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• Guidance: How to layout you files for an Ideal Solution

  - by Martin Hinshelwood

  Creating a solution and having it maintainable over time is an art and not a science. I like being pedantic and having a place for everything, no matter how small. For setting up the Areas to run Multiple projects under one solution see my post on  When should I use Areas in TFS instead of Team Projects and for an explanation of branching see Guidance: A Branching strategy for Scrum Teams. Update 17th May 2010 – We are currently trialling running a single Sprint branch to improve our history. Whenever I setup a new Team Project I implement the basic version control structure. I put “readme.txt” files in the folder structure explaining the different levels, and a solution file called “[Client].[Product].sln” located at “$/[Client]/[Product]/DEV/Main” within version control. Developers should add any projects you need to create to that solution in the format “[Client].[Product].[ProductArea].[Assembly]” and they will automatically be picked up and built automatically when you setup Automated Builds using Team Foundation Build. All test projects need to be done using MSTest to get proper IDE and Team Foundation Build integration out-of-the-box and be named for the assembly that it is testing with a naming convention of “[Client].[Product].[ProductArea].[Assembly].Tests” Here is a description of the folder layout; this content should be replicated in readme files under version control in the relevant locations so that even developers new to the project can see how to do it. Figure: The Team Project level - at this level there should be a folder for each the products that you are building if you are using Areas correctly in TFS 2010. You should try very hard to avoided spaces as these things always end up in a URL eventually e.g. "Code Auditor" should be "CodeAuditor". Figure: Product Level - At this level there should be only 3 folders (DEV, RELESE and SAFE) all of which should be in capitals. These folders represent the three stages of your application production line. Each of them may contain multiple branches but this format leaves all of your branches at the same level. Figure: The DEV folder is where all of the Development branches reside. The DEV folder will contain the "Main" branch and all feature branches is they are being used. The DEV designation specifies that all code in every branch under this folder has not been released or made ready for release. And feature branches MUST merge (Forward Integrate) from Main and stabilise prior to merging (Reverse Integration) back down into Main and being decommissioned. Figure: In the Feature branching scenario only merges are allowed onto Main, no development can be done there. Once we have a mature product it is important that new features being developed in parallel are kept separate. This would most likely be used if we had more than one Scrum team working on a single product. Figure: when we are ready to do a release of our software we will create a release branch that is then stabilised prior to deployment. This protects the serviceability of of our released code allowing developers to fix bugs and re-release an existing version. Figure: All bugs found on a release are fixed on the release.  All bugs found in a release are fixed on the release and a new deployment is created. After the deployment is created the bug fixes are then merged (Reverse Integration) into the Main branch. We do this so that we separate out our development from our production ready code.  Figure: SAFE or RTM is a read only record of what you actually released. Labels are not immutable so are useless in this circumstance.  When we have completed stabilisation of the release branch and we are ready to deploy to production we create a read-only copy of the code for reference. In some cases this could be a regulatory concern, but in most cases it protects the company building the product from legal entanglements based on what you did or did not release. Figure: This allows us to reference any particular version of our application that was ever shipped.   In addition I am an advocate of having a single solution with all the Project folders directly under the “Trunk”/”Main” folder and using the full name for the project folders.. Figure: The ideal solution If you must have multiple solutions, because you need to use more than one version of Visual Studio, name the solutions “[Client].[Product][VSVersion].sln” and have it reside in the same folder as the other solution. This makes it easier for Automated build and improves the discoverability of your code and its dependencies. Send me your feedback!   Technorati Tags: VS ALM,VSTS Developing,VS 2010,VS 2008,TFS 2010,TFS 2008,TFBS

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• Creating the Business Card Request InfoPath Form

  - by JKenderdine

  Business Card Request Demo Files Back in January I spoke at SharePoint Saturday Virginia Beach about InfoPath forms and Web Part deployment.  Below is some of the information and details regarding the form I created for the session.  There are many blogs and Microsoft articles on how to create a basic form so I won’t repeat that information here.   This blog will just explain a few of the options I chose when creating the solutions for SPS Virginia Beach.  The above link contains the zipped package files of the two InfoPath forms(no code solution and coded solution), the list template for the Location list I used, and the PowerPoint deck.  If you plan to use these templates, you will need to update the forms to work within your own environments (change data connections, code links, etc.).  Also, you must have the SharePoint Enterprise version, with InfoPath Services configured in order to use the Web Browser enabled forms. So what are the requirements for this template? Business Card Request Form Template Design Plan: Gather user information and requirements for card Pull in as much user information as possible. Use data from the user profile web services as a data source Show and hide fields as necessary for requirements Create multiple views – one for those submitting the form and Another view for the executive assistants placing the orders. Browser based form integrated into SharePoint team site Submitted directly to form library The base form was created using the blank template.  The table and rows were added using Insert tab and selecting Custom Table.  The use of tables is a great way to make sure everything lines up.  You do have to split the tables from time to time.  If you’ve ever split cells and then tried to re-align one to find that you impacted the others, you know why.  Here is what the base form looks like in InfoPath.   Show and hide fields as necessary for requirements You will notice I also used Sections within the form.  These show or hide depending on options selected or whether or not fields are blank.  This is a great way to prevent your users from feeling overwhelmed with a large form (this one wouldn’t apply).  Although not used in this one, you can also use various views with a tab interface.  I’ll show that in another post. Gather user information and requirements for card Pull in as much user information as possible. Use data from the user profile web services as a data source Utilizing rules you can load data when the form initiates (Data tab, Form Load).  Anything you can automate is always appreciated by the user as that is data they don’t have to enter.  For example, loading their user id or other user information on load: Always keep in mind though how much data you load and the method for loading that data (through rules, code, etc.).  They have an impact on form performance.  The form will take longer to load if you bring in a ton of data from external sources.  Laura Rogers has a great blog post on using the User Information List to load user information.   If the user has logged into SharePoint, then this can be used quite effectively and without a huge performance hit.   What I have found is that using the User Profile service via code behind or the Web Service “GetUserProfileByName” (as above) can take more time to load the user data.  Just food for thought. You must add the data connection in order for the above rules to work.  You can connect to the data connection through the Data tab, Data Connections or select Manage Data Connections link which appears under the main data source.  The data connections can be SharePoint lists or libraries, SQL data tables, XML files, etc.  Create multiple views – one for those submitting the form and Another view for the executive assistants placing the orders. You can also create multiple views for the users to enhance their experience.  Once they’ve entered the information and submitted their request for business cards, they don’t really need to see the main data input screen any more.  They just need to view what they entered. From the Page Design tab, select New View and give the view a name.  To review the existing views, click the down arrow under View: The ReviewView shows just what the user needs and nothing more: Once you have everything configured, the form should be tested within a Test SharePoint environment before final deployment to production.  This validates you don’t have any rules or code that could impact the server negatively. Submitted directly to form library   You will need to know the form library that you will be submitting to when publishing the template.  Configure the Submit data connection to connect to this library.  There is already one configured in the sample,  but it will need to be updated to your environment prior to publishing. The Design template is different from the Published template.  While both have the .XSN extension, the published template contains all the “package” information for the form.  The published form is what is loaded into Central Admin, not the design template. Browser based form integrated into SharePoint team site In Central Admin, under General Settings, select Manage Form Templates.  Upload the published form template and Activate it to a site collection. Now it is available as a content type to select in the form library.  Some documentation on publishing form templates:  Technet – Manage administrator approved form templates And that’s all our base requirements.  Hope this helps to give a good start.

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• Silverlight Relay Commands

  - by George Evjen

  v\:* {behavior:url(#default#VML);} o\:* {behavior:url(#default#VML);} w\:* {behavior:url(#default#VML);} .shape {behavior:url(#default#VML);} Normal 0 false false false false EN-US X-NONE X-NONE /* 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-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;} I am fairly new at Silverlight development and I usually have an issue that needs research every day. Which I enjoy, since I like the idea of going into a day knowing that I am  going to learn something new. The issue that I am currently working on centers around relay commands. I have a pretty good handle on Relay Commands and how we use them within our applications. <Button Command="{Binding ButtonCommand}" CommandParameter="NewRecruit" Content="New Recruit" /> Here in our xaml we have a button. The button has a Command and a CommandParameter. The command binds to the ButtonCommand that we have in our ViewModel RelayCommand _buttonCommand;         /// <summary>         /// Gets the button command.         /// </summary>         /// <value>The button command.</value>         public RelayCommand ButtonCommand         {             get             {                 if (_buttonCommand == null)                 {                     _buttonCommand = new RelayCommand(                         x => x != null && x.ToString().Length > 0 && CheckCommandAvailable(x.ToString()),                         x => ExecuteCommand(x.ToString()));                 }                 return _buttonCommand;             }         }   In our relay command we then do some checks with a lambda expression. We check if the command  parameter is null, is the length greater than 0 and we have a CheckCommandAvailable method that will tell  us if the button is even enabled. After we check on these three items we then pass the command parameter to an action method. This is all pretty straight forward, the issue that we solved a few days ago centered around having a control that needed to use a Relay Command and this control was a nested control and was using a different DataContext. The example below illustrates how we handled this scenario. In our xaml usercontrol we had to set a name to this control. <Controls3:RadTileViewItem x:Class="RecruitStatusTileView"     xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"     xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"     xmlns:d="http://schemas.microsoft.com/expression/blend/2008"     xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"      xmlns:Controls1="clr-namespace:Telerik.Windows.Controls;assembly=Telerik.Windows.Controls"      xmlns:Controls2="clr-namespace:Telerik.Windows.Controls;assembly=Telerik.Windows.Controls.Input"      xmlns:Controls3="clr-namespace:Telerik.Windows.Controls;assembly=Telerik.Windows.Controls.Navigation"      mc:Ignorable="d" d:DesignHeight="400" d:DesignWidth="800" Header="{Binding Title,Mode=TwoWay}" MinimizedHeight="100"                             x:Name="StatusView"> Here we are using a telerik RadTileViewItem. We set the name of this control to “StatusView”. In our button control we set our command parameters and commands different than the example above. <HyperlinkButton Content="{Binding BigBoardButtonText, Mode=TwoWay}" CommandParameter="{Binding 'Position.PositionName'}" Command="{Binding ElementName=StatusView, Path=DataContext.BigBoardCommand, Mode=TwoWay}" /> This hyperlink button lives in a ListBox control and this listbox has an ItemSource of PositionSelectors. The Command Parameter is binding to the Position.Position property of that PositionSelectors object. This again is pretty straight forward again. What gets a bit tricky is the Command property in the hyperlink. It is binding to the element name we created in the user control (StatusView) Because this hyperlink is in a listbox and is in the item template it doesn’t have a direct handle on the DataContext that the RadTileViewItem has so we have to make sure it does. We do that by binding to the element name of status view then set the path to DataContext.BigBoardCommand. BigBoardCommand is the name of the RelayCommand in the view model. private RelayCommand _bigBoardCommand = null;         /// <summary>         /// Gets the big board command.         /// </summary>         /// <value>The big board command.</value>         public RelayCommand BigBoardCommand         {             get             {                 if (_bigBoardCommand == null)                 {                     _bigBoardCommand = new RelayCommand(x => true, x => AddToBigBoard(x.ToString()));                 }                 return _bigBoardCommand;             }         } From there we check for true again and then call the action and pass in the parameter that we had as the command parameter. What we are working on now is a bit trickier than this second example. In the above example we are only creating this TileViewItem with this name “StatusView” once. In another part of our application we are generating multiple TileViewItems, so we cannot set the name in the control as we cant have multiple controls with the same name. When we run the application we get an error that reads that the value is out of expected range. My searching has led me to think we cannot have multiple controls with the same name. This is today’s problem and Ill post the solution to this once it is found.

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• The Sound of Two Toilets Flushing: Constructive Criticism for Virgin Atlantic Complaints Department

  - by Geertjan

  I recently had the experience of flying from London to Johannesburg and back with Virgin Atlantic. The good news was that it was the cheapest flight available and that the take off and landing were absolutely perfect. Hence I really have no reason to complain. Instead, I'd like to offer some constructive criticism which hopefully Richard Branson will find sometime while googling his name. Or maybe someone from the Virgin Atlantic Complaints Department will find it, whatever, just want to put this information out there. Arrangement of restroom facilities. Maybe next time you design an airplane, consider not putting your toilets at a right angle right next to your rows of seats. Being able to reach, without even needing to stretch your arm, from your seat to close, yet again, a toilet door that someone, someone obviously sitting very far from the toilets, carelessly forgot to close is not an indicator of quality interior design. Have you noticed how all other airplanes have their toilets in a cubicle separated from the rows of seats? On those airplanes, people sitting in the seats near the toilets are not constantly being woken up throughout the night whenever someone enters/exits the toilet, whenever the light in the toilet is suddenly switched on, and whenever one of the toilets flushes. Bonus points for Virgin Atlantic passengers in the seats adjoining the toilets is when multiple toilets are flushed simultaneously and multiple passengers enter/exit them at the same time, a bit like an unasked for low budget musical of suddenly illuminated grumpy people in crumpled clothes. What joy that brings at 3 AM is hard to describe. Seats with extra leg room. You know how other airplanes have the seats with the extra leg room? You know what those seats tend to have? Extra leg room. It's really interesting how Virgin Atlantic's seats with extra leg room actually have no extra leg room at all. It should have been a give away, the fact that these special seats are found in the same rows as the standard seats, rather than on the cusp of real glory which is where most airlines put their extra leg room seats, with the only actual difference being that they have a slightly different color. Had you called them "seats with a different color" (i.e., almost not quite green, rather than something vaguely hinting at blue), at least I'd have known what I was getting. Picture the joy at 3 AM, rudely awakened from nightmarish slumber, partly grateful to have been released from a grayish dream of faceless zombies resembling one or two of those in a recent toilet line, by multiple adjoining toilets flushing simultaneously, while you're sitting in a seat with extra leg room that has exactly as much leg room as the seats in neighboring rows. You then have a choice of things to be sincerely annoyed about. Food from the '80's. In the '80's, airplane food came in soggy containers and even breakfast, the most important meal of the day, was a sad heap of vaguely gray colors. The culinary highlight tended to be a squashed tomato, which must have been mashed to a pulp with a brick prior to being regurgitated by a small furry animal, and there was also always a piece of immensely horrid pumpkin, as well as a slice of spongy something you'd never seen before. Sausages and mash at 6 AM on an airplane was always a heavy lump of horribleness. Thankfully, all airlines throughout the world changed from this puke inducing strategy around 1987 sometime. Not Virgin Atlantic, of course. The fatty sausages and mash are still there, bringing you flashbacks to Duran Duran, which is what you were listening to (on your walkman) the last time you saw it in an airplane. Even the golden oldie "squashed tomato attached by slime to three wet peas" is on the menu. How wonderful to have all this in a cramped seat with a long row of early morning bleariness lined up for the toilets, right at your side, bumping into your elbow, groggily, one by one, one after another, more and more, fumble-open-door-silence-flush-fumble-open-door, and on and on, while you tentatively push your fork through a soggy pile of colorless mush, fighting the urge to throw up on the stinky socks of whatever nightmarish zombie is bumping into your elbow at the time. But, then again, the plane landed without a hitch, in fact, extremely smoothly, so I'm certainly not blaming the pilots.

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• await, WhenAll, WaitAll, oh my!!

  - by cibrax

  If you are dealing with asynchronous work in .NET, you might know that the Task class has become the main driver for wrapping asynchronous calls. Although this class was officially introduced in .NET 4.0, the programming model for consuming tasks was much more simplified in C# 5.0 in .NET 4.5 with the addition of the new async/await keywords. In a nutshell, you can use these keywords to make asynchronous calls as if they were sequential, and avoiding in that way any fork or callback in the code. The compiler takes care of the rest. I was yesterday writing some code for making multiple asynchronous calls to backend services in parallel. The code looked as follow, var allResults = new List<Result>(); foreach(var provider in providers) { var results = await provider.GetResults(); allResults.AddRange(results); } return allResults; You see, I was using the await keyword to make multiple calls in parallel. Something I did not consider was the overhead this code implied after being compiled. I started an interesting discussion with some smart folks in twitter. One of them, Tugberk Ugurlu, had the brilliant idea of actually write some code to make a performance comparison with another approach using Task.WhenAll. There are two additional methods you can use to wait for the results of multiple calls in parallel, WhenAll and WaitAll. WhenAll creates a new task and waits for results in that new task, so it does not block the calling thread. WaitAll, on the other hand, blocks the calling thread. This is the code Tugberk initially wrote, and I modified afterwards to also show the results of WaitAll. class Program { private static Func<Stopwatch, Task>[] funcs = new Func<Stopwatch, Task>[] { async (watch) => { watch.Start(); await Task.Delay(1000); Console.WriteLine("1000 one has been completed."); }, async (watch) => { await Task.Delay(1500); Console.WriteLine("1500 one has been completed."); }, async (watch) => { await Task.Delay(2000); Console.WriteLine("2000 one has been completed."); watch.Stop(); Console.WriteLine(watch.ElapsedMilliseconds + "ms has been elapsed."); } }; static void Main(string[] args) { Console.WriteLine("Await in loop work starts..."); DoWorkAsync().ContinueWith(task => { Console.WriteLine("Parallel work starts..."); DoWorkInParallelAsync().ContinueWith(t => { Console.WriteLine("WaitAll work starts..."); WaitForAll(); }); }); Console.ReadLine(); } static async Task DoWorkAsync() { Stopwatch watch = new Stopwatch(); foreach (var func in funcs) { await func(watch); } } static async Task DoWorkInParallelAsync() { Stopwatch watch = new Stopwatch(); await Task.WhenAll(funcs[0](watch), funcs[1](watch), funcs[2](watch)); } static void WaitForAll() { Stopwatch watch = new Stopwatch(); Task.WaitAll(funcs[0](watch), funcs[1](watch), funcs[2](watch)); } } After running this code, the results were very concluding. Await in loop work starts... 1000 one has been completed. 1500 one has been completed. 2000 one has been completed. 4532ms has been elapsed. Parallel work starts... 1000 one has been completed. 1500 one has been completed. 2000 one has been completed. 2007ms has been elapsed. WaitAll work starts... 1000 one has been completed. 1500 one has been completed. 2000 one has been completed. 2009ms has been elapsed. The await keyword in a loop does not really make the calls in parallel.

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• Computer Networks UNISA - Chap 8 &ndash; Wireless Networking

  - by MarkPearl

  After reading this section you should be able to Explain how nodes exchange wireless signals Identify potential obstacles to successful transmission and their repercussions, such as interference and reflection Understand WLAN architecture Specify the characteristics of popular WLAN transmission methods including 802.11 a/b/g/n Install and configure wireless access points and their clients Describe wireless MAN and WAN technologies, including 802.16 and satellite communications The Wireless Spectrum All wireless signals are carried through the air by electromagnetic waves. The wireless spectrum is a continuum of the electromagnetic waves used for data and voice communication. The wireless spectrum falls between 9KHZ and 300 GHZ. Characteristics of Wireless Transmission Antennas Each type of wireless service requires an antenna specifically designed for that service. The service’s specification determine the antenna’s power output, frequency, and radiation pattern. A directional antenna issues wireless signals along a single direction. An omnidirectional antenna issues and receives wireless signals with equal strength and clarity in all directions The geographical area that an antenna or wireless system can reach is known as its range Signal Propagation LOS (line of sight) uses the least amount of energy and results in the reception of the clearest possible signal. When there is an obstacle in the way, the signal may… pass through the object or be obsrobed by the object or may be subject to reflection, diffraction or scattering. Reflection – waves encounter an object and bounces off it. Diffraction – signal splits into secondary waves when it encounters an obstruction Scattering – is the diffusion or the reflection in multiple different directions of a signal Signal Degradation Fading occurs as a signal hits various objects. Because of fading, the strength of the signal that reaches the receiver is lower than the transmitted signal strength. The further a signal moves from its source, the weaker it gets (this is called attenuation) Signals are also affected by noise – the electromagnetic interference) Interference can distort and weaken a wireless signal in the same way that noise distorts and weakens a wired signal. Frequency Ranges Older wireless devices used the 2.4 GHZ band to send and receive signals. This had 11 communication channels that are unlicensed. Newer wireless devices can also use the 5 GHZ band which has 24 unlicensed bands Narrowband, Broadband, and Spread Spectrum Signals Narrowband – a transmitter concentrates the signal energy at a single frequency or in a very small range of frequencies Broadband – uses a relatively wide band of the wireless spectrum and offers higher throughputs than narrowband technologies The use of multiple frequencies to transmit a signal is known as spread-spectrum technology. In other words a signal never stays continuously within one frequency range during its transmission. One specific implementation of spread spectrum is FHSS (frequency hoping spread spectrum). Another type is known as DSS (direct sequence spread spectrum) Fixed vs. Mobile Each type of wireless communication falls into one of two categories Fixed – the location of the transmitted and receiver do not move (results in energy saved because weaker signal strength is possible with directional antennas) Mobile – the location can change WLAN (Wireless LAN) Architecture There are two main types of arrangements Adhoc – data is sent directly between devices – good for small local devices Infrastructure mode – a wireless access point is placed centrally, that all devices connect with 802.11 WLANs The most popular wireless standards used on contemporary LANs are those developed by IEEE’s 802.11 committee. Over the years several distinct standards related to wireless networking have been released. Four of the best known standards are also referred to as Wi-Fi. They are…. 802.11b 802.11a 802.11g 802.11n These four standards share many characteristics. i.e. All 4 use half duplex signalling Follow the same access method Access Method 802.11 standards specify the use of CSMA/CA (Carrier Sense Multiple Access with Collision Avoidance) to access a shared medium. Using CSMA/CA before a station begins to send data on an 802.11 network, it checks for existing wireless transmissions. If the source node detects no transmission activity on the network, it waits a brief period of time and then sends its transmission. If the source does detect activity, it waits a brief period of time before checking again. The destination node receives the transmission and, after verifying its accuracy, issues an acknowledgement (ACT) packet to the source. If the source receives the ACK it assumes the transmission was successful, – if it does not receive an ACK it assumes the transmission failed and sends it again. Association Two types of scanning… Active – station transmits a special frame, known as a prove, on all available channels within its frequency range. When an access point finds the probe frame, it issues a probe response. Passive – wireless station listens on all channels within its frequency range for a special signal, known as a beacon frame, issued from an access point – the beacon frame contains information necessary to connect to the point. Re-association occurs when a mobile user moves out of one access point’s range and into the range of another. Frames Read page 378 – 381 about frames and specific 802.11 protocols Bluetooth Networks Sony Ericson originally invented the Bluetooth technology in the early 1990s. In 1998 other manufacturers joined Ericsson in the Special Interest Group (SIG) whose aim was to refine and standardize the technology. Bluetooth was designed to be used on small networks composed of personal communications devices. It has become popular wireless technology for communicating among cellular telephones, phone headsets, etc. Wireless WANs and Internet Access Refer to pages 396 – 402 of the textbook for details.

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• High Availability for IaaS, PaaS and SaaS in the Cloud

  - by BuckWoody

  Outages, natural disasters and unforeseen events have proved that even in a distributed architecture, you need to plan for High Availability (HA). In this entry I'll explain a few considerations for HA within Infrastructure-as-a-Service (IaaS), Platform-as-a-Service (PaaS) and Software-as-a-Service (SaaS). In a separate post I'll talk more about Disaster Recovery (DR), since each paradigm has a different way to handle that. Planning for HA in IaaS IaaS involves Virtual Machines - so in effect, an HA strategy here takes on many of the same characteristics as it would on-premises. The primary difference is that the vendor controls the hardware, so you need to verify what they do for things like local redundancy and so on from the hardware perspective. As far as what you can control and plan for, the primary factors fall into three areas: multiple instances, geographical dispersion and task-switching. In almost every cloud vendor I've studied, to ensure your application will be protected by any level of HA, you need to have at least two of the Instances (VM's) running. This makes sense, but you might assume that the vendor just takes care of that for you - they don't. If a single VM goes down (for whatever reason) then the access to it is lost. Depending on multiple factors, you might be able to recover the data, but you should assume that you can't. You should keep a sync to another location (perhaps the vendor's storage system in another geographic datacenter or to a local location) to ensure you can continue to serve your clients. You'll also need to host the same VM's in another geographical location. Everything from a vendor outage to a network path problem could prevent your users from reaching the system, so you need to have multiple locations to handle this. This means that you'll have to figure out how to manage state between the geo's. If the system goes down in the middle of a transaction, you need to figure out what part of the process the system was in, and then re-create or transfer that state to the second set of systems. If you didn't write the software yourself, this is non-trivial. You'll also need a manual or automatic process to detect the failure and re-route the traffic to your secondary location. You could flip a DNS entry (if your application can tolerate that) or invoke another process to alias the first system to the second, such as load-balancing and so on. There are many options, but all of them involve coding the state into the application layer. If you've simply moved a state-ful application to VM's, you may not be able to easily implement an HA solution. Planning for HA in PaaS Implementing HA in PaaS is a bit simpler, since it's built on the concept of stateless applications deployment. Once again, you need at least two copies of each element in the solution (web roles, worker roles, etc.) to remain available in a single datacenter. Also, you need to deploy the application again in a separate geo, but the advantage here is that you could work out a "shared storage" model such that state is auto-balanced across the world. In fact, you don't have to maintain a "DR" site, the alternate location can be live and serving clients, and only take on extra load if the other site is not available. In Windows Azure, you can use the Traffic Manager service top route the requests as a type of auto balancer. Even with these benefits, I recommend a second backup of storage in another geographic location. Storage is inexpensive; and that second copy can be used for not only HA but DR. Planning for HA in SaaS In Software-as-a-Service (such as Office 365, or Hadoop in Windows Azure) You have far less control over the HA solution, although you still maintain the responsibility to ensure you have it. Since each SaaS is different, check with the vendor on the solution for HA - and make sure you understand what they do and what you are responsible for. They may have no HA for that solution, or pin it to a particular geo, or perhaps they have a massive HA built in with automatic load balancing (which is often the case).   All of these options (with the exception of SaaS) involve higher costs for the design. Do not sacrifice reliability for cost - that will always cost you more in the end. Build in the redundancy and HA at the very outset of the project - if you try to tack it on later in the process the business will push back and potentially not implement HA. References: http://www.bing.com/search?q=windows+azure+High+Availability  (each type of implementation is different, so I'm routing you to a search on the topic - look for the "Patterns and Practices" results for the area in Azure you're interested in)

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• Adaptive Connections For ADFBC

  - by Duncan Mills

  Some time ago I wrote an article on Adaptive Bindings showing how the pageDef for a an ADF UI does not have to be wedded to a fixed data control or collection / View Object. This article has proved pretty popular, so as a follow up I wanted to cover another "Adaptive" feature of your ADF applications, the ability to make multiple different connections from an Application Module, at runtime. Now, I'm sure you'll be aware that if you define your application to use a data-source rather than a hard-coded JDBC connection string, then you have the ability to change the target of that data-source after deployment to point to a different database. So that's great, but the reality of that is that this single connection is effectively fixed within the application right?  Well no, this it turns out is a common misconception. To be clear, yes a single instance of an ADF Application Module is associated with a single connection but there is nothing to stop you from creating multiple instances of the same Application Module within the application, all pointing at different connections.  If fact this has been possible for a long time using a custom extension point with code that which extends oracle.jbo.http.HttpSessionCookieFactory. This approach, however, involves writing code and no-one likes to write any more code than they need to, so, is there an easier way? Yes indeed.  It is in fact  a little publicized feature that's available in all versions of 11g, the ELEnvInfoProvider. What Does it Do?  The ELEnvInfoProvider  is  a pre-existing class (the full path is  oracle.jbo.client.ELEnvInfoProvider) which you can plug into your ApplicationModule configuration using the jbo.envinfoprovider property. Visuallty you can set this in the editor, or you can also set it directly in the bc4j.xcfg (see below for an example) . Once you have plugged in this envinfoprovider, here's the fun bit, rather than defining the hard-coded name of a datasource instead you can plug in a EL expression for the connection to use.  So what's the benefit of that? Well it allows you to defer the selection of a connection until the point in time that you instantiate the AM. To define the expression itself you'll need to do a couple of things: First of all you'll need a managed bean of some sort – e.g. a sessionScoped bean defined in your ViewController project. This will need a getter method that returns the name of the connection. Now this connection itself needs to be defined in your Application Server, and can be managed through Enterprise Manager, WLST or through MBeans. (You may need to read the documentation [http://docs.oracle.com/cd/E28280_01/web.1111/b31974/deployment_topics.htm#CHDJGBDD] here on how to configure connections at runtime if you're not familiar with this)   The EL expression (e.g. ${connectionManager.connection} is then defined in the configuration by editing the bc4j.xcfg file (there is a hyperlink directly to this file on the configuration editing screen in the Application Module editor). You simply replace the hardcoded JDBCName value with the expression.  So your cfg file would end up looking something like this (notice the reference to the ELEnvInfoProvider that I talked about earlier) <BC4JConfig version="11.1" xmlns="http://xmlns.oracle.com/bc4j/configuration">   <AppModuleConfigBag ApplicationName="oracle.demo.model.TargetAppModule">   <AppModuleConfig DeployPlatform="LOCAL"  JDBCName="${connectionManager.connection}" jbo.project="oracle.demo.model.Model" name="TargetAppModuleLocal" ApplicationName="oracle.demo.model.TargetAppModule"> <AM-Pooling jbo.doconnectionpooling="true"/> <Database jbo.locking.mode="optimistic">       <Security AppModuleJndiName="oracle.demo.model.TargetAppModule"/>    <Custom jbo.envinfoprovider="oracle.jbo.client.ELEnvInfoProvider"/> </AppModuleConfig> </AppModuleConfigBag> </BC4JConfig> Still Don't Quite Get It? So far you might be thinking, well that's fine but what difference does it make if the connection is resolved "just in time" rather than up front and changed as required through Enterprise Manager? Well a trivial example would be where you have a single application deployed to your application server, but for different users you want to connect to different databases. Because, the evaluation of the connection is deferred until you first reference the AM you have a decision point that can take the user identity into account. However, think about it for a second.  Under what circumstances does a new AM get instantiated? Well at the first reference of the AM within the application yes, but also whenever a Task Flow is entered -  if the data control scope for the Task Flow is ISOLATED.  So the reality is, that on a single screen you can embed multiple Task Flows, all of which are pointing at different database connections concurrently. Hopefully you'll find this feature useful, let me know... 

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• JSON undefined in IE7

  - by Joel

  Hey, I am using the following line of JQuery code: $.get('/ajax/buy', {'categoryname':chosenSelected}, function(data) { data = JSON.parse(data); ... However, when running it on IE7 I get error msg "JSON undefined:". How can I use the parser with compatibility to IE7 (and all major browsers)? Thanks in advance, Joel

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• AjaxControlToolkit: HtmlEditor Textarea not showing in Chrome/Safari

  - by pagetailor

  Hi, I am using the HtmlEditor Control included in the AjaxControlToolkit (patched version v62210 because I needed some of the included fixes). Unfortunately the textarea in the Html Editor control is never displayed in Chrome and Safari (both latest version). It doesn't matter if there is text in it or not. It does work on the AjaxControlToolkit Sample page with both browsers though. Any ideas?

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• C# Ignore certificate errors?

  - by JL

  I am getting the following error during a web service request to a remote web service: Could not establish trust relationship for the SSL/TLS secure channel. --- System.Security.Authentication.AuthenticationException: The remote certificate is invalid according to the validation procedure. Is there anyway to ignore this error, and continue. It seems the remote certificate is not signed. The site I connect to is www.czebox.cz - so feel free to visit the site, and notice even browsers through security exceptions. Thanks

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• What is the HTTP_PROFILE browser header and how is it used?

  - by Tom

  I've just come across the HTTP_PROFILE header that seems to be used by mobile browsers to point to an .xml document describing the device's capabilities. Doing a Google search doesn't turn up any definitive resources on what this is and how it should be used, can anyone point me to something along the lines of a spec/W3C standard?

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• jQuery ajax, firefox with 302 redirects?

  - by Lowgain

  I'm having problems in Firefox with 302 redirects coming from my Rails app. Right now I have $.ajax({ url: '/model/33', type: 'POST', data: 'authenticity_token=efjowiejfoiwej&_method=put&model[value]=aaa', complete: myFunc }); function myFunc() { //do what I want } This works fine in other browsers, but in Firefox nothing happens, even using a complete callback instead of just a success. Anything I can missing here?

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• What are the basic applications of Windows services?

  - by infant programmer

  I have been quite comfortable with windows-services, I have been practicing since from last two weeks. Would you please explain me some of the basic applications of Windows service, so that I can take it as homework and practice. (it need not be too basic) I have already designed and implemented a project/service which is meant for closing all the browsers, when I open a program(or process) saying "Gtalk". I am interested and very eager to learn more things about Windows services. Regards.

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• Difference in css-positioning in windows and linux

  - by andrii

  I have a problem with rendering my html page by the same browsers in different OS. There are 3 spans and position of each span is corrected through css(position:relative). But I have found out that the page that looks correct in firefox under Linux, shows not right at the same firefox(3.5.7) under Windows OS. Linux(Left - How it should be)/Windows(right): link text And the same with other browsers. What is the cause of this problem and how is possible to solve it. My code: question.html: <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"/> <title>Question</title> <link href="css/question.css" rel="stylesheet" media="all" /> </head> <body> <div class="eventFullDate"> <span class="eventYear">2010</span> <span class="eventDate">17</span> <span class="eventMonth">FEB</span> </div> </body> </html> question.css: html, body{ font-family: Georgia; } div.eventFullDate{ height: 39px; width: 31px; float: left; border: 1px solid; border-color: #E3E3E3; background-color: #F7FFFF; } span.eventYear, span.eventDate, span.eventMonth{ color: #EC5C1D; position: relative; width: 100%; } span.eventYear{ left: 1px; bottom: 3px; font-size: 0.8em; } span.eventDate{ left: 5px; bottom: 12px; font-size: 1.3em; } span.eventMonth{ left: 3px; bottom: 15px; font-size: 0.8em; }

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• HTTP Referrer and IE7 and IE8

  - by cocacola09

  Hi i've tried the following to find the referrer in MSIE / IE7 and IE8 but its returning blank each time; PHP: <? echo $_SERVER['HTTP_REFERER']; ?> JAVASCRIPT: document.write('Thanks for visiting from ' + document.referrer); Does any know what the issue could be I'm referering using document.location from a page on another domain and work fine with all other browsers minus MSIE. Any help would be great!

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• sIFR problem in IE document.defaultView.getComputedStyle

  - by Jai Ivarsson

  I have sIFR 3 r436 working perfectly in all browsers except IE. IE throws 2 errors. The first is: 'document.defaultView.getComputedStyle' is null of not an object This is on the sifr.js file The second is: 'sIFR' is null or not an object This one is happening I think due to the fact that the sifr.js script is failing in it's load. Has anyone had anything like this before? Thanks, Jai

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• Label wrapped around radio/checkbox compatibility?

  - by Mark

  I noticed that if you wrap a radio button or checkbox in a label, the whole thing becomes clickable, even without a for/id pair (in fact, it seems to ignore this because I screwed it up!) Example: <label><input type="checkbox"> some text</label> Then "some text" becomes clickable to check the box. I tested it in FF, Chrome and Opera, and IE8, does anyone know if it works in older browsers, like IE6?

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• IE6 (yes, IE6) css spacing issue

  - by Tim

  Hey Guys I'm basically building this page which obviously works fine in all browsers apart from IE6, where a small space appears below the cart. The background also has a gap in it in IE6, so I'm wondering what my be causing that, as it's probably related to the main issue. The html can be found here: http://bit.ly/94CjAJ If anyone could help I would REALLY appreciate it!!!! Many thanks

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• Can I use HTML5 Now to create a website

  - by Steve

  After all the latest news and talk about HTML5, I would like to know whether I can use HTML5 to create a website as of now. I mean, some features are supported by few browsers, while few features are not yet supported. So is it possible to create a full-fledged website at the current state?

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• How to scroll page to a custom location

  - by Rajat

  Hi, I am looking to scroll the page to a particular location.Something like this: function scrollTo(y){ document.body. some-property = y; } I am looking to solve this without using any libraries. I know scrollTop works in some browsers but I tried it if FF 3.6 and IE 8 and it doesn't work. Does anyone know how to complete that function ?

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• Css hacks Raison d'être

  - by Denis

  Hi, Since I build layouts with css, I always refuse to use css hacks for different browsers. In your opinion, is there real benefits to use hacks? Cheers

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• PHP Browser Detection and Redirection

  - by Vincent

  All, My application supports IE7+, MOZILLA and other modern browsers. Anybody know of a very good browser detection and redirection PHP class? I came across this, but I am not sure if anybody used this: http://chrisschuld.com/projects/browser-php-detecting-a-users-browser-from-php/#typicalusage Thanks

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• How to Include CSS and JS files via HTTPS when needed?

  - by nute

  I am adding an external CSS file and an external JS file to my headers and footers. When loading an HTTPS page, some browsers complain that I am loading unsecured content. Is there an easy way to make the browser load the external content via HTTPS when the page itself is HTTPS?

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• jquery horizontal scroll with mousewheel

  - by steve

  I currently have a site that is a sidescroller (http://www.studioimbrue.com) and I'm trying to bind a mousewheel to scroll sideways. Currently I'm using the one found at thehorizontalway.com (called thw.js) but it doesn't seem to work in all browsers (Chrome). I'm trying to get this one to work: http://brandonaaron.net/code/mousewheel/docs , to simply scroll the whole window, nothing else. There is very limited documentation so I can't figure it out. Any help is appreciated.

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