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• Community Branching

  - by Dane Morgridge

  As some may have noticed, I have taken a liking to Ruby (and Rails in particular) quite a bit recently. This last weekend I spoke at the NYC Code Camp on a comparison of ASP.NET and Rails as well as an intro to Entity Framework talk.  I am speaking at RubyNation in April and have submitted to other ruby conferences around the area and I am also doing a Rails and MongoDB talk at the Philly Code Camp in April. Before you start to think this is my "I'm leaving .NET post", which it isn't so I need to clarify. I am not, nor do I intend to any time in the near future plan on abandoning .NET.  I am simply branching out into another community based on a development technology that I very much enjoy.  If you look at my twitter bio, you will see that I am into Entity Framework, Ruby on Rails, C++ and ASP.NET MVC, and not necessarily in that order.  I know you're probably thinking to your self that I am crazy, which is probably true on several levels (especially the C++ part). I was actually crazy enough at the NYC Code Camp to show up wearing a Linux t-shirt, presenting with my MacBook Pro on Entity Framework, ASP.NET MVC and Rails. (I did get pelted in the head with candy by Rachel Appel for it though) At all of the code camps I am submitting to this year, i will be submitting sessions on likely all four topics, and some sessions will be a combination of 2 or more.  For example, my "ASP.NET MVC: A Gateway To Rails?" talk touches ASP.NET MVC, Entity Framework Code First and Rails. Simply put (and I talk about this in my MVC & Rails talk) is that learning and using Rails has made me a better ASP.NET MVC developer. Just one example of this is helper methods.  When I started working with ASP.NET MVC, I didn't really want to use helpers and preferred to just use standard html tags, especially where links were concerned.  It was just me being stubborn and not really seeing all of the benefit of the helpers.  To my defense, coming from WebForms, I wanted to be as bare metal as possible and it seemed at first like a lot of the helpers were an unnecessary abstraction. I took my first look at Rails back in v1 and didn't spend very much time with it so I dismissed it and went on my merry ASP.NET WebForms way.  Then I picked up ASP.NET MVC and grasped the MVC pattern itself much better. After this, I took another look at Rails and everything made sense.  I decided then to learn Rails. (I think it is important for developers to learn new languages and platforms regularly so it was a natural progression for me) I wanted to learn it the right way, so when I dug into code, everyone used helpers everywhere for pretty much everything possible. I took some time to dig in and found out how helpful they were and subsequently realized how awesome they were in ASP.NET MVC also and started using them. In short, I love Rails (and Ruby in general).  I also love ASP.NET MVC and Entity Framework and yes I still love C++.  I have varying degrees of love for them individually at any given moment and it is likely to shift based on the current project I am working on.  I know you're thinking it so before you ask the question. "Which do I use when?", I'm going to give the standard developer answer of: It depends.  There are a lot of factors that I am not going to even go into that would go into a decision.  The most basic question I would ask though is,  does this project depend on .NET?  If it does, then I'd say that ASP.NET MVC is probably going to be the more logical choice and I am going to leave it at that.  I am working on projects right now in both technologies and I don't see that changing anytime soon (one project even uses both). With all that being said, you'll find me at code camps, conferences and user groups presenting on .NET, Ruby or both, writing about .NET and Ruby and I will likely be blogging on both in the future.  I know of others that have successfully branched out to other communities and with any luck I'll be successful at it too. On a (sorta) side note, I read a post by Justin Etheredge the other day that pretty much sums up my feelings about Ruby as a language.  I highly recommend checking it out: What Is So Great About Ruby?

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• Cardinality Estimation Bug with Lookups in SQL Server 2008 onward

  - by Paul White

  Cost-based optimization stands or falls on the quality of cardinality estimates (expected row counts).  If the optimizer has incorrect information to start with, it is quite unlikely to produce good quality execution plans except by chance.  There are many ways we can provide good starting information to the optimizer, and even more ways for cardinality estimation to go wrong.  Good database people know this, and work hard to write optimizer-friendly queries with a schema and metadata (e.g. statistics) that reduce the chances of poor cardinality estimation producing a sub-optimal plan.  Today, I am going to look at a case where poor cardinality estimation is Microsoft’s fault, and not yours. SQL Server 2005 SELECT th.ProductID, th.TransactionID, th.TransactionDate FROM Production.TransactionHistory AS th WHERE th.ProductID = 1 AND th.TransactionDate BETWEEN '20030901' AND '20031231'; The query plan on SQL Server 2005 is as follows (if you are using a more recent version of AdventureWorks, you will need to change the year on the date range from 2003 to 2007): There is an Index Seek on ProductID = 1, followed by a Key Lookup to find the Transaction Date for each row, and finally a Filter to restrict the results to only those rows where Transaction Date falls in the range specified.  The cardinality estimate of 45 rows at the Index Seek is exactly correct.  The table is not very large, there are up-to-date statistics associated with the index, so this is as expected. The estimate for the Key Lookup is also exactly right.  Each lookup into the Clustered Index to find the Transaction Date is guaranteed to return exactly one row.  The plan shows that the Key Lookup is expected to be executed 45 times.  The estimate for the Inner Join output is also correct – 45 rows from the seek joining to one row each time, gives 45 rows as output. The Filter estimate is also very good: the optimizer estimates 16.9951 rows will match the specified range of transaction dates.  Eleven rows are produced by this query, but that small difference is quite normal and certainly nothing to worry about here.  All good so far. SQL Server 2008 onward The same query executed against an identical copy of AdventureWorks on SQL Server 2008 produces a different execution plan: The optimizer has pushed the Filter conditions seen in the 2005 plan down to the Key Lookup.  This is a good optimization – it makes sense to filter rows out as early as possible.  Unfortunately, it has made a bit of a mess of the cardinality estimates. The post-Filter estimate of 16.9951 rows seen in the 2005 plan has moved with the predicate on Transaction Date.  Instead of estimating one row, the plan now suggests that 16.9951 rows will be produced by each clustered index lookup – clearly not right!  This misinformation also confuses SQL Sentry Plan Explorer: Plan Explorer shows 765 rows expected from the Key Lookup (it multiplies a rounded estimate of 17 rows by 45 expected executions to give 765 rows total). Workarounds One workaround is to provide a covering non-clustered index (avoiding the lookup avoids the problem of course): CREATE INDEX nc1 ON Production.TransactionHistory (ProductID) INCLUDE (TransactionDate); With the Transaction Date filter applied as a residual predicate in the same operator as the seek, the estimate is again as expected: We could also force the use of the ultimate covering index (the clustered one): SELECT th.ProductID, th.TransactionID, th.TransactionDate FROM Production.TransactionHistory AS th WITH (INDEX(1)) WHERE th.ProductID = 1 AND th.TransactionDate BETWEEN '20030901' AND '20031231'; Summary Providing a covering non-clustered index for all possible queries is not always practical, and scanning the clustered index will rarely be optimal.  Nevertheless, these are the best workarounds we have today. In the meantime, watch out for poor cardinality estimates when a predicate is applied as part of a lookup. The worst thing is that the estimate after the lookup join in the 2008+ plans is wrong.  It’s not hopelessly wrong in this particular case (45 versus 16.9951 is not the end of the world) but it easily can be much worse, and there’s not much you can do about it.  Any decisions made by the optimizer after such a lookup could be based on very wrong information – which can only be bad news. If you think this situation should be improved, please vote for this Connect item. © 2012 Paul White – All Rights Reserved twitter: @SQL_Kiwi email: [email protected]

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• To Bit or Not To Bit

  - by Johnm

  'Twas a long day of troubleshooting and firefighting and now, with most of the office vacant, you face a blank scripting window to create a new table in his database. Many questions circle your mind like dirty water gurgling down the bathtub drain: "How normalized should this table be?", "Should I use an identity column?", "NVarchar or Varchar?", "Should this column be NULLABLE?", "I wonder what apple blue cheese bacon cheesecake tastes like?" Well, there are times when the mind goes it's own direction. A Bit About Bit At some point during your table creation efforts you will encounter the decision of whether to use the bit data type for a column. The bit data type is an integer data type that recognizes only the values of 1, 0 and NULL as valid. This data type is often utilized to store yes/no or true/false values. An example of its use would be a column called [IsGasoline] which would be intended to contain the value of 1 if the row's subject (a car) had a gasoline engine and a 0 if the subject did not have a gasoline engine. The bit data type can even be found in some of the system tables of SQL Server. For example, the sysssispackages table in the msdb database which contains SQL Server Integration Services Package information for the packages stored in SQL Server. This table contains a column called [IsEncrypted]. A value of 1 indicates that the package has been encrypted while the value of 0 indicates that it is not. I have learned that the most effective way to disperse the crowd that surrounds the office coffee machine is to engage into SQL Server debates. The bit data type has been one of the most reoccurring, as well as the most enjoyable, of these topics. It contains a practical side and a philosophical side. Practical Consideration This data type certainly has its place and is a valuable option for database design; but it is often used in situations where the answer is really not a pure true/false response. In addition, true/false values are not very informative or scalable. Let's use the previously noted [IsGasoline] column for illustration. While on the surface it appears to be a rather simple question when evaluating a car: "Does the car have a gasoline engine?" If the person entering data is entering a row for a Jeep Liberty, the response would be a 1 since it has a gasoline engine. If the person is entering data is entering a row for a Chevrolet Volt, the response would be a 0 since it is an electric engine. What happens when a person is entering a row for the gasoline/electric hybrid Toyota Prius? Would one person's conclusion be consistent with another person's conclusion? The argument could be made that the current intent for the database is to be used only for pure gasoline and pure electric engines; but this is where the scalability issue comes into play. With the use of a bit data type a database modification and data conversion would be required if the business decided to take on hybrid engines. Whereas, alternatively, if the int data type were used as a foreign key to a reference table containing the engine type options, the change to include the hybrid option would only require an entry into the reference table. Philosophical Consideration Since the bit data type is often used for true/false or yes/no data (also called Boolean) it presents a philosophical conundrum of what to do about the allowance of the NULL value. The inclusion of NULL in a true/false or yes/no response simply violates the logical principle of bivalence which states that "every proposition is either true or false". If NULL is not true, then it must be false. The mathematical laws of Boolean logic support this concept by stating that the only valid values of this scenario are 1 and 0. There is another way to look at this conundrum: NULL is also considered to be the absence of a response. In other words, it is the equivalent to "undecided". Anyone who watches the news can tell you that polls always include an "undecided" option. This could be considered a valid option in the world of yes/no/dunno. Through out all of these considerations I have discovered one absolute certainty: When you have found a person, or group of persons, who are willing to entertain a philosophical debate of the bit data type, you have found some true friends.

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• WIF, ADFS 2 and WCF&ndash;Part 5: Service Client (more Flexibility with WSTrustChannelFactory)

  - by Your DisplayName here!

  See the previous posts first. WIF includes an API to manually request tokens from a token service. This gives you more control over the request and more flexibility since you can use your own token caching scheme instead of being bound to the channel object lifetime. The API is straightforward. You first request a token from the STS and then use that token to create a channel to the relying party service. I’d recommend using the WS-Trust bindings that ship with WIF to talk to ADFS 2 – they are pre-configured to match the binding configuration of the ADFS 2 endpoints. The following code requests a token for a WCF service from ADFS 2: private static SecurityToken GetToken() {     // Windows authentication over transport security     var factory = new WSTrustChannelFactory(         new WindowsWSTrustBinding(SecurityMode.Transport),         stsEndpoint);     factory.TrustVersion = TrustVersion.WSTrust13;       var rst = new RequestSecurityToken     {         RequestType = RequestTypes.Issue,         AppliesTo = new EndpointAddress(svcEndpoint),         KeyType = KeyTypes.Symmetric     };       var channel = factory.CreateChannel();     return channel.Issue(rst); } Afterwards, the returned token can be used to create a channel to the service. Again WIF has some helper methods here that make this very easy: private static void CallService(SecurityToken token) {     // create binding and turn off sessions     var binding = new WS2007FederationHttpBinding(         WSFederationHttpSecurityMode.TransportWithMessageCredential);     binding.Security.Message.EstablishSecurityContext = false;       // create factory and enable WIF plumbing     var factory = new ChannelFactory<IService>(binding, new EndpointAddress(svcEndpoint));     factory.ConfigureChannelFactory<IService>();       // turn off CardSpace - we already have the token     factory.Credentials.SupportInteractive = false;       var channel = factory.CreateChannelWithIssuedToken<IService>(token);       channel.GetClaims().ForEach(c =>         Console.WriteLine("{0}\n {1}\n  {2} ({3})\n",             c.ClaimType,             c.Value,             c.Issuer,             c.OriginalIssuer)); } Why is this approach more flexible? Well – some don’t like the configuration voodoo. That’s a valid reason for using the manual approach. You also get more control over the token request itself since you have full control over the RST message that gets send to the STS. One common parameter that you may want to set yourself is the appliesTo value. When you use the automatic token support in the WCF federation binding, the appliesTo is always the physical service address. This means in turn that this address will be used as the audience URI value in the SAML token. Well – this in turn means that when you have an application that consists of multiple services, you always have to configure all physical endpoint URLs in ADFS 2 and in the WIF configuration of the service(s). Having control over the appliesTo allows you to use more symbolic realm names, e.g. the base address or a completely logical name. Since the URL is never de-referenced you have some degree of freedom here. In the next post we will look at the necessary code to request multiple tokens in a call chain. This is a common scenario when you first have to acquire a token from an identity provider and have to send that on to a federation gateway or Resource STS. Stay tuned.

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• Part 1 - Load Testing In The Cloud

  - by Tarun Arora

  Azure is fascinating, but even more fascinating is the marriage of Azure and TFS! Introduction Recently a client I worked for had 2 major business critical applications being delivered, with very little time budgeted for Performance testing, we immediately hit a bottleneck when the performance testing phase started, the in house infrastructure team could not support the hardware requirements in the short notice. It was suggested that the performance testing be performed on one of the QA environments which was a fraction of the production environment. This didn’t seem right, the team decided to turn to the cloud. The team took advantage of the elasticity offered by Azure, starting with a single test agent which was provisioned and ready for use with in 30 minutes the team scaled up to 17 test agents to perform a very comprehensive performance testing cycle. Issues were identified and resolved but the highlight was that the cost of running the ‘test rig’ proved to be less than if hosted on premise by the infrastructure team. Thank you for taking the time out to read this blog post, in the series of posts, I’ll try and cover the start to end of everything you need to know to use Azure to build your Test Rig in the cloud. But Why Azure? I have my own Data Centre… If the environment is provisioned in your own datacentre, - No matter what level of service agreement you may have with your infrastructure team there will be down time when the environment is patched - How fast can you scale up or down the environments (keeping the enterprise processes in mind) Administration, Cost, Flexibility and Scalability are the areas you would want to think around when taking the decision between your own Data Centre and Azure! How is Microsoft's Public Cloud Offering different from Amazon’s Public Cloud Offering? Microsoft's offering of the Cloud is a hybrid of Platform as a Service (PaaS) and Infrastructure as a Service (IaaS) which distinguishes Microsoft's offering from other providers such as Amazon (Amazon only offers IaaS). PaaS – Platform as a Service IaaS – Infrastructure as a Service Fills the needs of those who want to build and run custom applications as services. Similar to traditional hosting, where a business will use the hosted environment as a logical extension of the on-premises datacentre. A service provider offers a pre-configured, virtualized application server environment to which applications can be deployed by the development staff. Since the service providers manage the hardware (patching, upgrades and so forth), as well as application server uptime, the involvement of IT pros is minimized. On-demand scalability combined with hardware and application server management relieves developers from infrastructure concerns and allows them to focus on building applications. The servers (physical and virtual) are rented on an as-needed basis, and the IT professionals who manage the infrastructure have full control of the software configuration. This kind of flexibility increases the complexity of the IT environment, as customer IT professionals need to maintain the servers as though they are on-premises. The maintenance activities may include patching and upgrades of the OS and the application server, load balancing, failover clustering of database servers, backup and restoration, and any other activities that mitigate the risks of hardware and software failures.   The biggest advantage with PaaS is that you do not have to worry about maintaining the environment, you can focus all your time in solving the business problems with your solution rather than worrying about maintaining the environment. If you decide to use a VM Role on Azure, you are asking for IaaS, more on this later. A nice blog post here on the difference between Saas, PaaS and IaaS. Now that we are convinced why we should be turning to the cloud and why in specific Azure, let’s discuss about the Test Rig. The Load Test Rig – Topology Now the moment of truth, Of course a big part of getting value from cloud computing is identifying the most adequate workloads to take to the cloud, so I’ve decided to try to make a Load Testing rig where the Agents are running on Windows Azure.   I’ll talk you through the above Topology, - User: User kick starts the load test run from the developer workstation on premise. This passes the request to the Test Controller. - Test Controller: The Test Controller is on premise connected to the same domain as the developer workstation. As soon as the Test Controller receives the request it makes use of the Windows Azure Connect service to orchestrate the test responsibilities to all the Test Agents. The Windows Azure Connect endpoint software must be active on all Azure instances and on the Controller machine as well. This allows IP connectivity between them and, given that the firewall is properly configured, allows the Controller to send work loads to the agents. In parallel, the Controller will collect the performance data from the agents, using the traditional WMI mechanisms. - Test Agents: The Test Agents are on the Windows Azure Public Cloud, as soon as the test controller issues instructions to the test agents, the test agents start executing the load tests. The HTTP requests are issued against the web server on premise, the results are captured by the test agents. And finally the results are passed over to the controller. - Servers: The Web Server and DB Server are hosted on premise in the datacentre, this is usually the case with business critical applications, you probably want to manage them your self. Recap and What’s next? So, in the introduction in the series of blog posts on Load Testing in the cloud I highlighted why creating a test rig in the cloud is a good idea, what advantages does Windows Azure offer and the Test Rig topology that I will be using. I would also like to mention that i stumbled upon this [Video] on Azure in a nutshell, great watch if you are new to Windows Azure. In the next post I intend to start setting up the Load Test Environment and discuss pricing with respect to test agent machine types that will be used in the test rig. Hope you enjoyed this post, If you have any recommendations on things that I should consider or any questions or feedback, feel free to add to this blog post. Remember to subscribe to http://feeds.feedburner.com/TarunArora.  See you in Part II.   Share this post : CodeProject

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• Repeated disconnects on WPA PEAP network

  - by exasperated

  My school has a WPA PEAP network with GTC inner authentication. I am able to connect to the network, but once I load a website or two, the network become unresponsive (i.e. in Chromium, it gets stuck at "Sending request"), and I'm eventually disconnected. Any help will be greatly appreciated. Here's some log output. I can provide more if needed: Ubuntu 13.04 3.8.0-32-generic x86_64 lsusb: 03:00.0 Network controller: Intel Corporation Centrino Advanced-N 6235 (rev 24) lsmod: iwldvm                241872  0  mac80211              606457  1 iwldvm iwlwifi               173516  1 iwldvm cfg80211              511019  3 iwlwifi,mac80211,iwldvm dmesg: [    3.501227] iwlwifi 0000:03:00.0: irq 46 for MSI/MSI-X [    3.503541] iwlwifi 0000:03:00.0: loaded firmware version 18.168.6.1 [    3.527153] iwlwifi 0000:03:00.0: CONFIG_IWLWIFI_DEBUG disabled [    3.527162] iwlwifi 0000:03:00.0: CONFIG_IWLWIFI_DEBUGFS enabled [    3.527170] iwlwifi 0000:03:00.0: CONFIG_IWLWIFI_DEVICE_TRACING enabled [    3.527178] iwlwifi 0000:03:00.0: CONFIG_IWLWIFI_DEVICE_TESTMODE enabled [    3.527186] iwlwifi 0000:03:00.0: CONFIG_IWLWIFI_P2P disabled [    3.527192] iwlwifi 0000:03:00.0: Detected Intel(R) Centrino(R) Advanced-N 6235 AGN, REV=0xB0 [    3.527240] iwlwifi 0000:03:00.0: L1 Disabled; Enabling L0S [    3.551049] ieee80211 phy0: Selected rate control algorithm 'iwl-agn-rs' [  375.153065] iwlwifi 0000:03:00.0: L1 Disabled; Enabling L0S [  375.159727] iwlwifi 0000:03:00.0: Radio type=0x2-0x1-0x0 [  375.553201] iwlwifi 0000:03:00.0: L1 Disabled; Enabling L0S [  375.559871] iwlwifi 0000:03:00.0: Radio type=0x2-0x1-0x0 [ 1892.110738] iwlwifi 0000:03:00.0: L1 Disabled; Enabling L0S [ 1892.117357] iwlwifi 0000:03:00.0: Radio type=0x2-0x1-0x0 [ 5227.235372] iwlwifi 0000:03:00.0: L1 Disabled; Enabling L0S [ 5227.242122] iwlwifi 0000:03:00.0: Radio type=0x2-0x1-0x0 [ 5817.817954] iwlwifi 0000:03:00.0: L1 Disabled; Enabling L0S [ 5817.824560] iwlwifi 0000:03:00.0: Radio type=0x2-0x1-0x0 [ 5824.571917] iwlwifi 0000:03:00.0 wlan0: disabling HT/VHT due to WEP/TKIP use [ 5824.571929] iwlwifi 0000:03:00.0 wlan0: disabling HT as WMM/QoS is not supported by the AP [ 5824.571935] iwlwifi 0000:03:00.0 wlan0: disabling VHT as WMM/QoS is not supported by the AP [ 6956.290061] iwlwifi 0000:03:00.0: L1 Disabled; Enabling L0S [ 6956.296671] iwlwifi 0000:03:00.0: Radio type=0x2-0x1-0x0 [ 6963.080560] iwlwifi 0000:03:00.0 wlan0: disabling HT/VHT due to WEP/TKIP use [ 6963.080566] iwlwifi 0000:03:00.0 wlan0: disabling HT as WMM/QoS is not supported by the AP [ 6963.080570] iwlwifi 0000:03:00.0 wlan0: disabling VHT as WMM/QoS is not supported by the AP [ 7613.469241] iwlwifi 0000:03:00.0: L1 Disabled; Enabling L0S [ 7613.475870] iwlwifi 0000:03:00.0: Radio type=0x2-0x1-0x0 [ 7620.201265] iwlwifi 0000:03:00.0 wlan0: disabling HT/VHT due to WEP/TKIP use [ 7620.201278] iwlwifi 0000:03:00.0 wlan0: disabling HT as WMM/QoS is not supported by the AP [ 7620.201285] iwlwifi 0000:03:00.0 wlan0: disabling VHT as WMM/QoS is not supported by the AP [ 8232.762453] iwlwifi 0000:03:00.0: L1 Disabled; Enabling L0S [ 8232.769065] iwlwifi 0000:03:00.0: Radio type=0x2-0x1-0x0 [ 8239.581772] iwlwifi 0000:03:00.0 wlan0: disabling HT/VHT due to WEP/TKIP use [ 8239.581784] iwlwifi 0000:03:00.0 wlan0: disabling HT as WMM/QoS is not supported by the AP [ 8239.581792] iwlwifi 0000:03:00.0 wlan0: disabling VHT as WMM/QoS is not supported by the AP [13763.634808] iwlwifi 0000:03:00.0: L1 Disabled; Enabling L0S [13763.641427] iwlwifi 0000:03:00.0: Radio type=0x2-0x1-0x0 [16955.598953] iwlwifi 0000:03:00.0: L1 Disabled; Enabling L0S [16955.605574] iwlwifi 0000:03:00.0: Radio type=0x2-0x1-0x0 lshw:    *-network        description: Wireless interface        product: Centrino Advanced-N 6235        vendor: Intel Corporation        physical id: 0        bus info: pci@0000:03:00.0        logical name: wlan0        version: 24        serial: b4:b6:76:a0:4b:3c        width: 64 bits        clock: 33MHz        capabilities: pm msi pciexpress bus_master cap_list ethernet physical wireless        configuration: broadcast=yes driver=iwlwifi driverversion=3.8.0-32-generic firmware=18.168.6.1 ip=10.250.169.96 latency=0 link=yes multicast=yes wireless=IEEE 802.11abgn        resources: irq:46 memory:f7c00000-f7c01fff iwlist scan: Cell 02 - Address: 24:DE:C6:B0:C7:D9                     Channel:36                     Frequency:5.18 GHz (Channel 36)                     Quality=29/70  Signal level=-81 dBm                       Encryption key:on                     ESSID:"CatChat2x"                     Bit Rates:6 Mb/s; 9 Mb/s; 12 Mb/s; 18 Mb/s; 24 Mb/s                               36 Mb/s; 48 Mb/s; 54 Mb/s                     Mode:Master                     Extra:tsf=0000004ff3fe419b                     Extra: Last beacon: 27820ms ago                     IE: Unknown: 0009436174436861743278                     IE: Unknown: 01088C129824B048606C                     IE: Unknown: 030124                     IE: IEEE 802.11i/WPA2 Version 1                         Group Cipher : CCMP                         Pairwise Ciphers (1) : CCMP                         Authentication Suites (1) : 802.1x                     IE: Unknown: 2D1ACC011BFFFF000000000000000000000000000000000000000000                     IE: Unknown: 3D1624001B000000FF000000000000000000000000000000                     IE: Unknown: DD180050F2020101800003A4000027A4000042435E0062322F00                     IE: Unknown: DD1E00904C33CC011BFFFF000000000000000000000000000000000000000000                     IE: Unknown: DD1A00904C3424001B000000FF000000000000000000000000000000           Cell 04 - Address: 24:DE:C6:B0:C3:E9                     Channel:149                     Frequency:5.745 GHz                     Quality=28/70  Signal level=-82 dBm                       Encryption key:on                     ESSID:"CatChat2x"                     Bit Rates:6 Mb/s; 9 Mb/s; 12 Mb/s; 18 Mb/s; 24 Mb/s                               36 Mb/s; 48 Mb/s; 54 Mb/s                     Mode:Master                     Extra:tsf=000000181f60e19c                     Extra: Last beacon: 28680ms ago                     IE: Unknown: 0009436174436861743278                     IE: Unknown: 01088C129824B048606C                     IE: Unknown: 030195                     IE: Unknown: 050400010000                     IE: IEEE 802.11i/WPA2 Version 1                         Group Cipher : CCMP                         Pairwise Ciphers (1) : CCMP                         Authentication Suites (1) : 802.1x                     IE: Unknown: 2D1ACC011BFFFF000000000000000000000000000000000000000000                     IE: Unknown: 3D1695001B000000FF000000000000000000000000000000                     IE: Unknown: DD180050F2020101800003A4000027A4000042435E0062322F00                     IE: Unknown: DD1E00904C33CC011BFFFF000000000000000000000000000000000000000000                     IE: Unknown: DD1A00904C3495001B000000FF000000000000000000000000000000                     IE: Unknown: DD07000B8601040817                     IE: Unknown: DD0E000B860103006170313930333032           Cell 09 - Address: 24:DE:C6:B0:C0:29                     Channel:149                     Frequency:5.745 GHz                     Quality=39/70  Signal level=-71 dBm                       Encryption key:on                     ESSID:"CatChat2x"                     Bit Rates:6 Mb/s; 9 Mb/s; 12 Mb/s; 18 Mb/s; 24 Mb/s                               36 Mb/s; 48 Mb/s; 54 Mb/s                     Mode:Master                     Extra:tsf=00000112fb688ede                     Extra: Last beacon: 27716ms ago ifconfig (while connected): wlan0     Link encap:Ethernet  HWaddr b4:b6:76:a0:4b:3c             inet addr:10.250.16.220  Bcast:10.250.31.255  Mask:255.255.240.0           inet6 addr: fe80::b6b6:76ff:fea0:4b3c/64 Scope:Link           UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1           RX packets:230023 errors:0 dropped:0 overruns:0 frame:0           TX packets:130970 errors:0 dropped:0 overruns:0 carrier:0           collisions:0 txqueuelen:1000            RX bytes:255999759 (255.9 MB)  TX bytes:16652605 (16.6 MB) iwconfig (while connected): wlan0     IEEE 802.11abgn  ESSID:"CatChat2x"             Mode:Managed  Frequency:5.745 GHz  Access Point: 24:DE:C6:B0:C0:29              Bit Rate=6 Mb/s   Tx-Power=15 dBm              Retry  long limit:7   RTS thr:off   Fragment thr:off           Power Management:off           Link Quality=36/70  Signal level=-74 dBm             Rx invalid nwid:0  Rx invalid crypt:0  Rx invalid frag:0           Tx excessive retries:0  Invalid misc:3   Missed beacon:0

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• .NET development on a Retina MacBook Pro with Windows 8

  - by Jeff

  I remember sitting in Building 5 at Microsoft with some of my coworkers, when one of them came in with a shiny new 11” MacBook Air. It was nearly two years ago, and we found it pretty odd that the OEM’s building Windows machines sucked at industrial design in a way that defied logic. While Dell and HP were in a race to the bottom building commodity crap, Apple was staying out of the low-end market completely, and focusing on better design. In the process, they managed to build machines people actually wanted, and maintain an insanely high margin in the process. I stopped buying the commodity crap and custom builds in 2006, when Apple went Intel. As a .NET guy, I was still in it for Microsoft’s stack of development tools, which I found awesome, but had back to back crappy laptops from HP and Dell. After that original 15” MacBook Pro, I also had a Mac Pro tower (that I sold after three years for $1,500!), a 27” iMac, and my favorite, a 17” MacBook Pro (the unibody style) with an SSD added from OWC. The 17” was a little much to carry around because it was heavy, but it sure was nice getting as much as eight hours of battery life, and the screen was amazing. When the rumors started about a 15” model with a “retina” screen inspired by the Air, I made up my mind I wanted one, and ordered it the day it came out. I sold my 17”, after three years, for $750 to a friend who is really enjoying it. I got the base model with the upgrade to 16 gigs of RAM. It feels solid for being so thin, and if you’ve used the third generation iPad or the newer iPhone, you’ll be just as thrilled with the screen resolution. I’m typically getting just over six hours of battery life while running a VM, but Parallels 8 allegedly makes some power improvements, so we’ll see what happens. (It was just released today.) The nice thing about VM’s are that you can run more than one at a time. Primarily I run the Windows 8 VM with four cores (the laptop is quad-core, but has 8 logical cores due to hyperthreading or whatever Intel calls it) and 8 gigs of RAM. I also have a Windows Server 2008 R2 VM I spin up when I need to test stuff in a “real” server environment, and I give it two cores and 4 gigs of RAM. The Windows 8 VM spins up in about 8 seconds. Visual Studio 2012 takes a few more seconds, but count part of that as the “ReSharper tax” as it does its startup magic. The real beauty, the thing I looked most forward to, is that beautifully crisp C# text. Consolas has never looked as good as it does at 10pt. as it does on this display. You know how it looks great at 80pt. when conference speakers demo stuff on a projector? Think that sharpness, only tiny. It’s just gorgeous. Beyond that, everything is just so responsive and fast. Builds of large projects happen in seconds, hundreds of unit tests run in seconds… you just don’t spend a lot of time waiting for stuff. It’s kind of painful to go back to my 27” iMac (which would be better if I put an SSD in it before its third birthday). Are there negatives? A few minor issues, yes. As is the case with OS X, not everything scales right. You’ll see some weirdness at times with splash screens and icons and such. Chrome’s text rendering (in Windows) is apparently not aware of how to deal with higher DPI’s, so text is fuzzy (the OS X version is super sharp, however). You’ll also have to do some fiddling with keyboard settings to use the Windows 8 keyboard shortcuts. Overall, it’s as close to a no-compromise development experience as I’ve ever had. I’m not even going to bother with Boot Camp because the VM route already exceeds my expectations. You definitely get what you pay for. If this one also lasts three years and I can turn around and sell it, it’s worth it for something I use every day.

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• How many developers before continuous integration becomes effective for us?

  - by Carnotaurus

  There is an overhead associated with continuous integration, e.g., set up, re-training, awareness activities, stoppage to fix "bugs" that turn out to be data issues, enforced separation of concerns programming styles, etc. At what point does continuous integration pay for itself? EDIT: These were my findings The set-up was CruiseControl.Net with Nant, reading from VSS or TFS. Here are a few reasons for failure, which have nothing to do with the setup: Cost of investigation: The time spent investigating whether a red light is due a genuine logical inconsistency in the code, data quality, or another source such as an infrastructure problem (e.g., a network issue, a timeout reading from source control, third party server is down, etc., etc.) Political costs over infrastructure: I considered performing an "infrastructure" check for each method in the test run. I had no solution to the timeout except to replace the build server. Red tape got in the way and there was no server replacement. Cost of fixing unit tests: A red light due to a data quality issue could be an indicator of a badly written unit test. So, data dependent unit tests were re-written to reduce the likelihood of a red light due to bad data. In many cases, necessary data was inserted into the test environment to be able to accurately run its unit tests. It makes sense to say that by making the data more robust then the test becomes more robust if it is dependent on this data. Of course, this worked well! Cost of coverage, i.e., writing unit tests for already existing code: There was the problem of unit test coverage. There were thousands of methods that had no unit tests. So, a sizeable amount of man days would be needed to create those. As this would be too difficult to provide a business case, it was decided that unit tests would be used for any new public method going forward. Those that did not have a unit test were termed 'potentially infra red'. An intestesting point here is that static methods were a moot point in how it would be possible to uniquely determine how a specific static method had failed. Cost of bespoke releases: Nant scripts only go so far. They are not that useful for, say, CMS dependent builds for EPiServer, CMS, or any UI oriented database deployment. These are the types of issues that occured on the build server for hourly test runs and overnight QA builds. I entertain that these to be unnecessary as a build master can perform these tasks manually at the time of release, esp., with a one man band and a small build. So, single step builds have not justified use of CI in my experience. What about the more complex, multistep builds? These can be a pain to build, especially without a Nant script. So, even having created one, these were no more successful. The costs of fixing the red light issues outweighed the benefits. Eventually, developers lost interest and questioned the validity of the red light. Having given it a fair try, I believe that CI is expensive and there is a lot of working around the edges instead of just getting the job done. It's more cost effective to employ experienced developers who do not make a mess of large projects than introduce and maintain an alarm system. This is the case even if those developers leave. It doesn't matter if a good developer leaves because processes that he follows would ensure that he writes requirement specs, design specs, sticks to the coding guidelines, and comments his code so that it is readable. All this is reviewed. If this is not happening then his team leader is not doing his job, which should be picked up by his manager and so on. For CI to work, it is not enough to just write unit tests, attempt to maintain full coverage, and ensure a working infrastructure for sizable systems. The bottom line: One might question whether fixing as many bugs before release is even desirable from a business prespective. CI involves a lot of work to capture a handful of bugs that the customer could identify in UAT or the company could get paid for fixing as part of a client service agreement when the warranty period expires anyway.

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• Training a 'replacement', how to enforce standards?

  - by Mohgeroth

  Not sure that this is the right stack exchange site to ask this of, but here goes... Scope I work for a small company that employs a few hundred people. The development team for the company is small and works out of visual foxpro. A specific department in the company hired me in as a 'lone gunman' to fix and enhance a pre-existing invoicing system. I've successfully taken an Access application that suffered from a lot of risks and limitations and converted it into a C# application driven off of a SQL server backend. I have recently obtained my undergraduate and am no expert by any means. To help make up for that I've felt that earning microsoft certifications will force me to understand more about .net and how it functions. So, after giving my notice with 9 months in advance, 3 months ago a replacement finally showed up. Their role is to learn what I have been designing to an attempt to support the applications designed in C#. The Replacement Fresh out of college with no real-world work experience, the first instinct for anything involving data was and still is listboxes... any time data is mentioned the list box is the control of choice for the replacement. This has gotten to the point, no matter how many times I discuss other controls, where I've seen 5 listboxes on a single form. Classroom experience was almost all C++ console development. So, an example of where I have concern is in a winforms application: Users need to key Reasons into a table to select from later. Given that I know that a strongly typed data set exists, I can just drag the data source from the toolbox and it would create all of this for me. I realize this is a simple example but using databinding is the key. For the past few months now we have been talking about the strongly typed dataset, how to use it and where it interacts with other controls. Data sets, how they work in relation to binding sources, adapters and data grid views. After handing this project off I expected questions about how to implement these since for me this is the way to do it. What happened next simply floors me: An instance of an adapter from the strongly typed dataset was created in the activate event of the form, a table was created and filled with data. Then, a loop was made to manually add rows to a listbox from this table. Finally, a variable was kept to do lookups to figure out what ID the record was for updates if required. How do they modify records you ask? That was my first question too. You won't believe how simple it is, all you do it double click and they type into a pop-up prompt the new value to change it to. As a data entry operator, all the modal popups would drive me absolutely insane. The final solution exceeds 100 lines of code that must be maintained. So my concern is that none of this is sinking in... the department is only allowed 20 hours a week of their time. Up until last week, we've only been given 4-5 hours a week if I'm lucky. The past week or so, I've been lucky to get 10. Question WHAT DO I DO?! I have 4 weeks left until I leave and they fully 'support' this application. I love this job and the opportunity it has given me but it's time for me to spread my wings and find something new. I am in no way, shape or form convinced that they are ready to take over. I do feel that the replacement has the technical ability to 'figure it out' but instead of learning they just write code to do all of this stuff manually. If the replacement wants to code differently in the end, as long as it works I'm fine with that as horrifiying at it looks. However to support what I have designed they MUST to understand how it works and how I have used controls and the framework to make 'magic' happen. This project has about 40 forms, a database with over 30 some odd tables, triggers and stored procedures. It relates labor to invoices to contracts to projections... it's not as simple as it was three years ago when I began this project and the department is now in a position where they cannot survive without it. How in the world can I accomplish any of the following?: Enforce standards or understanding in constent design when the department manager keeps telling them they can do it however they want to Find a way to engage the replacement in active learning of the framework and system design that support must be given for Gracefully inform sr. management that 5-9 hours a week is simply not enough time to learn about the department, pre-existing processes, applications that need to be supported AND determine where potential enhancements to the system go... Yes I know this is a wall of text, thanks for reading through me but I simply don't know what I should be doing. For me, this job is a monster of a reference and things would look extremely bad if I left and things fell apart. How do I handle this?

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• Managing Your First SharePoint Project or Team

  - by Mark Rackley

  (*editor’s note* If you have proper SharePoint Training, know the difference between a site and a site collection, and have the utmost respect for the knowledge of your SharePoint team skip this blog and go directly to meetdux.com, do not pass go, do not collect $200… otherwise, please proceed) Dear Mr. or Mrs. I-know-nothing-about-SharePoint-but-hey,-I-have-manager-in-my-title-so-I’ll-tell-you-how-to-your-job, Thank you so much for joining the Acme corporation. We appreciate your eagerness and willingness to jump in and help us accomplish all of our goals here at acme (these roadrunner rockets don’t make themselves). You may have noticed that we have this thing called SharePoint lying around and we have invested some time in money to make it not a complete piece of garbage. So, I thought I’d give you some pointers to help make your stay here enjoyable and productive. Yeah… you don’t really know SharePoint Just because you had a mysite at your last organization or had a SharePoint 2003 team site does NOT mean you comprehend the vastness that is SharePoint. You don’t know what’s going on behind the scenes. You don’t know what should and should not be done. No, we CAN’T just query the SQL database directly. Yes, it really does take that long. No, we can’t do that out-of-the-box. Your experience doesn’t mean as much as you think it means… Yes, I’m aware that you co-created the internet with Al Gore and have been managing projects since I was blowing up GI Joe figures with firecrackers, however SharePoint is not like anything you have worked with before from a management perspective. Please don’t tell us the proper way to do our job or tell us how “you” would do it, and PLEASE don’t utter the words “I used to do some .NET development so let me know if you get stuck and need some guidance.” It MAY be possible for a incredible project manager to manage a SharePoint project and not understand the technology, but if you force your ideas on us or treat us like we don’t really know what we’re doing then you will prove yourself to NOT be one of those types. Oh no you didn’t… Please don’t tell us how you can bring in a group of guys of Kazakhstan to do the project for $20/hr. There are many companies out there who can do some really crappy SharePoint work and we don’t want to be stuck maintaining their junk. Do you know what it means to deploy a solution? Neither do some of those companies out there. However, there are are few AWESOME consulting firms out there but $150/hr is cheap for these guys. Believe me, it’s worth it though. You get what you pay for! Show us some respect We truly do appreciate and value your opinion and experience, but when we tell you something is different in SharePoint don’t be condescending and dismiss OUR experience and opinions. We have spent a lot of time and energy learning a very complicated technology that can open up a world of possibilities when used properly. We just want to make sure it is used properly. It’s not the same as .NET development. It’s not like a regular web application. There’s more going on behind the scenes than you can possibly fathom. Have a little faith in us please and listen when we talk. You may actually learn a thing or two. Take some time to learn the technology There is hope… you don’t have to be totally worthless. Take some time to learn SharePoint. Learn what it is and what it can do. Invest some time in learning our SharePoint environment. What’s our logical architecture and taxonomy? What governance do we have in place? If you just thought “huh?” then yes, I’m talking to you. Sincerely, Your SharePoint Team (This rant is not pointed at any particular organization or person. If you think it’s about you, you are wrong. This is just a general rant based upon things people have told me and things I’ve seen. If you don’t think it applies to you, please move on. If you think you might be guilty of handling your SharePoint team the wrong way, then just please listen, learn, and have a little faith in your team. You all have the same goal in mind. Also, take the time to learn something about SharePoint, you will all be less frustrated with each other.)

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• Best Practices - Dynamic Reconfiguration

  - by jsavit

  This post is one of a series of "best practices" notes for Oracle VM Server for SPARC (formerly named Logical Domains) Overview of dynamic Reconfiguration Oracle VM Server for SPARC supports Dynamic Reconfiguration (DR), making it possible to add or remove resources to or from a domain (virtual machine) while it is running. This is extremely useful because resources can be shifted to or from virtual machines in response to load conditions without having to reboot or interrupt running applications. For example, if an application requires more CPU capacity, you can add CPUs to improve performance, and remove them when they are no longer needed. You can use even use Dynamic Resource Management (DRM) policies that automatically add and remove CPUs to domains based on load. How it works (in broad general terms) Dynamic Reconfiguration is done in coordination with Solaris, which recognises a hypervisor request to change its virtual machine configuration and responds appropriately. In essence, Solaris receives a message saying "you now have 16 more CPUs numbered 16 to 31" or "8GB more RAM starting at address X" or "here's a new network or disk device - have fun with it". These actions take very little time. Solaris then can start using the new resource. In the case of added CPUs, that means dispatching processes and potentially binding interrupts to the new CPUs. For memory, Solaris adds the new memory pages to its "free" list and starts using them. Comparable actions occur with network and disk devices: they are recognised by Solaris and then used. Removing is the reverse process: after receiving the DR message to free specific CPUs, Solaris unbinds interrupts assigned to the CPUs and stops dispatching process threads. That takes very little time. primary # ldm list NAME STATE FLAGS CONS VCPU MEMORY UTIL UPTIME primary active -n-cv- SP 16 4G 1.0% 6d 22h 29m ldom1 active -n---- 5000 16 8G 0.9% 6h 59m primary # ldm set-core 5 ldom1 primary # ldm list NAME STATE FLAGS CONS VCPU MEMORY UTIL UPTIME primary active -n-cv- SP 16 4G 0.2% 6d 22h 29m ldom1 active -n---- 5000 40 8G 0.1% 6h 59m primary # ldm set-core 2 ldom1 primary # ldm list NAME STATE FLAGS CONS VCPU MEMORY UTIL UPTIME primary active -n-cv- SP 16 4G 1.0% 6d 22h 29m ldom1 active -n---- 5000 16 8G 0.9% 6h 59m Memory pages are vacated by copying their contents to other memory locations and wiping them clean. Solaris may have to swap memory contents to disk if the remaining RAM isn't enough to hold all the contents. For this reason, deallocating memory can take longer on a loaded system. Even on a lightly loaded system it took several 7 or 8 seconds to switch the domain below between 8GB and 24GB of RAM. primary # ldm set-mem 24g ldom1 primary # ldm list NAME STATE FLAGS CONS VCPU MEMORY UTIL UPTIME primary active -n-cv- SP 16 4G 0.1% 6d 22h 36m ldom1 active -n---- 5000 16 24G 0.2% 7h 6m primary # ldm set-mem 8g ldom1 primary # ldm list NAME STATE FLAGS CONS VCPU MEMORY UTIL UPTIME primary active -n-cv- SP 16 4G 0.7% 6d 22h 37m ldom1 active -n---- 5000 16 8G 0.3% 7h 7m What if the device is in use? (this is the anecdote that inspired this blog post) If CPU or memory is being removed, releasing it pretty straightforward, using the method described above. The resources are released, and Solaris continues with less capacity. It's not as simple with a network or I/O device: you don't want to yank a device out from underneath an application that might be using it. In the following example, I've added a virtual network device to ldom1 and want to take it away, even though it's been plumbed. primary # ldm rm-vnet vnet19 ldom1 Guest LDom returned the following reason for failing the operation: Resource Information ---------------------------------------------------------- ----------------------- /devices/virtual-devices@100/channel-devices@200/network@1 Network interface net1 VIO operation failed because device is being used in LDom ldom1 Failed to remove VNET instance That's what I call a helpful error message - telling me exactly what was wrong. In this case the problem is easily solved. I know this NIC is seen in the guest as net1 so: ldom1 # ifconfig net1 down unplumb Now I can dispose of it, and even the virtual switch I had created for it: primary # ldm rm-vnet vnet19 ldom1 primary # ldm rm-vsw primary-vsw9 If I had to take away the device disruptively, I could have used ldm rm-vnet -f but that could disrupt whoever was using it. It's better if that can be avoided. Summary Oracle VM Server for SPARC provides dynamic reconfiguration, which lets you modify a guest domain's CPU, memory and I/O configuration on the fly without reboot. You can add and remove resources as needed, and even automate this for CPUs by setting up resource policies. Taking things away can be more complicated than giving, especially for devices like disks and networks that may contain application and system state or be involved in a transaction. LDoms and Solaris cooperative work together to coordinate resource allocation and de-allocation in a safe and effective way. For best practices, use dynamic reconfiguration to make the best use of your system's resources.

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• How do I mount my External HDD with filesystem type errors?

  - by Snuggie

  I am a relatively new Ubuntu user and I am having some difficulty mounting my external 2TB HDD. When I first installed Linux my external HDD was working just fine, however, it has stopped working and I have a lot of important files on there that I need. Before my HDD would automatically mount and no worries. Now, however, it doesn't automatically mount and when I try to manually mount it I keep running into filesystem type errors that I can't seem to get past. Below are images that depict my step by step process of how I am trying to mount my HDD along with the errors I am receiving. If anybody has any idea what I am doing wrong or how to correct the issue I would greatly appreciate it. Step 1) Ensure the computer recognizes my external HDD. pj@PJ:~$ dmesg ... [ 5790.367910] scsi 7:0:0:0: Direct-Access WD My Passport 0748 1022 PQ: 0 ANSI: 6 [ 5790.368278] scsi 7:0:0:1: Enclosure WD SES Device 1022 PQ: 0 ANSI: 6 [ 5790.370122] sd 7:0:0:0: Attached scsi generic sg2 type 0 [ 5790.370310] ses 7:0:0:1: Attached Enclosure device [ 5790.370462] ses 7:0:0:1: Attached scsi generic sg3 type 13 [ 5792.971601] sd 7:0:0:0: [sdb] 3906963456 512-byte logical blocks: (2.00 TB/1.81 TiB) [ 5792.972148] sd 7:0:0:0: [sdb] Write Protect is off [ 5792.972162] sd 7:0:0:0: [sdb] Mode Sense: 47 00 10 08 [ 5792.972591] sd 7:0:0:0: [sdb] No Caching mode page found [ 5792.972605] sd 7:0:0:0: [sdb] Assuming drive cache: write through [ 5792.975235] sd 7:0:0:0: [sdb] No Caching mode page found [ 5792.975249] sd 7:0:0:0: [sdb] Assuming drive cache: write through [ 5792.987504] sdb: sdb1 [ 5792.988900] sd 7:0:0:0: [sdb] No Caching mode page found [ 5792.988911] sd 7:0:0:0: [sdb] Assuming drive cache: write through [ 5792.988920] sd 7:0:0:0: [sdb] Attached SCSI disk Step 2) Check if it mounted properly (it does not) pj@PJ:~$ df -ah Filesystem Size Used Avail Use% Mounted on /dev/sda1 682G 3.9G 644G 1% / proc 0 0 0 - /proc sysfs 0 0 0 - /sys none 0 0 0 - /sys/fs/fuse/connections none 0 0 0 - /sys/kernel/debug none 0 0 0 - /sys/kernel/security udev 2.9G 4.0K 2.9G 1% /dev devpts 0 0 0 - /dev/pts tmpfs 1.2G 928K 1.2G 1% /run none 5.0M 0 5.0M 0% /run/lock none 2.9G 156K 2.9G 1% /run/shm gvfs-fuse-daemon 0 0 0 - /home/pj/.gvfs Step 3) Try mounting manually using NTFS and VFAT (both as SDB and SDB1) pj@PJ:~$ sudo mount /dev/sdb /media/Passport/ NTFS signature is missing. Failed to mount '/dev/sdb': Invalid argument The device '/dev/sdb' doesn't seem to have a valid NTFS. Maybe the wrong device is used? Or the whole disk instead of a partition (e.g. /dev/sda, not /dev/sda1)? Or the other way around? pj@PJ:~$ sudo mount /dev/sdb1 /media/Passport/ NTFS signature is missing. Failed to mount '/dev/sdb1': Invalid argument The device '/dev/sdb1' doesn't seem to have a valid NTFS. Maybe the wrong device is used? Or the whole disk instead of a partition (e.g. /dev/sda, not /dev/sda1)? Or the other way around? pj@PJ:~$ sudo mount -t ntfs /dev/sdb /media/Passport/ NTFS signature is missing. Failed to mount '/dev/sdb': Invalid argument The device '/dev/sdb' doesn't seem to have a valid NTFS. Maybe the wrong device is used? Or the whole disk instead of a partition (e.g. /dev/sda, not /dev/sda1)? Or the other way around? pj@PJ:~$ sudo mount -t vfat /dev/sdb /media/Passport/ mount: wrong fs type, bad option, bad superblock on /dev/sdb, missing codepage or helper program, or other error In some cases useful info is found in syslog - try dmesg | tail or so pj@PJ:~$ sudo mount -t ntfs /dev/sdb1 /media/Passport/ NTFS signature is missing. Failed to mount '/dev/sdb1': Invalid argument The device '/dev/sdb1' doesn't seem to have a valid NTFS. Maybe the wrong device is used? Or the whole disk instead of a partition (e.g. /dev/sda, not /dev/sda1)? Or the other way around? pj@PJ:~$ sudo mount -t vfat /dev/sdb1 /media/Passport/ mount: wrong fs type, bad option, bad superblock on /dev/sdb1, missing codepage or helper program, or other error In some cases useful info is found in syslog - try dmesg | tail or so

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• Data management in unexpected places

  - by Ashok_Ora

  Normal 0 false false false EN-US X-NONE X-NONE Data management in unexpected places When you think of network switches, routers, firewall appliances, etc., it may not be obvious that at the heart of these kinds of solutions is an engine that can manage huge amounts of data at very high throughput with low latencies and high availability. Consider a network router that is processing tens (or hundreds) of thousands of network packets per second. So what really happens inside a router? Packets are streaming in at the rate of tens of thousands per second. Each packet has multiple attributes, for example, a destination, associated SLAs etc. For each packet, the router has to determine the address of the next “hop” to the destination; it has to determine how to prioritize this packet. If it’s a high priority packet, then it has to be sent on its way before lower priority packets. As a consequence of prioritizing high priority packets, lower priority data packets may need to be temporarily stored (held back), but addressed fairly. If there are security or privacy requirements associated with the data packet, those have to be enforced. You probably need to keep track of statistics related to the packets processed (someone’s sure to ask). You have to do all this (and more) while preserving high availability i.e. if one of the processors in the router goes down, you have to have a way to continue processing without interruption (the customer won’t be happy with a “choppy” VoIP conversation, right?). And all this has to be achieved without ANY intervention from a human operator – the router is most likely to be in a remote location – it must JUST CONTINUE TO WORK CORRECTLY, even when bad things happen. How is this implemented? As soon as a packet arrives, it is interpreted by the receiving software. The software decodes the packet headers in order to determine the destination, kind of packet (e.g. voice vs. data), SLAs associated with the “owner” of the packet etc. It looks up the internal database of “rules” of how to process this packet and handles the packet accordingly. The software might choose to hold on to the packet safely for some period of time, if it’s a low priority packet. Ah – this sounds very much like a database problem. For each packet, you have to minimally · Look up the most efficient next “hop” towards the destination. The “most efficient” next hop can change, depending on latency, availability etc. · Look up the SLA and determine the priority of this packet (e.g. voice calls get priority over data ftp) · Look up security information associated with this data packet. It may be necessary to retrieve the context for this network packet since a network packet is a small “slice” of a session. The context for the “header” packet needs to be stored in the router, in order to make this work. · If the priority of the packet is low, then “store” the packet temporarily in the router until it is time to forward the packet to the next hop. · Update various statistics about the packet. In most cases, you have to do all this in the context of a single transaction. For example, you want to look up the forwarding address and perform the “send” in a single transaction so that the forwarding address doesn’t change while you’re sending the packet. So, how do you do all this? Berkeley DB is a proven, reliable, high performance, highly available embeddable database, designed for exactly these kinds of usage scenarios. Berkeley DB is a robust, reliable, proven solution that is currently being used in these scenarios. First and foremost, Berkeley DB (or BDB for short) is very very fast. It can process tens or hundreds of thousands of transactions per second. It can be used as a pure in-memory database, or as a disk-persistent database. BDB provides high availability – if one board in the router fails, the system can automatically failover to another board – no manual intervention required. BDB is self-administering – there’s no need for manual intervention in order to maintain a BDB application. No need to send a technician to a remote site in the middle of nowhere on a freezing winter day to perform maintenance operations. BDB is used in over 200 million deployments worldwide for the past two decades for mission-critical applications such as the one described here. You have a choice of spending valuable resources to implement similar functionality, or, you could simply embed BDB in your application and off you go! I know what I’d do – choose BDB, so I can focus on my business problem. What will you do? /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin-top:0in; mso-para-margin-right:0in; mso-para-margin-bottom:10.0pt; mso-para-margin-left:0in; line-height:115%; mso-pagination:widow-orphan; font-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;}

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• PanelGridLayout - A Layout Revolution

  - by Duncan Mills

  With the most recent 11.1.2 patchset (11.1.2.3) there has been a lot of excitement around ADF Essentials (and rightly so), however, in all the fuss I didn't want an even more significant change to get missed - yes you read that correctly, a more significant change! I'm talking about the new panelGridLayout component, I can confidently say that this one of the most revolutionary components that we've introduced in 11g, even though it sounds rather boring. To be totally accurate, panelGrid was introduced in 11.1.2.2 but without any presence in the component palette or other design time support, so it was largely missed unless you read the release notes. However in this latest patchset it's finally front and center. Its time to explore - we (really) need to talk about layout.  Let's face it,with ADF Faces rich client, layout is a rather arcane pursuit, once you are a layout master, all bow before you, but it's more of an art than a science, and it is often, in fact, way too difficult to achieve what should (apparently) be a pretty simple. Here's a great example, it's a homework assignment I set for folks I'm teaching this stuff to:  The requirements for this layout are: The header is 80px high, the footer is 30px. These are both fixed.  The first section of the header containing the logo is 180px wide The logo is centered within the top left hand corner of the header  The title text is start aligned in the center zone of the header and will wrap if the browser window is narrowed. It should be aligned in the center of the vertical space  The about link is anchored to the right hand side of the browser with a 20px gap and again is center aligned vertically. It will move as the browser window is reduced in width. The footer has a right aligned copyright statement, again middle aligned within a 30px high footer region and with a 20px buffer to the right hand edge. It will move as the browser window is reduced in width. All remaining space is given to a central zone, which, in this case contains a panelSplitter. Expect that at some point in time you'll need a separate messages line in the center of the footer.  In the homework assigment I set I also stipulate that no inlineStyles can be used to control alignment or margins and no use of other taglibs (e.g. JSF HTML or Trinidad HTML). So, if we take this purist approach, that basic page layout (in my stock solution) requires 3 panelStretchLayouts, 5 panelGroupLayouts and 4 spacers - not including the spacer I use for the logo and the contents of the central zone splitter - phew! The point is that even a seemingly simple layout needs a bit of thinking about, particulatly when you consider strechting and browser re-size behavior. In fact, this little sample actually teaches you much of what you need to know to become vaguely competant at layouts in the framework. The underlying result of "the way things are" is that most of us reach for panelStretchLayout before even finishing the first sip of coffee as we embark on a new page design. In fact most pages you will see in any moderately complex ADF page will basically be nested panelStretchLayouts and panelGroupLayouts, sometimes many, many levels deep. So this is a problem, we've known this for some time and now we have a good solution. (I should point out that the oft-used Trinidad trh tags are not a particularly good solution as you're tie-ing yourself to an HTML table based layout in that case with a host of attendent issues in resize and bi-di behavior, but I digress.) So, tadaaa, I give to you panelGridLayout. PanelGrid, as the name suggests takes a grid like (dare I say slightly gridbag-like) approach to layout, dividing your layout into rows and colums with margins, sizing, stretch behaviour, colspans and rowspans all rolled in, all without the use of inlineStyle. As such, it provides for a much more powerful and consise way of defining a layout such as the one above that is actually simpler and much more logical to design. The basic building blocks are the panelGridLayout itself, gridRow and gridCell. Your content sits inside the cells inside the rows, all helpfully allowing both streching, valign and halign definitions without the need to nest further panelGroupLayouts. So much simpler!  If I break down the homework example above my nested comglomorate of 12 containers and spacers can be condensed down into a single panelGrid with 3 rows and 5 cell definitions (39 lines of source reduced to 24 in the case of the sample). What's more, the actual runtime representation in the browser DOM is much, much simpler, and clean, with basically one DIV per cell (Note that just because the panelGridLayout semantics looks like an HTML table does not mean that it's rendered that way!) . Another hidden benefit is the runtime cost. Because we can use a single layout to achieve much more complex geometries the client side layout code inside the browser is having to work a lot less. This will be a real benefit if your application needs to run on lower powered clients such as netbooks or tablets. So, it's time, if you're on 11.1.2.2 or above, to smile warmly at your panelStretchLayouts, wrap the blanket around it's knees and wheel it off to the Sunset Retirement Home for a well deserved rest. There's a new kid on the block and it wants to be your friend. 

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• Most Innovative IDM Projects: Awards at OpenWorld

  - by Tanu Sood

  On Tuesday at Oracle OpenWorld 2012, Oracle recognized the winners of Innovation Awards 2012 at a ceremony presided over by Hasan Rizvi, Executive Vice President at Oracle. Oracle Fusion Middleware Innovation Awards recognize customers for achieving significant business value through innovative uses of Oracle Fusion Middleware offerings. Winners are selected based on the uniqueness of their business case, business benefits, level of impact relative to the size of the organization, complexity and magnitude of implementation, and the originality of architecture. This year’s Award honors customers for their cutting-edge solutions driving business innovation and IT modernization using Oracle Fusion Middleware. The program has grown over the past 6 years, receiving a record number of nominations from customers around the globe. The winners were selected by a panel of judges that ranked each nomination across multiple different scoring categories. Congratulations to both Avea and ETS for winning this year’s Innovation Award for Identity Management. Identity Management Innovation Award 2012 Winner – Avea Company: Founded in 2004, AveA is the sole GSM 1800 mobile operator of Turkey and has reached a nationwide customer base of 12.8 million as of the end of 2011 Region: Turkey (EMEA) Products: Oracle Identity Manager, Oracle Identity Analytics, Oracle Access Management Suite Business Drivers: ·         To manage the agility and scale required for GSM Operations and enable call center efficiency by enabling agents to change their identity profiles (accounts and entitlements) rapidly based on call load. ·         Enhance user productivity and call center efficiency with self service password resets ·         Enforce compliance and audit reporting ·         Seamless identity management between AveA and parent company Turk Telecom Innovation and Results: ·         One of the first Sun2Oracle identity management migrations designed for high performance provisioning and trusted reconciliation built with connectors developed on the ICF architecture that provides custom user interfaces for  dynamic and rapid management of roles and entitlements along with entitlement level attestation using closed loop remediation between Oracle Identity Manager and Oracle Identity Analytics. ·         Dramatic reduction in identity administration and call center password reset tasks leading to 20% reduction in administration costs and 95% reduction in password related calls. ·         Enhanced user productivity by up to 25% to date ·         Enforced enterprise security and reduced risk ·         Cost-effective compliance management ·         Looking to seamlessly integrate with parent and sister companies’ infrastructure securely. Identity Management Innovation Award 2012 Winner – Education Testing Service (ETS)       See last year's winners here --Company: ETS is a private nonprofit organization devoted to educational measurement and research, primarily through testing. Region: U.S.A (North America) Products: Oracle Access Manager, Oracle Identity Federation, Oracle Identity Manager Business Drivers: ETS develops and administers more than 50 million achievement and admissions tests each year in more than 180 countries, at more than 9,000 locations worldwide.  As the business becomes more globally based, having a robust solution to security and user management issues becomes paramount. The organizations was looking for: ·         Simplified user experience for over 3000 company users and more than 6 million dynamic student and staff population ·         Infrastructure and administration cost reduction ·         Managing security risk by controlling 3rd party access to ETS systems ·         Enforce compliance and manage audit reporting ·         Automate on-boarding and decommissioning of user account to improve security, reduce administration costs and enhance user productivity ·         Improve user experience with simplified sign-on and user self service Innovation and Results: 1.    Manage Risk ·         Centralized system to control user access ·         Provided secure way of accessing service providers' application using federated SSO. ·         Provides reporting capability for auditing, governance and compliance. 2.    Improve efficiency ·         Real-Time provisioning to target systems ·         Centralized provisioning system for user management and access controls. ·         Enabling user self services. 3.    Reduce cost ·         Re-using common shared services for provisioning, SSO, Access by application reducing development cost and time. ·         Reducing infrastructure and maintenance cost by decommissioning legacy/redundant IDM services. ·         Reducing time and effort to implement security functionality in business applications (“onboard” instead of new development). ETS was able to fold in new and evolving requirement in addition to the initial stated goals realizing quick ROI and successfully meeting business objectives. Congratulations to the winners once again. We will be sure to bring you more from these Innovation Award winners over the next few months.

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• Oracle Enterprise Manager Cloud Control 12c Release 2 (12.1.0.2) is Available Now !

  - by Anand Akela

  Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:"Times New Roman","serif";} Oracle today announced the availability of Oracle Enterprise Manager Cloud Control 12c Release 2 (12.1.0.2). It is now available for download on OTN on ALL platforms. This is the first major release since the launch of Enterprise Manager 12c in October of 2011. This is the first time when Enterprise Manager release is available on all platforms simultaneously. This is primarily a stability release which incorporates many of issues and feedback reported by early adopters. In addition, this release contains many new features and enhancements in areas across the board. New Capabilities and Features Enhanced management capabilities for enterprise private clouds: Introduces new capabilities to allow customers to build and manage a Java Platform-as-a-Service (PaaS) cloud based on Oracle Weblogic Server. The new capabilities include guided set up of PaaS Cloud, self-service provisioning, automatic scale out and metering and chargeback. Enhanced lifecycle management capabilities for Oracle WebLogic Server environments: Combining in-context multiple domain, patching and configuration file synchronizations. Integrated Hardware-Software management for Oracle Exalogic Elastic Cloud through features such as rack schematics visualization and integrated monitoring of all hardware and software components. The latest management capabilities for business-critical applications include: Business Application Management: A new Business Application (BA) target type and dashboard with flexible definitions provides a logical view of an application’s business transactions, end-user experiences and the cloud infrastructure the monitored application is running on. Enhanced User Experience Reporting: Oracle Real User Experience Insight has been enhanced to provide reporting capabilities on client-side issues for applications running in the cloud and has been more tightly coupled with Oracle Business Transaction Management to help ensure that real-time user experience and transaction tracing data is provided to users in context. Several key improvements address ease of administration, reporting and extensibility for massively scalable cloud environments including dynamic groups, self-updateable monitoring templates, bulk operations against many events, etc. New and Revised Plug-Ins: Several plug-Ins have been updated as a part of this release resulting in either new versions or revisions. Revised plug-ins contain only bug-fixes and while new plug-ins incorporate both bug fixes as well as new functionality. Plug-In Name Version Enterprise Manager for Oracle Database 12.1.0.2 (revision) Enterprise Manager for Oracle Fusion Middleware 12.1.0.3 (new) Enterprise Manager for Chargeback and Capacity Planning 12.1.0.3 (new) Enterprise Manager for Oracle Fusion Applications 12.1.0.3 (new) Enterprise Manager for Oracle Virtualization 12.1.0.3 (new) Enterprise Manager for Oracle Exadata 12.1.0.3 (new) Enterprise Manager for Oracle Cloud 12.1.0.4 (new) Installation and Upgrade: All major platforms have been released simultaneously (Linux 32 / 64 bit, Solaris (SPARC), Solaris x86-64, IBM AIX 64-bit, and Windows x86-64 (64-bit) ) Enterprise Manager 12.1.0.2 is a complete release that includes both the EM OMS and Agent versions of 12.1.0.2. Installation options available with EM 12.1.0.2: User can do fresh Install or an upgrade from versions EM 10.2.0.5, 11.1, or 12.1.0.2 ( Bundle Patch 1 not mandatory). Upgrading to EM 12.1.0.2 from EM 12.1.0.1 is not a patch application (similar to Bundle Patch 1) but is achieved through a 1-system upgrade. Documentation: Oracle Enterprise Manager Cloud Control Introduction Document provides a broad overview of capabilities and highlights"What's New" in EM 12.1.0.2. All updated Oracle Enterprise Manager documentation can be found on OTN Upgrade Guide Please feel free to ask questions related to the new Oracle Enterprise Manager Cloud Control 12c Release 2 (12.1.0.2) at the Oracle Enterprise Manager Forum . You could also share your feedback at twitter  using hash tag #em12c or at Facebook . Stay Connected: Twitter |  Face book |  You Tube |  Linked in |  Newsletter

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• Thinking differently about BI delivery

  - by jamiet

  My day job involves implementing Business Intelligence (BI) solutions which, as I have said before, is simply about giving people the information they need to do their jobs. I’m always interested in learning about new ways of achieving that aim and that is my motivation for writing blog entries that are not concerned with SQL or SQL Server per se. Implementing BI systems usually involves hacking together a bunch third party products with some in-house “glue” and delivering information using some shiny, expensive web-based front-end tool; the list of vendors that supply such tools is big and ever-growing. No doubt these tools have their place and of late I have started to wonder whether they can be supplemented with different ways of delivering information. The problem I have with these separate web-based tools is exactly that – they are separate web-based tools. What’s the problem with that you might ask? I’ll explain! They force the information worker to go somewhere unfamiliar in order to get the information they need to do their jobs. Would it not be better if we could deliver information into the tools that those information workers are already using and not force them to go somewhere else? I look at the rise of blogging over recent years and I realise that what made them popular is that people can subscribe to RSS feeds and have information pushed to them in their tool of choice rather than them having to go and find the information for themselves in a tool that has been foisted upon them. Would it not be a good idea to adopt the principle of subscription for the benefit of delivering BI information as well? I think it would and in the rest of this blog entry I’ll outline such a scenario where the power of subscription could be used to enhance the delivery of information to information workers. Typical questions that information workers ask might be: What are my year-on-year sales figures? What was my footfall yesterday? How many widgets have I sold so far today? Each of those questions includes a time element and that shouldn’t surprise us, any BI system that I have worked on includes the dimension of time. Now, what do people use to view and organise their time-oriented information? Its not a trick question, they use a calendar and in the enterprise space more often than not that calendar is managed using Outlook. Given then that information workers are already looking at their calendar in Outlook anyway would it not make sense then to deliver information into that same calendar? Of course it would. Calendars are a great way of visualising information such as sales figures. Observe: Just in this single screenshot I have managed to convey a multitude of information. The information worker can see, at a glance, information about hourly/daily/weekly/monthly sales and, moreover, he/she is viewing that information right inside the tool that they use every day. There is no effort on the part of him/her, the information just appears hour after hour, day after day. Taking the idea further, each one of those calendar items could be a mini-dashboard in its own right. Double-clicking on an item could show a plethora of other information about that time slot such as breaking the sales down per region or year-over-year comparisons. Perhaps the title could employ a sparkline? Loads of possibilities. The point is that calendars are a completely natural way to visualise information; we should make more use of them! The real beauty of delivering information using calendars for us BI developers is that it should be so easy. In the case of Outlook we don’t need to write complicated VBA code that can go and manipulate a person’s calendar, simply publishing data in a format that Outlook can understand is sufficient and happily such formats already exist; iCalendar is the accepted format and the even more flexible xCalendar is hopefully on its way as well.   I’d like to make one last point and this one is with my SQL Server hat on. Reporting Services 2008 R2 introduced the ability to publish data as subscribable Atom feeds so it seems logical that it could also be a vehicle for delivering calendar feeds too. If you think this would be a good idea go and vote for it at Publish data as iCalendar feeds and please please please add some comments (especially if you vote it down). Work smarter, not harder! @Jamiet Share this post: email it! | bookmark it! | digg it! | reddit! | kick it! | live it!

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• Joining on NULLs

  - by Dave Ballantyne

  A problem I see on a fairly regular basis is that of dealing with NULL values.  Specifically here, where we are joining two tables on two columns, one of which is ‘optional’ ie is nullable.  So something like this: i.e. Lookup where all the columns are equal, even when NULL.   NULL’s are a tricky thing to initially wrap your mind around.  Statements like “NULL is not equal to NULL and neither is it not not equal to NULL, it’s NULL” can cause a serious brain freeze and leave you a gibbering wreck and needing your mummy. Before we plod on, time to setup some data to demo against. Create table #SourceTable ( Id integer not null, SubId integer null, AnotherCol char(255) not null ) go create unique clustered index idxSourceTable on #SourceTable(id,subID) go with cteNums as ( select top(1000) number from master..spt_values where type ='P' ) insert into #SourceTable select Num1.number,nullif(Num2.number,0),'SomeJunk' from cteNums num1 cross join cteNums num2 go Create table #LookupTable ( Id integer not null, SubID integer null ) go insert into #LookupTable Select top(100) id,subid from #SourceTable where subid is not null order by newid() go insert into #LookupTable Select top(3) id,subid from #SourceTable where subid is null order by newid() If that has run correctly, you will have 1 million rows in #SourceTable and 103 rows in #LookupTable.  We now want to join one to the other. First attempt – Lets just join select * from #SourceTable join #LookupTable on #LookupTable.id = #SourceTable.id and #LookupTable.SubID = #SourceTable.SubID OK, that’s a fail.  We had 100 rows back,  we didn’t correctly account for the 3 rows that have null values.  Remember NULL <> NULL and the join clause specifies SUBID=SUBID, which for those rows is not true. Second attempt – Lets deal with those pesky NULLS select * from #SourceTable join #LookupTable on #LookupTable.id = #SourceTable.id and isnull(#LookupTable.SubID,0) = isnull(#SourceTable.SubID,0) OK, that’s the right result, well done and 99.9% of the time that is where its left. It is a relatively trivial CPU overhead to wrap ISNULL around both columns and compare that result, so no problems.  But, although that’s true, this a relational database we are using here, not a procedural language.  SQL is a declarative language, we are making a request to the engine to get the results we want.  How we ask for them can make a ton of difference. Lets look at the plan for our second attempt, specifically the clustered index seek on the #SourceTable   There are 2 predicates. The ‘seek predicate’ and ‘predicate’.  The ‘seek predicate’ describes how SQLServer has been able to use an Index.  Here, it has been able to navigate the index to resolve where ID=ID.  So far so good, but what about the ‘predicate’ (aka residual probe) ? This is a row-by-row operation.  For each row found in the index matching the Seek Predicate, the leaf level nodes have been scanned and tested using this logical condition.  In this example [Expr1007] is the result of the IsNull operation on #LookupTable and that is tested for equality with the IsNull operation on #SourceTable.  This residual probe is quite a high overhead, if we can express our statement slightly differently to take full advantage of the index and make the test part of the ‘Seek Predicate’. Third attempt – X is null and Y is null So, lets state the query in a slightly manner: select * from #SourceTable join #LookupTable on #LookupTable.id = #SourceTable.id and ( #LookupTable.SubID = #SourceTable.SubID or (#LookupTable.SubID is null and #SourceTable.SubId is null) ) So its slightly wordier and may not be as clear in its intent to the human reader, that is what comments are for, but the key point is that it is now clearer to the query optimizer what our intention is. Let look at the plan for that query, again specifically the index seek operation on #SourceTable No ‘predicate’, just a ‘Seek Predicate’ against the index to resolve both ID and SubID.  A subtle difference that can be easily overlooked.  But has it made a difference to the performance ? Well, yes , a perhaps surprisingly high one. Clever query optimizer well done. If you are using a scalar function on a column, you a pretty much guaranteeing that a residual probe will be used.  By re-wording the query you may well be able to avoid this and use the index completely to resolve lookups. In-terms of performance and scalability your system will be in a much better position if you can.

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• Increasing efficiency of N-Body gravity simulation

  - by Postman

  I'm making a space exploration type game, it will have many planets and other objects that will all have realistic gravity. I currently have a system in place that works, but if the number of planets goes above 70, the FPS decreases an practically exponential rates. I'm making it in C# and XNA. My guess is that I should be able to do gravity calculations between 100 objects without this kind of strain, so clearly my method is not as efficient as it should be. I have two files, Gravity.cs and EntityEngine.cs. Gravity manages JUST the gravity calculations, EntityEngine creates an instance of Gravity and runs it, along with other entity related methods. EntityEngine.cs public void Update() { foreach (KeyValuePair<string, Entity> e in Entities) { e.Value.Update(); } gravity.Update(); } (Only relevant piece of code from EntityEngine, self explanatory. When an instance of Gravity is made in entityEngine, it passes itself (this) into it, so that gravity can have access to entityEngine.Entities (a dictionary of all planet objects)) Gravity.cs namespace ExplorationEngine { public class Gravity { private EntityEngine entityEngine; private Vector2 Force; private Vector2 VecForce; private float distance; private float mult; public Gravity(EntityEngine e) { entityEngine = e; } public void Update() { //First loop foreach (KeyValuePair<string, Entity> e in entityEngine.Entities) { //Reset the force vector Force = new Vector2(); //Second loop foreach (KeyValuePair<string, Entity> e2 in entityEngine.Entities) { //Make sure the second value is not the current value from the first loop if (e2.Value != e.Value ) { //Find the distance between the two objects. Because Fg = G * ((M1 * M2) / r^2), using Vector2.Distance() and then squaring it //is pointless and inefficient because distance uses a sqrt, squaring the result simple cancels that sqrt. distance = Vector2.DistanceSquared(e2.Value.Position, e.Value.Position); //This makes sure that two planets do not attract eachother if they are touching, completely unnecessary when I add collision, //For now it just makes it so that the planets are not glitchy, performance is not significantly improved by removing this IF if (Math.Sqrt(distance) > (e.Value.Texture.Width / 2 + e2.Value.Texture.Width / 2)) { //Calculate the magnitude of Fg (I'm using my own gravitational constant (G) for the sake of time (I know it's 1 at the moment, but I've been changing it) mult = 1.0f * ((e.Value.Mass * e2.Value.Mass) / distance); //Calculate the direction of the force, simply subtracting the positions and normalizing works, this fixes diagonal vectors //from having a larger value, and basically makes VecForce a direction. VecForce = e2.Value.Position - e.Value.Position; VecForce.Normalize(); //Add the vector for each planet in the second loop to a force var. Force = Vector2.Add(Force, VecForce * mult); //I have tried Force += VecForce * mult, and have not noticed much of an increase in speed. } } } //Add that force to the first loop's planet's position (later on I'll instead add to acceleration, to account for inertia) e.Value.Position += Force; } } } } I have used various tips (about gravity optimizing, not threading) from THIS question (that I made yesterday). I've made this gravity method (Gravity.Update) as efficient as I know how to make it. This O(N^2) algorithm still seems to be eating up all of my CPU power though. Here is a LINK (google drive, go to File download, keep .Exe with the content folder, you will need XNA Framework 4.0 Redist. if you don't already have it) to the current version of my game. Left click makes a planet, right click removes the last planet. Mouse moves the camera, scroll wheel zooms in and out. Watch the FPS and Planet Count to see what I mean about performance issues past 70 planets. (ALL 70 planets must be moving, I've had 100 stationary planets and only 5 or so moving ones while still having 300 fps, the issue arises when 70+ are moving around) After 70 planets are made, performance tanks exponentially. With < 70 planets, I get 330 fps (I have it capped at 300). At 90 planets, the FPS is about 2, more than that and it sticks around at 0 FPS. Strangely enough, when all planets are stationary, the FPS climbs back up to around 300, but as soon as something moves, it goes right back down to what it was, I have no systems in place to make this happen, it just does. I considered multithreading, but that previous question I asked taught me a thing or two, and I see now that that's not a viable option. I've also thought maybe I could do the calculations on my GPU instead, though I don't think it should be necessary. I also do not know how to do this, it is not a simple concept and I want to avoid it unless someone knows a really noob friendly simple way to do it that will work for an n-body gravity calculation. (I have an NVidia gtx 660) Lastly I've considered using a quadtree type system. (Barnes Hut simulation) I've been told (in the previous question) that this is a good method that is commonly used, and it seems logical and straightforward, however the implementation is way over my head and I haven't found a good tutorial for C# yet that explains it in a way I can understand, or uses code I can eventually figure out. So my question is this: How can I make my gravity method more efficient, allowing me to use more than 100 objects (I can render 1000 planets with constant 300+ FPS without gravity calculations), and if I can't do much to improve performance (including some kind of quadtree system), could I use my GPU to do the calculations?

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• How can I implement a database TableView like thing in C++?

  - by Industrial-antidepressant

  How can I implement a TableView like thing in C++? I want to emulating a tiny relation database like thing in C++. I have data tables, and I want to transform it somehow, so I need a TableView like class. I want filtering, sorting, freely add and remove items and transforming (ex. view as UPPERCASE and so on). The whole thing is inside a GUI application, so datatables and views are attached to a GUI (or HTML or something). So how can I identify an item in the view? How can I signal it when the table is changed? Is there some design pattern for this? Here is a simple table, and a simple data item: #include <string> #include <boost/multi_index_container.hpp> #include <boost/multi_index/member.hpp> #include <boost/multi_index/ordered_index.hpp> #include <boost/multi_index/random_access_index.hpp> using boost::multi_index_container; using namespace boost::multi_index; struct Data { Data() {} int id; std::string name; }; struct row{}; struct id{}; struct name{}; typedef boost::multi_index_container< Data, indexed_by< random_access<tag<row> >, ordered_unique<tag<id>, member<Data, int, &Data::id> >, ordered_unique<tag<name>, member<Data, std::string, &Data::name> > > > TDataTable; class DataTable { public: typedef Data item_type; typedef TDataTable::value_type value_type; typedef TDataTable::const_reference const_reference; typedef TDataTable::index<row>::type TRowIndex; typedef TDataTable::index<id>::type TIdIndex; typedef TDataTable::index<name>::type TNameIndex; typedef TRowIndex::iterator iterator; DataTable() : row_index(rule_table.get<row>()), id_index(rule_table.get<id>()), name_index(rule_table.get<name>()), row_index_writeable(rule_table.get<row>()) { } TDataTable::const_reference operator[](TDataTable::size_type n) const { return rule_table[n]; } std::pair<iterator,bool> push_back(const value_type& x) { return row_index_writeable.push_back(x); } iterator erase(iterator position) { return row_index_writeable.erase(position); } bool replace(iterator position,const value_type& x) { return row_index_writeable.replace(position, x); } template<typename InputIterator> void rearrange(InputIterator first) { return row_index_writeable.rearrange(first); } void print_table() const; unsigned size() const { return row_index.size(); } TDataTable rule_table; const TRowIndex& row_index; const TIdIndex& id_index; const TNameIndex& name_index; private: TRowIndex& row_index_writeable; }; class DataTableView { DataTableView(const DataTable& source_table) {} // How can I implement this? // I want filtering, sorting, signaling upper GUI layer, and sorting, and ... }; int main() { Data data1; data1.id = 1; data1.name = "name1"; Data data2; data2.id = 2; data2.name = "name2"; DataTable table; table.push_back(data1); DataTable::iterator it1 = table.row_index.iterator_to(table[0]); table.erase(it1); table.push_back(data1); Data new_data(table[0]); new_data.name = "new_name"; table.replace(table.row_index.iterator_to(table[0]), new_data); for (unsigned i = 0; i < table.size(); ++i) std::cout << table[i].name << std::endl; #if 0 // using scenarios: DataTableView table_view(table); table_view.fill_from_source(); // synchronization with source table_view.remove(data_item1); // remove item from view table_view.add(data_item2); // add item from source table table_view.filter(filterfunc); // filtering table_view.sort(sortfunc); // sorting // modifying from source_able, hot to signal the table_view? // FYI: Table view is atteched to a GUI item table.erase(data); table.replace(data); #endif return 0; }

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• How can I estimate the entropy of a password?

  - by Wug

  Having read various resources about password strength I'm trying to create an algorithm that will provide a rough estimation of how much entropy a password has. I'm trying to create an algorithm that's as comprehensive as possible. At this point I only have pseudocode, but the algorithm covers the following: password length repeated characters patterns (logical) different character spaces (LC, UC, Numeric, Special, Extended) dictionary attacks It does NOT cover the following, and SHOULD cover it WELL (though not perfectly): ordering (passwords can be strictly ordered by output of this algorithm) patterns (spatial) Can anyone provide some insight on what this algorithm might be weak to? Specifically, can anyone think of situations where feeding a password to the algorithm would OVERESTIMATE its strength? Underestimations are less of an issue. The algorithm: // the password to test password = ? length = length(password) // unique character counts from password (duplicates discarded) uqlca = number of unique lowercase alphabetic characters in password uquca = number of uppercase alphabetic characters uqd = number of unique digits uqsp = number of unique special characters (anything with a key on the keyboard) uqxc = number of unique special special characters (alt codes, extended-ascii stuff) // algorithm parameters, total sizes of alphabet spaces Nlca = total possible number of lowercase letters (26) Nuca = total uppercase letters (26) Nd = total digits (10) Nsp = total special characters (32 or something) Nxc = total extended ascii characters that dont fit into other categorys (idk, 50?) // algorithm parameters, pw strength growth rates as percentages (per character) flca = entropy growth factor for lowercase letters (.25 is probably a good value) fuca = EGF for uppercase letters (.4 is probably good) fd = EGF for digits (.4 is probably good) fsp = EGF for special chars (.5 is probably good) fxc = EGF for extended ascii chars (.75 is probably good) // repetition factors. few unique letters == low factor, many unique == high rflca = (1 - (1 - flca) ^ uqlca) rfuca = (1 - (1 - fuca) ^ uquca) rfd = (1 - (1 - fd ) ^ uqd ) rfsp = (1 - (1 - fsp ) ^ uqsp ) rfxc = (1 - (1 - fxc ) ^ uqxc ) // digit strengths strength = ( rflca * Nlca + rfuca * Nuca + rfd * Nd + rfsp * Nsp + rfxc * Nxc ) ^ length entropybits = log_base_2(strength) A few inputs and their desired and actual entropy_bits outputs: INPUT DESIRED ACTUAL aaa very pathetic 8.1 aaaaaaaaa pathetic 24.7 abcdefghi weak 31.2 H0ley$Mol3y_ strong 72.2 s^fU¬5ü;y34G< wtf 88.9 [a^36]* pathetic 97.2 [a^20]A[a^15]* strong 146.8 xkcd1** medium 79.3 xkcd2** wtf 160.5 * these 2 passwords use shortened notation, where [a^N] expands to N a's. ** xkcd1 = "Tr0ub4dor&3", xkcd2 = "correct horse battery staple" The algorithm does realize (correctly) that increasing the alphabet size (even by one digit) vastly strengthens long passwords, as shown by the difference in entropy_bits for the 6th and 7th passwords, which both consist of 36 a's, but the second's 21st a is capitalized. However, they do not account for the fact that having a password of 36 a's is not a good idea, it's easily broken with a weak password cracker (and anyone who watches you type it will see it) and the algorithm doesn't reflect that. It does, however, reflect the fact that xkcd1 is a weak password compared to xkcd2, despite having greater complexity density (is this even a thing?). How can I improve this algorithm? Addendum 1 Dictionary attacks and pattern based attacks seem to be the big thing, so I'll take a stab at addressing those. I could perform a comprehensive search through the password for words from a word list and replace words with tokens unique to the words they represent. Word-tokens would then be treated as characters and have their own weight system, and would add their own weights to the password. I'd need a few new algorithm parameters (I'll call them lw, Nw ~= 2^11, fw ~= .5, and rfw) and I'd factor the weight into the password as I would any of the other weights. This word search could be specially modified to match both lowercase and uppercase letters as well as common character substitutions, like that of E with 3. If I didn't add extra weight to such matched words, the algorithm would underestimate their strength by a bit or two per word, which is OK. Otherwise, a general rule would be, for each non-perfect character match, give the word a bonus bit. I could then perform simple pattern checks, such as searches for runs of repeated characters and derivative tests (take the difference between each character), which would identify patterns such as 'aaaaa' and '12345', and replace each detected pattern with a pattern token, unique to the pattern and length. The algorithmic parameters (specifically, entropy per pattern) could be generated on the fly based on the pattern. At this point, I'd take the length of the password. Each word token and pattern token would count as one character; each token would replace the characters they symbolically represented. I made up some sort of pattern notation, but it includes the pattern length l, the pattern order o, and the base element b. This information could be used to compute some arbitrary weight for each pattern. I'd do something better in actual code. Modified Example: Password: 1234kitty$$$$$herpderp Tokenized: 1 2 3 4 k i t t y $ $ $ $ $ h e r p d e r p Words Filtered: 1 2 3 4 @W5783 $ $ $ $ $ @W9001 @W9002 Patterns Filtered: @P[l=4,o=1,b='1'] @W5783 @P[l=5,o=0,b='$'] @W9001 @W9002 Breakdown: 3 small, unique words and 2 patterns Entropy: about 45 bits, as per modified algorithm Password: correcthorsebatterystaple Tokenized: c o r r e c t h o r s e b a t t e r y s t a p l e Words Filtered: @W6783 @W7923 @W1535 @W2285 Breakdown: 4 small, unique words and no patterns Entropy: 43 bits, as per modified algorithm The exact semantics of how entropy is calculated from patterns is up for discussion. I was thinking something like: entropy(b) * l * (o + 1) // o will be either zero or one The modified algorithm would find flaws with and reduce the strength of each password in the original table, with the exception of s^fU¬5ü;y34G<, which contains no words or patterns.

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• Using XA Transactions in Coherence-based Applications

  - by jpurdy

  While the costs of XA transactions are well known (e.g. increased data contention, higher latency, significant disk I/O for logging, availability challenges, etc.), in many cases they are the most attractive option for coordinating logical transactions across multiple resources. There are a few common approaches when integrating Coherence into applications via the use of an application server's transaction manager: Use of Coherence as a read-only cache, applying transactions to the underlying database (or any system of record) instead of the cache. Use of TransactionMap interface via the included resource adapter. Use of the new ACID transaction framework, introduced in Coherence 3.6.   Each of these may have significant drawbacks for certain workloads. Using Coherence as a read-only cache is the simplest option. In this approach, the application is responsible for managing both the database and the cache (either within the business logic or via application server hooks). This approach also tends to provide limited benefit for many workloads, particularly those workloads that either have queries (given the complexity of maintaining a fully cached data set in Coherence) or are not read-heavy (where the cost of managing the cache may outweigh the benefits of reading from it). All updates are made synchronously to the database, leaving it as both a source of latency as well as a potential bottleneck. This approach also prevents addressing "hot data" problems (when certain objects are updated by many concurrent transactions) since most database servers offer no facilities for explicitly controlling concurrent updates. Finally, this option tends to be a better fit for key-based access (rather than filter-based access such as queries) since this makes it easier to aggressively invalidate cache entries without worrying about when they will be reloaded. The advantage of this approach is that it allows strong data consistency as long as optimistic concurrency control is used to ensure that database updates are applied correctly regardless of whether the cache contains stale (or even dirty) data. Another benefit of this approach is that it avoids the limitations of Coherence's write-through caching implementation. TransactionMap is generally used when Coherence acts as system of record. TransactionMap is not generally compatible with write-through caching, so it will usually be either used to manage a standalone cache or when the cache is backed by a database via write-behind caching. TransactionMap has some restrictions that may limit its utility, the most significant being: The lock-based concurrency model is relatively inefficient and may introduce significant latency and contention. As an example, in a typical configuration, a transaction that updates 20 cache entries will require roughly 40ms just for lock management (assuming all locks are granted immediately, and excluding validation and writing which will require a similar amount of time). This may be partially mitigated by denormalizing (e.g. combining a parent object and its set of child objects into a single cache entry), at the cost of increasing false contention (e.g. transactions will conflict even when updating different child objects). If the client (application server JVM) fails during the commit phase, locks will be released immediately, and the transaction may be partially committed. In practice, this is usually not as bad as it may sound since the commit phase is usually very short (all locks having been previously acquired). Note that this vulnerability does not exist when a single NamedCache is used and all updates are confined to a single partition (generally implying the use of partition affinity). The unconventional TransactionMap API is cumbersome but manageable. Only a few methods are transactional, primarily get(), put() and remove(). The ACID transactions framework (accessed via the Connection class) provides atomicity guarantees by implementing the NamedCache interface, maintaining its own cache data and transaction logs inside a set of private partitioned caches. This feature may be used as either a local transactional resource or as logging XA resource. However, a lack of database integration precludes the use of this functionality for most applications. A side effect of this is that this feature has not seen significant adoption, meaning that any use of this is subject to the usual headaches associated with being an early adopter (greater chance of bugs and greater risk of hitting an unoptimized code path). As a result, for the moment, we generally recommend against using this feature. In summary, it is possible to use Coherence in XA-oriented applications, and several customers are doing this successfully, but it is not a core usage model for the product, so care should be taken before committing to this path. For most applications, the most robust solution is normally to use Coherence as a read-only cache of the underlying data resources, even if this prevents taking advantage of certain product features.

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• Can't control connection bit rate using iwconfig with Atheros TL-WN821N (AR7010)

  - by Paul H

  I'm trying to reduce the connection bit rate on my Atheros TP-Link TL-WN821N v3 usb wifi adapter due to frequent instability issues (reported connection speed goes down to 1Mb/s and I have to physically reconnect the adapter to regain a connection). I know this is a common problem with this device, and I have tried everything I can think of to fix it, including using drivers from linux-backports; compiling and installing a custom firmware (following instructions on https://wiki.debian.org/ath9k_htc#fw-free) and (as a last resort) using ndiswrapper. When using ndiswrapper, the wifi adapter is stable and operates in g mode at 54Mb/s (whilst when using the default ath9k_htc module, the adapter connects in n mode and the bit rate fluctuates constantly). Unfortunately, with this setup I have to run my processor using only one core, since using SMP with ndiswrapper causes a kernel oops on my system. So I want to lock my bit rate to 54Mb/s (or less, if need be) for connection stability, using the ath9k_htc module. I've tried 'sudo iwconfig wlan0 rate 54M'; the command runs with no error but when I check the bit rate with 'sudo iwlist wlan0 bitrate' the command returns: wlan0 unknown bit-rate information. Current Bit Rate:78 Mb/s Any ideas? Here's some info (hopefully relevant) on my setup: Xubuntu (12.04.3) 64bit (kernel 3.2.0-55.85-generic) using Network Manager. My Router is from Virgin Media, the VMDG480. lshw -C network : *-network description: Wireless interface physical id: 1 bus info: usb@1:4 logical name: wlan0 serial: 74:ea:3a:8f:16:b6 capabilities: ethernet physical wireless configuration: broadcast=yes driver=ath9k_htc driverversion=3.2.0-55 firmware=1.3 ip=192.168.0.9 link=yes multicast=yes wireless=IEEE 802.11bgn lsusb -v: Bus 001 Device 003: ID 0cf3:7015 Atheros Communications, Inc. TP-Link TL-WN821N v3 802.11n [Atheros AR7010+AR9287] Device Descriptor: bLength 18 bDescriptorType 1 bcdUSB 2.00 bDeviceClass 255 Vendor Specific Class bDeviceSubClass 255 Vendor Specific Subclass bDeviceProtocol 255 Vendor Specific Protocol bMaxPacketSize0 64 idVendor 0x0cf3 Atheros Communications, Inc. idProduct 0x7015 TP-Link TL-WN821N v3 802.11n [Atheros AR7010+AR9287] bcdDevice 2.02 iManufacturer 16 ATHEROS iProduct 32 UB95 iSerial 48 12345 bNumConfigurations 1 Configuration Descriptor: bLength 9 bDescriptorType 2 wTotalLength 60 bNumInterfaces 1 bConfigurationValue 1 iConfiguration 0 bmAttributes 0x80 (Bus Powered) MaxPower 500mA Interface Descriptor: bLength 9 bDescriptorType 4 bInterfaceNumber 0 bAlternateSetting 0 bNumEndpoints 6 bInterfaceClass 255 Vendor Specific Class bInterfaceSubClass 0 bInterfaceProtocol 0 iInterface 0 Endpoint Descriptor: bLength 7 bDescriptorType 5 bEndpointAddress 0x01 EP 1 OUT bmAttributes 2 Transfer Type Bulk Synch Type None Usage Type Data wMaxPacketSize 0x0200 1x 512 bytes bInterval 0 Endpoint Descriptor: bLength 7 bDescriptorType 5 bEndpointAddress 0x82 EP 2 IN bmAttributes 2 Transfer Type Bulk Synch Type None Usage Type Data wMaxPacketSize 0x0200 1x 512 bytes bInterval 0 Endpoint Descriptor: bLength 7 bDescriptorType 5 bEndpointAddress 0x83 EP 3 IN bmAttributes 3 Transfer Type Interrupt Synch Type None Usage Type Data wMaxPacketSize 0x0040 1x 64 bytes bInterval 1 Endpoint Descriptor: bLength 7 bDescriptorType 5 bEndpointAddress 0x04 EP 4 OUT bmAttributes 3 Transfer Type Interrupt Synch Type None Usage Type Data wMaxPacketSize 0x0040 1x 64 bytes bInterval 1 Endpoint Descriptor: bLength 7 bDescriptorType 5 bEndpointAddress 0x05 EP 5 OUT bmAttributes 2 Transfer Type Bulk Synch Type None Usage Type Data wMaxPacketSize 0x0200 1x 512 bytes bInterval 0 Endpoint Descriptor: bLength 7 bDescriptorType 5 bEndpointAddress 0x06 EP 6 OUT bmAttributes 2 Transfer Type Bulk Synch Type None Usage Type Data wMaxPacketSize 0x0200 1x 512 bytes bInterval 0 Device Qualifier (for other device speed): bLength 10 bDescriptorType 6 bcdUSB 2.00 bDeviceClass 255 Vendor Specific Class bDeviceSubClass 255 Vendor Specific Subclass bDeviceProtocol 255 Vendor Specific Protocol bMaxPacketSize0 64 bNumConfigurations 1 Device Status: 0x0000 (Bus Powered) iwlist wlan0 scanning: wlan0 Scan completed : Cell 01 - Address: C4:3D:C7:3A:1F:5D Channel:1 Frequency:2.412 GHz (Channel 1) Quality=37/70 Signal level=-73 dBm Encryption key:on ESSID:"my essid" Bit Rates:1 Mb/s; 2 Mb/s; 5.5 Mb/s; 11 Mb/s; 18 Mb/s 24 Mb/s; 36 Mb/s; 54 Mb/s Bit Rates:6 Mb/s; 9 Mb/s; 12 Mb/s; 48 Mb/s Mode:Master Extra:tsf=00000070cca77186 Extra: Last beacon: 5588ms ago IE: Unknown: 0007756E69636F726E IE: Unknown: 010882848B962430486C IE: Unknown: 030101 IE: Unknown: 2A0100 IE: Unknown: 2F0100 IE: IEEE 802.11i/WPA2 Version 1 Group Cipher : TKIP Pairwise Ciphers (2) : CCMP TKIP Authentication Suites (1) : PSK IE: Unknown: 32040C121860 IE: Unknown: 2D1AFC181BFFFF000000000000000000000000000000000000000000 IE: Unknown: 3D1601080400000000000000000000000000000000000000 IE: Unknown: DD7E0050F204104A0001101044000102103B00010310470010F99C335D7BAC57FB00137DFA79600220102100074E657467656172102300074E6574676561721024000631323334353610420007303030303030311054000800060050F20400011011000743473331303144100800022008103C0001011049000600372A000120 IE: Unknown: DD090010180203F02C0000 IE: WPA Version 1 Group Cipher : TKIP Pairwise Ciphers (2) : CCMP TKIP Authentication Suites (1) : PSK IE: Unknown: DD180050F2020101800003A4000027A4000042435E0062322F00 iwconfig: lo no wireless extensions. wlan0 IEEE 802.11bgn ESSID:"my essid" Mode:Managed Frequency:2.412 GHz Access Point: C4:3D:C7:3A:1F:5D Bit Rate=78 Mb/s Tx-Power=20 dBm Retry long limit:7 RTS thr:off Fragment thr:off Power Management:off Link Quality=36/70 Signal level=-74 dBm Rx invalid nwid:0 Rx invalid crypt:0 Rx invalid frag:0 Tx excessive retries:0 Invalid misc:0 Missed beacon:0,

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• C++ strongly typed typedef

  - by Kian

  I've been trying to think of a way of declaring strongly typed typedefs, to catch a certain class of bugs in the compilation stage. It's often the case that I'll typedef an int into several types of ids, or a vector to position or velocity: typedef int EntityID; typedef int ModelID; typedef Vector3 Position; typedef Vector3 Velocity; This can make the intent of code more clear, but after a long night of coding one might make silly mistakes like comparing different kinds of ids, or adding a position to a velocity perhaps. EntityID eID; ModelID mID; if ( eID == mID ) // <- Compiler sees nothing wrong { /*bug*/ } Position p; Velocity v; Position newP = p + v; // bug, meant p + v*s but compiler sees nothing wrong Unfortunately, suggestions I've found for strongly typed typedefs include using boost, which at least for me isn't a possibility (I do have c++11 at least). So after a bit of thinking, I came upon this idea, and wanted to run it by someone. First, you declare the base type as a template. The template parameter isn't used for anything in the definition, however: template < typename T > class IDType { unsigned int m_id; public: IDType( unsigned int const& i_id ): m_id {i_id} {}; friend bool operator==<T>( IDType<T> const& i_lhs, IDType<T> const& i_rhs ); }; Friend functions actually need to be forward declared before the class definition, which requires a forward declaration of the template class. We then define all the members for the base type, just remembering that it's a template class. Finally, when we want to use it, we typedef it as: class EntityT; typedef IDType<EntityT> EntityID; class ModelT; typedef IDType<ModelT> ModelID; The types are now entirely separate. Functions that take an EntityID will throw a compiler error if you try to feed them a ModelID instead, for example. Aside from having to declare the base types as templates, with the issues that entails, it's also fairly compact. I was hoping anyone had comments or critiques about this idea? One issue that came to mind while writing this, in the case of positions and velocities for example, would be that I can't convert between types as freely as before. Where before multiplying a vector by a scalar would give another vector, so I could do: typedef float Time; typedef Vector3 Position; typedef Vector3 Velocity; Time t = 1.0f; Position p = { 0.0f }; Velocity v = { 1.0f, 0.0f, 0.0f }; Position newP = p + v*t; With my strongly typed typedef I'd have to tell the compiler that multypling a Velocity by a Time results in a Position. class TimeT; typedef Float<TimeT> Time; class PositionT; typedef Vector3<PositionT> Position; class VelocityT; typedef Vector3<VelocityT> Velocity; Time t = 1.0f; Position p = { 0.0f }; Velocity v = { 1.0f, 0.0f, 0.0f }; Position newP = p + v*t; // Compiler error To solve this, I think I'd have to specialize every conversion explicitly, which can be kind of a bother. On the other hand, this limitation can help prevent other kinds of errors (say, multiplying a Velocity by a Distance, perhaps, which wouldn't make sense in this domain). So I'm torn, and wondering if people have any opinions on my original issue, or my approach to solving it.

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• InteropServices COMException when executing a .net app from a web CGI script on Windows Server 2003

  - by Kurt W. Leucht

  Disclaimer: I'm completely clueless about .net and COM. I have a vendor's application that appears to be written in .net and I'm trying to wrap it with a web form (a cgi-bin Perl script) so I can eventually launch this vendor's app from a separate computer. I'm on a Windows Server 2003 R2 SE SP1 system and I'm using Apache 2.2 for the web server and ActivePerl 5.10.0.1004 for the cgi script. My cgi script calls the vendor's app that resides on the same machine using the Perl backtick operator. ... $result = "Result: " . `$vendorsPath/$vendorsExecutable $arg1 $arg2`; ... Right now I'm just running IE web browser locally on the server machine and accessing "http://localhost/cgi-bin/myPerlScript.pl". The vendor's app fails and logs a debug message that includes the following stack trace (I changed a couple names so as to not give away the vendor's identity): ... System.Reflection.TargetInvocationException: Exception has been thrown by the target of an invocation. ---> System.Runtime.InteropServices.COMException (0x80043A1D): 0x80040154 - Class not registered --- End of inner exception stack trace --- at System.RuntimeType.InvokeDispMethod(String name, BindingFlags invokeAttr, Object target, Object[] args, Boolean[] byrefModifiers, Int32 culture, String[] namedParameters) at System.RuntimeType.InvokeMember(String name, BindingFlags invokeAttr, Binder binder, Object target, Object[] args, ParameterModifier[] modifiers, CultureInfo culture, String[] namedParameters) at VendorsTool.Engine.Core.VendorsEngine.LoadVendorsServices(String fileName, String& projectCommPath) ... When I run the vendors app from the Windows command line on the server machine with the exact same arguments that the cgi script is passing it runs just fine, so there's something about invoking their app via the web script that is causing a problem. This problem is likely security related because the whole thing runs just fine on a Windows XP Pro machine (both command line and web invocation). I actually developed my web script there and got it completely working there before I tried moving it to the Windows Server 2003 machine. So what's different about the Windows Server 2003 machine that would keep the vendor's .net app from being executed successfully by a web cgi script? Can I fix this problem somehow to make it work on my server or will the vendor have to make a change to their .net app and ship out a new version? I'm probably the only person in the world who is trying to execute this vendor's app from a separate program, so I hate to bother the vendor with the issue if there's a workaround that I can implement myself here on my server machine. Plus, I'm in kind of a hurry and I don't want to wait 4 or 6 months for the vendor to put in a fix and deploy a new version. Thanks for any advise you can give.

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