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• Can't the NetworkManager applet to appear in the Gnome panel in Ubuntu

  - by Nate

  I have researched this problem extensively and I can't seem to find an answer. In Ubuntu 10.04 LTS, I want to connect to my VPN through the NetworkManager applet. I installed all the network manager packages, including the gnome client. I understand I need to add the "Notification Area" to the panel, which I have done. I checked that the NetworkManager is running: nate@nate-desktop:~$ service network-manager status network-manager start/running, process 763 In /etc/NetworkManager/nm-system-settings.conf, I have added managed=true (don't know if this matters, but I saw it suggested on one forum): nate@nate-desktop:~$ more /etc/NetworkManager/nm-system-settings.conf # This file is installed into /etc/NetworkManager, and is loaded by # NetworkManager by default. To override, specify: '--config file' # during NM startup. This can be done by appending to DAEMON_OPTS in # the file: # # /etc/default/NetworkManager # [main] plugins=ifupdown,keyfile [ifupdown] #managed=false managed=true At this point, it looks like NetworkManager is running but it's not appearing in the NotificationArea of the panel. I don't know what else to try. Any ideas?

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• Can't the NetworkManager applet to appear in the Gnome panel in Ubuntu

  - by Nate

  I have researched this problem extensively and I can't seem to find an answer. In Ubuntu 10.04 LTS, I want to connect to my VPN through the NetworkManager applet. I installed all the network manager packages, including the gnome client. I understand I need to add the "Notification Area" to the panel, which I have done. I checked that the NetworkManager is running: nate@nate-desktop:~$ service network-manager status network-manager start/running, process 763 In /etc/NetworkManager/nm-system-settings.conf, I have added managed=true (don't know if this matters, but I saw it suggested on one forum): nate@nate-desktop:~$ more /etc/NetworkManager/nm-system-settings.conf # This file is installed into /etc/NetworkManager, and is loaded by # NetworkManager by default. To override, specify: '--config file' # during NM startup. This can be done by appending to DAEMON_OPTS in # the file: # # /etc/default/NetworkManager # [main] plugins=ifupdown,keyfile [ifupdown] #managed=false managed=true At this point, it looks like NetworkManager is running but it's not appearing in the NotificationArea of the panel. I don't know what else to try. Any ideas?

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• Virtual machine image compatibility between VMware Server and VMware Player

  - by alexandrul

  I'm trying to minimize the number of different product versions used on my PC's both at work and at home. So far I have a mixture of: VMware Server 1.0.7 VMware Server 2.0.2 VMware Player 2.5.3 VMware Player 3.0.0 and I would love to upgrade each product family to the latest version. Since Virtual Machine Mobility Guide is marked as deprecated, can anyone point me to some fresh information about virtual machine compatibility between VMware Player and VMware Server, in order to still be able to move virtual machines back and forth between the mentioned products? Update What I'm looking for is an updated document with virtual machines hardware versions, and the VMware products that are able to use that specific hardware version, so I can know - given the products that are using a specific virtual machine - what is the maximum hardware version that I can update the virtual machine to.

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• Laptop and 2 screens: use screens but not monitor display

  - by ClarkeyBoy

  Hi, I have 1 VGA socket on my laptop, and currently have that in use by a large screen. At some point in the future I would like to get another one of these screens and use both screens in dual screen mode but not use my laptop display (to be honest my laptop display is pretty rubbish as its like 2/3s the size of my screen - even if I had the choice to use all 3 I probably wouldn't want to). Is it possible to achieve this? If so, what do I need by way of hardware / software, and how much do you reckon it should cost me? Thanks in advance. Regards, Richard

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• Max ping response time?

  - by DougN

  I'm wondering what a maximum (practical) ping response time might be. As far as I know, there isn't a max defined anywhere (TTL, but that's hops, not time). As I think about it, I'm not sure I've ever seen a ping response time of more than a second or so. But as far as I know, there is nothing to stop a remote host from waiting (or being really busy) and not sending the response back for a few seconds. As a simple data point, I just pinged a number of servers around the world and the worst time I could find was 350ms.

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• Should we be able to deploy a single package to the SSIS Catalog?

  - by jamiet

  My buddy Sutha Thiru sent me an email recently asking about my opinion on a particular nuance of the project deployment model in SQL Server Integration Services (SSIS) 2012 and I’d like to share my response as I think it warrants a wider discussion. Sutha asked: Jamie What is your take on this? http://www.mattmasson.com/index.php/2012/07/can-i-deploy-a-single-ssis-package-from-my-project-to-the-ssis-catalog/ Overnight I was talking to Matt who confirmed that they got no plans to change the deployment model. For example if we have following scenrio how do we do deploy? Sprint 1 Pkg1, 2 & 3 has been developed and deployed to UAT. Once signed off its been deployed to Live. Sprint 2 Pkg 4 & 5 been developed. During this time users raised a bug on Pkg2. We want to make the change to Pkg2 and deploy that to UAT and eventually to LIVE without releasing Pkg 4 &5. How do we do it? Matt pointed me to his blog entry which I have seen before . http://www.mattmasson.com/index.php/2012/02/thoughts-on-branching-strategies-for-ssis-projects/ Thanks Sutha My response: Personally, even though I've experienced the exact problem you just outlined, I agree with the current approach. I steadfastly believe that there should not be a way for an unscrupulous developer to slide in a new version of a package under the covers. Deploying .ispac files brings a degree of rigour to your operational processes. Yes, that means that we as SSIS developers are going to have to get better at using source control and branching properly but that is no bad thing in my opinion. Claiming to be proper "developers" is a bit of a cheap claim if we don't even do the fundamentals correctly. I would be interested in the thoughts of others who have used the project deployment model. Do you agree with my point of view? @Jamiet

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• How to extend Wi-Fi signal across rooms?

  - by Sriram Krishnan

  I moved into a new place and my old Wi-Fi router just doesn't have the range to get into all the rooms. I've been investigating a lot of options and I'm wondering what other folks have done here. Moving the current location of my primary Wi-Fi router is not an option thanks to our cable provider and our landlord. Buy a bigger, beefier router (seems expensive). If so, should I go for one of those draft 802.11n ones to avoid microwave/other Wi-Fi router interference? Set up a router with DD-WRT as a repeater Leech the neighbors' open Wi-Fi access point. Alright, I was kidding about the last one but I'm genuinely curious as to what my best option is.

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• How to host customer developed code server side

  - by user963263

  I'm developing a multi-tenant web application, most likely using ASP.NET MVC5 and Web API. I have used business applications in the past where it was possible to upload custom DLL's or paste in custom code to a GUI to have custom functions run server side. These applications were self hosted and single-tenant though so the customer developed bits didn't impact other clients. I want to host the multi-tenant web application myself and allow customers to upload custom code that will run server side. This could be for things like custom web services that client side JavaScript could interact with, or it could be for automation steps that they want triggered server side asynchronously when a user takes a particular action. Additionally, I want to expose an API that allows customers' code to interact with data specific to the web application itself. Client code may need to be "wrapped" so that it has access to appropriate references - to our custom API and maybe to a white list of approved libraries. There are several issues to consider - security, performance (infinite loops, otherwise poorly written code, load balancing, etc.), receive compiled DLL's or require raw code, etc. Is there an established pattern for this sort of thing or a sample project anyone can point to? Or any general recommendations?

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• SQL SERVER – Technical Reference Guides for Designing Mission-Critical Solutions – A Must Read

  - by pinaldave

  Yesterday I was reading architecture reference material helping my friend who was looking for material in this respect. While working together we were searching twitter, facebook and search engines to find relevant material.While searching online we end up on very interactive reference point. Once I send the same to him, he replied he may not need anything more after referencing this material. The best part of this article was it gives access to various aspect of the technology of the image map. Here is the abstract of the original article from the site: The Technical Reference Guides for Designing Mission-Critical Solutions provide planning and architecture guidance for various mission-critical workloads deployed by users. These guides reflect the knowledge gained by Microsoft while working with customers on mission-critical deployments. Each guide provides not only the key technical concepts and information helpful for design, but also “lessons learned,” best practices, and references to customer case studies. Once you click on any of the desired topic, you will see further detailed image map of the selected topic. Personally once I ended up on this site, I was there for more than 2 hours clicking through various links. Click on image to see larger image Read more here: Technical Reference Guides for Designing Mission-Critical Solutions Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, SQL White Papers, T SQL, Technology

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• What are the best options for a root filesystem hosted on SSD under Linux

  - by stsquad

  I'm working on an embedded system which is going to be booting and hosting it's rootfs on an SSD disk. We are currently looking at using Intel X-18M SSDs. The file system structure will have a fairly static /usr section (modulo software upgrades) and an active /var and /var/log for maintaining state and logging. Given the wear-levelling done by the underlying flash does having separate partitions help or hinder? As modern SSDs appear as straight block devices and hide their mapping magic behind their firmware is there any point trying to optimise the choice of file-system that sits on-top of the SSD? Finally does enable SMART monitoring make any sense in this context or are their SSD specific ways of determining the underlying health of the storage hardware?

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• Learning to code first game, few questions on basic game development and 3D

  - by ProgrammerByDay

  I've been programming for a while, and I'm concurrently learning how to make a basic game and slimdx, and wanted to talk to someone to hopefully get a few pointers. I've read that Tetris is the "Hello, world" of game programming, which made sense to me, so I decided to give it a shot. I've been able to code up a basic version in a few hours, which I'm quite happy with, but I had a few questions about 3D programming. Right now I'm using Direct3D to do display the blocks without any textures (just colored squares). I have a data structure (2d array of bytes, where each byte denotes the presence of a block and its color) which is the "game board," and on every render() call I create a new vertex buffer of the existing squares in the game board, and draw those primitives. This feels very inefficient, and I wondering what would be the idiomatic way of doing this in a 3D world, with matrix/rotations/translation operations. I know 3D is overkill for such a project, but I want to learn any 3d concepts that I can while I'm doing it. I understand that what you'd usually want to do is keep the same vertices/vertex buffers but manipulate them with matrices to achieve rotations/translations, etc. To do so, I assume what would happen is I'd have one vertex buffer for the "active" piece, since that'll be constantly rotated and moved, and have one vertex buffer for the frozen pieces on the bottom of the board, which is pretty much stationary, but will need to be changed/recreated when the active piece becomes frozen. Right now I'm just clearing and redrawing on every render call, which seems like the easiest way to do things, although I wonder if there's a more efficient way to deal with changes. Obviously there are a lot of questions I'm asking here, but if you can even just point me a step or two ahead in terms of how I should be thinking, it'd be great. Thanks

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• IMAP and Folder Subscriptions

  - by tom

  Hey guys I'm trying to figure out how folder subscriptions work with IMAP Clients and, in my case, in an Exchange 2007 environment. I have managed to deduce, I think correctly, that the folder subscription settings for individuals are stored centrally on the mailbox (At least, having configured 2 profiles on thunderbird, on 2 different machines, they subscribe to the exact same folders and dont display the exact same ones). The point of this being that I have had 2 or 3 different people in the past day report to me that they are having problems subscribing to certain folders, and having certain folder subscriptions remembered (particularly sub-folders). This is across both Thunderbird 2 and 3. can anyone suggest anything? Tom

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• Webcast: Leveraging Mobile And Social Commerce To Deliver A Complete Customer Experience

  - by Michael Hylton

    Mobile and social media are emerging as new channels for customers to interact and transact with brands. Mobile users demand experiences that are relevant and engaging and are designed with the capabilities and constraints of devices in mind. Just having a mobile app or mobile-specific website is not a long-term strategy. Brands must invest in an optimized experience, especially as mobile becomes critical to an overall digital commerce strategy.Debating the merits of using Facebook or not is missing the point when it comes to social media. True innovators are thinking beyond the social channel and are building programs that leverage Facebook data to drive conversions and engagement both on and off Facebook.  Learn how to be more strategic about mobile and social commerce in this informative editorial webcast.Attend this webcast and you will learn: How to leverage mobile and social touchpoints in digital commerce Why having a Facebook page or a mobile app is not enough The benefits of a consistent, personalized and relevant customer experience Strategies for integrating mobile and social into an overall digital commerce strategy Featured Speakers: Peter Sheldon, Senior Analyst, eBusiness & Channel Strategy Professionals, Forrester Research Brenna Johnson, Product Manager, Oracle Commerce Click here to register.

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• Webcast: Leveraging Mobile And Social Commerce To Deliver A Complete Customer Experience

  - by Michael Hylton

    Mobile and social media are emerging as new channels for customers to interact and transact with brands. Mobile users demand experiences that are relevant and engaging and are designed with the capabilities and constraints of devices in mind. Just having a mobile app or mobile-specific website is not a long-term strategy. Brands must invest in an optimized experience, especially as mobile becomes critical to an overall digital commerce strategy.Debating the merits of using Facebook or not is missing the point when it comes to social media. True innovators are thinking beyond the social channel and are building programs that leverage Facebook data to drive conversions and engagement both on and off Facebook.  Learn how to be more strategic about mobile and social commerce in this informative editorial webcast.Attend this webcast and you will learn: How to leverage mobile and social touchpoints in digital commerce Why having a Facebook page or a mobile app is not enough The benefits of a consistent, personalized and relevant customer experience Strategies for integrating mobile and social into an overall digital commerce strategy Featured Speakers: Peter Sheldon, Senior Analyst, eBusiness & Channel Strategy Professionals, Forrester Research Brenna Johnson, Product Manager, Oracle Commerce Click here to register.

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• Bootstrapping in CloudFormation with Autoscale

  - by PapelPincel

  My CloudFormation template creates an autoscale group and bootstrap it with utility script /opt/aws/bin/cfn-init. When I remove the bootstrap part out of my template the, autoscale get created without any problem, but I add it the CloudFormation Stack fails and add line in /var/log/cloud-init.log : Error: AutoScalingGroupName does not specify any metadata The line above appens right after the following command : /opt/aws/bin/cfn-init --verbose --configsets orderedConfig --region us-east-1 --stack AS15 --resource AutoScalingGroupName --access-key XXXXXXXXXXXXX --secret-key XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX Digging a little bit deeper, in cfn-init I added the following lines the point where it exit: from pprint import pprint pprint(vars(detail)) and I get the following trace when running the previous cfn-init command : {'_description': None, '_lastUpdated': datetime.datetime(2012, 7, 12, 14, 52, 42), '_logicalResourceId': u'AutoScalingGroupName', '_metadata': None, '_physicalResourceId': u'AS15-AutoScalingGroupName-HNPOXXXXXXXX', '_resourceStatus': u'CREATE_COMPLETE', '_resourceStatusReason': None, '_resourceType': u'AWS::AutoScaling::AutoScalingGroup', '_stackId': u'arn:aws:cloudformation:us-east-1:XXXXXXXXXXXXX:stack/AS15/XXXXXXXX-cc30-11e1-XXXXXX-XXXXXXXXXX', '_stackName': u'AS15'} As you can see, the metadata field is empty and that's the reason why it fails to create the stack. Is there any known side effects for cfn-init when used with autoscale ?

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• Should we write detailed architecture design or just an outline when designing a program?

  - by EpsilonVector

  When I'm doing design for a task, I keep fighting this nagging feeling that aside from being a general outline it's going to be more or less ignored in the end. I'll give you an example: I was writing a frontend for a device that has read/write operations. It made perfect sense in the class diagram to give it a read and a write function. Yet when it came down to actually writing them I realized they were literally the same function with just one line of code changed (read vs write function call), so to avoid code duplication I ended up implementing a do_io function with a parameter that distinguishes between operations. Goodbye original design. This is not a terribly disruptive change, but it happens often and can happen in more critical parts of the program as well, so I can't help but wondering if there's a point to design more detail than a general outline, at least when it comes to the program's architecture (obviously when you are specifying an API you have to spell everything out). This might be just the result of my inexperience in doing design, but on the other hand we have agile methodologies which sort of say "we give up on planning far ahead, everything is going to change in a few days anyway", which is often how I feel. So, how exactly should I "use" design?

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• Which algorithms/data structures should I "recognize" and know by name?

  - by Earlz

  I'd like to consider myself a fairly experienced programmer. I've been programming for over 5 years now. My weak point though is terminology. I'm self-taught, so while I know how to program, I don't know some of the more formal aspects of computer science. So, what are practical algorithms/data structures that I could recognize and know by name? Note, I'm not asking for a book recommendation about implementing algorithms. I don't care about implementing them, I just want to be able to recognize when an algorithm/data structure would be a good solution to a problem. I'm asking more for a list of algorithms/data structures that I should "recognize". For instance, I know the solution to a problem like this: You manage a set of lockers labeled 0-999. People come to you to rent the locker and then come back to return the locker key. How would you build a piece of software to manage knowing which lockers are free and which are in used? The solution, would be a queue or stack. What I'm looking for are things like "in what situation should a B-Tree be used -- What search algorithm should be used here" etc. And maybe a quick introduction of how the more complex(but commonly used) data structures/algorithms work. I tried looking at Wikipedia's list of data structures and algorithms but I think that's a bit overkill. So I'm looking more for what are the essential things I should recognize?

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• JOGL hardware based shadow mapping - computing the texture matrix

  - by axel22

  I am implementing hardware shadow mapping as described here. I've rendered the scene successfully from the light POV, and loaded the depth buffer of the scene into a texture. This texture has correctly been loaded - I check this by rendering a small thumbnail, as you can see in the screenshot below, upper left corner. The depth of the scene appears to be correct - objects further away are darker, and that are closer to the light are lighter. However, I run into trouble while rendering the scene from the camera's point of view using the depth texture - the texture on the polygons in the scene is rendered in a weird, nondeterministic fashion, as shown in the screenshot. I believe I am making an error while computing the texture transformation matrix, but I am unsure where exactly. Since I have no matrix utilities in JOGL other then the gl[Load|Mult]Matrix procedures, I multiply the matrices using them, like this: void calcTextureMatrix() { glPushMatrix(); glLoadIdentity(); glLoadMatrixf(biasmatrix, 0); glMultMatrixf(lightprojmatrix, 0); glMultMatrixf(lightviewmatrix, 0); glGetFloatv(GL_MODELVIEW_MATRIX, shadowtexmatrix, 0); glPopMatrix(); } I obtained these matrices by using the glOrtho and gluLookAt procedures: glLoadIdentity() val wdt = width / 45 val hgt = height / 45 glOrtho(wdt, -wdt, -hgt, hgt, -45.0, 45.0) glGetFloatv(GL_MODELVIEW_MATRIX, lightprojmatrix, 0) glLoadIdentity() glu.gluLookAt( xlook + lightpos._1, ylook + lightpos._2, lightpos._3, xlook, ylook, 0.0f, 0.f, 0.f, 1.0f) glGetFloatv(GL_MODELVIEW_MATRIX, lightviewmatrix, 0) My bias matrix is: float[] biasmatrix = new float[16] { 0.5f, 0.f, 0.f, 0.f, 0.f, 0.5f, 0.f, 0.f, 0.f, 0.f, 0.5f, 0.f, 0.5f, 0.5f, 0.5f, 1.f } After applying the camera projection and view matrices, I do: glTexGeni(GL_S, GL_TEXTURE_GEN_MODE, GL_EYE_LINEAR) glTexGenfv(GL_S, GL_EYE_PLANE, shadowtexmatrix, 0) glEnable(GL_TEXTURE_GEN_S) for each component. Does anybody know why the texture is not being rendered correctly? Thank you.

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• Is there a quick way to create a Windows shortcut to a file without it validating the path?

  - by Alistair McMillan

  Trying to create a shortcut for someone else. It needs to point to files on one of their mapped drives. Instead of waiting for them to be available and create the shortcut on their PC, I was hoping to just create the shortcut on my PC and then transfer it over to their PC. However Windows tries to validate the path as you create the shortcut and since I don't have access to the same files it is throwing up an error and won't create the shortcut. Is there a way to create a shortcut without the path being validated?

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• Good Scoop: The PeopleSoft/IBM Backstory

  - by [email protected]

  By Brian Dayton on April 12, 2010 11:15 AM Sometimes you're searching for something online and you find an unrelated, bonus nugget. Last week I stumbled across an interesting blog post from Chris Heller of a PeopleSoft consulting shop in San Ramon, CA called Grey Sparling. I don't know these guys. But Chris, who apparently used to work on the PeopleTools team, wrote a great article on a pre-acquisition, would-be deal between IBM and PeopleSoft that would have standardized PeopleSoft on IBM technology. The behind-the-scenes perspective is interesting. His commentary on the challenges that the company and PeopleSoft customers would have encountered if the deal had gone through was also interesting: · "No common ownership. It's hard enough to get large groups of people to work together when they work for the same company, but with two separate companies it is much, much harder. Even within Oracle, progress on Fusion applications was slow until Thomas Kurian took over Fusion applications in addition to Fusion middleware." · "No customer buy-in. PeopleSoft customers weren't asking for a conversion to WebSphere, so the fact that doing that could have helped PeopleSoft stay independent wouldn't have meant much to them, especially since the cost of moving to whatever a "PeopleSoft built on WebSphere" would have been significant." · "No executive buy-in. This is related to the previous point, but it's worth calling out separately. If Oracle had walked away and the deal with IBM had gone through, and PeopleSoft customers got put through the wringer as part of WebSphere move, all of the PeopleSoft project teams would be put in the awkward position of explaining to their management why these additional costs and headaches were happening. Essentially they would need to "sell" the partnership internally to their own management team. That's not a fun conversation to have." I'm not surprised that something like this was in the works. But I did find the inside scoop and Heller's perspective on the challenges particularly interesting. Especially the advantages of aligning development of applications and infrastructure development under one roof. Here's a link to the whole blog entry.

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• Driver choice for addressing ubuntu wireless card issues

  - by Holly

  Hello, this should be a relatively simple question. I'm attempting to get my windows wireless card to work with ubuntu, booted from my portable hard drive. This is the guide I'm attempting to follow is on help.ubuntu.com, /community/WifiDocs/Driver/Ndiswrapper My wireless card is a Broadcom Corporation BCM4318 AirForce One 54g 802.11g Wireless LAN Controller. My computer is an HP Pavilion Entertainment dv5 notebook, which came with Vista 64. I would like confirmation about which of the drivers I should use. At this point, I'm leaning towards Broadcom BCM4318 HP Pavilion zv6000, but I thought it best to ask advice before taking action. The drivers I have to chose from are listed on this page http://sourceforge.net/apps/mediawiki/ndiswrapper/index.php?title=Category:Broadcom Thanks! Holly

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• Vista Enterprise doesn't find logon servers in a network with 802.1x authentication

  - by jneves

  In a network with 802.1x configuration and a samba server configured in the domain, I have a radius server that delegates the authentication against the samba domain for users (using LDAP). The radius defines which VLAN the user is supposed to have access. I'm trying to put a Windows Vista Enterprise in the same network, but it attempts to logon the domain before authenticating against the network in 802.1x and it doesn't find any logon servers. In the radius logs I see the machine trying to authenticate with 'host/'. Does Vista enterprise require that I put it in a network with access to the logon server at that point? Thanks in advance, João Miguel Neves

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• 'Binary XML' for game data?

  - by bluescrn

  I'm working on a level editing tool that saves its data as XML. This is ideal during development, as it's painless to make small changes to the data format, and it works nicely with tree-like data. The downside, though, is that the XML files are rather bloated, mostly due to duplication of tag and attribute names. Also due to numeric data taking significantly more space than using native datatypes. A small level could easily end up as 1Mb+. I want to get these sizes down significantly, especially if the system is to be used for a game on the iPhone or other devices with relatively limited memory. The optimal solution, for memory and performance, would be to convert the XML to a binary level format. But I don't want to do this. I want to keep the format fairly flexible. XML makes it very easy to add new attributes to objects, and give them a default value if an old version of the data is loaded. So I want to keep with the hierarchy of nodes, with attributes as name-value pairs. But I need to store this in a more compact format - to remove the massive duplication of tag/attribute names. Maybe also to give attributes native types, so, for example floating-point data is stored as 4 bytes per float, not as a text string. Google/Wikipedia reveal that 'binary XML' is hardly a new problem - it's been solved a number of times already. Has anyone here got experience with any of the existing systems/standards? - are any ideal for games use - with a free, lightweight and cross-platform parser/loader library (C/C++) available? Or should I reinvent this wheel myself? Or am I better off forgetting the ideal, and just compressing my raw .xml data (it should pack well with zip-like compression), and just taking the memory/performance hit on-load?

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• Timeout Considerations for Solicit Response

  - by Michael Stephenson

  Background One of the clients I work with had been experiencing some issues for a while surrounding web service timeouts.  It's been a little challenging to work through the problems due to limitations in the diagnostic information available from one of the applications, but I learned some interesting things while troubleshooting the problem which don't seem to have been discussed much in the community so I thought I'd share my findings. In the scenario we have BizTalk trying to make calls to a .net web service which was exposed as a WSE 2 endpoint.  In the process BizTalk will try to make a large number of concurrent web service calls to the application, and the backend application has more than enough infrastructure and capability to handle the load. We have configured the <ConnectionManagement> section of the BizTalk configuration file to support up to 100 concurrent connections from each of our 2 BizTalk send servers to the web servers of the application. The problem we were facing was that the BizTalk side was reporting a significant number of timeouts when calling the web service.   One of the biggest issues was the challenge of being able to correlate a message from BizTalk to the IIS log in the .net application and the custom logs in the application especially when there was a fairly large number of servers hosting the web services.  However the key moment came when we were able to identify a specific call which had taken 40 seconds to execute on the server (yes a long time I know but that's a different story!).  Anyway we were able to identify that this had timed out on the BizTalk side.  Based on the normal 2 minute timeout we knew something unexpected was going on. From here I decided to do some experimentation and I wanted to start outside of BizTalk because my hunch was this was not a BizTalk behaviour but something which was being highlighted by BizTalk because of our large load.     Server-side - Sample Web Service To begin with I created a sample web service.  Nothing special just a vanilla asmx web service hosted in IIS6 on Windows 2003 Standard Edition.  The web service is just a hello world style web service as shown in the below picture.  The only key feature is that the server side web method has a 30 second sleep in it and will trace out some information before and after the thread is set to sleep.      In the configuration for this web service there again is nothing special it's pretty much the most plain simple web service you could build. Client-Side To begin looking at what was happening with our example I created a number of different ways to consume the web service. SoapHttpClientProtocol Example I created a small application which would use a normal proxy generated to call the web service.  It would iterate around a loop and make calls using the begin/end methods so I can do this asynchronously.  I would do a loop of 20 calls with the ConnectionManager configuration section supporting only 5 concurrent connections to the server.     <connectionManagement> <remove address="*"/> <add address = "*" maxconnection = "12" /> <add address = "http://<ServerName>" maxconnection = "5" />                         </connectionManagement> </system.net>     The below picture shows an example of the service calling code, key points are: I have configured the timeout of 40 seconds for the proxy I am using the asynchronous methods on the proxy to call the web service         The Test I would run the client and execute 21 calls to the web service.   The Results  Below is the client side trace showing what's happening on the client. In the below diagram is the web service side trace showing what's happening on the server Some observations on the results are: All of the calls were successful from the clients perspective You could see the next call starting on the server as soon as the previous one had completed Calls took significantly longer than 40 seconds from the start of our call to the return. In fact call 20 took 2 minutes and 30 seconds from the perspective of my code to execute even though I had set the timeout to 40 seconds     WSE 2 Sample In the second example I used the exact same code to call the web service again with a single exception that I modified the web service proxy to derive from WebServiceClient protocol which is part of WSE 2 (using SP3).  The below picture shows the basic code and the key points are: I have configured the timeout of 40 seconds for the proxy I am using the asynchronous methods on the proxy to call the web service        The Test This test would execute 21 calls from the client to the web service.   The Results  The below trace is from the client side: The below trace is from the server side:   Some observations on the trace results for this scenario are: With call 4 if you look at the server side trace it did not start executing on the server for a number of seconds after the other 4 initial calls which were accepted by the server. I re-ran the test and this happened a couple of times and not on most others so at this point I'm just putting this down to something unexpected happening on the development machine and we will leave this observation out of scope of this article. You can see that the client side trace statement executed almost immediately in all cases All calls after the initial few calls would timeout On the client side the calls that did timeout; timed out in a longer duration than the 40 seconds we set as the timeout You can see that as calls were completing on the server the next calls were starting to come through The calls that timed out on the client did actually connect to the server and their server side execution completed successfully     Elaboration on the findings Based on the above observations I have drawn the below sequence diagram to illustrate conceptually what is happening.  Everything except the final web service object is on the client side of the call. In the diagram below I've put two notes on the Web Service Proxy to show the two different places where the different base classes seem to start their timeout counters. From the earlier samples we can work out that the timeout counter for the WSE web service proxy starts before the one for the SoapHttpClientProtocol proxy and the WSE one includes the time to get a connection from the pool; whereas the Soap proxy timeout just covers the method execution. One interesting observation is if we rerun the above sample and increase the number of calls from 21 to 100,000 then for the WSE sample we will see a similar pattern where everything after the first few calls will timeout on the client as soon as it makes a connection to the server whereas the soap proxy will happily plug away and process all of the calls without a single timeout. I have actually set the sample running overnight and this did happen. At this point you are probably thinking the same thoughts I was at the time about the differences in behaviour and which is right and why are they different? I'm not sure there is a definitive answer to this in the documentation, or at least not that I could find! I think you just have to consider that they are different and they could have different effects depending on your messaging solution. In lots of situations this is just not an issue as your concurrent requests doesn't get to the situation where you end up throttling the web service calls on the client side, however this is definitely more common with an integration broker such as BizTalk where you often have high throughput requirements.  Some of the considerations you should make Based on this behaviour you should be aware of the following: In a .net application if you are making lots of concurrent web service calls from an application in an asynchronous manner your user may thing they are experiencing poor performance but you think your web service is working well. The problem could be that the client will have a default of 2 connections to remote servers so you should bear this in mind When you are developing a BizTalk solution or a .net solution with the WSE 2 stack you may experience timeouts under load and throttling the number of connections using the max connections element in the configuration file will not help you For an application using WSE2 or SoapHttpClientProtocol an expired timeout will not throw an error until after a connection to the server has been made so you should consider this in your transaction and durability patterns     Our Work Around In the short term for our specific scenario we know that we can handle this by just increasing our timeout value.  There is only a specific small window when we get lots of concurrent traffic that causes this scenario so we should be able to increase the timeout to take into consideration the additional client side wait, and on the odd occasion where we do get a timeout the BizTalk send port retry will handle this. What was causing our original problem was that for that short window we were getting a lot of retries which significantly increased the load on our send servers and highlighted the issue.  Longer Term Solution As a longer term solution this really gives us more ammunition to argue a migration to WCF. The application we are calling has some factors which limit the protocols we can use but with WCF we would have more control on the various timeout options because in WCF you can configure specific parts of the timeout. Summary I've had this blog post on my to do list for ages but hopefully it will be useful to some people to just understand this behaviour and to possibly help you with some performance issues you may have. I do not believe there is too much in the way of documentation particularly around WSE2 and ASMX in this area so again another bit of ammunition for migrating to WCF. I'll try to do a follow up post with the sample for WCF to show how this changes things.

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• How do graphics programmers deal with rendering vertices that don't change the image?

  - by canisrufus

  So, the title is a little awkward. I'll give some background, and then ask my question. Background: I work as a web GIS application developer, but in my spare time I've been playing with map rendering and improving data interchange formats. I work only in 2D space. One interesting issue I've encountered is that when you're rendering a polygon at a small scale (zoomed way out), many of the vertices are redundant. An extreme case would be that you have a polygon with 500,000 vertices that only takes up a single pixel. If you're sending this data to the browser, it would make sense to omit ~499,999 of those vertices. One way we achieve that is by rendering an image on a server and and sending it as a PNG: voila, it's a point. Sometimes, though, we want data sent to the browser where it can be rendered with SVG (or canvas, or webgl) so that it can be interactive. The problem: It turns out that, using modern geographic data sets, it's very easy to overload SVG's rendering abilities. In an effort to cope with those limitations, I'm trying to figure out how to visually losslessly reduce a data set for a given scale and map extent (and, if necessary, for a known map pixel width and height). I got a great reduction in data size just using the Douglas-Peucker algorithm, and I believe I was able to get it to keep the polygons true to within one pixel. Unfortunately, Douglas-Peucker doesn't preserve topology, so it changed how borders between polygons got rendered. I couldn't readily find other algorithms to try out and adapt to the purpose, but I don't have much CS/algorithm background and might not recognize them if I saw them.

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