (Initiator, Main-Mode message 4). 7/1/13 8:19:05.295 PM racoon[1269]: IKE Packet: transmit success. (Initiator, Main-Mode message 5). 7/1/13 8:19:05.315 PM racoon[1269]: IKEv1 Phase 1 AUTH: success. (Initiator, Main-Mode Message 6). 7/1/13 8:19:05.315 PM racoon[1269]: IKE Packet: receive success. (Initiator, Main-Mode message 6). 7/1/13 8:19:05.315 PM racoon[1269]: IKEv1 Phase 1 Initiator: success. (Initiator, Main-Mode). 7/1/13 8:19:05.315 PM racoon[1269]: IPSec Phase 1 established (Initiated by me). 7/1/13 8:19:06.307 PM racoon[1269]: IPSec Phase 2 started (Initiated by me). 7/1/13 8:19:06.307 PM racoon[1269]: >>>>> phase change status = Phase 2 started 7/1/13 8:19:06.308 PM racoon[1269]: IKE Packet: transmit success. (Initiator, Quick-Mode message 1). 7/1/13 8:19:06.332 PM racoon[1269]: attribute has been modified. 7/1/13 8:19:06.332 PM racoon[1269]: IKE Packet: receive success. (Initiator, Quick-Mode message 2). 7/1/13 8:19:06.332 PM racoon[1269]: IKE Packet: transmit success. (Initiator, Quick-Mode message 3). 7/1/13 8:19:06.333 PM racoon[1269]: IKEv1 Phase 2 Initiator: success. (Initiator, Quick-Mode). 7/1/13 8:19:06.333 PM racoon[1269]: IPSec Phase 2 established (Initiated by me). 7/1/13 8:19:06.333 PM racoon[1269]: >>>>> phase change status = Phase 2 established 7/1/13 8:19:06.333 PM pppd[1268]: IPSec connection established 7/1/13 8:19:07.145 PM pppd[1268]: L2TP connection established. 7/1/13 8:19:07.000 PM kernel[0]: ppp0: is now delegating en0 (type 0x6, family 2, sub-family 3) 7/1/13 8:19:07.146 PM pppd[1268]: Connect: ppp0 <--> socket[34:18] 7/1/13 8:19:08.709 PM pppd[1268]: MS-CHAPv2 mutual authentication failed. 7/1/13 8:19:08.710 PM pppd[1268]: Connection terminated. 7/1/13 8:19:08.710 PM pppd[1268]: L2TP disconnecting... 7/1/13 8:19:08.711 PM pppd[1268]: L2TP disconnected 7/1/13 8:19:08.711 PM racoon[1269]: IPSec disconnecting from server 0.0.0.0 7/1/13 8:19:08.711 PM racoon[1269]: IKE Packet: transmit success. (Information message). 7/1/13 8:19:08.712 PM racoon[1269]: IKEv1 Information-Notice: transmit success. (Delete IPSEC-SA). 7/1/13 8:19:08.712 PM racoon[1269]: IKE Packet: transmit success. (Information message). 7/1/13 8:19:08.712 PM racoon[1269]: IKEv1 Information-Notice: transmit success. (Delete ISAKMP-SA). 7/1/13 8:19:08.713 PM racoon[1269]: glob found no matches for path "/var/run/racoon/*.conf" 7/1/13 8:19:08.714 PM racoon[1269]: pfkey DELETE failed: No such file or directory

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  • Standards Corner: OAuth WG Client Registration Problem

    - by Tanu Sood
    Phil Hunt is an active member of multiple industry standards groups and committees (see brief bio at the end of the post) and has spearheaded discussions, creation and ratifications of  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:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-family:"Calibri","sans-serif"; mso-ascii- mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi- mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;} industry standards including the Kantara Identity Governance Framework, among others. Being an active voice in the industry standards development world, we have invited him to share his discussions, thoughts, news & updates, and discuss use cases, implementation success stories (and even failures) around industry standards on this monthly column. Author: Phil Hunt This afternoon, the OAuth Working Group will meet at IETF88 in Vancouver to discuss some important topics important to the maturation of OAuth. One of them is the OAuth client registration problem.OAuth (RFC6749) was initially developed with a simple deployment model where there is only monopoly or singleton cloud instance of a web API (e.g. there is one Facebook, one Google, on LinkedIn, and so on). When the API publisher and API deployer are the same monolithic entity, it easy for developers to contact the provider and register their app to obtain a client_id and credential.But what happens when the API is for an open source project where there may be 1000s of deployed copies of the API (e.g. such as wordpress). In these cases, the authors of the API are not the people running the API. In these scenarios, how does the developer obtain a client_id? An example of an "open deployed" API is OpenID Connect. Connect defines an OAuth protected resource API that can provide personal information about an authenticated user -- in effect creating a potentially common API for potential identity providers like Facebook, Google, Microsoft, Salesforce, or Oracle. In Oracle's case, Fusion applications will soon have RESTful APIs that are deployed in many different ways in many different environments. How will developers write apps that can work against an openly deployed API with whom the developer can have no prior relationship?At present, the OAuth Working Group has two proposals two consider: Dynamic RegistrationDynamic Registration was originally developed for OpenID Connect and UMA. It defines a RESTful API in which a prospective client application with no client_id creates a new client registration record with a service provider and is issued a client_id and credential along with a registration token that can be used to update registration over time.As proof of success, the OIDC community has done substantial implementation of this spec and feels committed to its use. Why not approve?Well, the answer is that some of us had some concerns, namely: Recognizing instances of software - dynamic registration treats all clients as unique. It has no defined way to recognize that multiple copies of the same client are being registered other then assuming if the registration parameters are similar it might be the same client. Versioning and Policy Approval of open APIs and clients - many service providers have to worry about change management. They expect to have approval cycles that approve versions of server and client software for use in their environment. In some cases approval might be wide open, but in many cases, approval might be down to the specific class of software and version. Registration updates - when does a client actually need to update its registration? Shouldn't it be never? Is there some characteristic of deployed code that would cause it to change? Options lead to complexity - because each client is treated as unique, it becomes unclear how the clients and servers will agree on what credentials forms are acceptable and what OAuth features are allowed and disallowed. Yet the reality is, developers will write their application to work in a limited number of ways. They can't implement all the permutations and combinations that potential service providers might choose. Stateful registration - if the primary motivation for registration is to obtain a client_id and credential, why can't this be done in a stateless fashion using assertions? Denial of service - With so much stateful registration and the need for multiple tokens to be issued, will this not lead to a denial of service attack / risk of resource depletion? At the very least, because of the information gathered, it would difficult for service providers to clean up "failed" registrations and determine active from inactive or false clients. There has yet to be much wide-scale "production" use of dynamic registration other than in small closed communities. Client Association A second proposal, Client Association, has been put forward by Tony Nadalin of Microsoft and myself. We took at look at existing use patterns to come up with a new proposal. At the Berlin meeting, we considered how WS-STS systems work. More recently, I took a review of how mobile messaging clients work. I looked at how Apple, Google, and Microsoft each handle registration with APNS, GCM, and WNS, and a similar pattern emerges. This pattern is to use an existing credential (mutual TLS auth), or client bearer assertion and swap for a device specific bearer assertion.In the client association proposal, the developer's registration with the API publisher is handled by having the developer register with an API publisher (as opposed to the party deploying the API) and obtaining a software "statement". Or, if there is no "publisher" that can sign a statement, the developer may include their own self-asserted software statement.A software statement is a special type of assertion that serves to lock application registration profile information in a signed assertion. The statement is included with the client application and can then be used by the client to swap for an instance specific client assertion as defined by section 4.2 of the OAuth Assertion draft and profiled in the Client Association draft. The software statement provides a way for service provider to recognize and configure policy to approve classes of software clients, and simplifies the actual registration to a simple assertion swap. Because the registration is an assertion swap, registration is no longer "stateful" - meaning the service provider does not need to store any information to support the client (unless it wants to). Has this been implemented yet? Not directly. We've only delivered draft 00 as an alternate way of solving the problem using well-known patterns whose security characteristics and scale characteristics are well understood. Dynamic Take II At roughly the same time that Client Association and Software Statement were published, the authors of Dynamic Registration published a "split" version of the Dynamic Registration (draft-richer-oauth-dyn-reg-core and draft-richer-oauth-dyn-reg-management). While some of the concerns above are addressed, some differences remain. Registration is now a simple POST request. However it defines a new method for issuing client tokens where as Client Association uses RFC6749's existing extension point. The concern here is whether future client access token formats would be addressed properly. Finally, Dyn-reg-core does not yet support software statements. Conclusion The WG has some interesting discussion to bring this back to a single set of specifications. Dynamic Registration has significant implementation, but Client Association could be a much improved way to simplify implementation of the overall OpenID Connect specification and improve adoption. In fairness, the existing editors have already come a long way. Yet there are those with significant investment in the current draft. There are many that have expressed they don't care. They just want a standard. There is lots of pressure on the working group to reach consensus quickly.And that folks is how the sausage is made.Note: John Bradley and Justin Richer recently published draft-bradley-stateless-oauth-client-00 which on first look are getting closer. Some of the details seem less well defined, but the same could be said of client-assoc and software-statement. I hope we can merge these specs this week. 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:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-family:"Calibri","sans-serif"; mso-ascii- mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi- mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;} About the Writer: Phil Hunt joined Oracle as part of the November 2005 acquisition of OctetString Inc. where he headed software development for what is now Oracle Virtual Directory. Since joining Oracle, Phil works as CMTS in the Identity Standards group at Oracle where he developed the Kantara Identity Governance Framework and provided significant input to JSR 351. Phil participates in several standards development organizations such as IETF and OASIS working on federation, authorization (OAuth), and provisioning (SCIM) standards.  Phil blogs at www.independentid.com and a Twitter handle of @independentid.

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  • Const-correctness semantics in C++

    - by thirtythreeforty
    For fun and profit™, I'm writing a trie class in C++ (using the C++11 standard.) My trie<T> has an iterator, trie<T>::iterator. (They're all actually functionally const_iterators, because you cannot modify a trie's value_type.) The iterator's class declaration looks partially like this: template<typename T> class trie<T>::iterator : public std::iterator<std::bidirectional_iterator_tag, T> { friend class trie<T>; struct state { state(const trie<T>* const node, const typename std::vector<std::pair<typename T::value_type, std::unique_ptr<trie<T>>>>::const_iterator& node_map_it ) : node{node}, node_map_it{node_map_it} {} // This pointer is to const data: const trie<T>* node; typename std::vector<std::pair<typename T::value_type, std::unique_ptr<trie<T>>>>::const_iterator node_map_it; }; public: typedef const T value_type; iterator() =default; iterator(const trie<T>* node) { parents.emplace(node, node->children.cbegin()); // ... } // ... private: std::stack<state> parents; // ... }; Notice that the node pointer is declared const. This is because (in my mind) the iterator should not be modifying the node that it points to; it is just an iterator. Now, elsewhere in my main trie<T> class, I have an erase function that has a common STL signature--it takes an iterator to data to erase (and returns an iterator to the next object). template<typename T> typename trie<T>::iterator trie<T>::erase(const_iterator it) { // ... // Cannot modify a const object! it.parents.top().node->is_leaf = false; // ... } The compiler complains because the node pointer is read-only! The erase function definitely should modify the trie that the iterator points to, even though the iterator shouldn't. So, I have two questions: Should iterator's constructors be public? trie<T> has the necessary begin() and end() members, and of course trie<T>::iterator and trie<T> are mutual friends, but I don't know what the convention is. Making them private would solve a lot of the angst I'm having about removing the const "promise" from the iterator's constructor. What are the correct const semantics/conventions regarding the iterator and its node pointer here? Nobody has ever explained this to me, and I can't find any tutorials or articles on the Web. This is probably the more important question, but it does require a good deal of planning and proper implementation. I suppose it could be circumvented by just implementing 1, but it's the principle of the thing!

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  • SQLAuthority News – Job Interviewing the Right Way (and for the Right Reasons) – Guest Post by Feodor Georgiev

    - by pinaldave
    Feodor Georgiev is a SQL Server database specialist with extensive experience of thinking both within and outside the box. He has wide experience of different systems and solutions in the fields of architecture, scalability, performance, etc. Feodor has experience with SQL Server 2000 and later versions, and is certified in SQL Server 2008. Feodor has written excellent article on Job Interviewing the Right Way. Here is his article in his own language. A while back I was thinking to start a blog post series on interviewing and employing IT personnel. At that time I had just read the ‘Smart and gets things done’ book (http://www.joelonsoftware.com/items/2007/06/05.html) and I was hyped up on some debatable topics regarding finding and employing the best people in the branch. I have no problem with hiring the best of the best; it’s just the definition of ‘the best of the best’ that makes things a bit more complicated. One of the fundamental books one can read on the topic of interviewing is the one mentioned above. If you have not read it, then you must do so; not because it contains the ultimate truth, and not because it gives the answers to most questions on the subject, but because the book contains an extensive set of questions about interviewing and employing people. Of course, a big part of these questions have different answers, depending on location, culture, available funds and so on. (What works in the US may not necessarily work in the Nordic countries or India, or it may work in a different way). The only thing that is valid regardless of any external factor is this: curiosity. In my belief there are two kinds of people – curious and not-so-curious; regardless of profession. Think about it – professional success is directly proportional to the individual’s curiosity + time of active experience in the field. (I say ‘active experience’ because vacations and any distractions do not count as experience :)  ) So, curiosity is the factor which will distinguish a good employee from the not-so-good one. But let’s shift our attention to something else for now: a few tips and tricks for successful interviews. Tip and trick #1: get your priorities straight. Your status usually dictates your priorities; for example, if the person looking for a job has just relocated to a new country, they might tend to ignore some of their priorities and overload others. In other words, setting priorities straight means to define the personal criteria by which the interview process is lead. For example, similar to the following questions can help define the criteria for someone looking for a job: How badly do I need a (any) job? Is it more important to work in a clean and quiet environment or is it important to get paid well (or both, if possible)? And so on… Furthermore, before going to the interview, the candidate should have a list of priorities, sorted by the most importance: e.g. I want a quiet environment, x amount of money, great helping boss, a desk next to a window and so on. Also it is a good idea to be prepared and know which factors can be compromised and to what extent. Tip and trick #2: the interview is a two-way street. A job candidate should not forget that the interview process is not a one-way street. What I mean by this is that while the employer is interviewing the potential candidate, the job seeker should not miss the chance to interview the employer. Usually, the employer and the candidate will meet for an interview and talk about a variety of topics. In a quality interview the candidate will be presented to key members of the team and will have the opportunity to ask them questions. By asking the right questions both parties will define their opinion about each other. For example, if the candidate talks to one of the potential bosses during the interview process and they notice that the potential manager has a hard time formulating a question, then it is up to the candidate to decide whether working with such person is a red flag for them. There are as many interview processes out there as there are companies and each one is different. Some bigger companies and corporates can afford pre-selection processes, 3 or even 4 stages of interviews, small companies usually settle with one interview. Some companies even give cognitive tests on the interview. Why not? In his book Joel suggests that a good candidate should be pampered and spoiled beyond belief with a week-long vacation in New York, fancy hotels, food and who knows what. For all I can imagine, an interview might even take place at the top of the Eifel tower (right, Mr. Joel, right?) I doubt, however, that this is the optimal way to capture the attention of a good employee. The ‘curiosity’ topic What I have learned so far in my professional experience is that opinions can be subjective. Plus, opinions on technology subjects can also be subjective. According to Joel, only hiring the best of the best is worth it. If you ask me, there is no such thing as best of the best, simply because human nature (well, aside from some physical limitations, like putting your pants on through your head :) ) has no boundaries. And why would it have boundaries? I have seen many curious and interesting people, naturally good at technology, though uninterested in it as one  can possibly be; I have also seen plenty of people interested in technology, who (in an ideal world) should have stayed far from it. At any rate, all of this sums up at the end to the ‘supply and demand’ factor. The interview process big-bang boils down to this: If there is a mutual benefit for both the employer and the potential employee to work together, then it all sorts out nicely. If there is no benefit, then it is much harder to get to a common place. Tip and trick #3: word-of-mouth is worth a thousand words Here I would just mention that the best thing a job candidate can get during the interview process is access to future team members or other employees of the new company. Nowadays the world has become quite small and everyone knows everyone. Look at LinkedIn, look at other professional networks and you will realize how small the world really is. Knowing people is a good way to become more approachable and to approach them. Tip and trick #4: Be confident. It is true that for some people confidence is as natural as breathing and others have to work hard to express it. Confidence is, however, a key factor in convincing the other side (potential employer or employee) that there is a great chance for success by working together. But it cannot get you very far if it’s not backed up by talent, curiosity and knowledge. Tip and trick #5: The right reasons What really bothers me in Sweden (and I am sure that there are similar situations in other countries) is that there is a tendency to fill quotas and to filter out candidates by criteria different from their skill and knowledge. In job ads I see quite often the phrases ‘positive thinker’, ‘team player’ and many similar hints about personality features. So my guess here is that discrimination has evolved to a new level. Let me clear up the definition of discrimination: ‘unfair treatment of a person or group on the basis of prejudice’. And prejudice is the ‘partiality that prevents objective consideration of an issue or situation’. In other words, there is not much difference whether a job candidate is filtered out by race, gender or by personality features – it is all a bad habit. And in reality, there is no proven correlation between the technology knowledge paired with skills and the personal features (gender, race, age, optimism). It is true that a significantly greater number of Darwin awards were given to men than to women, but I am sure that somewhere there is a paper or theory explaining the genetics behind this. J This topic actually brings to mind one of my favorite work related stories. A while back I was working for a big company with many teams involved in their processes. One of the teams was occupying 2 rooms – one had the team members and was full of light, colorful posters, chit-chats and giggles, whereas the other room was dark, lighted only by a single monitor with a quiet person in front of it. Later on I realized that the ‘dark room’ person was the guru and the ultimate problem-solving-brain who did not like the chats and giggles and hence was in a separate room. In reality, all severe problems which the chatty and cheerful team members could not solve and all emergencies were directed to ‘the dark room’. And thus all worked out well. The moral of the story: Personality has nothing to do with technology knowledge and skills. End of story. Summary: I’d like to stress the fact that there is no ultimately perfect candidate for a job, and there is no such thing as ‘best-of-the-best’. From my personal experience, the main criteria by which I measure people (co-workers and bosses) is the curiosity factor; I know from experience that the more curious and inventive a person is, the better chances there are for great achievements in their field. Related stories: (for extra credit) 1) Get your priorities straight. A while back as a consultant I was working for a few days at a time at different offices and for different clients, and so I was able to compare and analyze the work environments. There were two different places which I compared and recently I asked a friend of mine the following question: “Which one would you prefer as a work environment: a noisy office full of people, or a quiet office full of faulty smells because the office is rarely cleaned?” My friend was puzzled for a while, thought about it and said: “Hmm, you are talking about two different kinds of pollution… I will probably choose the second, since I can clean the workplace myself a bit…” 2) The interview is a two-way street. One time, during a job interview, I met a potential boss that had a hard time phrasing a question. At that particular time it was clear to me that I would not have liked to work under this person. According to my work religion, the properly asked question contains at least half of the answer. And if I work with someone who cannot ask a question… then I’d be doing double or triple work. At another interview, after the technical part with the team leader of the department, I was introduced to one of the team members and we were left alone for 5 minutes. I immediately jumped on the occasion and asked the blunt question: ‘What have you learned here for the past year and how do you like your job?’ The team member looked at me and said ‘Nothing really. I like playing with my cats at home, so I am out of here at 5pm and I don’t have time for much.’ I was disappointed at the time and I did not take the job offer. I wasn’t that shocked a few months later when the company went bankrupt. 3) The right reasons to take a job: personality check. A while back I was asked to serve as a job reference for a coworker. I agreed, and after some weeks I got a phone call from the company where my colleague was applying for a job. The conversation started with the manager’s question about my colleague’s personality and about their social skills. (You can probably guess what my internal reaction was… J ) So, after 30 minutes of pouring common sense into the interviewer’s head, we finally agreed on the fact that a shy or quiet personality has nothing to do with work skills and knowledge. Some years down the road my former colleague is taking the manager’s position as the manager is demoted to a different department. Reference: Feodor Georgiev, Pinal Dave (http://blog.SQLAuthority.com) Filed under: PostADay, Readers Contribution, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

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  • CodePlex Daily Summary for Friday, May 18, 2012

    CodePlex Daily Summary for Friday, May 18, 2012Popular ReleasesMSP Toolkit: MSP Toolkit 1.5.18: Func StringToTextBlock renamed to StringToTextBlockWithTransform Func UriToImage renamed to UriToImageWithTransform GenerateTile (message overload). Removed imageFormat parameter GenerateTile (message overload). Margins and behavior updated GenerateTile (message overload). New sample image Experimental GenerateGraphOnTile method for plotting graphs with tendencies Sample for the GenerateGraphOnTile method HTMLViewer addedAvalonDock: AvalonDock 2.0.0795: Welcome to the Beta release of AvalonDock 2.0 After 4 months of hard work I'm ready to upload the beta version of AvalonDock 2.0. This new version boosts a lot of new features and now is stable enough to be deployed in production scenarios. For this reason I encourage everyone is using AD 1.3 or earlier to upgrade soon to this new version. The final version is scheduled for the end of June. What is included in Beta: 1) Stability! thanks to all users contribution I’ve corrected a lot of issues...myCollections: Version 2.1.0.0: New in this version : Improved UI New Metro Skin Improved Performance Added Proxy Settings New Music and Books Artist detail Lot of Bug FixingfastJSON: v1.9.8: v1.9.8 - added DeepCopy(obj) and DeepCopy<T>(obj) - refactored code to JSONParameters and removed the JSON overloads - added support to serialize anonymous types (deserialize is not possible at the moment) - bug fix $types output with non object rootPoshPAIG: PoshPAIG 2.0: Bug Fixes Fixed issue where reboot would reboot all systems regardless of what systems were selected Reporting bug fixes Features Completely new UI design Added Services query to show non-running services set to Automatic Keyboard shortcuts Must select a system in order to run an action against it Options menu to set some basic settings such as max jobs, mas reboot jobs and location to save report files More reporting options via combo boxAspxCommerce: AspxCommerce1.1: AspxCommerce - 'Flexible and easy eCommerce platform' offers a complete e-Commerce solution that allows you to build and run your fully functional online store in minutes. You can create your storefront; manage the products through categories and subcategories, accept payments through credit cards and ship the ordered products to the customers. We have everything set up for you, so that you can only focus on building your own online store. Note: To login as a superuser, the username and pass...SiteMap Editor for Microsoft Dynamics CRM 2011: SiteMap Editor (1.1.1616.403): BUG FIX Hide save button when Titles or Descriptions element is selectedMapWindow 6 Desktop GIS: MapWindow 6.1.2: Looking for a .Net GIS Map Application?MapWindow 6 Desktop GIS is an open source desktop GIS for Microsoft Windows that is built upon the DotSpatial Library. This release requires .Net 4 (Client Profile). Are you a software developer?Instead of downloading MapWindow for development purposes, get started with with the DotSpatial template. The extensions you create from the template can be loaded in MapWindow.DotSpatial: DotSpatial 1.2: This is a Minor Release. See the changes in the issue tracker. Minimal -- includes DotSpatial core and essential extensions Extended -- includes debugging symbols and additional extensions Tutorials are available. Just want to run the software? End user (non-programmer) version available branded as MapWindow Want to add your own feature? Develop a plugin, using the template and contribute to the extension feed (you can also write extensions that you distribute in other ways). Components ...Mugen Injection: Mugen Injection 2.2.1 (WinRT supported): Added ManagedScopeLifecycle. Increase performance. Added support for resolve 'params'.51Degrees.mobi - Mobile Device Detection and Redirection: 2.1.4.9: One Click Install from NuGet Data ChangesIncludes 42 new browser properties in both the Lite and Premium data sets. Premium Data includes many new devices including Nokia Lumia 900, BlackBerry 9220 and HTC One, the Samsung Galaxy Tab 2 range and Samsung Galaxy S III. Lite data includes devices released in January 2012. Changes to Version 2.1.4.91. Added Microsoft.Web.Infrastructure.DynamicModuleHelper back into Activator.cs to ensure redirection works when .NET 4 PreApplicationStart use...Microsoft Ajax Minifier: Microsoft Ajax Minifier 4.52: Make preprocessor comment-statements nestable; add the ///#IFNDEF statement. (Discussion #355785) Don't throw an error for old-school JScript event handlers, and don't rename them if they aren't global functions.DotNetNuke® Events: 06.00.00: This is a serious release of Events. DNN 6 form pattern - We have take the full route towards DNN6: most notably the incorporation of the DNN6 form pattern with streamlined UX/UI. We have also tried to change all formatting to a div based structure. A daunting task, since the Events module contains a lot of forms. Roger has done a splendid job by going through all the forms in great detail, replacing all table style layouts into the new DNN6 div class="dnnForm XXX" type of layout with chang...LogicCircuit: LogicCircuit 2.12.5.15: Logic Circuit - is educational software for designing and simulating logic circuits. Intuitive graphical user interface, allows you to create unrestricted circuit hierarchy with multi bit buses, debug circuits behavior with oscilloscope, and navigate running circuits hierarchy. Changes of this versionThis release is fixing one but nasty bug. Two functions XOR and XNOR when used with 3 or more inputs were incorrectly evaluating their results. If you have a circuit that is using these functions...SharpCompress - a fully native C# library for RAR, 7Zip, Zip, Tar, GZip, BZip2: SharpCompress 0.8.1: Two fixes: Rar Decompression bug fixed. Error only occurred on some files Rar Decompression will throw an exception when another volume isn't found but one is expected.LINQ to Twitter: LINQ to Twitter Beta v2.0.25: Supports .NET 3.5, .NET 4.0, Silverlight 4.0, Windows Phone 7.1, Client Profile, and Windows 8. 100% Twitter API coverage. Also available via NuGet! Follow @JoeMayo.BlogEngine.NET: BlogEngine.NET 2.6: Get DotNetBlogEngine for 3 Months Free! Click Here for More Info BlogEngine.NET Hosting - 3 months free! Cheap ASP.NET Hosting - $4.95/Month - Click Here!! Click Here for More Info Cheap ASP.NET Hosting - $4.95/Month - Click Here! If you want to set up and start using BlogEngine.NET right away, you should download the Web project. If you want to extend or modify BlogEngine.NET, you should download the source code. If you are upgrading from a previous version of BlogEngine.NET, please take...BlackJumboDog: Ver5.6.2: 2012.05.07 Ver5.6.2 (1) Web???????、????????·????????? (2) Web???????、?????????? COMSPEC PATHEXT WINDIR SERVERADDR SERVERPORT DOCUMENTROOT SERVERADMIN REMOTE_PORT HTTPACCEPTCHRSET HTTPACCEPTLANGUAGE HTTPACCEPTEXCODINGMedia Companion: Media Companion 3.502b: It has been a slow week, but this release addresses a couple of recent bugs: Movies Multi-part Movies - Existing .nfo files that differed in name from the first part, were missed and scraped again. Trailers - MC attempted to scrape info for existing trailers. TV Shows Show Scraping - shows available only in the non-default language would not show up in the main browser. The correct language can now be selected using the TV Show Selector for a single show. General Will no longer prompt for ...NewLife XCode ??????: XCode v8.5.2012.0508、XCoder v4.7.2012.0320: X????: 1,????For .Net 4.0?? XCoder????: 1,???????,????X????,?????? XCode????: 1,Insert/Update/Delete???????????????,???SQL???? 2,IEntityOperate?????? 3,????????IEntityTree 4,????????????????? 5,?????????? 6,??????????????New Projects2atgroup: 2atgroupApplication for sharing work with client: School Butchelor's Thesis project. System for sharing work with client.arth: project1C++ AMP LAPACK Library: Project Description C++ AMP LAPACK Library is a library of linear algebra subroutines that C++ AMP developers can freely use in their own projects. Note that this project builds upon and is dependent upon the C++ AMP BLAS library. Prerequisite Understanding C++ AMP is an open specification, with an implementation from Microsoft in Visual Studio 11, currently in Beta. There are many C++ AMP samples for you to get started. This codeplex project, is about additional library support for C++ ...CDX Lib: CDX Lib is a set of helper classes and utilities to aid game developers building XNA games on the Windows Phone platoform. It includes core XNA features along with services to tie into Mogade and Farseer libraries.CodeLib: codeContinuumSL: This project is a Silverlight 5 port of one of my other Codeplex projects called Continuum. The project is designed to manage personal finances via a means of a simulation-like environment. Changes can be made which immediately get reflected in graphs projecting its effects over whatever timeframe you choose.DjAmolWap Auto Index (Advance Download Portal Site Desiner): Create Database Mysql Or Another Software for php Extract All File In YOur Cpanel/PHP account after Open Your Site extract Link http://www.mydomain.com/install.php After Enter Your Database details And Submit...... Done............... Upload All files "files" folder ::::::::::::::::::::::::::::::::Login Admin Panel:::::::::::::::::::: http://mydomain.com/cp/ With Password after click ON "Full update database" Check Your Site all files added :::::::::::::::::::::::::::::::...HMS - Hospital Management System: D? án là m?t s?n ph?m có tính ch?t d?t phá trong công ngh? m?i, Bao g?m c? s? d?ng m?ng Neural vào khám b?nh trong t?ng b?nh vi?nHomeAutomation: HomeAutomationInteractive Gravitational Simulator: The Interactive Gravitational Simulator (IGS) represents an effort to merge high performance, code readability, and interactive visualization of gravitational n-body simulations into one project. This software framework was developed by Mike Bantegui as part of a honors thesis at Hofstra University. It is meant to be a freely available tool for educational and scientific use. Some applications may include: - Real time visualization of stellar dynamics - Accurate and high performance s...JFrameWeb: JFrameWebLMKJ: For DWAD AssignmentMISNPong: Projet de découverte du C# et de l'IDE Visual Studio 2010. Nous allons appliquer les connaissances acquises à un jeu de type PongMvcPages: MvcPages combines the simplicity of ASP.NET Web Pages with the power of ASP.NET MVC. Use model binding, model validation, strongly-typed HTML helpers, editor and display templates, etc. directly from your Razor pages, no need for routes or controllers.Natteravnen Vagtsystem Eksamensprojekt: A shift-system made for a local bar.Orchard AppFabric: App Fabric Module for Orchard CMSPalmetto Consulting: Repository for Palmetto Consulting projectsPOBR: Rozpoznawanie obrazów ze ja cie przepraszam.Pong Application C#: Pong ApplicationQuickSummary: Plugin for Microsoft Outlook that parses text and highlight the number of lines that the user selects as being the most important. For example, the user defines 3 important sentences. The first one appears highlighted in green, the second one highlighted in yellow, the third in red. In another instance the user defines 4 most important sentences, it outputs in green, blue, yellow, and red.Sharif_OOD_Project: This project is for OOD course in Department of Computer Engineering in Sharif University Of Technology.specunit - BDD-style extension for unit testing frameworks: A simple BDD-style extension for unit testing frameworks.SQL Database to Script Generator: Generate individual script for procedures, functions, triggers, views etc from SQL Server DatabaseStockato API: Stockato Web Services (SWS) is a collection of remote computing services, which apply Stockato’s signal classification technology to mutual funds, exchange-traded-funds, and stocks. Stockato or its customers can build client-side applications based on the web services such as a similarity-based search engine or a similarity-based portfolio managing system. The web services can also be used to embed the technology in existing products such as finance screeners or in a web page that contains an...tango: TangoToken Title Orchard module: Adds token configuration capability to the TitlePart in Orchard.Tutor: Tutor FinderWorld Fly: Web Sitewww.coursera.org: https://class.coursera.org/algo/forum/thread?thread_id=961 Sharing code for programming assignments

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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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