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  • does such a c++ tool exist? [I dont know what to call it]

    - by VSC
    Hello, I am going through the process of trying to figure out how a library of code works. I would like some sort of tool that would analyze the program that I run off of the library and tells me what functions are called in what order by each thread. Does such a tool exist? What google terms would I use to find such a program? Note: Using VS2008/Win7/C++

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  • How can I dynamically resize the jQuery Colorbox plugin?

    - by James Skidmore
    The AJAX content loaded in a Colorbox has some JavaScript included that resizes things within the content. Colorbox determines its sizing based on the sizes before all of the AJAX happens. How can I make the Colorbox resize after the content has been loaded? Here is a link where someone said that you can call colorbox() again after it's been loaded, but I can't figure out how to do that: http://groups.google.com/group/colorbox/browse_thread/thread/535d21c69e9006b0

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  • Tell me what's wrong [closed]

    - by steve care
    public class Sample { public static void main (String[]a){ int[] x; x = new int[10]; int i;' int n=0; for (i=0;i<=10;i++){ n++; x[i]=n; System.out.print(x[i] + " "); } } } the problem is I got an error of "Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: 10"

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  • SQLAuthority News – Wireless Router Security and Attached Devices – Complex Password

    - by pinaldave
    In the last four days (April 21-24), I have received calls from friends who told me that they have got strange emails from me. To my surprise, I did not send them any emails. I was not worried until my wife complained that she was not able to find one of the very important folders containing our daughter’s photo that is located in our shared drive. This was alarming in my par, so I started a search around my computer’s folders. Again, please note that I am by no means a security expert. I checked my entire computer with virus and spyware, and strangely, there I found nothing. I tried to think what can cause this happening. I suddenly realized that there was a power outage in my area for about two hours during the days I have mentioned. Back then, my wireless router needed to be reset, and so I did. I had set up my WPA-PSK [TKIP] + WPA2-PSK [AES] very well. My key was very simple ( ‘SQLAuthority1′), and I never thought of changing it. (It is now replaced with a very complex one). While checking the Attached Devices, I found out that there was another very strange computer name and IP attached to my network. And so as soon as I found out that there is strange device attached to my computer, I shutdown my local network. Afterwards, I reconfigured my wireless router with a more complex security key. Since I created the complex password, I noticed that the user is no more connecting to my machine. Subsequently, I figured out that I can also set up Access Control List. I added my networked computer to that list as well. When I tried to connect from an external laptop which was not in the list but with a valid security key, I was not able to access the network, neither able to connect to it. I wasn’t also able to connect using a remote desktop, so I think it was good. If you have received any nasty emails from me (from my gmail account) during the afore-mentioned days, I want to apologize. I am already paying for my negligence of not putting a complex password; by way of losing the important photos of my daughter. I have already checked with my client, whose password I saved in SSMS, so there was no issue at all. In fact, I have decided to never leave any saved password of production server in my SSMS. Here is the tip SQL SERVER – Clear Drop Down List of Recent Connection From SQL Server Management Studio to clean them. I think after doing all this, I am feeling safe right now. However, I believe that safety is an illusion of many times. I need your help and advice if there is anymore I can do to stop unauthorized access. I am seeking advice and help through your comments. Reference : Pinal Dave (http://www.SQLAuthority.com) Filed under: SQL, SQL Authority, SQL Query, SQL Security, SQL Server, SQL Tips and Tricks, SQLAuthority News, T SQL, Technology

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  • Chalk Talk with John: Business Value of Identity and Access Management

    - by John Brunswick
    Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin-top:0in; mso-para-margin-right:0in; mso-para-margin-bottom:10.0pt; mso-para-margin-left:0in; line-height:115%; mso-pagination:widow-orphan; font-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;} Conveying the business value of Identity and Access Management to non technologists can potentially be challenging, especially considering the breadth capability supplied by these technologies. In this episode of Chalk Talk with John, Bob at Codeaway Valley asks Jim from Middleware Fields how they are able to manage access to buildings and facilities throughout their community. Bob and his team struggle to keep up with the needs of their community members, while ensuring the community’s safety. Jim shares his creative solution to simplifying the management of access throughout their community in Middleware Fields. Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin-top:0in; mso-para-margin-right:0in; mso-para-margin-bottom:10.0pt; mso-para-margin-left:0in; line-height:115%; mso-pagination:widow-orphan; font-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 me: Hi, I am John Brunswick, an Oracle Enterprise Architect. As an Oracle Enterprise Architect, I focus on the alignment of technical capabilities in support of business vision and objectives, as well as the overall business value of technology.  Before coming to Oracle, I was a Practice Manager within BEA System's Business Interaction Division consulting organization, orchestrating enterprise systems in support of line of business goals. Follow me on Twitter and visit my site for Oracle Fusion Middleware related tips.

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  • MySQL – Video Course – MySQL Backup and Recovery Fundamentals

    - by Pinal Dave
    Data is the one of the most crucial things for any organization and keeping data safe is the biggest challenge for any DBA. This is true for any organizations. Think about the scenario that you have a database which is extremely important and suddenly you accidently delete the most important table from that database. I am sure this is a very difficult time. In times like this people often get stressed or just make even second mistake. In my career of 10 years I have done often this mistake and often got stressed out due to un-availability of the database backup. In the SQL Server field, we have plenty of the help on this subject, but in MySQL domain there is not enough help. For the same reason I have build this MySQL course on Backup and Recovery. Course Outline Data is very important to any application and business. It is very important that every business plan for data safety. Database backup strategies are often discussed after the disaster has already happened. In this introductory course we will explore a few of the basic backup strategies every business should implement for data safely. We will explore how we can recover our server quickly after any unfriendly incident to our MySQL database. Click to View Course Here are various important aspects which we have discussed in this course. How to take backup of single database? How to take backup of multiple database? How to backup various database objects? How to restore a single database? How to restore multiple databases? How to use MySQL Workbench for Backup and Restore? How to restore Point in Time for any database? What is the best time to backup? How to copy database from one server to another server? All of the above concepts and many more subjects are covered in the MySQL Backup and Recovery Fundamentals course. It is available on Pluralsight. Scenarios As learning about Backup and Recovery can be very much boring, I decided to create two fictitious characters and demonstrate the entire course based on their conversation. The story is about Mike and Rahul. Mike is Sr. Database administrator in USA and Rahul is an intern in India. Rahul aspires to become a senior database administrator and this is a story about his challenges and how he overcomes those challenges. I had a great time to build this course and I have got very good feedback on this course. I encourage all of you to attempt to learn MySQL Backup and Recovery Fundamental course with this innovative effort. It will be very valuable to know your feedback. You will need a valid Pluralsight subscription to watch this course. Reference: Pinal Dave (http://blog.sqlauthority.com)Filed under: MySQL, PostADay, SQL, SQL Authority, SQL Backup and Restore, SQL Query, SQL Tips and Tricks, T SQL

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  • WebCenter Marketing and Upcoming Events

    - by rituchhibber
    Events: Events: Date Event Name Location/Country October 30, 2012 ResCare Solves Content Lifecycle Challenges with Oracle WebCenter Webcast November 1, 2012 Paper Burying Your HR Processes? Dig Your Way Out With Oracle WebCenter! Webcast November 15, 2012 Social Business Thought Leader Webcast: Three Ways to Fix Your Broken Organization, featuring Christian Finn Webcast Marketing: Marketing: WebCenter Sites Sales eVite:Embrace the Base: Create an Exceptional Online Customer Experience with Oracle WebCenter Sites Directs recipients to the Connected Customer Experience Resource Center to see the latest demos, analyst reports, and customer webcasts promoting WebCenter Sites. For more information Click  here. WebCenter Social Business Thought Leaders Series: Digital Darwinism: How Brands Can Survive the Rapid Evolution of Society and TechnologyBrian Solis, Altimeter Group digital analyst and futuristDecember 13, 2012 10am PDTRegistration available soon, find other content from this speaker here. Webcast: WebCenter Sites for Applications: Disconnected Online Customer Experience? Connect it with Oracle WebCenter November 8, 2012  eVite | Registration Page WebCenter in Action Customer & Partner webcast series: Started earlier in FY13, a new webcast series featuring WebCenter customer deployments that are executed by a partner.The next webcast in the series will be November 14th:Los Angeles Department of Building & Safety Lowers Customer Service Costs with Oracle WebCenter Click here to learn more. OnDemand Webcast: ResCare Solves Content Lifecycle Challenges with Oracle WebCenterComplex documents must be created, assembled, reviewed, and tracked. To avoid fragmented, chaotic information processes, organizations must adopt an integrated set of strategies, standards, best practices, and technologies for managing information. Attend this webcast to learn how Oracle WebCenter has allowed ResCare to: solve content lifecycle challenges, reduce compliance and business risks and increase adoption of intranet as primary business communication tool. On-Demand Assets Date Event Name Location/Country On Demand Avoid Social Media Fatigue - Learn the 9 C’s of Customer Engagement, featuring Ray Wang, Principal Analyst and CEO, Constellation Research Webcast On Demand WebCenter in Action Series: Hitachi Data Systems Improves Global Web Experience with Oracle WebCenter, presented by Hitachi Data Systems and Lingotek. Webcast On Demand Managing Social Relationships for the Enterprise, featuring Jeremiah Owyang, Industry Analyst, Altimeter Group and Reggie Bradford, Vice President, Oracle Webcast On Demand Oracle’s Vision for the Social-Enabled Enterprise, presented by Mark Hurd, Thomas Kurian and Reggie Bradford Webcast On Demand WebCenter in Action Series: Qualcomm Provides a Seamless Experience for Customers with Oracle WebCenter, presented by Qualcomm and Keste. Webcast On Demand Social Business Thought Leaders Series: 6 Counterintuitive Best Practices for Social Collaboration Adoption, featuring John Brunswick, Oracle. Webcast On Demand Oracle WebCenter Connects Patients and Researchers in Cancer Control Mission, presented by Canadian Partnership Against Cancer and App-Systems Webcast On Demand Oracle WebCenter: Modernize, Aggregate and Extend Your Portals Webcast On Demand Top 10 Technology Trends Driving Business Innovation, featuring Andy Mulholland, CTO, Capgemini Webcast On Demand Ancestry.com Helps Families Uncover History with Oracl e WebCenter Webcast On Demand Organic Business Networks: Doing Business in a Hyper-Connected World, featuring Mike Fauscette, GVP, IDC Webcast On Demand Social Business and Innovation, featuring John Mancini, President, AIIM Webcast On Demand Do More with Oracle WebCenter: Expand Beyond Web Experience Management Webcast On Demand Race Against the Machine, featuring Andrew McAfee, author and principal scientist at MIT Webcast On Demand Introducing Oracle WebCenter Sites 11gR1: Transforming the Online Experience Webcast On Demand Mobile is the New Face of Engagement, featuring Ted Schadler, Vice President & Principal Analyst, Forrester Research Inc Webcast Analyst Report: IDC Research: Oracle Debuts New Release of Oracle WebCenter Sites.

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  • Low level programming - what's in it for me?

    - by back2dos
    For years I have considered digging into what I consider "low level" languages. For me this means C and assembly. However I had no time for this yet, nor has it EVER been neccessary. Now because I don't see any neccessity arising, I feel like I should either just schedule some point in time when I will study the subject or drop the plan forever. My Position For the past 4 years I have focused on "web technologies", which may change, and I am an application developer, which is unlikely to change. In application development, I think usability is the most important thing. You write applications to be "consumed" by users. The more usable those applications are, the more value you have produced. In order to achieve good usability, I believe the following things are viable Good design: Well-thought-out features accessible through a well-thought-out user interface. Correctness: The best design isn't worth anything, if not implemented correctly. Flexibility: An application A should constantly evolve, so that its users need not switch to a different application B, that has new features, that A could implement. Applications addressing the same problem should not differ in features but in philosophy. Performance: Performance contributes to a good user experience. An application is ideally always responsive and performs its tasks reasonably fast (based on their frequency). The value of performance optimization beyond the point where it is noticeable by the user is questionable. I think low level programming is not going to help me with that, except for performance. But writing a whole app in a low level language for the sake of performance is premature optimization to me. My Question What could low level programming teach me, what other languages wouldn't teach me? Am I missing something, or is it just a skill, that is of very little use for application development? Please understand, that I am not questioning the value of C and assembly. It's just that in my everyday life, I am quite happy that all the intricacies of that world are abstracted away and managed for me (mostly by layers written in C/C++ and assembly themselves). I just don't see any concepts, that could be new to me, only details I would have to stuff my head with. So what's in it for me? My Conclusion Thanks to everyone for their answers. I must say, nobody really surprised me, but at least now I am quite sure I will drop this area of interest until any need for it arises. To my understanding, writing assembly these days for processors as they are in use in today's CPUs is not only unneccesarily complicated, but risks to result in poorer runtime performance than a C counterpart. Optimizing by hand is nearly impossible due to OOE, while you do not get all kinds of optimizations a compiler can do automatically. Also, the code is either portable, because it uses a small subset of available commands, or it is optimized, but then it probably works on one architecture only. Writing C is not nearly as neccessary anymore, as it was in the past. If I were to write an application in C, I would just as much use tested and established libraries and frameworks, that would spare me implementing string copy routines, sorting algorithms and other kind of stuff serving as exercise at university. My own code would execute faster at the cost of type safety. I am neither keen on reeinventing the wheel in the course of normal app development, nor trying to debug by looking at core dumps :D I am currently experimenting with languages and interpreters, so if there is anything I would like to publish, I suppose I'd port a working concept to C, although C++ might just as well do the trick. Again, thanks to everyone for your answers and your insight.

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  • When is your interview?

    - by Rob Farley
    Sometimes it’s tough to evaluate someone – to figure out if you think they’d be worth hiring. These days, since starting LobsterPot Solutions, I have my share of interviews, on both sides of the desk. Sometimes I’m checking out potential staff members; sometimes I’m persuading someone else to get us on board for a project. Regardless of who is on which side of the desk, we’re both checking each other out. The world is not how it was some years ago. I’m pretty sure that every time I walk into a room for an interview, I’ve searched for them online, and they’ve searched for me. I suspect they usually have the easier time finding me, although there are obviously other Rob Farleys in the world. They may have even checked out some of my presentations from conferences, read my blog posts, maybe even heard me tell jokes or sing. I know some people need me to explain who I am, but for the most part, I think they’ve done plenty of research long before I’ve walked in the room. I remember when this was different (as it could be for you still). I remember a time when I dealt with recruitment agents, looking for work. I remember sitting in rooms having been giving a test designed to find out if I knew my stuff or not, and then being pulled into interviews with managers who had to find out if I could communicate effectively. I’d need to explain who I was, what kind of person I was, what my value-system involved, and so on. I’m sure you understand what I’m getting at. (Oh, and in case you hadn’t realised, it’s a T-SQL Tuesday post, this month about interviews.) At TechEd Australia some years ago (either 2009 or 2010 – I forget which), I remember hearing a comment made during the ‘locknote’, the closing session. The presenter described a conversation he’d heard between two girls, discussing a guy that one of them had just started dating. The other girl expressed horror at the fact that her friend had met this guy in person, rather than through an online dating agency. The presenter pointed out that people realise that there’s a certain level of safety provided through the checks that those sites do. I’m not sure I completely trust this, but I’m sure it’s true for people’s technical profiles. If I interview someone, I hope they have a profile. I hope I can look at what they already know. I hope I can get samples of their work, and see how they communicate. I hope I can get a feel for their sense of humour. I hope I already know exactly what kind of person they are – their value system, their beliefs, their passions. Even their grammar. I can work out if the person is a good risk or not from who they are online. If they don’t have an online presence, then I don’t have this information, and the risk is higher. So if you’re interviewing with me, your interview started long before the conversation. I hope it started before I’d ever heard of you. I know the interview in which I’m being assessed started before I even knew there was a product called SQL Server. It’s reflected in what I write. It’s in the way I present. I have spent my life becoming me – so let’s talk! @rob_farley

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  • What Counts For a DBA: Imagination

    - by drsql
    "Imagination…One little spark, of inspiration… is at the heart, of all creation." – From the song "One Little Spark", by the Sherman Brothers I have a confession to make. Despite my great enthusiasm for databases and programming, it occurs to me that every database system I've ever worked on has been, in terms of its inputs and outputs, downright dull. Most have been glorified e-spreadsheets, many replacing manual systems built on actual spreadsheets. I've created a lot of database-driven software whose main job was to "count stuff"; phone calls, web visitors, payments, donations, pieces of equipment and so on. Sometimes, instead of counting stuff, the database recorded values from other stuff, such as data from sensors or networking devices. Yee hah! So how do we, as DBAs, maintain high standards and high spirits when we realize that so much of our work would fail to raise the pulse of even the most easily excitable soul? The answer lies in our imagination. To understand what I mean by this, consider a role that, in terms of its output, offers an extreme counterpoint to that of the DBA: the Disney Imagineer. Their job is to design Disney's Theme Parks, of which I'm a huge fan. To me this has always seemed like a fascinating and exciting job. What must an Imagineer do, every day, to inspire the feats of creativity that are so clearly evident in those spectacular rides and shows? Here, if ever there was one, is a role where "dull moments" must be rare indeed, surely? I wanted to find out, and so parted with a considerable sum of money for my wife and I to have lunch with one; I reasoned that if I found one small way to apply their secrets to my own career, it would be money well spent. Early in the conversation with our Imagineer (Cindy Cote), the job did indeed sound magical. However, as talk turned to management meetings, budget-wrangling and insane deadlines, I came to the strange realization that, in fact, her job was a lot more like mine than I would ever have guessed. Much like databases, all those spectacular Disney rides bring with them a vast array of complex plumbing, lighting, safety features, and all manner of other "boring bits", kept well out of sight of the end user, but vital for creating the desired experience; and, of course, it is these "boring bits" that take up much of the Imagineer's time. Naturally, there is still a vital part of their job that is spent testing out new ideas, putting themselves in the place of a park visitor, from a 9-year-old boy to a 90-year-old grandmother, and trying to imagine what experiences they'd like to have. It is these small, but vital, sparks of imagination and creativity that have the biggest impact. The real feat of a successful Imagineer is clearly to never to lose sight of this fact, in among all the rote tasks. It is the same for a DBA. Not matter how seemingly dull is the task at hand, try to put yourself in the shoes of the end user, and imagine how your input will affect the experience he or she will have with the database you're building, and how that may affect the world beyond the bits stored in your database. Then, despite the inevitable rush to be "done", find time to go the extra mile and hone the design so that it delivers something as close to that imagined experience as you can get. OK, our output still can't and won't reach the same spectacular heights as the "Journey into The Imagination" ride at EPCOT Theme Park in Orlando, where I first heard "One Little Spark". However, our imaginative sparks and efforts can, and will, make a difference to the user who now feels slightly more at home with a database application, or to the manager holding a report presented with enough clarity to drive an interesting decision or two. They are small victories, but worth having, and appreciated, or at least that's how I imagine it.

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  • 5.1 surround sound on Acer Aspire 5738ZG with Ubuntu 11.10

    - by kbargais_LV
    I got a problem with sound. I tried everything but no results. :( I got 3 sound ports. my daemon: # This file is part of PulseAudio. # # PulseAudio is free software; you can redistribute it and/or modify # it under the terms of the GNU Lesser General Public License as published by # the Free Software Foundation; either version 2 of the License, or # (at your option) any later version. # # PulseAudio is distributed in the hope that it will be useful, but # WITHOUT ANY WARRANTY; without even the implied warranty of # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU # General Public License for more details. # # You should have received a copy of the GNU Lesser General Public License # along with PulseAudio; if not, write to the Free Software # Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 # USA. ## Configuration file for the PulseAudio daemon. See pulse-daemon.conf(5) for ## more information. Default values are commented out. Use either ; or # for ## commenting. ; daemonize = no ; fail = yes ; allow-module-loading = yes ; allow-exit = yes ; use-pid-file = yes ; system-instance = no ; local-server-type = user ; enable-shm = yes ; shm-size-bytes = 0 # setting this 0 will use the system-default, usually 64 MiB ; lock-memory = no ; cpu-limit = no ; high-priority = yes ; nice-level = -11 ; realtime-scheduling = yes ; realtime-priority = 5 ; exit-idle-time = 20 ; scache-idle-time = 20 ; dl-search-path = (depends on architecture) ; load-default-script-file = yes ; default-script-file = /etc/pulse/default.pa ; log-target = auto ; log-level = notice ; log-meta = no ; log-time = no ; log-backtrace = 0 resample-method = speex-float-1 ; enable-remixing = yes ; enable-lfe-remixing = no flat-volumes = no ; rlimit-fsize = -1 ; rlimit-data = -1 ; rlimit-stack = -1 ; rlimit-core = -1 ; rlimit-as = -1 ; rlimit-rss = -1 ; rlimit-nproc = -1 ; rlimit-nofile = 256 ; rlimit-memlock = -1 ; rlimit-locks = -1 ; rlimit-sigpending = -1 ; rlimit-msgqueue = -1 ; rlimit-nice = 31 ; rlimit-rtprio = 9 ; rlimit-rttime = 1000000 ; default-sample-format = s16le ; default-sample-rate = 44100 ; default-sample-channels = 6 ; default-channel-map = front-left,front-right default-fragments = 8 default-fragment-size-msec = 10 ; enable-deferred-volume = yes ; deferred-volume-safety-margin-usec = 8000 ; deferred-volume-extra-delay-usec = 0

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  • Nest reinvents smoke detectors. Introduces smart and talking smoke detector that keeps quite when you wave

    - by Gopinath
    Nest, the leading smart thermostat maker has introduced a smart home device today- Nest Protect, a smart, talking smoke & carbon monoxide detector that can quite when you wave your hand. Less annoyances and more intelligence Smoke detectors are around for hundreds of years and playing a major role in providing safety from fire accidents at home. But the technology of these devices is stale and there is no major innovation for the past several years. With the introduction of Nest Protect, the landscape of smoke detectors is all set to change just like how Nest thermostat redefined the industry two years ago. Nest Protect is internet enabled and equipped with motion- and smoke-detection sensors so that when it starts beeping you can silence it by waving hand instead of doing circus feats to turn off the alarm. Everyone who cooks in a home equipped with smoke detector would know how annoying it is to turn off sensitive smoke detectors that goes off control quite often. Apart from addressing the annoyances of regular smoke detector, Nest Protect has talking capabilities. It can alert users with clear & actionable instructions when it detects a danger. Instead of harsh beeps it actually speak to you so you know what is happening. It will tell you what smoke it has detected and in which room it is detected. Multiple Nest Protects installed in a home can communicate with each other. Lets say that there is a smoke in bed room, the Nest Protect installed in bed room shares this information to all Nest Protects installed in the home and your kitchen device can alert you that there is a smoke in bed room. There is an App for that The internet enabled Nest Protect has an app to view its status and various alerts. When the Protect is running on low battery it alerts you to replace them soon. If there is a smoke at home and you are away, you will get message alerts. The app works on all major smartphones as well as tablets. Auto shuts down gas furnaces/heaters on smoke Apart from forming a network with other Nest Protect devices installed at home, they can also communicate with Nest Thermostat if it is installed. When carbon monoxide is detected it can shut off your gas furnace automatically. Also with the help of motion detectors it improves Nest Thermostat’s auto-away functionality. It looks elegant and costs a lot more than a regular smoke detector Just like Nest Thermostat, Nest Protect is elegant and adorable. You just fall in love with it the moment you see it. It’s another master piece from the designer of Apple’s iPod. All is good with the Nest Protect, except the price!! It costs whooping $129, which is almost 4 times more expensive than the best selling conventional thermostats available at $30. A single bed room apartment would require at least 3 detectors and it costs around $390 to install Nest Protects compared to 90$ required for conventional smoke detectors. Though Nest Thermostat is an expensive one compared to conventional thermostats, it offered great savings through its intelligent auto-away feature. Users were able to able to see returns on their investments. If Nest Protect also can provide good return on investment the it will be very successful.

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  • Impressions on jQuery Mobile

    - by Jeff
    For the uninitiated, jQuery Mobile is a sweet little client framework that turns regular HTML into something more touch and mobile friendly. It results in a user interface that has bigger targets, rounded corners and simple skinning capability. When it was announced that ASP.NET MVC 4 would include support for a mobile-sensitive view engine, offering up alternate views for clients that fit the mobile profile, I was all over that. Combined with jQuery Mobile, it brought a chance to do some experimentation. I blitzed through the views in POP Forums and converted them all to mobile views. (For the curious, this first pass can be found here on CodePlex, while a more recent update that uses RC 2 of jQuery Mobile v1.1.0 is running on the demo site.) Initially, it was kind of a mixed bag. The jQuery demo site also acts as documentation, and it’s reasonably complete. I had no problem getting up a lot of basic views quickly, splitting out portions of some pages as subpages that they quickly load in. The default behavior in the older version was to slide the pages in, which looked a little weird when you were using a back button. They’ve since changed it so the default transition is a fade in/out. Because you’re dealing with Web pages, I don’t think anyone is really under the illusion that you’re not using a native app, so I don’t know that this matters. I’ve tested extensively on iPad and Windows Phone, and to be honest, I’ve encountered a lot of issues. On Windows Phone, there is some kind of inconsistency that prevents the proper respect for the viewport settings. The text background on text fields (for labeling) doesn’t work, either. On both platforms, certain in-DOM page navigation links work only half of the time. Is this an issue of user error? Probably, but that’s what’s frustrating about it. Most of what you accomplish with this framework involves decorating various elements with CSS classes. There isn’t any design-time safety to speak of to make sure that you’re doing it right. I think the issues can be overcome, but there are some trade-offs to consider. The first is download size. Yes, the scripts and CSS do get cached, but that first hit will cost nearly 40k for the mobile parts. That’s still a lot when you’re on some crappy AT&T EDGE network, or hotel Wi-Fi. Then you have to ask yourself, do you really want your app to look like it’s native to iOS? I’m not saying that’s a bad thing, because consistent UI is good, but you will end up feeling a whole lot of sameness, and maybe you don’t want that. I did some experimentation to try and Metro-ize the jQuery Mobile theme, and it’s kind of a mixed bag. It mostly works, but you get some weirdness on badges and with buttons that I’m not crazy about. It probably just means you need to keep tweaking. At this point, I’m a little torn about whether or not I’ll use it for POP Forums or one of the sites I’m working on. The benefits are pretty strong, but figuring out where I’m doing it wrong is proving a little time consuming.

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  • Create a Remote Git Repository from an Existing XCode Repository

    - by codeWithoutFear
    Introduction Distributed version control systems (VCS’s), like Git, provide a rich set of features for managing source code.  Many development tools, including XCode, provide built-in support for various VCS’s.  These tools provide simple configuration with limited customization to get you up and running quickly while still providing the safety net of basic version control. I hate losing (and re-doing) work.  I have OCD when it comes to saving and versioning source code.  Save early, save often, and commit to the VCS often.  I also hate merging code.  Smaller and more frequent commits enable me to minimize merge time and effort as well. The work flow I prefer even for personal exploratory projects is: Make small local changes to the codebase to create an incrementally improved (and working) system. Commit these changes to the local repository.  Local repositories are quick to access, function even while offline, and provides the confidence to continue making bold changes to the system.  After all, I can easily recover to a recent working state. Repeat 1 & 2 until the codebase contains “significant” functionality and I have connectivity to the remote repository. Push the accumulated changes to the remote repository.  The smaller the change set, the less likely extensive merging will be required.  Smaller is better, IMHO. The remote repository typically has a greater degree of fault tolerance and active management dedicated to it.  This can be as simple as a network share that is backed up nightly or as complex as dedicated hardware with specialized server-side processing and significant administrative monitoring. XCode’s out-of-the-box Git integration enables steps 1 and 2 above.  Time Machine backups of the local repository add an additional degree of fault tolerance, but do not support collaboration or take advantage of managed infrastructure such as on-premises or cloud-based storage. Creating a Remote Repository These are the steps I use to enable the full workflow identified above.  For simplicity the “remote” repository is created on the local file system.  This location could easily be on a mounted network volume. Create a Test Project My project is called HelloGit and is located at /Users/Don/Dev/HelloGit.  Be sure to commit all outstanding changes.  XCode always leaves a single changed file for me after the project is created and the initial commit is submitted. Clone the Local Repository We want to clone the XCode-created Git repository to the location where the remote repository will reside.  In this case it will be /Users/Don/Dev/RemoteHelloGit. Open the Terminal application. Clone the local repository to the remote repository location: git clone /Users/Don/Dev/HelloGit /Users/Don/Dev/RemoteHelloGit Convert the Remote Repository to a Bare Repository The remote repository only needs to contain the Git database.  It does not need a checked out branch or local files. Go to the remote repository folder: cd /Users/Don/Dev/RemoteHelloGit Indicate the repository is “bare”: git config --bool core.bare true Remove files, leaving the .git folder: rm -R * Remove the “origin” remote: git remote rm origin Configure the Local Repository The local repository should reference the remote repository.  The remote name “origin” is used by convention to indicate the originating repository.  This is set automatically when a repository is cloned.  We will use the “origin” name here to reflect that relationship. Go to the local repository folder: cd /Users/Don/Dev/HelloGit Add the remote: git remote add origin /Users/Don/Dev/RemoteHelloGit Test Connectivity Any changes made to the local Git repository can be pushed to the remote repository subject to the merging rules Git enforces. Create a new local file: date > date.txt /li> Add the new file to the local index: git add date.txt Commit the change to the local repository: git commit -m "New file: date.txt" Push the change to the remote repository: git push origin master Now you can save, commit, and push/pull to your OCD hearts’ content! Code without fear! --Don

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  • The Power of Goals

    - by BuckWoody
    Every year we read blogs, articles, magazines, hear news stories and blurbs on making New Year’s Resolutions. Well, I for one don’t do that. I do something else. Each year, on January 1, my wife, daughter and I get up early - like before 6:00 A.M. - and find a breakfast place that’s open. When I used to live in Safety Harbor, Florida, that was the “Paradise Café”, which has some of the best waffles around…but I digress. We find that restaurant and have a great breakfast while everyone else is recuperating from the night before. And we bring along a worn leather book that we’ve been writing in since my daughter wasn’t even old enough to read. It’s our book of Goals. A resolution, as it is purely defined, is a decision to change, stop or start an action. It has a sense of continuance, and that’s the issue. Some people decide things like “I’m going to lose weight” or “I’m going to spend more time with my family or hobby”. But a goal is different. A goal tends to have a defined start and end point. It’s something that can be measured. So each year on January 1 we sit down with the little leather book and we make a few - and only a few - individual and family goals. Sometimes it’s to exercise three times a week at the gym, sometimes it’s to save a certain percentage of income, and sometimes it’s to give away some of our possessions or to help someone we know in a specific way. Each person is responsible for their own goals - coming up with them, and coming up with a plan to meet them. Then we write it down in the little leather book. But it doesn’t end there. Each month, we grab the little leather book and read out the goals from that year to each person with a question or two: How are you doing on your goal? And what are you doing about reaching it? Can I help? Am I helping? At the end of the year, we put a checkmark by the goals we reached, and an X by the ones we didn’t. There’s no judgment, there’s no statements, each person is just expected to handle the success or failure in their own way. We also have family goals, and those we work on together. This might seem a little “corny” to some people. “I don’t need to write goals down” they say, “I keep track in my head of the things I do all the time. That’s silly.” But let me give you a little challenge: find a book, get with your family, and write down the things you want to do by the next January 1. Each month, look at the book. You can make goals for your career, your education, your spiritual side, your family, whatever. But if you make your goals realistic, think them through, and think about how you will achieve them, you will be surprised by the power of written goals.

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  • Is there a theory for "transactional" sequences of failing and no-fail actions?

    - by Ross Bencina
    My question is about writing transaction-like functions that execute sequences of actions, some of which may fail. It is related to the general C++ principle "destructors can't throw," no-fail property, and maybe also with multi-phase transactions or exception safety. However, I'm thinking about it in language-neutral terms. My concern is with correctly designing error handling in C++ functions that must be reliable. I would like to know what the concepts below are called so that I can learn more about them. I'm sorry that I can't ask the question more directly. Since I don't know this area I have provided an example to explain my question. The question is at the end. Here goes: Consider a sequence of steps or actions executed sequentially, where actions belong to one of two classes: those that always succeed, and those that may fail. In the examples below: S stands for an action that always succeeds (called "no-fail" in some settings). F stands for an action that may fail (for example, it might fail to allocate memory or do I/O that could fail). Consider a sequences of actions (executed sequentially from left to right): S->S->S->S Since each action in the sequence above succeeds, the whole sequence succeeds. On the other hand, the following sequence may fail because the last action may fail: S->S->S->F So, claim: a sequence has the no-fail (S) property if and only if all of its actions are no-fail. Now, I'm interested in action sequences that form "atomic transactions", with "failure atomicity," i.e. where either the whole sequence completes successfully, or there is no effect. I.e. if some action fails, the earlier ones must be rolled back. This requires that any successfully executed actions prior to a failing action must always be able to be rolled back. Consider the sequence: S->S->S->F S<-S<-S In the example above, the first row is the forward path of the transaction, and the second row are inverse actions (executed from right to left) that can be used to roll back if the final top row actions fails. It seems to me that for a transaction to support failure atomicity, the following invariant must hold: Claim: To support failure atomicity (either completion or complete roll-back on failure) all actions preceding the latest failable (F) action on the forward path (marked * in the example below) must have no-fail (S) inverses. The following is an example of a sequence that supports failure atomicity: * S->F->F->F S<-S<-S Further, if we want the transaction to be able to attempt cancellation mid-way through, but still guarantee either full completion or full rollback then we need the following property: Claim: To support failure atomicity and cancellation mid-way through execution, in the face of errors in the inverse (cancellation) path, all actions following the earliest failable (F) inverse on the reverse path (marked *) must be no-fail (S). F->F->F->S->S S<-S<-F<-F * I believe that these two conditions guarantee that an abortable/cancelable transaction will never get "stuck". My questions are: What is the study and theory of these properties called? are my claims correct? and what else is there to know? UPDATE 1: Updated terminology: what I previously called "robustness" is called atomicity in the database literature. UPDATE 2: Added explicit reference to failure atomicity, which seems to be a thing.

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  • Why do I need two Instances in Windows Azure?

    - by BuckWoody
    Windows Azure as a Platform as a Service (PaaS) means that there are various components you can use in it to solve a problem: Compute “Roles” - Computers running an OS and optionally IIS - you can have more than one "Instance" of a given Role Storage - Blobs, Tables and Queues for Storage Other Services - Things like the Service Bus, Azure Connection Services, SQL Azure and Caching It’s important to understand that some of these services are Stateless and others maintain State. Stateless means (at least in this case) that a system might disappear from one physical location and appear elsewhere. You can think of this as a cashier at the front of a store. If you’re in line, a cashier might take his break, and another person might replace him. As long as the order proceeds, you as the customer aren’t really affected except for the few seconds it takes to change them out. The cashier function in this example is stateless. The Compute Role Instances in Windows Azure are Stateless. To upgrade hardware, because of a fault or many other reasons, a Compute Role's Instance might stop on one physical server, and another will pick it up. This is done through the controlling fabric that Windows Azure uses to manage the systems. It’s important to note that storage in Azure does maintain State. Your data will not simply disappear - it is maintained - in fact, it’s maintained three times in a single datacenter and all those copies are replicated to another for safety. Going back to our example, storage is similar to the cash register itself. Even though a cashier leaves, the record of your payment is maintained. So if a Compute Role Instance can disappear and re-appear, the things running on that first Instance would stop working. If you wrote your code in a Stateless way, then another Role Instance simply re-starts that transaction and keeps working, just like the other cashier in the example. But if you only have one Instance of a Role, then when the Role Instance is re-started, or when you need to upgrade your own code, you can face downtime, since there’s only one. That means you should deploy at least two of each Role Instance not only for scale to handle load, but so that the first “cashier” has someone to replace them when they disappear. It’s not just a good idea - to gain the Service Level Agreement (SLA) for our uptime in Azure it’s a requirement. We point this out right in the Management Portal when you deploy the application: (Click to enlarge) When you deploy a Role Instance you can also set the “Upgrade Domain”. Placing Roles on separate Upgrade Domains means that you have a continuous service whenever you upgrade (more on upgrades in another post) - the process looks like this for two Roles. This example covers the scenario for upgrade, so you have four roles total - One Web and one Worker running the "older" code, and one of each running the new code. In all those Roles you want at least two instances, and this example shows that you're covered for High Availability and upgrade paths: The take-away is this - always plan for forward-facing Roles to have at least two copies. For Worker Roles that do background processing, there are ways to architect around this number, but it does affect the SLA if you have only one.

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  • Openmatics Revolutionizes Fleet Management with Standards-Based Vehicle Telematics Platform

    - by Michael Snow
    Openmatics s.r.o. was founded in 2010 as a subsidiary of ZF Friedrichshafen AG, a global player in driveline and chassis technology. Oracle Customer:  Openmatics s.r.o.Location:  Pilsen, Czech RepublicIndustry:  AutomotiveEmployees:  70 Its goal was to develop and operate a flexible, open telematics platform for automotive applications, which is independent from vehicle and component suppliers—recognizing that the fragmented telematics market was not meeting today’s fleet management needs. Openmatics provides a rich product portfolio, and customers can extend the platform, as required, to meet their needs. Partners and third-parties can develop their own applications using the Openmatics’ software development kit and can sell them via the Openmatics app shop.ZF Friedrichshafen AG is a global player in driveline and chassis technology. With 121 production companies and 650 service partners in 26 countries, ZF is among the top 10 largest automotive suppliers worldwide. Founded in 1915 to develop and produce transmissions for airships and vehicles, the group’s product offerings now include transmissions and steering systems as well as chassis components and complete axle systems and modules.  A word from Openmatics s.r.o.  “Oracle WebCenter Portal, together with the underlying Oracle Application Development Framework, provided the fundamental infrastructure for the Openmatics platform. Fleet managers can now reduce fuel consumption and operating costs, and more efficiently manage vehicle usage, maintenance, and safety. The standards-based platform allows third-party suppliers to deploy their own vehicle telematics services as Openmatics apps and creates a de facto standard for the automotive industry, independent from a single manufacturer or service provider.” – Gero Strobel, Head of Development, Openmatics s.r.o. Challenges Create an industry standard for vehicle telematics by establishing a customizable platform that enables access to telematics information, such as current and past fuel consumption, through a web browser to better meet automotive market and customer needs Reduce fleet-management costs by eliminating the need to invest in isolated telematics hardware and software solutions per vehicle brand and vehicle component manufacturer Establish an open platform where third-party providers—such as original equipment manufacturers (OEM), insurers, fleet operators, and individual developers—can deploy their own vehicle telematics services Allow users to purchase targeted telematics services as single apps to reduce costs and ensure rapid growth of telematics services available on the platform Enable users to configure their telematics apps with ease to make sure the platform meets individual fleet management requirements, such as analyzing past and current fuel consumption of a truck fleet Solutions Deployed Oracle WebCenter Portal as a foundation for Openmatics, a standards-based automotive telematics platform that provides next-generation fleet management with unified digital communication from and to vehicles on the move Used Oracle Application Development Framework as the development framework for Oracle WebCenter Portal’s components and services, providing developers with ready-to-use software development kits with application programming interfaces, design templates, and visual tools that accelerated time to market Used Oracle Enterprise Pack for Eclipse to simplify telematics application development in Java Enabled fleet monitoring by recording vehicle data—such as fuel consumption information—through onboard units, delivering the information to Oracle Database, and making it accessible through a customizable app portfolio on any web browser Stored vehicle telematics data—sent as encrypted information—in Oracle Database, ensuring data integrity and immediate availability for the platform’s telematics applications Enabled a wide range of telematics services suppliers, from vehicle component manufacturers to fleet application developers, to offer vehicle telematics services on the Openmatics platform, ensuring platform independence from OEMs Provided Openmatics customers with the means to individually select the automotive telematics services that are relevant to their business requirements, eliminating the need to pay for superfluous information and reducing fleet management costs Oracle Products & Services Oracle Application Development Framework Oracle WebCenter Portal Oracle SOA Suite Oracle Enterprise Pack for Eclipse Oracle Database Oracle Consulting &amp;amp;amp;amp;amp;amp;amp;&amp;amp;amp;amp;amp;lt;span id=&amp;amp;amp;amp;amp;quot;XinhaEditingPostion&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;lt;/span&amp;amp;amp;amp;amp;gt;amp;&amp;amp;amp;amp;amp;amp;lt;span id=&amp;amp;amp;amp;amp;amp;quot;XinhaEditingPostion&amp;amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;amp;lt;/span&amp;amp;amp;amp;amp;amp;gt;lt;p&amp;amp;amp;amp;amp;amp;amp;amp;gt; &amp;amp;amp;amp;amp;amp;amp;amp;lt;/p&amp;amp;amp;amp;amp;amp;amp;amp;gt;

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  • The Future of Air Travel: Intelligence and Automation

    - by BobEvans
    Remember those white-knuckle flights through stormy weather where unexpected plunges in altitude result in near-permanent relocations of major internal organs? Perhaps there’s a better way, according to a recent Wall Street Journal article: “Pilots of a Honeywell International Inc. test plane stayed on their initial flight path, relying on the company's latest onboard radar technology to steer through the worst of the weather. The specially outfitted Boeing 757 barely shuddered as it gingerly skirted some of the most ferocious storm cells over Fort Walton Beach and then climbed above the rest in zero visibility.” Or how about the multifaceted check-in process, which might not wreak havoc on liver location but nevertheless makes you wonder if you’ve been trapped in some sort of covert psychological-stress test? Another WSJ article, called “The Self-Service Airport,” says there’s reason for hope there as well: “Airlines are laying the groundwork for the next big step in the airport experience: a trip from the curb to the plane without interacting with a single airline employee. At the airport of the near future, ‘your first interaction could be with a flight attendant,’ said Ben Minicucci, chief operating officer of Alaska Airlines, a unit of Alaska Air Group Inc.” And in the topsy-turvy world of air travel, it’s not just the passengers who’ve been experiencing bumpy rides: the airlines themselves are grappling with a range of challenges—some beyond their control, some not—that make profitability increasingly elusive in spite of heavy demand for their services. A recent piece in The Economist illustrates one of the mega-challenges confronting the airline industry via a striking set of contrasting and very large numbers: while the airlines pay $7 billion per year to third-party computerized reservation services, the airlines themselves earn a collective profit of only $3 billion per year. In that context, the anecdotes above point unmistakably to the future that airlines must pursue if they hope to be able to manage some of the factors outside of their control (e.g., weather) as well as all of those within their control (operating expenses, end-to-end visibility, safety, load optimization, etc.): more intelligence, more automation, more interconnectedness, and more real-time awareness of every facet of their operations. Those moves will benefit both passengers and the air carriers, says the WSJ piece on The Self-Service Airport: “Airlines say the advanced technology will quicken the airport experience for seasoned travelers—shaving a minute or two from the checked-baggage process alone—while freeing airline employees to focus on fliers with questions. ‘It's more about throughput with the resources you have than getting rid of humans,’ said Andrew O'Connor, director of airport solutions at Geneva-based airline IT provider SITA.” Oracle’s attempting to help airlines gain control over these challenges by blending together a range of its technologies into a solution called the Oracle Airline Data Model, which suggests the following steps: • To retain and grow their customer base, airlines need to focus on the customer experience. • To personalize and differentiate the customer experience, airlines need to effectively manage their passenger data. • The Oracle Airline Data Model can help airlines jump-start their customer-experience initiatives by consolidating passenger data into a customer data hub that drives realtime business intelligence and strategic customer insight. • Oracle’s Airline Data Model brings together multiple types of data that can jumpstart your data-warehousing project with rich out-of-the-box functionality. • Oracle’s Intelligent Warehouse for Airlines brings together the powerful capabilities of Oracle Exadata and the Oracle Airline Data Model to give you real-time strategic insights into passenger demand, revenues, sales channels and your flight network. The airline industry aside, the bullet points above offer a broad strategic outline for just about any industry because the customer experience is becoming pre-eminent in each and there is simply no way to deliver world-class customer experiences unless a company can capture, manage, and analyze all of the relevant data in real-time. I’ll leave you with two thoughts from the WSJ article about the new in-flight radar system from Honeywell: first, studies show that a single episode of serious turbulence can wrack up $150,000 in additional costs for an airline—so, it certainly behooves the carriers to gain the intelligence to avoid turbulence as much as possible. And second, it’s back to that top-priority customer-experience thing and the value that ever-increasing levels of intelligence can deliver. As the article says: “In the cabin, reporters watched screens showing the most intense parts of the nearly 10-mile wide storm, which churned some 7,000 feet below, in vibrant red and other colors. The screens also were filled with tiny symbols depicting likely locations of lightning and hail, which can damage planes and wreak havoc on the nerves of white-knuckle flyers.”  (Bob Evans is senior vice-president, communications, for Oracle.)  

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  • RemoveHandler Issues with Custom Events

    - by Jeff Certain
    This is a case of things being more complicated that I thought they should be. Since it took a while to figure this one out, I thought it was worth explaining and putting all of the pieces to the answer in one spot. Let me set the stage. Architecturally, I have the notion of generic producers and consumers. These put items onto, and remove items from, a queue. This provides a generic, thread-safe mechanism to load balance the creation and processing of work items in our application. Part of the IProducer(Of T) interface is: 1: Public Interface IProducer(Of T) 2: Event ItemProduced(ByVal sender As IProducer(Of T), ByVal item As T) 3: Event ProductionComplete(ByVal sender As IProducer(Of T)) 4: End Interface Nothing sinister there, is there? In order to simplify our developers’ lives, I wrapped the queue with some functionality to manage the produces and consumers. Since the developer can specify the number of producers and consumers that are spun up, the queue code manages adding event handlers as the producers and consumers are instantiated. Now, we’ve been having some memory leaks and, in order to eliminate the possibility that this was caused by weak references to event handles, I wanted to remove them. This is where it got dicey. My first attempt looked like this: 1: For Each producer As P In Producers 2: RemoveHandler producer.ItemProduced, AddressOf ItemProducedHandler 3: RemoveHandler producer.ProductionComplete, AddressOf ProductionCompleteHandler 4: producer.Dispose() 5: Next What you can’t see in my posted code are the warnings this caused. The 'AddressOf' expression has no effect in this context because the method argument to 'AddressOf' requires a relaxed conversion to the delegate type of the event. Assign the 'AddressOf' expression to a variable, and use the variable to add or remove the method as the handler.  Now, what on earth does that mean? Well, a quick Bing search uncovered a whole bunch of talk about delegates. The first solution I found just changed all parameters in the event handler to Object. Sorry, but no. I used generics precisely because I wanted type safety, not because I wanted to use Object. More searching. Eventually, I found this forum post, where Jeff Shan revealed a missing piece of the puzzle. The other revelation came from Lian_ZA in this post. However, these two only hinted at the solution. Trying some of what they suggested led to finally getting an invalid cast exception that revealed the existence of ItemProducedEventHandler. Hold on a minute! I didn’t create that delegate. There’s nothing even close to that name in my code… except the ItemProduced event in the interface. Could it be? Naaaaah. Hmmm…. Well, as it turns out, there is a delegate created by the compiler for each event. By explicitly creating a delegate that refers to the method in question, implicitly cast to the generated delegate type, I was able to remove the handlers: 1: For Each producer As P In Producers 2: Dim _itemProducedHandler As IProducer(Of T).ItemProducedEventHandler = AddressOf ItemProducedHandler 3: RemoveHandler producer.ItemProduced, _itemProducedHandler 4:  5: Dim _productionCompleteHandler As IProducer(Of T).ProductionCompleteEventHandler = AddressOf ProductionCompleteHandler 6: RemoveHandler producer.ProductionComplete, _productionCompleteHandler 7: producer.Dispose() 8: Next That’s “all” it took to finally be able to remove the event handlers and maintain type-safe code. Hopefully, this will save you the same challenges I had in trying to figure out how to fix this issue!

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  • Caching factory design

    - by max
    I have a factory class XFactory that creates objects of class X. Instances of X are very large, so the main purpose of the factory is to cache them, as transparently to the client code as possible. Objects of class X are immutable, so the following code seems reasonable: # module xfactory.py import x class XFactory: _registry = {} def get_x(self, arg1, arg2, use_cache = True): if use_cache: hash_id = hash((arg1, arg2)) if hash_id in _registry: return _registry[hash_id] obj = x.X(arg1, arg2) _registry[hash_id] = obj return obj # module x.py class X: # ... Is it a good pattern? (I know it's not the actual Factory Pattern.) Is there anything I should change? Now, I find that sometimes I want to cache X objects to disk. I'll use pickle for that purpose, and store as values in the _registry the filenames of the pickled objects instead of references to the objects. Of course, _registry itself would have to be stored persistently (perhaps in a pickle file of its own, in a text file, in a database, or simply by giving pickle files the filenames that contain hash_id). Except now the validity of the cached object depends not only on the parameters passed to get_x(), but also on the version of the code that created these objects. Strictly speaking, even a memory-cached object could become invalid if someone modifies x.py or any of its dependencies, and reloads it while the program is running. So far I ignored this danger since it seems unlikely for my application. But I certainly cannot ignore it when my objects are cached to persistent storage. What can I do? I suppose I could make the hash_id more robust by calculating hash of a tuple that contains arguments arg1 and arg2, as well as the filename and last modified date for x.py and every module and data file that it (recursively) depends on. To help delete cache files that won't ever be useful again, I'd add to the _registry the unhashed representation of the modified dates for each record. But even this solution isn't 100% safe since theoretically someone might load a module dynamically, and I wouldn't know about it from statically analyzing the source code. If I go all out and assume every file in the project is a dependency, the mechanism will still break if some module grabs data from an external website, etc.). In addition, the frequency of changes in x.py and its dependencies is quite high, leading to heavy cache invalidation. Thus, I figured I might as well give up some safety, and only invalidate the cache only when there is an obvious mismatch. This means that class X would have a class-level cache validation identifier that should be changed whenever the developer believes a change happened that should invalidate the cache. (With multiple developers, a separate invalidation identifier is required for each.) This identifier is hashed along with arg1 and arg2 and becomes part of the hash keys stored in _registry. Since developers may forget to update the validation identifier or not realize that they invalidated existing cache, it would seem better to add another validation mechanism: class X can have a method that returns all the known "traits" of X. For instance, if X is a table, I might add the names of all the columns. The hash calculation will include the traits as well. I can write this code, but I am afraid that I'm missing something important; and I'm also wondering if perhaps there's a framework or package that can do all of this stuff already. Ideally, I'd like to combine in-memory and disk-based caching.

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  • Learn Many Languages

    - by Jeff Foster
    My previous blog, Deliberate Practice, discussed the need for developers to “sharpen their pencil” continually, by setting aside time to learn how to tackle problems in different ways. However, the Sapir-Whorf hypothesis, a contested and somewhat-controversial concept from language theory, seems to hold reasonably true when applied to programming languages. It states that: “The structure of a language affects the ways in which its speakers conceptualize their world.” If you’re constrained by a single programming language, the one that dominates your day job, then you only have the tools of that language at your disposal to think about and solve a problem. For example, if you’ve only ever worked with Java, you would never think of passing a function to a method. A good developer needs to learn many languages. You may never deploy them in production, you may never ship code with them, but by learning a new language, you’ll have new ideas that will transfer to your current “day-job” language. With the abundant choices in programming languages, how does one choose which to learn? Alan Perlis sums it up best. “A language that doesn‘t affect the way you think about programming is not worth knowing“ With that in mind, here’s a selection of languages that I think are worth learning and that have certainly changed the way I think about tackling programming problems. Clojure Clojure is a Lisp-based language running on the Java Virtual Machine. The unique property of Lisp is homoiconicity, which means that a Lisp program is a Lisp data structure, and vice-versa. Since we can treat Lisp programs as Lisp data structures, we can write our code generation in the same style as our code. This gives Lisp a uniquely powerful macro system, and makes it ideal for implementing domain specific languages. Clojure also makes software transactional memory a first-class citizen, giving us a new approach to concurrency and dealing with the problems of shared state. Haskell Haskell is a strongly typed, functional programming language. Haskell’s type system is far richer than C# or Java, and allows us to push more of our application logic to compile-time safety. If it compiles, it usually works! Haskell is also a lazy language – we can work with infinite data structures. For example, in a board game we can generate the complete game tree, even if there are billions of possibilities, because the values are computed only as they are needed. Erlang Erlang is a functional language with a strong emphasis on reliability. Erlang’s approach to concurrency uses message passing instead of shared variables, with strong support from both the language itself and the virtual machine. Processes are extremely lightweight, and garbage collection doesn’t require all processes to be paused at the same time, making it feasible for a single program to use millions of processes at once, all without the mental overhead of managing shared state. The Benefits of Multilingualism By studying new languages, even if you won’t ever get the chance to use them in production, you will find yourself open to new ideas and ways of coding in your main language. For example, studying Haskell has taught me that you can do so much more with types and has changed my programming style in C#. A type represents some state a program should have, and a type should not be able to represent an invalid state. I often find myself refactoring methods like this… void SomeMethod(bool doThis, bool doThat) { if (!(doThis ^ doThat)) throw new ArgumentException(“At least one arg should be true”); if (doThis) DoThis(); if (doThat) DoThat(); } …into a type-based solution, like this: enum Action { DoThis, DoThat, Both }; void SomeMethod(Action action) { if (action == Action.DoThis || action == Action.Both) DoThis(); if (action == Action.DoThat || action == Action.Both) DoThat(); } At this point, I’ve removed the runtime exception in favor of a compile-time check. This is a trivial example, but is just one of many ideas that I’ve taken from one language and implemented in another.

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  • How do I get 5.1 surround sound working on an Acer Aspire 5738ZG?

    - by kbargais_LV
    I got a problem with sound. I tried everything but no results. :( I got 3 sound ports. my daemon: # This file is part of PulseAudio. # # PulseAudio is free software; you can redistribute it and/or modify # it under the terms of the GNU Lesser General Public License as published by # the Free Software Foundation; either version 2 of the License, or # (at your option) any later version. # # PulseAudio is distributed in the hope that it will be useful, but # WITHOUT ANY WARRANTY; without even the implied warranty of # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU # General Public License for more details. # # You should have received a copy of the GNU Lesser General Public License # along with PulseAudio; if not, write to the Free Software # Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 # USA. ## Configuration file for the PulseAudio daemon. See pulse-daemon.conf(5) for ## more information. Default values are commented out. Use either ; or # for ## commenting. ; daemonize = no ; fail = yes ; allow-module-loading = yes ; allow-exit = yes ; use-pid-file = yes ; system-instance = no ; local-server-type = user ; enable-shm = yes ; shm-size-bytes = 0 # setting this 0 will use the system-default, usually 64 MiB ; lock-memory = no ; cpu-limit = no ; high-priority = yes ; nice-level = -11 ; realtime-scheduling = yes ; realtime-priority = 5 ; exit-idle-time = 20 ; scache-idle-time = 20 ; dl-search-path = (depends on architecture) ; load-default-script-file = yes ; default-script-file = /etc/pulse/default.pa ; log-target = auto ; log-level = notice ; log-meta = no ; log-time = no ; log-backtrace = 0 resample-method = speex-float-1 ; enable-remixing = yes ; enable-lfe-remixing = no flat-volumes = no ; rlimit-fsize = -1 ; rlimit-data = -1 ; rlimit-stack = -1 ; rlimit-core = -1 ; rlimit-as = -1 ; rlimit-rss = -1 ; rlimit-nproc = -1 ; rlimit-nofile = 256 ; rlimit-memlock = -1 ; rlimit-locks = -1 ; rlimit-sigpending = -1 ; rlimit-msgqueue = -1 ; rlimit-nice = 31 ; rlimit-rtprio = 9 ; rlimit-rttime = 1000000 ; default-sample-format = s16le ; default-sample-rate = 44100 ; default-sample-channels = 6 ; default-channel-map = front-left,front-right default-fragments = 8 default-fragment-size-msec = 10 ; enable-deferred-volume = yes ; deferred-volume-safety-margin-usec = 8000 ; deferred-volume-extra-delay-usec = 0

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  • The long road to bug-free software

    - by Tony Davis
    The past decade has seen a burgeoning interest in functional programming languages such as Haskell or, in the Microsoft world, F#. Though still on the periphery of mainstream programming, functional programming concepts are gradually seeping into the imperative C# language (for example, Lambda expressions have their root in functional programming). One of the more interesting concepts from functional programming languages is the use of formal methods, the lofty ideal behind which is bug-free software. The idea is that we write a specification that describes exactly how our function (say) should behave. We then prove that our function conforms to it, and in doing so have proved beyond any doubt that it is free from bugs. All programmers already use one form of specification, specifically their programming language's type system. If a value has a specific type then, in a type-safe language, the compiler guarantees that value cannot be an instance of a different type. Many extensions to existing type systems, such as generics in Java and .NET, extend the range of programs that can be type-checked. Unfortunately, type systems can only prevent some bugs. To take a classic problem of retrieving an index value from an array, since the type system doesn't specify the length of the array, the compiler has no way of knowing that a request for the "value of index 4" from an array of only two elements is "unsafe". We restore safety via exception handling, but the ideal type system will prevent us from doing anything that is unsafe in the first place and this is where we start to borrow ideas from a language such as Haskell, with its concept of "dependent types". If the type of an array includes its length, we can ensure that any index accesses into the array are valid. The problem is that we now need to carry around the length of arrays and the values of indices throughout our code so that it can be type-checked. In general, writing the specification to prove a positive property, even for a problem very amenable to specification, such as a simple sorting algorithm, turns out to be very hard and the specification will be different for every program. Extend this to writing a specification for, say, Microsoft Word and we can see that the specification would end up being no simpler, and therefore no less buggy, than the implementation. Fortunately, it is easier to write a specification that proves that a program doesn't have certain, specific and undesirable properties, such as infinite loops or accesses to the wrong bit of memory. If we can write the specifications to prove that a program is immune to such problems, we could reuse them in many places. The problem is the lack of specification "provers" that can do this without a lot of manual intervention (i.e. hints from the programmer). All this might feel a very long way off, but computing power and our understanding of the theory of "provers" advances quickly, and Microsoft is doing some of it already. Via their Terminator research project they have started to prove that their device drivers will always terminate, and in so doing have suddenly eliminated a vast range of possible bugs. This is a huge step forward from saying, "we've tested it lots and it seems fine". What do you think? What might be good targets for specification and verification? SQL could be one: the cost of a bug in SQL Server is quite high given how many important systems rely on it, so there's a good incentive to eliminate bugs, even at high initial cost. [Many thanks to Mike Williamson for guidance and useful conversations during the writing of this piece] Cheers, Tony.

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