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• CD/DVD drive not mounted when inserted with Disc of any kind

  - by Cisco Sán

  I just noticed that if a insert a CD or a DVD of any kind, the Drive will start spinning but it will not show the mounted disc. Before it used to ask me what to do with the media inserted. Now it doesn't even do that. I ran in the terminal this code: eject -n and it displays this: " eject: device is `/dev/sr0'" what can I do to get the functionality back on my drive. also ran this command: sudo mount -o ro,unhide,uid=1000 /dev/cdrom /mnt/cdrom but in return i get this: " mount: mount point /mnt/cdrom does not exist" Running Ubuntu 11.10 HERE IS THE HISTORY UNTIL NOW thanks Waltinator: I ran the 'dmesg' but don't know what I'm looking for. Im a newbie on this. The same thing with the 'ls -rlt /var/log' command. Should I create the directory for the mount? at this point really don't know what to do. – Cisco Sán 7 hours ago Here are 3 lines from my dmesg after I successfully inserted a CD: [ 4804.416018] wlan0: no IPv6 routers present [ 8214.125450] ISdit ISO 9660 Extensions: Microsoft Joliet Level 3 [ 8214.136556] ISO 9660 Extensions: RRIP_1991A The first line is a previous event, my wireless going online. The next 2 lines are a good result. The number in square brackets is "seconds since boot", the rest of the line is usually helpful. And no, you should NOT create the mount point. Let's try to get the automatic mounting to work. – waltinator 7 hours ago ok this are my last 3 lines on the 'dmesg' [ 18.130819] init: plymouth-stop pre-start process (1396) terminated with status 1 [ 28.780011] wlan0: no IPv6 routers present [ 505.632119] CE: hpet increased min_delta_ns to 20113 nsec – Cisco Sán 6 hours ago It looks like your CD/DVD drive is not connected to the data bus, and not causing an interrupt when you insert a platter. – waltinator 6 hours ago Try dmesg | grep -A8 CD-ROM which should show you what the system thought was available when it came up. – waltinator 6 hours ago here is my printout [0.774351] scsi 0:0:0:0: CD-ROM HL-DT-ST DVD+-RW GSA-T40N A100 PQ: 0 ANSI: 5 [0.778117] sr0: scsi3-mmc drive: 24x/24x writer dvd-ram cd/rw xa/form2 cdda tray [0.778122] cdrom: Uniform CD-ROM driver Revision: 3.20 [0.778282] sr 0:0:0:0: Attached scsi CD-ROM sr0 [0.778340] sr 0:0:0:0: Attached scsi generic sg0 type 5 [0.780416] Freeing unused kernel memory: 984k freed [0.780732] Write protecting the kernel read-only data: 10240k [0.780986] Freeing unused kernel memory: 20k freed [0.786331] Freeing unused kernel memory: 1400k freed [0.804912] udevd[90]: starting version 173 [0.874178] r8169 Gigabit Ethernet driver 2.3LK-NAPI loaded [0.874208] r8169 0000:02:00.0: PCI INT A - GSI 16 (level, low) - IRQ 16 OK, your system sees the drive. Can you open and close the tray with eject and eject -t? Run udevadm monitor while you insert a CD (type ^C when done) and see if you get "change" and "add" messages. – waltinator 6 hours ago ok, "eject" works perfectly "eject -t" does nothing. this is the message for "udevadm monitor": KERNEL[13771.009267] change /devices/pci0000:00/0000:00:1f.1/host0/target0:0:0/0:0:0:0/block/sr0 (block) UDEV [13773.878887] change /devices/pci0000:00/0000:00:1f.1/host0/target0:0:0/0:0:0 /block/sr0 (block) – Cisco Sán 6 hours ago sudo hwinfo --cdrom (the hwinfo package is installable through Software Center) describes my CD-ROM, try it. – waltinator 4 hours ago My read out from the "sudo hwinfo --cdrom" are the following: hal.1: read hal dataprocess 2753: arguments to dbus_move_error() were incorrect, assertion "(dest) == NULL || !dbus_error_is_set ((dest))" failed in file ../../dbus/dbus-errors.c line 280. This is normally a bug in some application using the D-Bus library. libhal.c 3483 : Error unsubscribing to signals, error=The name org.freedesktop.Hal was not provided by any .service files 22: SCSI 00.0: 10602 CD-ROM (DVD) [Created at block.247] Unique ID: KD9E.JgkxTS4hgl2 Parent ID: 3p2J.gdUMCD83e+E SysFS ID: /class/block/sr0 SysFS BusID: 0:0:0:0 SysFS Device Link: /devices/pci0000:00/0000:00:1f.1/host0/target0:0:0/0:0:0:0 Hardware Class: cdrom Model: "HL-DT-ST DVD+-RW GSA-T40N" Vendor: "HL-DT-ST" Device: "DVD+-RW GSA-T40N" Revision: "A100" Driver: "ata_piix", "sr" Driver Modules: "ata_piix" Device File: /dev/sr0 (/dev/sg0) Device Files: /dev/sr0, /dev/scd0, /dev/disk/by-id/ata-HL-DT-ST_DVD+_-RW_GSA-T40N_K048BJ74257, /dev/disk/by-path/pci-0000:00:1f.1-scsi-0:0:0:0, /dev/cdrom, /dev/cdrw, /dev/dvd, /dev/dvdrw Device Number: block 11:0 (char 21:0) Features: DVD Config Status: cfg=new, avail=yes, need=no, active=unknown Attached to: #17 (IDE interface) Drive Speed: 31 Volume ID: "Movie" Publisher: "INTERVIDEO" Creation date: "20050424162207000" Thanks for the help. To Castro, hope this is what you meant and sorry for the comments..

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• .NET Security Part 4

  - by Simon Cooper

  Finally, in this series, I am going to cover some of the security issues that can trip you up when using sandboxed appdomains. DISCLAIMER: I am not a security expert, and this is by no means an exhaustive list. If you actually are writing security-critical code, then get a proper security audit of your code by a professional. The examples below are just illustrations of the sort of things that can go wrong. 1. AppDomainSetup.ApplicationBase The most obvious one is the issue covered in the MSDN documentation on creating a sandbox, in step 3 – the sandboxed appdomain has the same ApplicationBase as the controlling appdomain. So let’s explore what happens when they are the same, and an exception is thrown. In the sandboxed assembly, Sandboxed.dll (IPlugin is an interface in a partially-trusted assembly, with a single MethodToDoThings on it): public class UntrustedPlugin : MarshalByRefObject, IPlugin { // implements IPlugin.MethodToDoThings() public void MethodToDoThings() { throw new EvilException(); } } [Serializable] internal class EvilException : Exception { public override string ToString() { // show we have read access to C:\Windows // read the first 5 directories Console.WriteLine("Pwned! Mwuahahah!"); foreach (var d in Directory.EnumerateDirectories(@"C:\Windows").Take(5)) { Console.WriteLine(d.FullName); } return base.ToString(); } } And in the controlling assembly: // what can possibly go wrong? AppDomainSetup appDomainSetup = new AppDomainSetup { ApplicationBase = AppDomain.CurrentDomain.SetupInformation.ApplicationBase } // only grant permissions to execute // and to read the application base, nothing else PermissionSet restrictedPerms = new PermissionSet(PermissionState.None); restrictedPerms.AddPermission( new SecurityPermission(SecurityPermissionFlag.Execution)); restrictedPerms.AddPermission( new FileIOPermission(FileIOPermissionAccess.Read, appDomainSetup.ApplicationBase); restrictedPerms.AddPermission( new FileIOPermission(FileIOPermissionAccess.pathDiscovery, appDomainSetup.ApplicationBase); // create the sandbox AppDomain sandbox = AppDomain.CreateDomain("Sandbox", null, appDomainSetup, restrictedPerms); // execute UntrustedPlugin in the sandbox // don't crash the application if the sandbox throws an exception IPlugin o = (IPlugin)sandbox.CreateInstanceFromAndUnwrap("Sandboxed.dll", "UntrustedPlugin"); try { o.MethodToDoThings() } catch (Exception e) { Console.WriteLine(e.ToString()); } And the result? Oops. We’ve allowed a class that should be sandboxed to execute code with fully-trusted permissions! How did this happen? Well, the key is the exact meaning of the ApplicationBase property: The application base directory is where the assembly manager begins probing for assemblies. When EvilException is thrown, it propagates from the sandboxed appdomain into the controlling assembly’s appdomain (as it’s marked as Serializable). When the exception is deserialized, the CLR finds and loads the sandboxed dll into the fully-trusted appdomain. Since the controlling appdomain’s ApplicationBase directory contains the sandboxed assembly, the CLR finds and loads the assembly into a full-trust appdomain, and the evil code is executed. So the problem isn’t exactly that the sandboxed appdomain’s ApplicationBase is the same as the controlling appdomain’s, it’s that the sandboxed dll was in such a place that the controlling appdomain could find it as part of the standard assembly resolution mechanism. The sandbox then forced the assembly to load in the controlling appdomain by throwing a serializable exception that propagated outside the sandbox. The easiest fix for this is to keep the sandbox ApplicationBase well away from the ApplicationBase of the controlling appdomain, and don’t allow the sandbox permissions to access the controlling appdomain’s ApplicationBase directory. If you do this, then the sandboxed assembly can’t be accidentally loaded into the fully-trusted appdomain, and the code can’t be executed. If the plugin does try to induce the controlling appdomain to load an assembly it shouldn’t, a SerializationException will be thrown when it tries to load the assembly to deserialize the exception, and no damage will be done. 2. Loading the sandboxed dll into the application appdomain As an extension of the previous point, you shouldn’t directly reference types or methods in the sandboxed dll from your application code. That loads the assembly into the fully-trusted appdomain, and from there code in the assembly could be executed. Instead, pull out methods you want the sandboxed dll to have into an interface or class in a partially-trusted assembly you control, and execute methods via that instead (similar to the example above with the IPlugin interface). If you need to have a look at the assembly before executing it in the sandbox, either examine the assembly using reflection from within the sandbox, or load the assembly into the Reflection-only context in the application’s appdomain. The code in assemblies in the reflection-only context can’t be executed, it can only be reflected upon, thus protecting your appdomain from malicious code. 3. Incorrectly asserting permissions You should only assert permissions when you are absolutely sure they’re safe. For example, this method allows a caller read-access to any file they call this method with, including your documents, any network shares, the C:\Windows directory, etc: [SecuritySafeCritical] public static string GetFileText(string filePath) { new FileIOPermission(FileIOPermissionAccess.Read, filePath).Assert(); return File.ReadAllText(filePath); } Be careful when asserting permissions, and ensure you’re not providing a loophole sandboxed dlls can use to gain access to things they shouldn’t be able to. Conclusion Hopefully, that’s given you an idea of some of the ways it’s possible to get past the .NET security system. As I said before, this post is not exhaustive, and you certainly shouldn’t base any security-critical applications on the contents of this blog post. What this series should help with is understanding the possibilities of the security system, and what all the security attributes and classes mean and what they are used for, if you were to use the security system in the future.

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• Easy Made Easier

  - by dragonfly

      How easy is it to deploy a 2 node, fully redundant Oracle RAC cluster? Not very. Unless you use an Oracle Database Appliance. The focus of this member of Oracle's Engineered Systems family is to simplify the configuration, management and maintenance throughout the life of the system, while offering pay-as-you-grow scaling. Getting a 2-node RAC cluster up and running in under 2 hours has been made possible by the Oracle Database Appliance. Don't take my word for it, just check out these blog posts from partners and end users. The Oracle Database Appliance Experience - Zip Zoom Zoom http://www.fuadarshad.com/2012/02/oracle-database-appliance-experience.html Off-the-shelf Oracle database servers http://normanweaver.wordpress.com/2011/10/10/off-the-shelf-oracle-database-servers/ Oracle Database Appliance – Deployment Steps http://marcel.vandewaters.nl/oracle/database-appliance/oracle-database-appliance-deployment-steps     See how easy it is to deploy an Oracle Database Appliance for high availability with RAC? Now for the meat of this post, which is the first in a series of posts describing tips for making the deployment of an ODA even easier. The key to the easy deployment of an Oracle Database Appliance is the Appliance Manager software, which does the actual software deployment and configuration, based on best practices. But in order for it to do that, it needs some basic information first, including system name, IP addresses, etc. That's where the Appliance Manager GUI comes in to play, taking a wizard approach to specifying the information needed.     Using the Appliance Manager GUI is pretty straight forward, stepping through several screens of information to enter data in typical wizard style. Like most configuration tasks, it helps to gather the required information before hand. But before you rush out to a committee meeting on what to use for host names, and rely on whatever IP addresses might be hanging around, make sure you are familiar with some of the auto-fill defaults for the Appliance Manager. I'll step through the key screens below to highlight the results of the auto-fill capability of the Appliance Manager GUI.     Depending on which of the 2 Configuration Types (Config Type screen) you choose, you will get a slightly different set of screens. The Typical configuration assumes certain default configuration choices and has the fewest screens, where as the Custom configuration gives you the most flexibility in what you configure from the start. In the examples below, I have used the Custom config type.     One of the first items you are asked for is the System Name (System Info screen). This is used to identify the system, but also as the base for the default hostnames on following screens. In this screen shot, the System Name is "oda".     When you get to the next screen (Generic Network screen), you enter your domain name, DNS IP address(es), and NTP IP address(es). Next up is the Public Network screen, seen below, where you will see the host name fields are automatically filled in with default host names based on the System Name, in this case "oda". The System Name is also the basis for default host names for the extra ethernet ports available for configuration as part of a Custom configuration, as seen in the 2nd screen shot below (Other Network). There is no requirement to use these host names, as you can easily edit any of the host names. This does make filling in the configuration details easier and less prone to "fat fingers" if you are OK with these host names. Here is a full list of the automatically filled in host names. 1 2 1-vip 2-vip -scan 1-ilom 2-ilom 1-net1 2-net1 1-net2 2-net2 1-net3 2-net3     Another auto-fill feature of the Appliance Manager GUI follows a common practice of deploying IP Addresses for a RAC cluster in sequential order. In the screen shot below, I entered the first IP address (Node1-IP), then hit Tab to move to the next field. As a result, the next 5 IP address fields were automatically filled in with the next 5 IP addresses sequentially from the first one I entered. As with the host names, these are not required, and can be changed to whatever your IP address values are. One note of caution though, if the first IP Address field (Node1-IP) is filled out and you click in that field and back out, the following 5 IP addresses will be set to the sequential default. If you don't use the sequential IP addresses, pay attention to where you click that mouse. :-)     In the screen shot below, by entering the netmask value in the Netmask field, in this case 255.255.255.0, the gateway value was auto-filled into the Gateway field, based on the IP addresses and netmask previously entered. As always, you can change this value.     My last 2 screen shots illustrate that the same sequential IP address autofill and netmask to gateway autofill works when entering the IP configuration details for the Integrated Lights Out Manager (ILOM) for both nodes. The time these auto-fill capabilities save in entering data is nice, but from my perspective not as important as the opportunity to avoid data entry errors. In my next post in this series, I will touch on the benefit of using the network validation capability of the Appliance Manager GUI prior to deploying an Oracle Database Appliance.

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• Siemens AG, Sector Healthcare, Increases Transparency and Improves Customer Loyalty with Web Portal Solution

  - by Kellsey Ruppel

  Siemens AG, Sector Healthcare, Increases Transparency and Improves Customer Loyalty with Web Portal Solution CUSTOMER AND PARTNER INFORMATION Customer Name – Siemens AG, Sector Healthcare Customer Revenue – 73,515 Billion Euro (2011, Siemens AG total) Customer Quote – “The realization of our complex requirements within a very short amount of time was enabled through the competent implementation partner Sapient, who fully used the  very broad scope of standard functionality provided in the Oracle WebCenter Portal, and the management of customer services, who continuously supported the project setup. ” – Joerg Modlmayr, Project Manager, Healthcare Customer Service Portal, Siemens AG The Siemens Healthcare Sector is one of the world's largest suppliers to the healthcare industry and a trendsetter in medical imaging, laboratory diagnostics, medical information technology and hearing aids. Siemens offers its customers products and solutions for the entire range of patient care from a single source – from prevention and early detection to diagnosis, and on to treatment and aftercare. By optimizing clinical workflows for the most common diseases, Siemens also makes healthcare faster, better and more cost-effective. To ensure greater transparency, increased efficiency, higher user acceptance, and additional services, Siemens AG, Sector Healthcare, replaced several existing legacy portal solutions that could not meet the company’s future needs with Oracle WebCenter Portal. Various existing portal solutions that cannot meet future demands will be successively replaced by the new central service portal, which will also allow for the efficient and intuitive implementation of new service concepts.  With Oracle, doctors and hospitals using Siemens medical solutions now have access to a central information portal that provides important information and services at just the push of a button.  Customer Name – Siemens AG, Sector Healthcare Customer URL – www.siemens.com Customer Headquarters – Erlangen, Germany Industry – Industrial Manufacturing Employees – 360,000  Challenges – Replace disparate medical service portals to meet future demands and eliminate an  unnecessarily high level of administrative work caused by heterogeneous installations Ensure portals meet current user demands to improve user-acceptance rates and increase number of total users Enable changes and expansion through standard functionality to eliminate the need for reliance on IT and reduce administrative efforts and associated high costs Ensure efficient and intuitive implementation of new service concepts for all devices and systems Ensure hospitals and clinics to transparently monitor and measure services rendered for the various medical devices and systems  Increase electronic interaction and expand services to achieve a higher level of customer loyalty Solution –  Deployed Oracle WebCenter Portal to ensure greater transparency, and as a result, a higher level of customer loyalty  Provided a centralized platform for doctors and hospitals using Siemens’ medical technology solutions that provides important information and services at the push of a button Reduced significantly the administrative workload by centralizing the solution in the new customer service portal Secured positive feedback from customers involved in the pilot program developed by design experts from Oracle partner Sapient. The interfaces were created with customer needs in mind. The first survey taken shortly after implementation came back with 2.4 points on a scale of 0-3 in the category “customer service portal intuitiveness level” Met all requirements including alignment with the Siemens Style Guide without extensive programming Implemented additional services via the portal such as benchmarking options to ensure the optimal use of the Customer Device Park Provided option for documentation of all services rendered in conjunction with the medical technology systems to ensure that the value of the services are transparent for the decision makers in the hospitals  Saved and stored all machine data from approximately 100,000 remote systems in the central service and information platform Provided the option to register errors online and follow the call status in real-time on the portal Made  available at the push of a button all information on the medical technology devices used in hospitals or clinics—from security checks and maintenance activities to current device statuses Provided PDF format Service Performance Reports that summarize information from periods of time ranging from previous weeks up to one year, meeting medical product law requirements  Why Oracle – Siemens AG favored Oracle for many reasons, however, the company ultimately decided to go with Oracle due to the enormous range of functionality the solutions offered for the healthcare sector.“We are not programmers; we are service providers in the medical technology segment and focus on the contents of the portal. All the functionality necessary for internet-based customer interaction is already standard in Oracle WebCenter Portal, which is a huge plus for us. Having Oracle as our technology partner ensures that the product will continually evolve, providing a strong technology platform for our customer service portal well into the future,” said Joerg Modlmayr project manager, Healthcare Customer Service Portal, Siemens AG. Partner Involvement – Siemens AG selected Oracle Partner Sapient because the company offered a service portfolio that perfectly met Siemens’ requirements and had a wealth of experience implementing Oracle WebCenter Portal. Additionally, Sapient had designers with a very high level of expertise in usability—an aspect that Siemens considered to be of vast importance for the project.  “The Sapient team completely met all our expectations. Our tightly timed project was completed on schedule, and the positive feedback from our users proves that we set the right measures in terms of usability—all thanks to the folks at Sapient,” Modlmayr said.  Partner Name – Sapient GmbH Deutschland Partner URL – www.sapient.com

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• Most efficient way to implement delta time

  - by Starkers

  Here's one way to implement delta time: /// init /// var duration = 5000, currentTime = Date.now(); // and create cube, scene, camera ect ////// function animate() { /// determine delta /// var now = Date.now(), deltat = now - currentTime, currentTime = now, scalar = deltat / duration, angle = (Math.PI * 2) * scalar; ////// /// animate /// cube.rotation.y += angle; ////// /// update /// requestAnimationFrame(render); ////// } Could someone confirm I know how it works? Here what I think is going on: Firstly, we set duration at 5000, which how long the loop will take to complete in an ideal world. With a computer that is slow/busy, let's say the animation loop takes twice as long as it should, so 10000: When this happens, the scalar is set to 2.0: scalar = deltat / duration scalar = 10000 / 5000 scalar = 2.0 We now times all animation by twice as much: angle = (Math.PI * 2) * scalar; angle = (Math.PI * 2) * 2.0; angle = (Math.PI * 4) // which is 2 rotations When we do this, the cube rotation will appear to 'jump', but this is good because the animation remains real-time. With a computer that is going too quickly, let's say the animation loop takes half as long as it should, so 2500: When this happens, the scalar is set to 0.5: scalar = deltat / duration scalar = 2500 / 5000 scalar = 0.5 We now times all animation by a half: angle = (Math.PI * 2) * scalar; angle = (Math.PI * 2) * 0.5; angle = (Math.PI * 1) // which is half a rotation When we do this, the cube won't jump at all, and the animation remains real time, and doesn't speed up. However, would I be right in thinking this doesn't alter how hard the computer is working? I mean it still goes through the loop as fast as it can, and it still has render the whole scene, just with different smaller angles! So this a bad way to implement delta time, right? Now let's pretend the computer is taking exactly as long as it should, so 5000: When this happens, the scalar is set to 1.0: angle = (Math.PI * 2) * scalar; angle = (Math.PI * 2) * 1; angle = (Math.PI * 2) // which is 1 rotation When we do this, everything is timsed by 1, so nothing is changed. We'd get the same result if we weren't using delta time at all! My questions are as follows Mostly importantly, have I got the right end of the stick here? How do we know to set the duration to 5000 ? Or can it be any number? I'm a bit vague about the "computer going too quickly". Is there a way loop less often rather than reduce the animation steps? Seems like a better idea. Using this method, do all of our animations need to be timesed by the scalar? Do we have to hunt down every last one and times it? Is this the best way to implement delta time? I think not, due to the fact the computer can go nuts and all we do is divide each animation step and because we need to hunt down every step and times it by the scalar. Not a very nice DSL, as it were. So what is the best way to implement delta time? Below is one way that I do not really get but may be a better way to implement delta time. Could someone explain please? // Globals INV_MAX_FPS = 1 / 60; frameDelta = 0; clock = new THREE.Clock(); // In the animation loop (the requestAnimationFrame callback)… frameDelta += clock.getDelta(); // API: "Get the seconds passed since the last call to this method." while (frameDelta >= INV_MAX_FPS) { update(INV_MAX_FPS); // calculate physics frameDelta -= INV_MAX_FPS; } How I think this works: Firstly we set INV_MAX_FPS to 0.01666666666 How we will use this number number does not jump out at me. We then intialize a frameDelta which stores how long the last loop took to run. Come the first loop frameDelta is not greater than INV_MAX_FPS so the loop is not run (0 = 0.01666666666). So nothing happens. Now I really don't know what would cause this to happen, but let's pretend that the loop we just went through took 2 seconds to complete: We set frameDelta to 2: frameDelta += clock.getDelta(); frameDelta += 2.00 Now we run an animation thanks to update(0.01666666666). Again what is relevance of 0.01666666666?? And then we take away 0.01666666666 from the frameDelta: frameDelta -= INV_MAX_FPS; frameDelta = frameDelta - INV_MAX_FPS; frameDelta = 2 - 0.01666666666 frameDelta = 1.98333333334 So let's go into the second loop. Let's say it took 2(? Why not 2? Or 12? I am a bit confused): frameDelta += clock.getDelta(); frameDelta = frameDelta + clock.getDelta(); frameDelta = 1.98333333334 + 2 frameDelta = 3.98333333334 This time we enter the while loop because 3.98333333334 = 0.01666666666 We run update We take away 0.01666666666 from frameDelta again: frameDelta -= INV_MAX_FPS; frameDelta = frameDelta - INV_MAX_FPS; frameDelta = 3.98333333334 - 0.01666666666 frameDelta = 3.96666666668 Now let's pretend the loop is super quick and runs in just 0.1 seconds and continues to do this. (Because the computer isn't busy any more). Basically, the update function will be run, and every loop we take away 0.01666666666 from the frameDelta untill the frameDelta is less than 0.01666666666. And then nothing happens until the computer runs slowly again? Could someone shed some light please? Does the update() update the scalar or something like that and we still have to times everything by the scalar like in the first example?

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• ROracle support for TimesTen In-Memory Database

  - by Sam Drake

  Today's guest post comes from Jason Feldhaus, a Consulting Member of Technical Staff in the TimesTen Database organization at Oracle.  He shares with us a sample session using ROracle with the TimesTen In-Memory database.  Beginning in version 1.1-4, ROracle includes support for the Oracle Times Ten In-Memory Database, version 11.2.2. TimesTen is a relational database providing very fast and high throughput through its memory-centric architecture.  TimesTen is designed for low latency, high-volume data, and event and transaction management. A TimesTen database resides entirely in memory, so no disk I/O is required for transactions and query operations. TimesTen is used in applications requiring very fast and predictable response time, such as real-time financial services trading applications and large web applications. TimesTen can be used as the database of record or as a relational cache database to Oracle Database. ROracle provides an interface between R and the database, providing the rich functionality of the R statistical programming environment using the SQL query language. ROracle uses the OCI libraries to handle database connections, providing much better performance than standard ODBC.The latest ROracle enhancements include: Support for Oracle TimesTen In-Memory Database Support for Date-Time using R's POSIXct/POSIXlt data types RAW, BLOB and BFILE data type support Option to specify number of rows per fetch operation Option to prefetch LOB data Break support using Ctrl-C Statement caching support Times Ten 11.2.2 contains enhanced support for analytics workloads and complex queries: Analytic functions: AVG, SUM, COUNT, MAX, MIN, DENSE_RANK, RANK, ROW_NUMBER, FIRST_VALUE and LAST_VALUE Analytic clauses: OVER PARTITION BY and OVER ORDER BY Multidimensional grouping operators: Grouping clauses: GROUP BY CUBE, GROUP BY ROLLUP, GROUP BY GROUPING SETS Grouping functions: GROUP, GROUPING_ID, GROUP_ID WITH clause, which allows repeated references to a named subquery block Aggregate expressions over DISTINCT expressions General expressions that return a character string in the source or a pattern within the LIKE predicate Ability to order nulls first or last in a sort result (NULLS FIRST or NULLS LAST in the ORDER BY clause) Note: Some functionality is only available with Oracle Exalytics, refer to the TimesTen product licensing document for details. Connecting to TimesTen is easy with ROracle. Simply install and load the ROracle package and load the driver. > install.packages("ROracle") > library(ROracle) Loading required package: DBI > drv <- dbDriver("Oracle") Once the ROracle package is installed, create a database connection object and connect to a TimesTen direct driver DSN as the OS user. > conn <- dbConnect(drv, username ="", password="", dbname = "localhost/SampleDb_1122:timesten_direct") You have the option to report the server type - Oracle or TimesTen? > print (paste ("Server type =", dbGetInfo (conn)$serverType)) [1] "Server type = TimesTen IMDB" To create tables in the database using R data frame objects, use the function dbWriteTable. In the following example we write the built-in iris data frame to TimesTen. The iris data set is a small example data set containing 150 rows and 5 columns. We include it here not to highlight performance, but so users can easily run this example in their R session. > dbWriteTable (conn, "IRIS", iris, overwrite=TRUE, ora.number=FALSE) [1] TRUE Verify that the newly created IRIS table is available in the database. To list the available tables and table columns in the database, use dbListTables and dbListFields, respectively. > dbListTables (conn) [1] "IRIS" > dbListFields (conn, "IRIS") [1] "SEPAL.LENGTH" "SEPAL.WIDTH" "PETAL.LENGTH" "PETAL.WIDTH" "SPECIES" To retrieve a summary of the data from the database we need to save the results to a local object. The following call saves the results of the query as a local R object, iris.summary. The ROracle function dbGetQuery is used to execute an arbitrary SQL statement against the database. When connected to TimesTen, the SQL statement is processed completely within main memory for the fastest response time. > iris.summary <- dbGetQuery(conn, 'SELECT SPECIES, AVG ("SEPAL.LENGTH") AS AVG_SLENGTH, AVG ("SEPAL.WIDTH") AS AVG_SWIDTH, AVG ("PETAL.LENGTH") AS AVG_PLENGTH, AVG ("PETAL.WIDTH") AS AVG_PWIDTH FROM IRIS GROUP BY ROLLUP (SPECIES)') > iris.summary SPECIES AVG_SLENGTH AVG_SWIDTH AVG_PLENGTH AVG_PWIDTH 1 setosa 5.006000 3.428000 1.462 0.246000 2 versicolor 5.936000 2.770000 4.260 1.326000 3 virginica 6.588000 2.974000 5.552 2.026000 4 <NA> 5.843333 3.057333 3.758 1.199333 Finally, disconnect from the TimesTen Database. > dbCommit (conn) [1] TRUE > dbDisconnect (conn) [1] TRUE We encourage you download Oracle software for evaluation from the Oracle Technology Network. See these links for our software: Times Ten In-Memory Database,  ROracle.  As always, we welcome comments and questions on the TimesTen and  Oracle R technical forums.

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• JustCode Provides Reflector Alternative

  - by Joe Mayo

  If you've been a loyal Reflector user, you've probably been exposed to the debacle surrounding RedGate's decision to no longer offer a free version.  Since then, the race has begun for a replacement with a provider that would stand by their promises to the community.  Mono has an ongoing free alternative, which has been available for a long time.  However, other vendors are stepping up to the plate, with their own offerings. If Not Reflector, Then What? One of these vendors is Telerik.  In their recent Q1 2011 release of JustCode, Telerik offers a decompilation utility rivaling what we've become accustomed to in Reflector.  Not only does Telerik offer a usable replacement, but they've (in my opinion), produced a product that integrates more naturally with visual Studio than any other product ever has.  Telerik's decompilation process is so easy that the accompanying demo in this post is blindingly short (except for the presence of verbose narrative). If you want to follow along with this demo, you'll need to have Telerik JustCode installed.  If you don't have JustCode yet, you can buy it or download a trial at the Telerik Web site . A Tall Tale; Prove It! With JustCode, you can view code in the .NET Framework or any other 3rd party library (that isn't well obfuscated).  This demo depends on LINQ to Twitter, which you can download from CodePlex.com and create a reference or install the package online as described in my previous post on NuGet.  Regardless of the method, you'll have a project with a reference to LINQ to Twitter.  Use a Console Project if you want to follow along with this demo. Note:  If you've created a Console project, remember to ensure that the Target Framework is set to .NET Framework 4.  The default is .NET Framework 4 Client Profile, which doesn't work with LINQ to Twitter.  You can check by double-clicking the Properties folder on the project and inspecting the Target Framework setting. Next, you'll need to add some code to your program that you want to inspect. Here, I add code to instantiate a TwitterContext, which is like a LINQ to SQL DataContext, but works with Twitter: var l2tCtx = new TwitterContext(); If you're following along add the code above to the Main method, which will look similar to this: using LinqToTwitter; namespace NuGetInstall { class Program { static void Main(string[] args) { var l2tCtx = new TwitterContext(); } } } The code above doesn't really do anything, but it does give something that I can show and demonstrate how JustCode decompilation works. Once the code is in place, click on TwitterContext and press the F12 (Go to Definition) key.  As expected, Visual Studio opens a metadata file with prototypes for the TwitterContext class.  Here's the result: Opening a metadata file is the normal way that Visual Studio works when navigating to the definition of a type where you don't have the code.  The scenario with TwitterContext happens because you don't have the source code to the file.  Visual Studio has always done this and you can experiment by selecting any .NET type, i.e. a string type, and observing that Visual Studio opens a metadata file for the .NET String type. The point I'm making here is that JustCode works the way Visual Studio works and you'll see how this can make your job easier. In the previous figure, you only saw prototypes associated with the code. i.e. Notice that the default constructor is empty.  Again, this is normal because Visual Studio doesn't have the ability to decompile code.  However, that's the purpose of this post; showing you how JustCode fills that gap. To decompile code, right click on TwitterContext in the metadata file and select JustCode Navigate -> Decompile from the context menu.  The shortcut keys are Ctrl+1.  After a brief pause, accompanied by a progress window, you'll see the metadata expand into full decompiled code. Notice below how the default constructor now has code as opposed to the empty member prototype in the original metadata: And Why is This So Different? Again, the big deal is that Telerik JustCode decompilation works in harmony with the way that Visual Studio works.  The navigate to functionality already exists and you can use that, along with a simple context menu option (or shortcut key) to transform prototypes into decompiled code. Telerik is filling the the Reflector/Red Gate gap by providing a supported alternative to decompiling code.  Many people, including myself, used Reflector to decompile code when we were stuck with buggy libraries or insufficient documentation.  Now we have an alternative that's officially supported by a company with an excellent track record for customer (developer) service, Telerik.  Not only that, JustCode has several other IDE productivity tools that make the deal even sweeter. Joe

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• Checksum Transformation

  The Checksum Transformation computes a hash value, the checksum, across one or more columns, returning the result in the Checksum output column. The transformation provides functionality similar to the T-SQL CHECKSUM function, but is encapsulated within SQL Server Integration Services, for use within the pipeline without code or a SQL Server connection. As featured in The Microsoft Data Warehouse Toolkit by Joy Mundy and Warren Thornthwaite from the Kimbal Group. Have a look at the book samples especially Sample package for custom SCD handling. All input columns are passed through the transformation unaltered, those selected are used to generate the checksum which is passed out through a single output column, Checksum. This does not restrict the number of columns available downstream from the transformation, as columns will always flow through a transformation. The Checksum output column is in addition to all existing columns within the pipeline buffer. The Checksum Transformation uses an algorithm based on the .Net framework GetHashCode method, it is not consistent with the T-SQL CHECKSUM() or BINARY_CHECKSUM() functions. The transformation does not support the following Integration Services data types, DT_NTEXT, DT_IMAGE and DT_BYTES. ChecksumAlgorithm Property There ChecksumAlgorithm property is defined with an enumeration. It was first added in v1.3.0, when the FrameworkChecksum was added. All previous algorithms are still supported for backward compatibility as ChecksumAlgorithm.Original (0). Original - Orginal checksum function, with known issues around column separators and null columns. This was deprecated in the first SQL Server 2005 RTM release. FrameworkChecksum - The hash function is based on the .NET Framework GetHash method for object types. This is based on the .NET Object.GetHashCode() method, which unfortunately differs between x86 and x64 systems. For that reason we now default to the CRC32 option. CRC32 - Using a standard 32-bit cyclic redundancy check (CRC), this provides a more open implementation. The component is provided as an MSI file, however to complete the installation, you will have to add the transformation to the Visual Studio toolbox by hand. This process has been described in detail in the related FAQ entry for How do I install a task or transform component?, just select Checksum from the SSIS Data Flow Items list in the Choose Toolbox Items window. Downloads The Checksum Transformation is available for SQL Server 2005, SQL Server 2008 (includes R2) and SQL Server 2012. Please choose the version to match your SQL Server version, or you can install multiple versions and use them side by side if you have more than one version of SQL Server installed. Checksum Transformation for SQL Server 2005 Checksum Transformation for SQL Server 2008 Checksum Transformation for SQL Server 2012 Version History SQL Server 2012 Version 3.0.0.27 – SQL Server 2012 release. Includes upgrade support for both 2005 and 2008 packages to 2012. (5 Jun 2010) SQL Server 2008 Version 2.0.0.27 – Fix for CRC-32 algorithm that inadvertently made it sort dependent. Fix for race condition which sometimes lead to the error Item has already been added. Key in dictionary: '79764919' . Fix for upgrade mappings between 2005 and 2008. (19 Oct 2010) Version 2.0.0.24 - SQL Server 2008 release. Introduces the new CRC-32 algorithm, which is consistent across x86 and x64.. The default algorithm is now CRC32. (29 Oct 2008) Version 2.0.0.6 - SQL Server 2008 pre-release. This version was released by mistake as part of the site migration, and had known issues. (20 Oct 2008) SQL Server 2005 Version 1.5.0.43 – Fix for CRC-32 algorithm that inadvertently made it sort dependent. Fix for race condition which sometimes lead to the error Item has already been added. Key in dictionary: '79764919' . (19 Oct 2010) Version 1.5.0.16 - Introduces the new CRC-32 algorithm, which is consistent across x86 and x64. The default algorithm is now CRC32. (20 Oct 2008) Version 1.4.0.0 - Installer refresh only. (22 Dec 2007) Version 1.4.0.0 - Refresh for minor UI enhancements. (5 Mar 2006) Version 1.3.0.0 - SQL Server 2005 RTM. The checksum algorithm has changed to improve cardinality when calculating multiple column checksums. The original algorithm is still available for backward compatibility. Fixed custom UI bug with Output column name not persisting. (10 Nov 2005) Version 1.2.0.1 - SQL Server 2005 IDW 15 June CTP. A user interface is provided, as well as the ability to change the checksum output column name. (29 Aug 2005) Version 1.0.0 - Public Release (Beta). (30 Oct 2004) Screenshot

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• XmlWriter and lower ASCII characters

  - by Rick Strahl

  Ran into an interesting problem today on my CodePaste.net site: The main RSS and ATOM feeds on the site were broken because one code snippet on the site contained a lower ASCII character (CHR(3)). I don't think this was done on purpose but it was enough to make the feeds fail. After quite a bit of debugging and throwing in a custom error handler into my actual feed generation code that just spit out the raw error instead of running it through the ASP.NET MVC and my own error pipeline I found the actual error. The lovely base exception and error trace I got looked like this: Error: '', hexadecimal value 0x03, is an invalid character. at System.Xml.XmlUtf8RawTextWriter.InvalidXmlChar(Int32 ch, Byte* pDst, Boolean entitize)at System.Xml.XmlUtf8RawTextWriter.WriteElementTextBlock(Char* pSrc, Char* pSrcEnd)at System.Xml.XmlUtf8RawTextWriter.WriteString(String text)at System.Xml.XmlWellFormedWriter.WriteString(String text)at System.Xml.XmlWriter.WriteElementString(String localName, String ns, String value)at System.ServiceModel.Syndication.Rss20FeedFormatter.WriteItemContents(XmlWriter writer, SyndicationItem item, Uri feedBaseUri)at System.ServiceModel.Syndication.Rss20FeedFormatter.WriteItem(XmlWriter writer, SyndicationItem item, Uri feedBaseUri)at System.ServiceModel.Syndication.Rss20FeedFormatter.WriteItems(XmlWriter writer, IEnumerable`1 items, Uri feedBaseUri)at System.ServiceModel.Syndication.Rss20FeedFormatter.WriteFeed(XmlWriter writer)at System.ServiceModel.Syndication.Rss20FeedFormatter.WriteTo(XmlWriter writer)at CodePasteMvc.Controllers.ApiControllerBase.GetFeed(Object instance) in C:\Projects2010\CodePaste\CodePasteMvc\Controllers\ApiControllerBase.cs:line 131 XML doesn't like extended ASCII Characters It turns out the issue is that XML in general does not deal well with lower ASCII characters. According to the XML spec it looks like any characters below 0x09 are invalid. If you generate an XML document in .NET with an embedded &#x3; entity (as mine did to create the error above), you tend to get an XML document error when displaying it in a viewer. For example, here's what the result of my  feed output looks like with the invalid character embedded inside of Chrome which displays RSS feeds as raw XML by default: Other browsers show similar error messages. The nice thing about Chrome is that you can actually view source and jump down to see the line that causes the error which allowed me to track down the actual message that failed. If you create an XML document that contains a 0x03 character the XML writer fails outright with the error: '', hexadecimal value 0x03, is an invalid character. The good news is that this behavior is overridable so XML output can at least be created by using the XmlSettings object when configuring the XmlWriter instance. In my RSS configuration code this looks something like this:MemoryStream ms = new MemoryStream(); var settings = new XmlWriterSettings() { CheckCharacters = false }; XmlWriter writer = XmlWriter.Create(ms,settings); and voila the feed now generates. Now generally this is probably NOT a good idea, because as mentioned above these characters are illegal and if you view a raw XML document you'll get validation errors. Luckily though most RSS feed readers however don't care and happily accept and display the feed correctly, which is good because it got me over an embarrassing hump until I figured out a better solution. How to handle extended Characters? I was glad to get the feed fixed for the time being, but now I was still stuck with an interesting dilemma. CodePaste.net accepts user input for code snippets and those code snippets can contain just about anything. This means that ASP.NET's standard request filtering cannot be applied to this content. The code content displayed is encoded before display so for the HTML end the CHR(3) input is not really an issue. While invisible characters are hardly useful in user input it's not uncommon that odd characters show up in code snippets. You know the old fat fingering that happens when you're in the middle of a coding session and those invisible characters do end up sometimes in code editors and then end up pasted into the HTML textbox for pasting as a Codepaste.net snippet. The question is how to filter this text? Looking back at the XML Charset Spec it looks like all characters below 0x20 (space) except for 0x09 (tab), 0x0A (LF), 0x0D (CR) are illegal. So applying the following filter with a RegEx should work to remove invalid characters:string code = Regex.Replace(item.Code, @"[\u0000-\u0008,\u000B,\u000C,\u000E-\u001F]", ""); Applying this RegEx to the code snippet (and title) eliminates the problems and the feed renders cleanly.© Rick Strahl, West Wind Technologies, 2005-2012Posted in .NET  XML   Tweet !function(d,s,id){var js,fjs=d.getElementsByTagName(s)[0];if(!d.getElementById(id)){js=d.createElement(s);js.id=id;js.src="//platform.twitter.com/widgets.js";fjs.parentNode.insertBefore(js,fjs);}}(document,"script","twitter-wjs"); (function() { var po = document.createElement('script'); po.type = 'text/javascript'; po.async = true; po.src = 'https://apis.google.com/js/plusone.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(po, s); })();

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• BizTalk: Sample: Context routing and Throttling with orchestration

  - by Leonid Ganeline

  The sample demonstrates using orchestration for throttling and using context routing. Usually throttling is implemented on the host level (in BizTalk 2010 we can also using the host instance level throttling). Here is demonstrated the throttling with orchestration convoy that slows down message flow from some customers. Sample implements sort of quality service agreement layer for different kind of customers. The sample demonstrates the context routing between orchestrations. It has several advantages over the content routing. For example, we don’t have to create the property schema and promote properties on the schemas; we don’t have to change the message content to change routing. Use case:  The BizTalk application has a main processing orchestration that process all input messages. The application usually works as an OLTP application. Input messages came in random order without peaks, typical scenario for the on-line users. But sometimes the big data batch payloads come. These batches overload processing orchestrations. All processes, activated by on-line users after the payload, come to the same queue and are processed only after the payload. Result is on-line users can see significant delay in processing. It can be minutes or hours, depending of the batch size. Requirements: On-line user’s processing should work without delays. Big batches cannot disturb on-line users. There should be higher priority for the on-line users and the lower priority for the batches. Design: Decision is to divide the message flow in two branches, one for on-line users and second for batches. Branch with batches provides messages to the processing line with low priority, and the on-line user’s branch – with high priority. All messages are provided by hi-speed receive port. BTS.ReceivePortName context property is used for routing. The Router orchestration separates messages sent from on-line users and from the batch messages. But the Router does not use the BizTalk provided value of this property, the Router set up this value by itself. Router uses the content of the messages to decide if it is from on-line users or from batches. The message context property the BTS.ReceivePortName is changed respectively, its value works as a recipient address, as the “To” address for the next recipient orchestrations. Those next orchestrations are the BatchBottleneck and the MainProcess orchestrations. Messages with context equal “ToBatch” are filtered up by the BatchBottleneck orchestration. It is a unified convoy orchestration and it throttles the message flow, delaying the message delivery to the MainProcess orchestration. The BatchBottleneck orchestration changes the message context to the “ToProcess” and sends messages one after another with small delay in between. Delay can be configured in the BizTalk config file as:                 <appSettings>                                 <add key="GLD_Tests_TwoWayRouting_BatchBottleneck_DelayMillisec" value="100"/>                 </appSettings>   Of course, messages with context equal “ToProcess” are filtered up by the MainProcess orchestration.   NOTES: Filters with string values: In Orchestrations (the first Receive shape in orchestration) use string values WITH quotes; in Send Ports use string values WITHOUT quotes. Filters on the Send Ports are dynamic; we can change them in run-time. Filters on the Orchestrations are static; we can change them only in design-time. To check the existence of the promoted property inside orchestration use the Expression shape with construction like this:       if (BTS.ReceivePortName exists myMessage) { …; } It is not possible in the Message Assignment shape because using the “if” statement inside Message Assignment is prohibited. Several predefined context properties can behave in specific way. Say MessageTracking.OriginatingMessage or XMLNORM.DocumentSpecName, they are required some internal rules should be applied to the format or usage of this properties. MessageTracking.* parameters require you have to use tracking and you can get unexpected run-time errors in some cases. My recommendation is - use very limited set of the predefined context properties. To “attach” the new promoted property to the message, we have to use correlation. The correlation type should include this property. [Here is a good explanation by Saravana ] The sample code is here [sorry, temporary trubles with CodePlex].

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• Windows for IoT, continued

  - by Valter Minute

  Originally posted on: http://geekswithblogs.net/WindowsEmbeddedCookbook/archive/2014/08/05/windows-for-iot-continued.aspxI received many interesting feedbacks on my previous blog post and I tried to find some time to do some additional tests. Bert Kleinschmidt pointed out that pins 2,3 and 10 of the Galileo are connected directly to the SOC, while pin 13, the one used for the sample sketch is controlled via an I2C I/O expander. I changed my code to use pin 2 instead of 13 (just changing the variable assignment at the beginning of the code) and latency was greatly reduced. Now each pulse lasts for 1.44ms, 44% more than the expected time, but ways better that the result we got using pin 13. I also used SetThreadPriority to increase the priority of the thread that was running the sketch to THREAD_PRIORITY_HIGHEST but that didn't change the results. When I was using the I2C-controlled pin I tried the same and the timings got ways worse (increasing more than 10 times) and so I did not commented on that part, wanting to investigate the issua a bit more in detail. It seems that increasing the priority of the application thread impacts negatively the I2C communication. I tried to use also the Linux-based implementation (using a different Galileo board since the one provided by MS seems to use a different firmware) and the results of running the sample blink sketch modified to use pin 2 and blink the led for 1ms are similar to those we got on the same board running Windows. Here the difference between expected time and measured time is worse, getting around 3.2ms instead of 1 (320% compared to 150% using Windows but far from the 100.1% we got with the 8-bit Arduino). Both systems were not under load during the test, maybe loading some applications that use part of the CPU time would make those timings even less reliable, but I think that those numbers are enough to draw some conclusions. It may not be worth running a full OS if what you need is Arduino compatibility. The Arduino UNO is probably the best Arduino you can find to perform this kind of development. The Galileo running the Linux-based stack or running Windows for IoT is targeted to be a platform for "Internet of Things" devices, whatever that means. At the moment I don't see the "I" part of IoT. We have low level interfaces (SPI, I2C, the GPIO pins) that can be used to connect sensors but the support for connectivity is limited and the amount of work required to deliver some data to the cloud (using a secure HTTP request or a message queuing system like APMQS or MQTT) is still big and the rich OS underneath seems to not provide any help doing that.Why should I use sockets and can't access all the high level connectivity features we have on "full" Windows?I know that it's possible to use some third party libraries, try to build them using the Windows For IoT SDK etc. but this means re-inventing the wheel every time and can also lead to some IP concerns if used for products meant to be closed-source. I hope that MS and Intel (and others) will focus less on the "coolness" of running (some) Arduino sketches and more on providing a better platform to people that really want to design devices that leverage internet connectivity and the cloud processing power to deliver better products and services. Providing a reliable set of connectivity services would be a great start. Providing support for .NET would be even better, leaving native code available for hardware access etc. I know that those components may require additional storage and memory etc. So making the OS componentizable (or, at least, provide a way to install additional components) would be a great way to let developers pick the parts of the system they need to develop their solution, knowing that they will integrate well together. I can understand that the Arduino and Raspberry Pi* success may have attracted the attention of marketing departments worldwide and almost any new development board those days is promoted as "XXX response to Arduino" or "YYYY alternative to Raspberry Pi", but this is misleading and prevents companies from focusing on how to deliver good products and how to integrate "IoT" features with their existing offer to provide, at the end, a better product or service to their customers. Marketing is important, but can't decide the key features of a product (the OS) that is going to be used to develop full products for end customers integrating it with hardware and application software. I really like the "hackable" nature of open-source devices and like to see that companies are getting more and more open in releasing information, providing "hackable" devices and supporting developers with documentation, good samples etc. On the other side being able to run a sketch designed for an 8 bit microcontroller on a full-featured application processor may sound cool and an easy upgrade path for people that just experimented with sensors etc. on Arduino but it's not, in my humble opinion, the main path to follow for people who want to deliver real products.   *Shameless self-promotion: if you are looking for a good book in Italian about the Raspberry Pi , try mine: http://www.amazon.it/Raspberry-Pi-alluso-Digital-LifeStyle-ebook/dp/B00GYY3OKO

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• Educause Top-Ten IT Issues - the most change in a decade or more

  - by user739873

  The Education IT Issue Panel has released the 2012 top-ten issues facing higher education IT leadership, and instead of the customary reshuffling of the same deck, the issues reflect much of the tumult and dynamism facing higher education generally.  I find it interesting (and encouraging) that at the top of this year's list is "Updating IT Professionals' Skills and Roles to Accommodate Emerging Technologies and Changing IT Management and Service Delivery Models."  This reflects, in my view, the realization that higher education IT must change in order to fully realize the potential for transforming the institution, and therefore it's people must learn new skills, understand and accept new ways of solving problems, and not be tied down by past practices or institutional inertia. What follows in the remaining 9 top issues all speak, in some form or fashion, to the need for dramatic change, but not just in the areas of "funding IT" (code for cost containment or reduction), but rather the need to increase effectiveness and efficiency of the institution through the use of technology—leveraging the wave of BYOD (Bring Your Own Device) to the institution's advantage, rather than viewing it as a threat and a problem to be contained. Although it's #10 of 10, IT Governance (and establishment and implementation of the governance model throughout the institution) is key to effectively acting upon many of the preceding issues in this year's list.  In the majority of cases, technology exists to meet the needs and requirements to effectively address many of the challenges outlined in top-ten issues list. Which brings me to my next point. Although I try not to sound too much like an Oracle commercial in these (all too infrequent) blog posts, I can't help but point out how much confluence there is between several of the top issues this year and what my colleagues and I have been evangelizing for some time. Starting from the bottom of the list up: 1) I'm gratified that research and the IT challenges it presents has made the cut.  Big Data (or Large Data as it's phased in the report) is rapidly going to overwhelm much of what exists today even at our most prepared and well-equipped research universities.  Combine large data with the significantly more stringent requirements around data preservation, archiving, sharing, curation, etc. coming from granting agencies like NSF, and you have the brewing storm that could result in a lot of "one-off" solutions to a problem that could very well be addressed collectively and "at scale."   2) Transformative effects of IT – while I see more and more examples of this, there is still much more that can be achieved. My experience tells me that culture (as the report indicates or at least poses the question) gets in the way more than technology not being up to task.  We spend too much time on "context" and not "core," and get lost in the weeds on the journey to truly transforming the institution with technology. 3) Analytics as a key element in improving various institutional outcomes.  In our work around Student Success, we see predictive "academic" analytics as essential to getting in front of the Student Success issue, regardless of how an institution or collections of institutions defines success.  Analytics must be part of the fabric of the key academic enterprise applications, not a bolt-on.  We will spend a significant amount of time on this topic during our semi-annual Education Industry Strategy Council meeting in Washington, D.C. later this month. 4) Cloud strategy for the broad range of applications in the academic enterprise.  Some of the recent work by Casey Green at the Campus Computing Survey would seem to indicate that there is movement in this area but mostly in what has been termed "below the campus" application areas such as collaboration tools, recruiting, and alumni relations.  It's time to get serious about sourcing elements of mature applications like student information systems, HR, Finance, etc. leveraging a model other than traditional on-campus custom. I've only selected a few areas of the list to highlight, but the unifying theme here (and this is where I run the risk of sounding like an Oracle commercial) is that these lofty goals cry out for partners that can bring economies of scale to bear on the problems married with a deep understanding of the nuances unique to higher education.  In a recent piece in Educause Review on Student Information Systems, the author points out that "best of breed is back". Unfortunately I am compelled to point out that best of breed is a large part of the reason we have made as little progress as we have as an industry in advancing some of the causes outlined above.  Don't confuse "integrated" and "full stack" for vendor lock-in.  The best-of-breed market forces that Ron points to ensure that solutions have to be "integratable" or they don't survive in the marketplace. However, by leveraging the efficiencies afforded by adopting solutions that are pre-integrated (and possibly metered out as a service) allows us to shed unnecessary costs – as difficult as these decisions are to make and to drive throughout the organization. Cole

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• When is my View too smart?

  - by Kyle Burns

  In this posting, I will discuss the motivation behind keeping View code as thin as possible when using patterns such as MVC, MVVM, and MVP.  Once the motivation is identified, I will examine some ways to determine whether a View contains logic that belongs in another part of the application.  While the concepts that I will discuss are applicable to most any pattern which favors a thin View, any concrete examples that I present will center on ASP.NET MVC. Design patterns that include a Model, a View, and other components such as a Controller, ViewModel, or Presenter are not new to application development.  These patterns have, in fact, been around since the early days of building applications with graphical interfaces.  The reason that these patterns emerged is simple – the code running closest to the user tends to be littered with logic and library calls that center around implementation details of showing and manipulating user interface widgets and when this type of code is interspersed with application domain logic it becomes difficult to understand and much more difficult to adequately test.  By removing domain logic from the View, we ensure that the View has a single responsibility of drawing the screen which, in turn, makes our application easier to understand and maintain. I was recently asked to take a look at an ASP.NET MVC View because the developer reviewing it thought that it possibly had too much going on in the view.  I looked at the .CSHTML file and the first thing that occurred to me was that it began with 40 lines of code declaring member variables and performing the necessary calculations to populate these variables, which were later either output directly to the page or used to control some conditional rendering action (such as adding a class name to an HTML element or not rendering another element at all).  This exhibited both of what I consider the primary heuristics (or code smells) indicating that the View is too smart: Member variables – in general, variables in View code are an indication that the Model to which the View is being bound is not sufficient for the needs of the View and that the View has had to augment that Model.  Notable exceptions to this guideline include variables used to hold information specifically related to rendering (such as a dynamically determined CSS class name or the depth within a recursive structure for indentation purposes) and variables which are used to facilitate looping through collections while binding. Arithmetic – as with member variables, the presence of arithmetic operators within View code are an indication that the Model servicing the View is insufficient for its needs.  For example, if the Model represents a line item in a sales order, it might seem perfectly natural to “normalize” the Model by storing the quantity and unit price in the Model and multiply these within the View to show the line total.  While this does seem natural, it introduces a business rule to the View code and makes it impossible to test that the rounding of the result meets the requirement of the business without executing the View.  Within View code, arithmetic should only be used for activities such as incrementing loop counters and calculating element widths. In addition to the two characteristics of a “Smart View” that I’ve discussed already, this View also exhibited another heuristic that commonly indicates to me the need to refactor a View and make it a bit less smart.  That characteristic is the existence of Boolean logic that either does not work directly with properties of the Model or works with too many properties of the Model.  Consider the following code and consider how logic that does not work directly with properties of the Model is just another form of the “member variable” heuristic covered earlier: @if(DateTime.Now.Hour < 12) {     <div>Good Morning!</div> } else {     <div>Greetings</div> } This code performs business logic to determine whether it is morning.  A possible refactoring would be to add an IsMorning property to the Model, but in this particular case there is enough similarity between the branches that the entire branching structure could be collapsed by adding a Greeting property to the Model and using it similarly to the following: <div>@Model.Greeting</div> Now let’s look at some complex logic around multiple Model properties: @if (ModelPageNumber + Model.NumbersToDisplay == Model.PageCount         || (Model.PageCount != Model.CurrentPage             && !Model.DisplayValues.Contains(Model.PageCount))) {     <div>There's more to see!</div> } In this scenario, not only is the View code difficult to read (you shouldn’t have to play “human compiler” to determine the purpose of the code), but it also complex enough to be at risk for logical errors that cannot be detected without executing the View.  Conditional logic that requires more than a single logical operator should be looked at more closely to determine whether the condition should be evaluated elsewhere and exposed as a single property of the Model.  Moving the logic above outside of the View and exposing a new Model property would simplify the View code to: @if(Model.HasMoreToSee) {     <div>There’s more to see!</div> } In this posting I have briefly discussed some of the more prominent heuristics that indicate a need to push code from the View into other pieces of the application.  You should now be able to recognize these symptoms when building or maintaining Views (or the Models that support them) in your applications.

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• Defaulting the HLSL Vertex and Pixel Shader Levels to Feature Level 9_1 in VS 2012

  - by Michael B. McLaughlin

  I love Visual Studio 2012. But this is not a post about that. This is a post about tweaking one particular parameter that I’ve found a bit annoying. Disclaimer: You will be modifying important MSBuild files. If you screw up you will break your build tools. And maybe your computer will catch fire. I’m not responsible. No warranties or guaranties of any sort. This info is provided “as is”. By default, if you add a new vertex shader or pixel shader item to a project, it will be set to build with shader profile 4.0_level_9_3. If you need 9_3 functionality, this is all well and good. But (especially for Windows Store apps) you really want to target the lowest shader profile possible so that your game will run on as many computers as possible. So it’s a good idea to default to 9_1. To do this you could add in new HLSL files via “Add->New Item->Visual C++->HLSL->______ Shader File (.hlsl)” and then edit the shader files’ properties to set them manually to use 9_1 via “Properties->HLSL Compiler->General->Shader Model”. This is fine unless you forget to do this once and then submit your game with 9_3 shaders instead of 9_1 shaders to the Windows Store or to some other game store. Then you’d wind up with either rejection or angry “this doesn’t work on my computer! ripoff!” messages. There’s another option though. In “Program Files (x86)\Microsoft Visual Studio 11.0\Common7\IDE\ItemTemplates\VC\HLSL\1033\VertexShader” (note the path might vary slightly for you if you are using a 32-bit system or have a non-ENU version of Visual Studio 2012) you will find a “VertexShader.vstemplate” file. If you open this file in a text editor (e.g. Notepad++), then inside the CustomParameters tag within the TemplateContent tag you should see a CustomParameter tag for the ShaderType, i.e.: <CustomParameter Name="$ShaderType$" Value="Vertex"/> On a new line, we are going to add another CustomParameter tag to the CustomParameters tag. It will look like this: <CustomParameter Name="$ShaderModel$" Value="4.0_level_9_1"/> such that we now have:     <CustomParameters>       <CustomParameter Name="$ShaderType$" Value="Vertex"/>       <CustomParameter Name="$ShaderModel$" Value="4.0_level_9_1"/>     </CustomParameters> You can then save the file (you will need to be an Administrator or have Administrator access). Back in the 1033 directory (or whatever the number is for your language), go into the “PixelShader” directory. Edit the “PixelShader.vstemplate” file and make the same change (note that this time $ShaderType$ is “Pixel” not “Vertex”; you shouldn’t be changing that line anyway, but if you were to just copy and replace the above four lines then you will wind up creating pixel shaders that the HLSL compiler would try to compile as vertex shaders, with all sort of weird errors as a result). Once you’ve added the $ShaderModel$ line to “PixelShader.vstemplate” and have saved it, everything should be done. Since Feature Level 9_1 and 9_3 don’t support any of the other shader types, those are set to default to their appropriate minimums already (Compute and Geometry are set to “4.0” and Domain and Hull are set to “5.0”, which are their respective minimums (though not all 4.0 cards support Compute shaders; they were an optional feature added with DirectX 10.1 and only became required for DirectX 11 hardware). In case you are wondering where these magic values come from, you can find them all in the “fxc.xml” file in the “\Program Files (x86)\MSBuild\Microsoft.CPP\v4.0\V110\1033” directory (or whatever your language number is; 1033 is ENU and various other product languages have their own respective numbers (see: http://msdn.microsoft.com/en-us/goglobal/bb964664.aspx ) such that Japanese is 1041 (for example), though for all I know MSBuild tasks might be 1033 for everyone). If, like me, you installed VS 2012 to a drive other than the C:\ drive, you will find the vstemplate files in the drive to which you installed VS 2012 (D:\ in my case) but you will find the fxc.xml file on the C:\ drive. You should not edit fxc.xml. You will almost definitely break things by doing that; it’s just something you can look through to see all the other options that the FXC task takes such that you could, if needed, add further CustomParameter tags if you wanted to default to other supported options. I haven’t tried any others though so I don’t have any advice on how to set them.

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• SQL SERVER – Weekly Series – Memory Lane – #004

  - by pinaldave

  Here is the list of curetted articles of SQLAuthority.com across all these years. Instead of just listing all the articles I have selected a few of my most favorite articles and have listed them here with additional notes below it. Let me know which one of the following is your favorite article from memory lane. 2006 Auto Generate Script to Delete Deprecated Fields in Current Database In early career everytime I have to drop a column, I had hard time doing it because I was scared what if that column was needed somewhere in the code. Due to this fear I never dropped any column. I just renamed the column. If the column which I renamed was needed afterwards it was very easy to rename it back again. However, it is not recommended to keep the deleted column renamed in the database. At every interval I used to drop the columns which was prefixed with specific word. This script is 6 years old but still works. Give it a look, I am open for improvements. 2007 Shrinking Truncate Log File – Log Full – Part 2 Shrinking database or mdf file is indeed bad thing and it creates lots of problems. However, once in a while there is legit requirement to shrink the log file – a very rare one. In the rare occasion shrinking or truncating the log file may be the only solution. However, one should make sure to take backup before and after the truncate or shrink as in case of a disaster they can be very useful. Remember that truncating log file will break the log chain and while restore it can create major issue. Anyway, use this feature with caution. 2008 Simple Use of Cursor to Print All Stored Procedures of Database Including Schema This is a very interesting requirement I used to face in my early career days, I needed to print all the Stored procedures of my database. Interesting enough I had written a cursor to do so. Today when I look back at this stored procedure, I believe there will be a much cleaner way to do the same task, however, I still use this SP quite often when I have to document all the stored procedures of my database. Interesting Observation about Order of Resultset without ORDER BY In industry many developers avoid using ORDER BY clause to display the result in particular order thinking that Index is enforcing the order. In this interesting example, I demonstrate that without using ORDER BY, same table and similar query can return different results. Query optimizer always returns results using any method which is optimized for performance. The learning is There is no order unless ORDER BY is used. 2009 Size of Index Table – A Puzzle to Find Index Size for Each Index on Table I asked this puzzle earlier where I asked how to find the Index size for each of the tables. The puzzle was very well received and lots of interesting answers were received. To answer this question I have written following blog posts. I suggest this weekend you try to solve this problem and see if you can come up with a better solution. If not, well here are the solutions. Solution 1 | Solution 2 | Solution 3 Understanding Table Hints with Examples Hints are options and strong suggestions specified for enforcement by the SQL Server query processor on DML statements. The hints override any execution plan the query optimizer might select for a query. The SQL Server Query optimizer is a very smart tool and it makes a better selection of execution plan. Suggesting hints to the Query Optimizer should be attempted when absolutely necessary and by experienced developers who know exactly what they are doing (or in development as a way to experiment and learn). Interesting Observation – TOP 100 PERCENT and ORDER BY I have seen developers and DBAs using TOP very causally when they have to use the ORDER BY clause. Theoretically, there is no need of ORDER BY in the view at all. All the ordering should be done outside the view and view should just have the SELECT statement in it. It was quite common that to save this extra typing by including ordering inside of the view. At several instances developers want a complete resultset and for the same they include TOP 100 PERCENT along with ORDER BY, assuming that this will simulate the SELECT statement with ORDER BY. 2010 SQLPASS Nov 8-11, 2010-Seattle – An Alternative Look at Experience In year 2010 I attended most prestigious SQL Server event SQLPASS between Nov 8-11, 2010 at Seattle. I have only one expression for the event - Best Summit Ever. Instead of writing about my usual routine or the event, I wrote about the interesting things I did and how I felt about it! When I go back and read it, I feel that this is the best event I attended in year 2010. Change Database Access to Single User Mode Using SSMS Image says all. 2011 SQL Server 2012 has introduced new analytic functions. These functions were long awaited and I am glad that they are now here. Before when any of this function was needed, people used to write long T-SQL code to simulate these functions. But now there’s no need of doing so. Having available native function also helps performance as well readability. Function SQLAuthority MSDN CUME_DIST CUME_DIST CUME_DIST FIRST_VALUE FIRST_VALUE FIRST_VALUE LAST_VALUE LAST_VALUE LAST_VALUE LEAD LEAD LEAD LAG LAG LAG PERCENTILE_CONT PERCENTILE_CONT PERCENTILE_CONT PERCENTILE_DISC PERCENTILE_DISC PERCENTILE_DISC PERCENT_RANK PERCENT_RANK PERCENT_RANK Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: Memory Lane, PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

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• await, WhenAll, WaitAll, oh my!!

  - by cibrax

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

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• Extra Life 2012 - The Final Plea ... Until the Next One

  - by Chris Gardner

  I thought I'd share the email stream that my friends and family get about the event.So, here we are again. We scream closer to the event, and the goal is not met.I was approached by the ghost of feral platypii past last night. Well, approached is putting it lightly. I was mugged by the ghost of platypii past last night. He reminded me, in no uncertain terms that I have only reached the midway point of my fundraising goal. He then reminded me, in even less uncertain terms, that we are one week away from the event. There were other reminders past that, but this is a family broadcast. *shudder*Now, let us be serious for a moment. The event organizers claim a personal story helps to tug heart strings, whatever those are...I've been to Children's Hospital of Birmingham. I had to take Spawn, the Latter, there to verify she was not going to die. Instead, she's just a ticking time bomb for the next generation, but I digress.While I was there, I saw things. I saw child after child after child waiting for their appointment. I saw the most sublime displays of children's art juxtaposed with hospital sterilization that I could ever possibly imagine. I saw and heard things that only occur in the nightmares of parents, and I was only in the waiting rooms.But I will never forget the 10-ish year old girl that came in for her regularly scheduled dialysis appointment ... as if it was just another Friday afternoon. She had her school books, a little snack, a book to read for pleasure, and a DVD, in case she finished her homework a little early. You know, everything you'd need for an afternoon hooked up to a huge medical machine that going to clean out all the toxins in your blood. As she entered the secured area, she warmly greeted all the doctors and nurses with the same familiarity that I would greet the staff of my favorite coffee shop as I stopped in for my morning cup of coffee.I don't know the status of that little girl. I don't know if she's healthy or, quite frankly, alive. I don't even know her name, as I only heard it in passing for the 37 seconds our paths crossed. However, I do remember being incredibly moved and touched by her upbeat attitude about the situations, and I hope that my efforts last two Octobers got her, in some way, a little comfort.And, if she is still with us, I hope we can get her a little more.=== PREVIOUS MESSAGE FOLLOWS ===Greetings (Again),If you are receiving this updated message, then you didn't feel generous the first time. Now, I tried to be nice the first time. I tried to send a simple, unobtrusive email message to get you into the spirit. Well, much like the bell ringers that I ignore in front of the Wal-Mart, you ignored me.I probably should have seen that coming...However, unlike those poor souls, I know how to contact you. And I can find out where you live. So, so, so, you better feel lucky that I'm too lazy to terrorize you people, but cause I could do it.Remember, it's not for me, it's for those poor kids... and the feral platypii.  Because, we can make more children, but platypii are hard to come by.=== ORIGINAL MESSAGE FOLLOWS ===It's that time of year again. The time when I beg you for money for charity. See, unlike those bell ringers outside Wal-Mart, I don't do it when you have ten bazillion holiday obligations...Once again, I will be enduring a 24-hour marathon of gaming to raise money for Children Hospital in Birmingham. All the money goes straight to them, and you get to tell Uncie Samuel that you're good for that money. I'd REALLY like to break $1000 this year, as I have come REALLY close for the past 2 year to doing so.This year, the event will take place on October 20th, beginning at 8 A.M. Once again, I will try to provide some web streams, etc, if you want to point and laugh (especially if I have to result to playing Dance Central at 4 AM to stay awake for the last part.)Look at it this way, I'm going to badger you about this for the next month. You might as well donate some money so you can righteously tell me to shut the Smurf up.You can place your bid at the link below. Feel free to spread the word to anyone and everyone.I thank you. The children thank you. Several breeds of feral platypus thank you. Maybe, just maybe, doing so will help you feel the love felt by re-fried beans when lovingly hugged in a warm tortilla.Enjoy your burrito.http://www.extra-life.org/participant/cgardner

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• How is the gimbal locked problem solved using accumulative matrix transformations

  - by Luke San Antonio

  I am reading the online "Learning Modern 3D Graphics Programming" book by Jason L. McKesson As of now, I am up to the gimbal lock problem and how to solve it using quaternions. However right here, at the Quaternions page. Part of the problem is that we are trying to store an orientation as a series of 3 accumulated axial rotations. Orientations are orientations, not rotations. And orientations are certainly not a series of rotations. So we need to treat the orientation of the ship as an orientation, as a specific quantity. I guess this is the first spot I start to get confused, the reason is because I don't see the dramatic difference between orientations and rotations. I also don't understand why an orientation cannot be represented by a series of rotations... Also: The first thought towards this end would be to keep the orientation as a matrix. When the time comes to modify the orientation, we simply apply a transformation to this matrix, storing the result as the new current orientation. This means that every yaw, pitch, and roll applied to the current orientation will be relative to that current orientation. Which is precisely what we need. If the user applies a positive yaw, you want that yaw to rotate them relative to where they are current pointing, not relative to some fixed coordinate system. The concept, I understand, however I don't understand how if accumulating matrix transformations is a solution to this problem, how the code given in the previous page isn't just that. Here's the code: void display() { glClearColor(0.0f, 0.0f, 0.0f, 0.0f); glClearDepth(1.0f); glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); glutil::MatrixStack currMatrix; currMatrix.Translate(glm::vec3(0.0f, 0.0f, -200.0f)); currMatrix.RotateX(g_angles.fAngleX); DrawGimbal(currMatrix, GIMBAL_X_AXIS, glm::vec4(0.4f, 0.4f, 1.0f, 1.0f)); currMatrix.RotateY(g_angles.fAngleY); DrawGimbal(currMatrix, GIMBAL_Y_AXIS, glm::vec4(0.0f, 1.0f, 0.0f, 1.0f)); currMatrix.RotateZ(g_angles.fAngleZ); DrawGimbal(currMatrix, GIMBAL_Z_AXIS, glm::vec4(1.0f, 0.3f, 0.3f, 1.0f)); glUseProgram(theProgram); currMatrix.Scale(3.0, 3.0, 3.0); currMatrix.RotateX(-90); //Set the base color for this object. glUniform4f(baseColorUnif, 1.0, 1.0, 1.0, 1.0); glUniformMatrix4fv(modelToCameraMatrixUnif, 1, GL_FALSE, glm::value_ptr(currMatrix.Top())); g_pObject->Render("tint"); glUseProgram(0); glutSwapBuffers(); } To my understanding, isn't what he is doing (modifying a matrix on a stack) considered accumulating matrices, since the author combined all the individual rotation transformations into one matrix which is being stored on the top of the stack. My understanding of a matrix is that they are used to take a point which is relative to an origin (let's say... the model), and make it relative to another origin (the camera). I'm pretty sure this is a safe definition, however I feel like there is something missing which is blocking me from understanding this gimbal lock problem. One thing that doesn't make sense to me is: If a matrix determines the difference relative between two "spaces," how come a rotation around the Y axis for, let's say, roll, doesn't put the point in "roll space" which can then be transformed once again in relation to this roll... In other words shouldn't any further transformations to this point be in relation to this new "roll space" and therefore not have the rotation be relative to the previous "model space" which is causing the gimbal lock. That's why gimbal lock occurs right? It's because we are rotating the object around set X, Y, and Z axes rather than rotating the object around it's own, relative axes. Or am I wrong? Since apparently this code I linked in isn't an accumulation of matrix transformations can you please give an example of a solution using this method. So in summary: What is the difference between a rotation and an orientation? Why is the code linked in not an example of accumulation of matrix transformations? What is the real, specific purpose of a matrix, if I had it wrong? How could a solution to the gimbal lock problem be implemented using accumulation of matrix transformations? Also, as a bonus: Why are the transformations after the rotation still relative to "model space?" Another bonus: Am I wrong in the assumption that after a transformation, further transformations will occur relative to the current? Also, if it wasn't implied, I am using OpenGL, GLSL, C++, and GLM, so examples and explanations in terms of these are greatly appreciated, if not necessary. The more the detail the better! Thanks in advance...

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• C#/.NET Little Wonders: Getting Caller Information

  - by James Michael Hare

  Originally posted on: http://geekswithblogs.net/BlackRabbitCoder/archive/2013/07/25/c.net-little-wonders-getting-caller-information.aspx Once again, in this series of posts I look at the parts of the .NET Framework that may seem trivial, but can help improve your code by making it easier to write and maintain. The index of all my past little wonders posts can be found here. There are times when it is desirable to know who called the method or property you are currently executing.  Some applications of this could include logging libraries, or possibly even something more advanced that may server up different objects depending on who called the method. In the past, we mostly relied on the System.Diagnostics namespace and its classes such as StackTrace and StackFrame to see who our caller was, but now in C# 5, we can also get much of this data at compile-time. Determining the caller using the stack One of the ways of doing this is to examine the call stack.  The classes that allow you to examine the call stack have been around for a long time and can give you a very deep view of the calling chain all the way back to the beginning for the thread that has called you. You can get caller information by either instantiating the StackTrace class (which will give you the complete stack trace, much like you see when an exception is generated), or by using StackFrame which gets a single frame of the stack trace.  Both involve examining the call stack, which is a non-trivial task, so care should be done not to do this in a performance-intensive situation. For our simple example let's say we are going to recreate the wheel and construct our own logging framework.  Perhaps we wish to create a simple method Log which will log the string-ified form of an object and some information about the caller.  We could easily do this as follows: 1: static void Log(object message) 2: { 3: // frame 1, true for source info 4: StackFrame frame = new StackFrame(1, true); 5: var method = frame.GetMethod(); 6: var fileName = frame.GetFileName(); 7: var lineNumber = frame.GetFileLineNumber(); 8: 9: // we'll just use a simple Console write for now 10: Console.WriteLine("{0}({1}):{2} - {3}", 11: fileName, lineNumber, method.Name, message); 12: } So, what we are doing here is grabbing the 2nd stack frame (the 1st is our current method) using a 2nd argument of true to specify we want source information (if available) and then taking the information from the frame.  This works fine, and if we tested it out by calling from a file such as this: 1: // File c:\projects\test\CallerInfo\CallerInfo.cs 2:  3: public class CallerInfo 4: { 5: Log("Hello Logger!"); 6: } We'd see this: 1: c:\projects\test\CallerInfo\CallerInfo.cs(5):Main - Hello Logger! This works well, and in fact CallStack and StackFrame are still the best ways to examine deeper into the call stack.  But if you only want to get information on the caller of your method, there is another option… Determining the caller at compile-time In C# 5 (.NET 4.5) they added some attributes that can be supplied to optional parameters on a method to receive caller information.  These attributes can only be applied to methods with optional parameters with explicit defaults.  Then, as the compiler determines who is calling your method with these attributes, it will fill in the values at compile-time. These are the currently supported attributes available in the  System.Runtime.CompilerServices namespace": CallerFilePathAttribute – The path and name of the file that is calling your method. CallerLineNumberAttribute – The line number in the file where your method is being called. CallerMemberName – The member that is calling your method. So let’s take a look at how our Log method would look using these attributes instead: 1: static int Log(object message, 2: [CallerMemberName] string memberName = "", 3: [CallerFilePath] string fileName = "", 4: [CallerLineNumber] int lineNumber = 0) 5: { 6: // we'll just use a simple Console write for now 7: Console.WriteLine("{0}({1}):{2} - {3}", 8: fileName, lineNumber, memberName, message); 9: } Again, calling this from our sample Main would give us the same result: 1: c:\projects\test\CallerInfo\CallerInfo.cs(5):Main - Hello Logger! However, though this seems the same, there are a few key differences. First of all, there are only 3 supported attributes (at this time) that give you the file path, line number, and calling member.  Thus, it does not give you as rich of detail as a StackFrame (which can give you the calling type as well and deeper frames, for example).  Also, these are supported through optional parameters, which means we could call our new Log method like this: 1: // They're defaults, why not fill 'em in 2: Log("My message.", "Some member", "Some file", -13); In addition, since these attributes require optional parameters, they cannot be used in properties, only in methods. These caveats aside, they do let you get similar information inside of methods at a much greater speed!  How much greater?  Well lets crank through 1,000,000 iterations of each.  instead of logging to console, I’ll return the formatted string length of each.  Doing this, we get: 1: Time for 1,000,000 iterations with StackTrace: 5096 ms 2: Time for 1,000,000 iterations with Attributes: 196 ms So you see, using the attributes is much, much faster!  Nearly 25x faster in fact.  Summary There are a few ways to get caller information for a method.  The StackFrame allows you to get a comprehensive set of information spanning the whole call stack, but at a heavier cost.  On the other hand, the attributes allow you to quickly get at caller information baked in at compile-time, but to do so you need to create optional parameters in your methods to support it. Technorati Tags: Little Wonders,CSharp,C#,.NET,StackFrame,CallStack,CallerFilePathAttribute,CallerLineNumberAttribute,CallerMemberName

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• Modularity through HTTP

  - by Michael Williamson

  As programmers, we strive for modularity in the code we write. We hope that splitting the problem up makes it easier to solve, and allows us to reuse parts of our code in other applications. Object-orientation is the most obvious of many attempts to get us closer to this ideal, and yet one of the most successful approaches is almost accidental: the web. Programming languages provide us with functions and classes, and plenty of other ways to modularize our code. This allows us to take our large problem, split it into small parts, and solve those small parts without having to worry about the whole. It also makes it easier to reason about our code. So far, so good, but now that we’ve written our small, independent module, for example to send out e-mails to my customers, we’d like to reuse it in another application. By creating DLLs, JARs or our platform’s package container of choice, we can do just that – provided our new application is on the same platform. Want to use a Java library from C#? Well, good luck – it might be possible, but it’s not going to be smooth sailing. Even if a library exists, it doesn’t mean that using it going to be a pleasant experience. Say I want to use Java to write out an XML document to an output stream. You’d imagine this would be a simple one-liner. You’d be wrong: import org.w3c.dom.*; import java.io.*; import javax.xml.transform.*; import javax.xml.transform.dom.*; import javax.xml.transform.stream.*; private static final void writeDoc(Document doc, OutputStream out) throws IOException { try { Transformer t = TransformerFactory.newInstance().newTransformer(); t.setOutputProperty(OutputKeys.DOCTYPE_SYSTEM, doc.getDoctype().getSystemId()); t.transform(new DOMSource(doc), new StreamResult(out)); } catch (TransformerException e) { throw new AssertionError(e); // Can't happen! } } Most of the time, there is a good chance somebody else has written the code before, but if nobody can understand the interface to that code, nobody’s going to use it. The result is that most of the code we write is just a variation on a theme. Despite our best efforts, we’ve fallen a little short of our ideal, but the web brings us closer. If we want to send e-mails to our customers, we could write an e-mail-sending library. More likely, we’d use an existing one for our language. Even then, we probably wouldn’t have niceties like A/B testing or DKIM signing. Alternatively, we could just fire some HTTP requests at MailChimp, and get a whole slew of features without getting anywhere near the code that implements them. The web is inherently language agnostic. So long as your language can send and receive text over HTTP, and probably parse some JSON, you’re about as well equipped as anybody. Instead of building libraries for a specific language, we can build a service that almost every language can reuse. The text-based nature of HTTP also helps to limit the complexity of the API. As SOAP will attest, you can still make a horrible mess using HTTP, but at least it is an obvious horrible mess. Complex data structures are tedious to marshal to and from text, providing a strong incentive to keep things simple. By contrast, spotting the complexities in a class hierarchy is often not as easy. HTTP doesn’t solve every problem. It probably isn’t such a good idea to use it inside an inner loop that’s executed thousands of times per second. What’s more, the HTTP approach might introduce some new problems. We often need to add a thin shim to each application that we wish to communicate over HTTP. For instance, we might need to write a small plugin in PHP if we want to integrate WordPress into our system. Suddenly, instead of a system written in one language, we’re maintaining a system with several distinct languages and platforms. Even then, we should strive to avoid re-implementing the same old thing. As programmers, we consistently underestimate both the cost of building a system and the ongoing maintenance. If we allow ourselves to integrate existing applications, even if they’re in unfamiliar languages, we save ourselves those development and maintenance costs, as well as being able to pick the best solution for our problem. Thanks to the web, HTTP is often the easiest way to get there.

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• Namespaces are obsolete

  - by Bertrand Le Roy

  To those of us who have been around for a while, namespaces have been part of the landscape. One could even say that they have been defining the large-scale features of the landscape in question. However, something happened fairly recently that I think makes this venerable structure obsolete. Before I explain this development and why it’s a superior concept to namespaces, let me recapitulate what namespaces are and why they’ve been so good to us over the years… Namespaces are used for a few different things: Scope: a namespace delimits the portion of code where a name (for a class, sub-namespace, etc.) has the specified meaning. Namespaces are usually the highest-level scoping structures in a software package. Collision prevention: name collisions are a universal problem. Some systems, such as jQuery, wave it away, but the problem remains. Namespaces provide a reasonable approach to global uniqueness (and in some implementations such as XML, enforce it). In .NET, there are ways to relocate a namespace to avoid those rare collision cases. Hierarchy: programmers like neat little boxes, and especially boxes within boxes within boxes. For some reason. Regular human beings on the other hand, tend to think linearly, which is why the Windows explorer for example has tried in a few different ways to flatten the file system hierarchy for the user. 1 is clearly useful because we need to protect our code from bleeding effects from the rest of the application (and vice versa). A language with only global constructs may be what some of us started programming on, but it’s not desirable in any way today. 2 may not be always reasonably worth the trouble (jQuery is doing fine with its global plug-in namespace), but we still need it in many cases. One should note however that globally unique names are not the only possible implementation. In fact, they are a rather extreme solution. What we really care about is collision prevention within our application. What happens outside is irrelevant. 3 is, more than anything, an aesthetical choice. A common convention has been to encode the whole pedigree of the code into the namespace. Come to think about it, we never think we need to import “Microsoft.SqlServer.Management.Smo.Agent” and that would be very hard to remember. What we want to do is bring nHibernate into our app. And this is precisely what you’ll do with modern package managers and module loaders. I want to take the specific example of RequireJS, which is commonly used with Node. Here is how you import a module with RequireJS: var http = require("http"); .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } This is of course importing a HTTP stack module into the code. There is no noise here. Let’s break this down. Scope (1) is provided by the one scoping mechanism in JavaScript: the closure surrounding the module’s code. Whatever scoping mechanism is provided by the language would be fine here. Collision prevention (2) is very elegantly handled. Whereas relocating is an afterthought, and an exceptional measure with namespaces, it is here on the frontline. You always relocate, using an extremely familiar pattern: variable assignment. We are very much used to managing our local variable names and any possible collision will get solved very easily by picking a different name. Wait a minute, I hear some of you say. This is only taking care of collisions on the client-side, on the left of that assignment. What if I have two libraries with the name “http”? Well, You can better qualify the path to the module, which is what the require parameter really is. As for hierarchical organization, you don’t really want that, do you? RequireJS’ module pattern does elegantly cover the bases that namespaces used to cover, but it also promotes additional good practices. First, it promotes usage of self-contained, single responsibility units of code through the closure-based, stricter scoping mechanism. Namespaces are somewhat more porous, as using/import statements can be used bi-directionally, which leads us to my second point… Sane dependency graphs are easier to achieve and sustain with such a structure. With namespaces, it is easy to construct dependency cycles (that’s bad, mmkay?). With this pattern, the equivalent would be to build mega-components, which are an easier problem to spot than a decay into inter-dependent namespaces, for which you need specialized tools. I really like this pattern very much, and I would like to see more environments implement it. One could argue that dependency injection has some commonalities with this for example. What do you think? This is the half-baked result of some morning shower reflections, and I’d love to read your thoughts about it. What am I missing?

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• Drive Online Engagement with Intuitive Portals and Websites

  - by kellsey.ruppel

  As more and more business is being conducted via online channels, engaging users and making them more productive and efficient though these online channels is becoming critical. These users could be customers, partners or employees and while the respective channels through which they interact might be different, these users do increasingly interact with your business through the Web, or mobile devices or now through various social mediums.  Businesses need a user engagement strategy and solution that allows them to deliver targeted and personalized content and applications to users through the various online mediums and touch points.  The customer experience today is made up of an ongoing set of interactions with organizations across many channels, online and offline.  The Direct channel (including sales reps, email and mail) is an important point of contact, as is the Contact Center.  Contact Centers rely on the phone as a means of interacting with customers, and also more now than ever, the Web as well.  However, the online organization is often managed separately from the Contact Center organization within a business. In-store is an important channel for retailers, offering Point-of-Service for human interactions, and Kiosks which enable self-service. Kiosks are a Web-enabled touch point but in-store kiosks are often managed by the head of retail operations, rather than the online organization.  And of course, the online channel, including customer interactions with an organization via digital means -- on the website, mobile websites, and social networking sites, has risen to paramount importance in recent years in the customer experience. Historically all of these channels have been managed separately. The result of all of this fragmentation is that the customer touch points with an organization are siloed.  Their interactions online are not known and respected in their dealings in-store.  Their calls to the contact center are not taken as input into what the website offers them when they arrive. Think of how many times you’ve fallen victim to this. Your experience with the company call center is different than the experience in-store. Your experience with the company website on your desktop computer is different than your experience on your iPad. I think you get the point. But the customer isn’t the only one we need to look at here, as employees and the IT organization have challenges as well when it comes to online engagement. There are many common tools and technologies that organizations have been using to try and engage users, whether it’s customers, employees or partners. Some have adopted different blog and wiki technologies (some hosted, some open source, sometimes embedded in platforms), to things like tagging, file sharing and content management, or composite applications for self-service applications and activity streams. Basically, there are so many different tools & technologies that each address different aspects of user engagement. Now, one of the challenges with this, is that if we look at each individual tool, typically just implementing for example a file sharing and basic collaboration solution, may meet the needs of the business user for one aspect of user engagement, but it may not be the best solution to engage with customers and partners, or it may not fit with IT standards such as integrating with their single sign on tools or their corporate website. Often, the scenario is that businesses are having to acquire multiple pieces and parts as well as build custom applications to meet their needs. Leaving customers and partners with a more fragmented way of interacting with the company. Every organization has some sort of enterprise balancing act between the needs of the business user and the needs and restrictions enforced by enterprise IT groups. As we’ve been discussing, we all know that the expectations for online engagement have changed since the days of the static, one-size fits all website. With these changes have come some very difficult organizational challenges as well. Today, as a business user, you want to engage with your customers, and your customers expect you to know who they are. They expect you to recall the details they’ve provided to you on your website, to your CSRs and to your sales people. They expect you to remember their purchases, their preferences and their problems. And they expect you to know who they are, equally well, across channels, including your web presence. This creates a host of challenges for today’s business users. Delivering targeted, relevant content online is now essential for converting prospects into customers and for engendering long term loyalty. Business users need the ability to leverage customer data from different sources to fuel their segmentation and targeting strategies and to easily set-up, manage and optimize online campaigns. Also critical, they need the ability to accomplish these things on-the-fly, at the speed of the marketplace, while making iterative improvements.  These changing expectations put a host of demands on the IT organization as well. The web presence must be able to scale to support the delivery of personalized and targeted content to thousands of site visitors without sacrificing performance. And integration between systems becomes more important as well, as organizations strive to obtain one view of the customer culled from WCM data, CRM data and more. So then, how do you solve these challenges and meet the growing demands of your users?  You need a solution that: Unifies every customer interaction across all channels Personalizes the products and content that interest the customer and to the device Delivers targeted promotions to the right customer Engages and improve employee productivity Provides self-service access to applications Includes embedded in-context social   So how then do you achieve this level of online engagement, complete customer experience and engage your employees? The answer: Oracle WebCenter. If you want to learn how to get there, we encourage you to attend this webcast on Thursday Drive Online Engagement with Intuitive Portals and Websites, where we'll talk about how you are able to transform your portal experience and optimize online engagement -- making your portals more interactive and more engaging across multiple channels. Register today!

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• Centered Content using panelGridLayout

  - by Duncan Mills

  A classic layout conundrum,  which I think pretty much every ADF developer may have faced at some time or other, is that of truly centered (centred) layout. Typically this requirement comes up in relation to say displaying a login type screen or similar. Superficially the  problem seems easy, but as my buddy Eduardo explained when discussing this subject a couple of years ago it's actually a little more complex than you might have thought. If fact, even the "solution" provided in that posting is not perfect and suffers from a several issues (not Eduardo's fault, just limitations of panelStretch!) The top, bottom, end and start facets all need something in them The percentages you apply to the topHeight, startWidth etc. are calculated as part of the whole width.  This means that you have to guestimate the correct percentage based on your typical screen size and the sizing of the centered content. So, at best, you will in fact only get approximate centering, and the more you tune that centering for a particular browser size the more it will fail if the user resizes. You can't attach styles to the panelStretchLayout facets so to provide things like background color or fixed sizing you need to embed another container that you can apply styles to, typically a panelgroupLayout   For reference here's the code to print a simple 100px x 100px red centered square  using the panelStretchLayout solution, approximately tuned to a 1980 x 1080 maximized browser (IDs omitted for brevity): <af:panelStretchLayout startWidth="45%" endWidth="45%"                        topHeight="45%"  bottomHeight="45%" >   <f:facet name="center">     <af:panelGroupLayout inlineStyle="height:100px;width:100px;background-color:red;"                          layout="vertical"/>   </f:facet>   <f:facet name="top">     <af:spacer height="1" width="1"/>   </f:facet>   <f:facet name="bottom">     <af:spacer height="1" width="1"/>   </f:facet>   <f:facet name="start">     <af:spacer height="1" width="1"/>   </f:facet>   <f:facet name="end">     <af:spacer height="1" width="1"/>    </f:facet> </af:panelStretchLayout>  And so to panelGridLayout  So here's the  good news, panelGridLayout makes this really easy and it works without the caveats above.  The key point is that percentages used in the grid definition are evaluated after the fixed sizes are taken into account, so rather than having to guestimate what percentage will "more, or less", center the content you can just say "allocate half of what's left" to the flexible content and you're done. Here's the same example using panelGridLayout: <af:panelGridLayout> <af:gridRow height="50%"/> <af:gridRow height="100px"> <af:gridCell width="50%" /> <af:gridCell width="100px" halign="stretch" valign="stretch"  inlineStyle="background-color:red;"> <af:spacer width="1" height="1"/> </af:gridCell> <af:gridCell width="50%" /> </af:gridRow> <af:gridRow height="50%"/> </af:panelGridLayout>  So you can see that the amount of markup is somewhat smaller (as is, I should mention, the generated DOM structure in the browser), mainly because we don't need to introduce artificial components to ensure that facets are actually observed in the final result.  But the key thing here is that the centering is no longer approximate and it will work as expected as the user resizes the browser screen.  By far this is a more satisfactory solution and although it's only a simple example, it will hopefully open your eyes to the potential of panelGridLayout as your number one, go-to layout container. Just a reminder though, right now, panelGridLayout is only available in 11.1.2.2 and above.

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• The Enterprise is a Curmudgeon

  - by John K. Hines

  Working in an enterprise environment is a unique challenge.  There's a lot more to software development than developing software.  A project lead or Scrum Master has to manage personalities and intra-team politics, has to manage accomplishing the task at hand while creating the opportunities and a reputation for handling desirable future work, has to create a competent, happy team that actually delivers while being careful not to burn bridges or hurt feelings outside the team.  Which makes me feel surprised to read advice like: " The enterprise should figure out what is likely to work best for itself and try to use it." - Ken Schwaber, The Enterprise and Scrum. The enterprises I have experience with are fundamentally unable to be self-reflective.  It's like asking a Roman gladiator if he'd like to carve out a little space in the arena for some silent meditation.  I'm currently wondering how compatible Scrum is with the top-down hierarchy of life in a large organization.  Specifically, manufacturing-mindset, fixed-release, harmony-valuing large organizations.  Now I understand why Agile can be a better fit for companies without much organizational inertia. Recently I've talked with nearly two dozen software professionals and their managers about Scrum and Agile.  I've become convinced that a developer, team, organization, or enterprise can be Agile without using Scrum.  But I'm not sure about what process would be the best fit, in general, for an enterprise that wants to become Agile.  It's possible I should read more than just the introduction to Ken's book. I do feel prepared to answer some of the questions I had asked in a previous post: How can Agile practices (including but not limited to Scrum) be adopted in situations where the highest-placed managers in a company demand software within extremely aggressive deadlines? Answer: In a very limited capacity at the individual level.  The situation here is that the senior management of this company values any software release more than it values developer well-being, end-user experience, or software quality.  Only if the developing organization is given an immediate refactoring opportunity does this sort of development make sense to a person who values sustainable software.   How can Agile practices be adopted by teams that do not perform a continuous cycle of new development, such as those whose sole purpose is to reproduce and debug customer issues? Answer: It depends.  For Scrum in particular, I don't believe Scrum is meant to manage unpredictable work.  While you can easily adopt XP practices for bug fixing, the project-management aspects of Scrum require some predictability.  My question here was meant toward those who want to apply Scrum to non-development teams.  In some cases it works, in others it does not. How can a team measure if its development efforts are both Agile and employ sound engineering practices? Answer: I'm currently leaning toward measuring these independently.  The Agile Principles are a terrific way to measure if a software team is agile.  Sound engineering practices are those practices which help developers meet the principles.  I think Scrum is being mistakenly applied as an engineering practice when it is essentially a project management practice.  In my opinion, XP and Lean are examples of good engineering practices. How can Agile be explained in an accurate way that describes its benefits to sceptical developers and/or revenue-focused non-developers? Answer: Agile techniques will result in higher-quality, lower-cost software development.  This comes primarily from finding defects earlier in the development cycle.  If there are individual developers who do not want to collaborate, write unit tests, or refactor, then these are simply developers who are either working in an area where adding these techniques will not add value (i.e. they are an expert) or they are a developer who is satisfied with the status quo.  In the first case they should be left alone.  In the second case, the results of Agile should be demonstrated by other developers who are willing to receive recognition for their efforts.  It all comes down to individuals, doesn't it?  If you're working in an organization whose Agile adoption consists exclusively of Scrum, consider ways to form individual Agile teams to demonstrate its benefits.  These can even be virtual teams that span people across org-chart boundaries.  Once you can measure real value, whether it's Scrum, Lean, or something else, people will follow.  Even the curmudgeons.

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• yield – Just yet another sexy c# keyword?

  - by George Mamaladze

  yield (see NSDN c# reference) operator came I guess with .NET 2.0 and I my feeling is that it’s not as wide used as it could (or should) be.   I am not going to talk here about necessarity and advantages of using iterator pattern when accessing custom sequences (just google it).   Let’s look at it from the clean code point of view. Let's see if it really helps us to keep our code understandable, reusable and testable.   Let’s say we want to iterate a tree and do something with it’s nodes, for instance calculate a sum of their values. So the most elegant way would be to build a recursive method performing a classic depth traversal returning the sum.           private int CalculateTreeSum(Node top)         {             int sumOfChildNodes = 0;             foreach (Node childNode in top.ChildNodes)             {                 sumOfChildNodes += CalculateTreeSum(childNode);             }             return top.Value + sumOfChildNodes;         }     “Do One Thing” Nevertheless it violates one of the most important rules “Do One Thing”. Our  method CalculateTreeSum does two things at the same time. It travels inside the tree and performs some computation – in this case calculates sum. Doing two things in one method is definitely a bad thing because of several reasons: ·          Understandability: Readability / refactoring ·          Reuseability: when overriding - no chance to override computation without copying iteration code and vice versa. ·          Testability: you are not able to test computation without constructing the tree and you are not able to test correctness of tree iteration.   I want to spend some more words on this last issue. How do you test the method CalculateTreeSum when it contains two in one: computation & iteration? The only chance is to construct a test tree and assert the result of the method call, in our case the sum against our expectation. And if the test fails you do not know wether was the computation algorithm wrong or was that the iteration? At the end to top it all off I tell you: according to Murphy’s Law the iteration will have a bug as well as the calculation. Both bugs in a combination will cause the sum to be accidentally exactly the same you expect and the test will PASS. J   Ok let’s use yield! That’s why it is generally a very good idea not to mix but isolate “things”. Ok let’s use yield!           private int CalculateTreeSumClean(Node top)         {             IEnumerable<Node> treeNodes = GetTreeNodes(top);             return CalculateSum(treeNodes);         }             private int CalculateSum(IEnumerable<Node> nodes)         {             int sumOfNodes = 0;             foreach (Node node in nodes)             {                 sumOfNodes += node.Value;             }             return sumOfNodes;         }           private IEnumerable<Node> GetTreeNodes(Node top)         {             yield return top;             foreach (Node childNode in top.ChildNodes)             {                 foreach (Node currentNode in GetTreeNodes(childNode))                 {                     yield return currentNode;                 }             }         }   Two methods does not know anything about each other. One contains calculation logic another jut the iteration logic. You can relpace the tree iteration algorithm from depth traversal to breath trevaersal or use stack or visitor pattern instead of recursion. This will not influence your calculation logic. And vice versa you can relace the sum with product or do whatever you want with node values, the calculateion algorithm is not aware of beeng working on some tree or graph.  How about not using yield? Now let’s ask the question – what if we do not have yield operator? The brief look at the generated code gives us an answer. The compiler generates a 150 lines long class to implement the iteration logic.       [CompilerGenerated]     private sealed class <GetTreeNodes>d__0 : IEnumerable<Node>, IEnumerable, IEnumerator<Node>, IEnumerator, IDisposable     {         ...        150 Lines of generated code        ...     }   Often we compromise code readability, cleanness, testability, etc. – to reduce number of classes, code lines, keystrokes and mouse clicks. This is the human nature - we are lazy. Knowing and using such a sexy construct like yield, allows us to be lazy, write very few lines of code and at the same time stay clean and do one thing in a method. That's why I generally welcome using staff like that.   Note: The above used recursive depth traversal algorithm is possibly the compact one but not the best one from the performance and memory utilization point of view. It was taken to emphasize on other primary aspects of this post.

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