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  • Oracle Database 12c Spatial: Vector Performance Acceleration

    - by Okcan Yasin Saygili-Oracle
    Most business information has a location component, such as customer addresses, sales territories and physical assets. Businesses can take advantage of their geographic information by incorporating location analysis and intelligence into their information systems. This allows organizations to make better decisions, respond to customers more effectively, and reduce operational costs – increasing ROI and creating competitive advantage. Oracle Database, the industry’s most advanced database,  includes native location capabilities, fully integrated in the kernel, for fast, scalable, reliable and secure spatial and massive graph applications. It is a foundation for deploying enterprise-wide spatial information systems and locationenabled business applications. Developers can extend existing Oracle-based tools and applications, since they can easily incorporate location information directly in their applications, workflows, and services. Spatial Features The geospatial data features of Oracle Spatial and Graph option support complex geographic information systems (GIS) applications, enterprise applications and location services applications. Oracle Spatial and Graph option extends the spatial query and analysis features included in every edition of Oracle Database with the Oracle Locator feature, and provides a robust foundation for applications that require advanced spatial analysis and processing in the Oracle Database. It supports all major spatial data types and models, addressing challenging business-critical requirements from various industries, including transportation, utilities, energy, public sector, defense and commercial location intelligence. Network Data Model Graph Features The Network Data Model graph explicitly stores and maintains a persistent data model withnetwork connectivity and provides network analysis capability such as shortest path, nearest neighbors, within cost and reachability. It loads partitioned networks into memory on demand, overcomingthe limitations of in-memory analysis. Partitioning massive networks into manageable sub-networkssimplifies the network analysis. RDF Semantic Graph Features RDF Semantic Graph has native support for World Wide Web Consortium standards. It has open, scalable, and secure features for storing RDF/OWL ontologies anddata; native inference with OWL 2, SKOS and user-defined rules; and querying RDF/OWL data withSPARQL 1.1, Java APIs, and SPARQLgraph patterns in SQL. Video: Oracle Spatial and Graph Overview Oracle spatial is embeded on oracle database product. So ,we can use oracle installer (OUI).The Oracle Universal Installer (OUI) is used to install Oracle Database software. OUI is a graphical user interface utility that enables you to view the Oracle software that is installed on your machine, install new Oracle Database software, and delete Oracle software that you no longer need to use. Online Help is available to guide you through the installation process. One of the installation options is to create a database. If you select database creation, OUI automatically starts Oracle Database Configuration Assistant (DBCA) to guide you through the process of creating and configuring a database. If you do not create a database during installation, you must invoke DBCA after you have installed the software to create a database. You can also use DBCA to create additional databases. For installing Oracle Database 12c you may check the Installing Oracle Database Software and Creating a Database tutorial under the Oracle Database 12c 2-Day DBA Series.You can always check if spatial is available in your database using  "select comp_id, version, status, comp_name from dba_registry where comp_id='SDO';"   One of the most notable improvements with Oracle Spatial and Graph 12c can be seen in performance increases in vector data operations. Enabling the Spatial Vector Acceleration feature (available with the Spatial option) dramatically improves the performance of commonly used vector data operations, such as sdo_distance, sdo_aggr_union, and sdo_inside. With 12c, these operations also run more efficiently in parallel than in prior versions through the use of metadata caching. For organizations that have been facing processing limitations, these enhancements enable developers to make a small set of configuration changes and quickly realize significant performance improvements. Results include improved index performance, enhanced geometry engine performance, optimized secondary filter optimizations for Spatial operators, and improved CPU and memory utilization for many advanced vector functions. Vector performance acceleration is especially beneficial when using Oracle Exadata Database Machine and other large-scale systems. Oracle Spatial and Graph vector performance acceleration builds on general improvements available to all SDO_GEOMETRY operations in these areas: Caching of index metadata, Concurrent update mechanisms, and Optimized spatial predicate selectivity and cost functions. These optimizations enable more efficient use of: CPU, Memory, and Partitioning Resulting in substantial query performance improvements.UsageTo accelerate the performance of spatial operators, it is recommended that you set the SPATIAL_VECTOR_ACCELERATION database system parameter to the value TRUE. (This parameter is authorized for use only by licensed Oracle Spatial users, and its default value is FALSE.) You can set this parameter for the whole system or for a single session. To set the value for the whole system, do either of the following:Enter the following statement from a suitably privileged account:   ALTER SYSTEM SET SPATIAL_VECTOR_ACCELERATION = TRUE;Add the following to the database initialization file (xxxinit.ora):   SPATIAL_VECTOR_ACCELERATION = TRUE;To set the value for the current session, enter the following statement from a suitably privileged account:   ALTER SESSION SET SPATIAL_VECTOR_ACCELERATION = TRUE; Checkout the complete list of new features on Oracle.com @ http://www.oracle.com/technetwork/database/options/spatialandgraph/overview/index.html Spatial and Graph Data Sheet (PDF) Spatial and Graph White Paper (PDF)

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  • NTFS Issues in Windows 7 and 2008 R2 - 'Is it a Bug?'

    - by renewieldraaijer
    I have been using the various versions of the Microsoft Windows product line since NT4 and I really thought I knew the ins and outs about the NTFS filesystem by now. There were always a few rules of thumb to understand what happens if you move data around. These rules were: "If you copy data, the copied data will inherit the permissions of the location it is being copied to. The same goes for moving data between disk partitions. Only when you move data within the same partition, the permissions are kept."  Recently I was asked to assist in troubleshooting some NTFS related issues. This forced me to have another good look at this theory. To my surprise I found out that this theory does not completely stand anymore. Apparently some things have changed since the release of Windows Vista / Windows 2008. Since the release of these Operating Systems, a move within the same disk partition results in the data inheriting the permissions of the location it is being copied into. A major change in the NTFS filesystem you would think!  Not quite! The above only counts when the move operation is being performed by using Windows Explorer. A move by using the 'move' command from within a cmd prompt for example, retains the NTFS permissions, just like before in Windows XP and older systems. Conclusion: The Windows Explorer is responsible for changing the ACL's of the moved data. This is a remarkable change, but if you follow this theory, the resulting ACL after a move operation is still predictable.  We could say that since Windows Vista and Windows 2008, a new rule set applies: "If you copy data, the copied data will inherit the permissions of the location it is being copied to. Same goes for moving data between disk partitions and within disk partitions. Only when you move data within the same partition by using something else than the Windows Explorer, the permissions are kept." The above behavior should be unchanged in Windows 7 / Windows 2008 R2, compared to Windows Vista / 2008. But somehow the NTFS permissions are not so predictable in Windows 7 and Windows 2008 R2. Moving data within the same disk partition the one time results in the permissions being kept and the next time results in inherited permissions from the destination location. I will try to demonstrate this in a few examples: Example 1 (Incorrect behavior): Consider two folders, 'Folder A' and 'Folder B' with the following permissions configured.                    Now we create the test file 'test file 1.txt' in 'Folder A' and afterwards move this file to 'Folder B' using Windows Explorer.                       According to the new theory, the file should inherit the permissions of 'Folder B' and therefore 'Group B' should appear in the ACL of 'test file 1.txt'. In the screenshot below the resulting permissions are displayed. The permissions from the originating location are kept, while the permissions of 'Folder B' should be inherited.                   Example 2 (Correct behavior): Again, consider the same two folders. This time we make a small modification to the ACL of 'Folder A'. We add 'Group C' to the ACL and again we create a file in 'Folder A' which we name 'test file 2.txt'.                    Next, we move 'test file 2.txt' to 'Folder B'.                       Again, we check the permissions of 'test file 2.txt' at the target location. We can now see that the permissions are inherited. This is what should be happening, and can be considered 'correct behavior' for Windows Vista / 2008 / 7 / 2008 R2. It remains uncertain why this behavior is so inconsistent. At this time, this is under investigation with Microsoft Support. The investigation has been going for the last two weeks and it is beginning to look like there is no rational reason for this, other than a bug in the Windows Explorer in Windows 7 and 2008 R2. As soon as there is any certainty on this, I will note it here in this blog.                   The examples above are harmless tests, by using my own laptop. If you would create the same set of folders and groups, and configure exactly the same permissions, you will see exactly the same behavior. Be sure to use Windows 7 or Windows 2008 R2.   Initially the problem arose at a customer site where move operations on data on the fileserver by users would result in unpredictable results. This resulted in the wrong set of people having àccess permissions on data that they should not have permissions to. Off course this is something we want to prevent at all costs.   I have also done several tests with move operations by using the move command in a cmd prompt. This way the behavior is always consistent. The inconsistent behavior is only exposed when using the Windows Explorer to initiate the move operation, and only when using Windows 7 or Windows 2008 R2 systems. It is evident that this behavior changes when the ACL of a folder has been changed, for example by adding an extra entry. The reason for this remains uncertain though. To be continued…. A dutch version of this post can be found at: http://blogs.platani.nl/?p=612

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  • HTML5 and Visual Studio 2010

    - by Harish Ranganathan
    All of us work with Visual Studio (or the free Visual Web Developer Express Edition) for developing web applications targeting ASP.NET / ASP.NET MVC or Silverlight etc.,  Over the years, Visual Studio has grown to a great extent.  From being a simple limited functionality tool in VS.NET 2002 to the multi-faceted, MEF driven Visual Studio 2010, it has come a long way.  And as much as Visual Studio supports rapid web development by generating HTML mark up, it also added intellisense for some of the HTML specifications that one has otherwise monotonously type every time.  Ex.- In Visual Studio 2010, one can just type the angular bracket “<” and then the first keyword “h” or “x” for html or xhtml respectively and then press tab twice and it would render the entire markup required for XHTML or HTML 1.0/1.1 strict/transitional and the fully qualified W3C URL. The same holds good for specifying HTML type declaration.  Now, the difference between HTML and XHTML has been discussed in detail already, though, if you are interested to know, you can read it from http://www.w3schools.com/xhtml/xhtml_html.asp But, the industry trend or the buzz around is HTML5.  With browsers like IE9 Beta, Google Chrome, Firefox 4 etc., supporting HTML5 standards big time, everyone wants to start developing HTML5 based websites. VS developers (like me) often get the question around when would VS start supporting HTML5.  VS 2010 was released last year and HTML5 is still specifications under development.  Clearly, with the timelines we started developing Visual Studio (way back in 2008), HTML5 specs were almost non-existent.  Even today, the HTML5 body recommends not to fully depend on the entire mark up set as they are still under development specs and might change in the future. However, with Visual Studio 2010 SP1 beta, there is quite a bit of support for HTML5 based web development.  In fact, one of my colleagues pointed out that SP1 beta’s major enhancement is its ability to support HTML5 tags and even add server mode to them. Lets look at the existing validation schema available in Visual Studio (Tools – Options – Validation) This is before installing Visual Studio 2010 SP1 Beta.  Clearly, the validation options are restricted to HTML 4.01 and XHTML 1.1 transitional and below. Also, lets consider using some of the new HTML5 input type elements.  (I found out this, just today from my friend, also an, ASP.NET team member) <input type=”email”> is one of the new input type elements according to the HTML5 specification.  Now, this works well if you type it as is  in Visual Studio and the page renders without any issue (since the default behaviour is, if there is an “undefined” type specified to input tag, it would fall back on the default mode, which is text. The moment you add <input type=”email” runat=”server” >, you get an error Naturally you don’t get intellisense support as well for these new tags.  Once you install Visual Studio 2010 Service Pack 1 Beta from here (it takes a while so you need to be patient for the installation to complete), you will start getting additional Validation templates for HTML5, as below:- Once you set this, you can start using HTML5 elements in your web page without getting errors/warnings.  Look at the screen shot below, for the new “video” tag which is showing up in intellisense (video is a part of the new HTML5 specifications)     note that, you still need to hook up the <!DOCTYPE html /> on the top manually as it doesn’t change automatically  (from the default XHTML 1.0 strict) when you create a new page. Also, the new input type tags in HTML5 are also supported One, can also use the <asp:TextBox type=”email” which would in turn generate the <input type=”email”> markup when the page is rendered.  In fact, as of SP1 beta, this is the only way to put the new input type tags with the runat=”server” attribute (otherwise you will get the parser error mentioned above.  This issue would be fixed by the final release of SP1 beta) Going further, there may be more support for having server tags for some of the common HTML5 elements, but this is work in progress currently. So, other than not having runat=”server” support for the new HTML5  input tags, you can pretty much build and target HTML5 websites with Visual Studio 2010 SP1 Beta, today.  For those who are running Visual Studio 2008, you also have the “HTML5 intellisense for Visual Studio 2010 and 2008” available for download, from http://visualstudiogallery.msdn.microsoft.com/d771cbc8-d60a-40b0-a1d8-f19fc393127d/ Note that, if you are running Visual Studio 2010, the recommended approach is to install the SP1 beta which would be the way forward for HTML5 support in Visual Studio. Of course, you need to test these on a browser supporting HTML5 such as IE9 Beta or Chrome or FireFox 4.  You can download IE9 Beta from here You can also follow the Visual Web Developer Team Blog for more updates on the stuff they are building. Cheers !!!

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  • Slow boot on Ubuntu 12.04

    - by Hailwood
    My Ubuntu is booting really slow (Windows is booting faster...). I am using Ubuntu a Dell Inspiron 1545 Pentium(R) Dual-Core CPU T4300 @ 2.10GHz, 4GB Ram, 500GB HDD running Ubuntu 12.04 with gnome-shell 3.4.1. After running dmesg the culprit seems to be this section, in particular the last three lines: [26.557659] ADDRCONF(NETDEV_UP): eth0: link is not ready [26.565414] ADDRCONF(NETDEV_UP): eth0: link is not ready [27.355355] Console: switching to colour frame buffer device 170x48 [27.362346] fb0: radeondrmfb frame buffer device [27.362347] drm: registered panic notifier [27.362357] [drm] Initialized radeon 2.12.0 20080528 for 0000:01:00.0 on minor 0 [27.617435] init: udev-fallback-graphics main process (1049) terminated with status 1 [30.064481] init: plymouth-stop pre-start process (1500) terminated with status 1 [51.708241] CE: hpet increased min_delta_ns to 20113 nsec [59.448029] eth2: no IPv6 routers present But I have no idea how to start debugging this. sudo lshw -C video $ sudo lshw -C video *-display description: VGA compatible controller product: RV710 [Mobility Radeon HD 4300 Series] vendor: Hynix Semiconductor (Hyundai Electronics) physical id: 0 bus info: pci@0000:01:00.0 version: 00 width: 32 bits clock: 33MHz capabilities: pm pciexpress msi vga_controller bus_master cap_list rom configuration: driver=fglrx_pci latency=0 resources: irq:48 memory:e0000000-efffffff ioport:de00(size=256) memory:f6df0000-f6dfffff memory:f6d00000-f6d1ffff After loading the propriety driver my new dmesg log is below (starting from the first major time gap): [2.983741] EXT4-fs (sda6): mounted filesystem with ordered data mode. Opts: (null) [25.094327] ADDRCONF(NETDEV_UP): eth0: link is not ready [25.119737] udevd[520]: starting version 175 [25.167086] lp: driver loaded but no devices found [25.215341] fglrx: module license 'Proprietary. (C) 2002 - ATI Technologies, Starnberg, GERMANY' taints kernel. [25.215345] Disabling lock debugging due to kernel taint [25.231924] wmi: Mapper loaded [25.318414] lib80211: common routines for IEEE802.11 drivers [25.318418] lib80211_crypt: registered algorithm 'NULL' [25.331631] [fglrx] Maximum main memory to use for locked dma buffers: 3789 MBytes. [25.332095] [fglrx] vendor: 1002 device: 9552 count: 1 [25.334206] [fglrx] ioport: bar 1, base 0xde00, size: 0x100 [25.334229] pci 0000:01:00.0: PCI INT A -> GSI 16 (level, low) -> IRQ 16 [25.334235] pci 0000:01:00.0: setting latency timer to 64 [25.337109] [fglrx] Kernel PAT support is enabled [25.337140] [fglrx] module loaded - fglrx 8.96.4 [Mar 12 2012] with 1 minors [25.342803] Adding 4189180k swap on /dev/sda7. Priority:-1 extents:1 across:4189180k [25.364031] type=1400 audit(1338241723.027:2): apparmor="STATUS" operation="profile_load" name="/sbin/dhclient" pid=606 comm="apparmor_parser" [25.364491] type=1400 audit(1338241723.031:3): apparmor="STATUS" operation="profile_load" name="/usr/lib/NetworkManager/nm-dhcp-client.action" pid=606 comm="apparmor_parser" [25.364760] type=1400 audit(1338241723.031:4): apparmor="STATUS" operation="profile_load" name="/usr/lib/connman/scripts/dhclient-script" pid=606 comm="apparmor_parser" [25.394328] wl 0000:0c:00.0: PCI INT A -> GSI 17 (level, low) -> IRQ 17 [25.394343] wl 0000:0c:00.0: setting latency timer to 64 [25.415531] acpi device:36: registered as cooling_device2 [25.416688] input: Video Bus as /devices/LNXSYSTM:00/device:00/PNP0A03:00/device:34/LNXVIDEO:00/input/input6 [25.416795] ACPI: Video Device [VID] (multi-head: yes rom: no post: no) [25.416865] [Firmware Bug]: Duplicate ACPI video bus devices for the same VGA controller, please try module parameter "video.allow_duplicates=1"if the current driver doesn't work. [25.425133] lib80211_crypt: registered algorithm 'TKIP' [25.448058] snd_hda_intel 0000:00:1b.0: PCI INT A -> GSI 21 (level, low) -> IRQ 21 [25.448321] snd_hda_intel 0000:00:1b.0: irq 47 for MSI/MSI-X [25.448353] snd_hda_intel 0000:00:1b.0: setting latency timer to 64 [25.738867] eth1: Broadcom BCM4315 802.11 Hybrid Wireless Controller 5.100.82.38 [25.761213] input: HDA Intel Mic as /devices/pci0000:00/0000:00:1b.0/sound/card0/input7 [25.761406] input: HDA Intel Headphone as /devices/pci0000:00/0000:00:1b.0/sound/card0/input8 [25.783432] dcdbas dcdbas: Dell Systems Management Base Driver (version 5.6.0-3.2) [25.908318] EXT4-fs (sda6): re-mounted. Opts: errors=remount-ro [25.928155] input: Dell WMI hotkeys as /devices/virtual/input/input9 [25.960561] udevd[543]: renamed network interface eth1 to eth2 [26.285688] init: failsafe main process (835) killed by TERM signal [26.396426] input: PS/2 Mouse as /devices/platform/i8042/serio2/input/input10 [26.423108] input: AlpsPS/2 ALPS GlidePoint as /devices/platform/i8042/serio2/input/input11 [26.511297] Bluetooth: Core ver 2.16 [26.511383] NET: Registered protocol family 31 [26.511385] Bluetooth: HCI device and connection manager initialized [26.511388] Bluetooth: HCI socket layer initialized [26.511391] Bluetooth: L2CAP socket layer initialized [26.512079] Bluetooth: SCO socket layer initialized [26.530164] Bluetooth: BNEP (Ethernet Emulation) ver 1.3 [26.530168] Bluetooth: BNEP filters: protocol multicast [26.553893] type=1400 audit(1338241724.219:5): apparmor="STATUS" operation="profile_replace" name="/sbin/dhclient" pid=928 comm="apparmor_parser" [26.554860] Bluetooth: RFCOMM TTY layer initialized [26.554866] Bluetooth: RFCOMM socket layer initialized [26.554868] Bluetooth: RFCOMM ver 1.11 [26.557910] type=1400 audit(1338241724.223:6): apparmor="STATUS" operation="profile_load" name="/usr/lib/lightdm/lightdm/lightdm-guest-session-wrapper" pid=927 comm="apparmor_parser" [26.559166] type=1400 audit(1338241724.223:7): apparmor="STATUS" operation="profile_replace" name="/usr/lib/NetworkManager/nm-dhcp-client.action" pid=928 comm="apparmor_parser" [26.559574] type=1400 audit(1338241724.223:8): apparmor="STATUS" operation="profile_replace" name="/usr/lib/connman/scripts/dhclient-script" pid=928 comm="apparmor_parser" [26.575519] type=1400 audit(1338241724.239:9): apparmor="STATUS" operation="profile_load" name="/usr/lib/telepathy/mission-control-5" pid=931 comm="apparmor_parser" [26.581100] type=1400 audit(1338241724.247:10): apparmor="STATUS" operation="profile_load" name="/usr/lib/telepathy/telepathy-*" pid=931 comm="apparmor_parser" [26.582794] type=1400 audit(1338241724.247:11): apparmor="STATUS" operation="profile_load" name="/usr/bin/evince" pid=929 comm="apparmor_parser" [26.605672] ppdev: user-space parallel port driver [27.592475] sky2 0000:09:00.0: eth0: enabling interface [27.604329] ADDRCONF(NETDEV_UP): eth0: link is not ready [27.606962] ADDRCONF(NETDEV_UP): eth0: link is not ready [27.852509] vesafb: mode is 1024x768x32, linelength=4096, pages=0 [27.852513] vesafb: scrolling: redraw [27.852515] vesafb: Truecolor: size=0:8:8:8, shift=0:16:8:0 [27.852523] mtrr: type mismatch for e0000000,400000 old: write-back new: write-combining [27.852527] mtrr: type mismatch for e0000000,200000 old: write-back new: write-combining [27.852531] mtrr: type mismatch for e0000000,100000 old: write-back new: write-combining [27.852534] mtrr: type mismatch for e0000000,80000 old: write-back new: write-combining [27.852538] mtrr: type mismatch for e0000000,40000 old: write-back new: write-combining [27.852541] mtrr: type mismatch for e0000000,20000 old: write-back new: write-combining [27.852544] mtrr: type mismatch for e0000000,10000 old: write-back new: write-combining [27.852548] mtrr: type mismatch for e0000000,8000 old: write-back new: write-combining [27.852551] mtrr: type mismatch for e0000000,4000 old: write-back new: write-combining [27.852554] mtrr: type mismatch for e0000000,2000 old: write-back new: write-combining [27.852558] mtrr: type mismatch for e0000000,1000 old: write-back new: write-combining [27.853154] vesafb: framebuffer at 0xe0000000, mapped to 0xffffc90005580000, using 3072k, total 3072k [27.853405] Console: switching to colour frame buffer device 128x48 [27.853426] fb0: VESA VGA frame buffer device [28.539800] fglrx_pci 0000:01:00.0: irq 48 for MSI/MSI-X [28.540552] [fglrx] Firegl kernel thread PID: 1168 [28.540679] [fglrx] Firegl kernel thread PID: 1169 [28.540789] [fglrx] Firegl kernel thread PID: 1170 [28.540932] [fglrx] IRQ 48 Enabled [29.845620] [fglrx] Gart USWC size:1236 M. [29.845624] [fglrx] Gart cacheable size:489 M. [29.845629] [fglrx] Reserved FB block: Shared offset:0, size:1000000 [29.845632] [fglrx] Reserved FB block: Unshared offset:fc21000, size:3df000 [29.845635] [fglrx] Reserved FB block: Unshared offset:1fffb000, size:5000 [59.700023] eth2: no IPv6 routers present

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  • MVVM Light V4 preview 2 (BL0015) #mvvmlight

    - by Laurent Bugnion
    Over the past few weeks, I have worked hard on a few new features for MVVM Light V4. Here is a second early preview (consider this pre-alpha if you wish). The features are unit-tested, but I am now looking for feedback and there might be bugs! Bug correction: Messenger.CleanupList is now thread safe This was an annoying bug that is now corrected: In some circumstances, an exception could be thrown when the Messenger’s recipients list was cleaned up (i.e. the “dead” instances were removed). The method is called now and then and the exception was thrown apparently at random. In fact it was really a multi-threading issue, which is now corrected. Bug correction: AllowPartiallyTrustedCallers prevents EventToCommand to work This is a particularly annoying regression bug that was introduced in BL0014. In order to allow MVVM Light to work in XBAPs too, I added the AllowPartiallyTrustedCallers attribute to the assemblies. However, we just found out that this causes issues when using EventToCommand. In order to allow EventToCommand to continue working, I reverted to the previous state by removing the AllowPartiallyTrustedCallers attribute for now. I will work with my friends at Microsoft to try and find a solution. Stay tuned. Bug correction: XML documentation file is now generated in Release configuration The XML documentation file was not generated for the Release configuration. This was a simple flag in the project file that I had forgotten to set. This is corrected now. Applying EventToCommand to non-FrameworkElements This feature has been requested in order to be able to execute a command when a Storyboard is completed. I implemented this, but unfortunately found out that EventToCommand can only be added to Storyboards in Silverlight 3 and Silverlight 4, but not in WPF or in Windows Phone 7. This obviously limits the usefulness of this change, but I decided to publish it anyway, because it is pretty damn useful in Silverlight… Why not in WPF? In WPF, Storyboards added to a resource dictionary are frozen. This is a feature of WPF which allows to optimize certain objects for performance: By freezing them, it is a contract where we say “this object will not be modified anymore, so do your perf optimization on them without worrying too much”. Unfortunately, adding a Trigger (such as EventTrigger) to an object in resources does not work if this object is frozen… and unfortunately, there is no way to tell WPF not to freeze the Storyboard in the resources… so there is no way around that (at least none I can see. In Silverlight, objects are not frozen, so an EventTrigger can be added without problems. Why not in WP7? In Windows Phone 7, there is a totally different issue: Adding a Trigger can only be done to a FrameworkElement, which Storyboard is not. Here I think that we might see a change in a future version of the framework, so maybe this small trick will work in the future. Workaround? Since you cannot use the EventToCommand on a Storyboard in WPF and in WP7, the workaround is pretty obvious: Handle the Completed event in the code behind, and call the Command from there on the ViewModel. This object can be obtained by casting the DataContext to the ViewModel type. This means that the View needs to know about the ViewModel, but I never had issues with that anyway. New class: NotifyPropertyChanged Sometimes when you implement a model object (for example Customer), you would like to have it implement INotifyPropertyChanged, but without having all the frills of a ViewModelBase. A new class named NotifyPropertyChanged allows you to do that. This class is a simple implementation of INotifyPropertyChaned (with all the overloads of RaisePropertyChanged that were implemented in BL0014). In fact, ViewModelBase inherits NotifyPropertyChanged. ViewModelBase does not implement IDisposable anymore The IDisposable interface and the Dispose method had been marked obsolete in the ViewModelBase class already in V3. Now they have been removed. Note: By this, I do not mean that IDisposable is a bad interface, or that it shouldn’t be used on viewmodels. In the contrary, I know that this interface is very useful in certain circumstances. However, I think that having it by default on every instance of ViewModelBase was sending a wrong message. This interface has a strong meaning in .NET: After Dispose has been executed, the instance should not be used anymore, and should be ready for garbage collection. What I really wanted to have on ViewModelBase was rather a simple cleanup method, something that can be executed now and then during runtime. This is fulfilled by the ICleanup interface and its Cleanup method. If your ViewModels need IDisposable, you can still use it! You will just have to implement the interface on the class itself, because it is not available on ViewModelBase anymore. What’s next? I have a couple exciting new features implemented already but that need more testing before they go live… Just stay tuned and by MIX11 (12-14 April 2011), we should see at least a major addition to MVVM Light Toolkit, as well as another smaller feature which is pretty cool nonetheless More about this later! Happy Coding Laurent   Laurent Bugnion (GalaSoft) Subscribe | Twitter | Facebook | Flickr | LinkedIn

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  • SQL SERVER – SmallDateTime and Precision – A Continuous Confusion

    - by pinaldave
    Some kinds of confusion never go away. Here is one of the ancient confusing things in SQL. The precision of the SmallDateTime is one concept that confuses a lot of people, proven by the many messages I receive everyday relating to this subject. Let me start with the question: What is the precision of the SMALLDATETIME datatypes? What is your answer? Write it down on your notepad. Now if you do not want to continue reading the blog post, head to my previous blog post over here: SQL SERVER – Precision of SMALLDATETIME. A Social Media Question Since the increase of social media conversations, I noticed that the amount of the comments I receive on this blog is a bit staggering. I receive lots of questions on facebook, twitter or Google+. One of the very interesting questions yesterday was asked on Facebook by Raghavendra. I am re-organizing his script and asking all of the questions he has asked me. Let us see if we could help him with his question: CREATE TABLE #temp (name VARCHAR(100),registered smalldatetime) GO DECLARE @test smalldatetime SET @test=GETDATE() INSERT INTO #temp VALUES ('Value1',@test) INSERT INTO #temp VALUES ('Value2',@test) GO SELECT * FROM #temp ORDER BY registered DESC GO DROP TABLE #temp GO Now when the above script is ran, we will get the following result: Well, the expectation of the query was to have the following result. The row which was inserted last was expected to return as first row in result set as the ORDER BY descending. Side note: Because the requirement is to get the latest data, we can’t use any  column other than smalldatetime column in order by. If we use name column in the order by, we will get an incorrect result as it can be any name. My Initial Reaction My initial reaction was as follows: 1) DataType DateTime2: If file precision of the column is expected from the column which store date and time, it should not be smalldatetime. The precision of the column smalldatetime is One Minute (Read Here) for finer precision use DateTime or DateTime2 data type. Here is the code which includes above suggestion: CREATE TABLE #temp (name VARCHAR(100), registered datetime2) GO DECLARE @test datetime2 SET @test=GETDATE() INSERT INTO #temp VALUES ('Value1',@test) INSERT INTO #temp VALUES ('Value2',@test) GO SELECT * FROM #temp ORDER BY registered DESC GO DROP TABLE #temp GO 2) Tie Breaker Identity: There are always possibilities that two rows were inserted at the same time. In that case, you may need a tie breaker. If you have an increasing identity column, you can use that as a tie breaker as well. CREATE TABLE #temp (ID INT IDENTITY(1,1), name VARCHAR(100),registered datetime2) GO DECLARE @test datetime2 SET @test=GETDATE() INSERT INTO #temp VALUES ('Value1',@test) INSERT INTO #temp VALUES ('Value2',@test) GO SELECT * FROM #temp ORDER BY ID DESC GO DROP TABLE #temp GO Those two were the quick suggestions I provided. It is not necessary that you should use both advices. It is possible that one can use only DATETIME datatype or Identity column can have datatype of BIGINT or have another tie breaker. An Alternate NO Solution In the facebook thread this was also discussed as one of the solutions: CREATE TABLE #temp (name VARCHAR(100),registered smalldatetime) GO DECLARE @test smalldatetime SET @test=GETDATE() INSERT INTO #temp VALUES ('Value1',@test) INSERT INTO #temp VALUES ('Value2',@test) GO SELECT name, registered, ROW_NUMBER() OVER(ORDER BY registered DESC) AS "Row Number" FROM #temp ORDER BY 3 DESC GO DROP TABLE #temp GO However, I believe it is not the solution and can be further misleading if used in a production server. Here is the example of why it is not a good solution: CREATE TABLE #temp (name VARCHAR(100) NOT NULL,registered smalldatetime) GO DECLARE @test smalldatetime SET @test=GETDATE() INSERT INTO #temp VALUES ('Value1',@test) INSERT INTO #temp VALUES ('Value2',@test) GO -- Before Index SELECT name, registered, ROW_NUMBER() OVER(ORDER BY registered DESC) AS "Row Number" FROM #temp ORDER BY 3 DESC GO -- Create Index ALTER TABLE #temp ADD CONSTRAINT [PK_#temp] PRIMARY KEY CLUSTERED (name DESC) GO -- After Index SELECT name, registered, ROW_NUMBER() OVER(ORDER BY registered DESC) AS "Row Number" FROM #temp ORDER BY 3 DESC GO DROP TABLE #temp GO Now let us examine the resultset. You will notice that an index which is created on the base table which is (indeed) schema change the table but can affect the resultset. As you can see, an index can change the resultset, so this method is not yet perfect to get the latest inserted resultset. No Schema Change Requirement After giving these two suggestions, I was waiting for the feedback of the asker. However, the requirement of the asker was there can’t be any schema change because the application was used by many other applications. I validated again, and of course, the requirement is no schema change at all. No addition of the column of change of datatypes of any other columns. There is no further help as well. This is indeed an interesting question. I personally can’t think of any solution which I could provide him given the requirement of no schema change. Can you think of any other solution to this? Need of Database Designer This question once again brings up another ancient question:  “Do we need a database designer?” I often come across databases which are facing major performance problems or have redundant data. Normalization is often ignored when a database is built fast under a very tight deadline. Often I come across a database which has table with unnecessary columns and performance problems. While working as Developer Lead in my earlier jobs, I have seen developers adding columns to tables without anybody’s consent and retrieving them as SELECT *.  There is a lot to discuss on this subject in detail, but for now, let’s discuss the question first. Do you have any suggestions for the above question? Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: CodeProject, Developer Training, PostADay, SQL, SQL Authority, SQL DateTime, SQL Query, SQL Server, SQL Tips and Tricks, SQLServer, T SQL, Technology

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  • Towards an F# .NET Reflector add-in

    - by CliveT
    When I had the opportunity to spent some time during Red Gate's recent "down tools" week on a project of my choice, the obvious project was an F# add-in for Reflector . To be honest, this was a bit of a misnomer as the amount of time in the designated week for coding was really less than three days, so it was always unlikely that very much progress would be made in such a small amount of time (and that certainly proved to be the case), but I did learn some things from the experiment. Like lots of problems, one useful technique is to take examples, get them to work, and then generalise to get something that works across the board. Unfortunately, I didn't have enough time to do the last stage. The obvious first step is to take a few function definitions, starting with the obvious hello world, moving on to a non-recursive function and finishing with the ubiquitous recursive Fibonacci function. let rec printMessage message  =     printfn  message let foo x  =    (x + 1) let rec fib x  =     if (x >= 2) then (fib (x - 1) + fib (x - 2)) else 1 The major problem in decompiling these simple functions is that Reflector has an in-memory object model that is designed to support object-oriented languages. In particular it has a return statement that allows function bodies to finish early. I used some of the in-built functionality to take the IL and produce an in-memory object model for the language, but then needed to write a transformer to push the return statements to the top of the tree to make it easy to render the code into a functional language. This tree transform works in some scenarios, but not in others where we simply regenerate code that looks more like CPS style. The next thing to get working was library level bindings of values where these values are calculated at runtime. let x = [1 ; 2 ; 3 ; 4] let y = List.map  (fun x -> foo x) x The way that this is translated into a set of classes for the underlying platform means that the code needs to follow references around, from the property exposing the calculated value to the class in which the code for generating the value is embedded. One of the strongest selling points of functional languages is the algebraic datatypes, which allow definitions via standard mathematical-style inductive definitions across the union cases. type Foo =     | Something of int     | Nothing type 'a Foo2 =     | Something2 of 'a     | Nothing2 Such a definition is compiled into a number of classes for the cases of the union, which all inherit from a class representing the type itself. It wasn't too hard to get such a de-compilation happening in the cases I tried. What did I learn from this? Firstly, that there are various bits of functionality inside Reflector that it would be useful for us to allow add-in writers to access. In particular, there are various implementations of the Visitor pattern which implement algorithms such as calculating the number of references for particular variables, and which perform various substitutions which could be more generally useful to add-in writers. I hope to do something about this at some point in the future. Secondly, when you transform a functional language into something that runs on top of an object-based platform, you lose some fidelity in the representation. The F# compiler leaves attributes in place so that tools can tell which classes represent classes from the source program and which are there for purposes of the implementation, allowing the decompiler to regenerate these constructs again. However, decompilation technology is a long way from being able to take unannotated IL and transform it into a program in a different language. For a simple function definition, like Fibonacci, I could write a simple static function and have it come out in F# as the same function, but it would be practically impossible to take a mass of class definitions and have a decompiler translate it automatically into an F# algebraic data type. What have we got out of this? Some data on the feasibility of implementing an F# decompiler inside Reflector, though it's hard at the moment to say how long this would take to do. The work we did is included the 6.5 EAP for Reflector that you can get from the EAP forum. All things considered though, it was a useful way to gain more familiarity with the process of writing an add-in and understand difficulties other add-in authors might experience. If you'd like to check out a video of Down Tools Week, click here.

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  • List of Commonly Used Value Types in XNA Games

    - by Michael B. McLaughlin
    Most XNA programmers are concerned about generating garbage. More specifically about allocating GC-managed memory (GC stands for “garbage collector” and is both the name of the class that provides access to the garbage collector and an acronym for the garbage collector (as a concept) itself). Two of the major target platforms for XNA (Windows Phone 7 and Xbox 360) use variants of the .NET Compact Framework. On both variants, the GC runs under various circumstances (Windows Phone 7 and Xbox 360). Of concern to XNA programmers is the fact that it runs automatically after a fixed amount of GC-managed memory has been allocated (currently 1MB on both systems). Many beginning XNA programmers are unaware of what constitutes GC-managed memory, though. So here’s a quick overview. In .NET, there are two different “types” of types: value types and reference types. Only reference types are managed by the garbage collector. Value types are not managed by the garbage collector and are instead managed in other ways that are implementation dependent. For purposes of XNA programming, the important point is that they are not managed by the GC and thus do not, by themselves, increment that internal 1 MB allocation counter. (n.b. Structs are value types. If you have a struct that has a reference type as a member, then that reference type, when instantiated, will still be allocated in the GC-managed memory and will thus count against the 1 MB allocation counter. Putting it in a struct doesn’t change the fact that it gets allocated on the GC heap, but the struct itself is created outside of the GC’s purview). Both value types and reference types use the keyword ‘new’ to allocate a new instance of them. Sometimes this keyword is hidden by a method which creates new instances for you, e.g. XmlReader.Create. But the important thing to determine is whether or not you are dealing with a value types or a reference type. If it’s a value type, you can use the ‘new’ keyword to allocate new instances of that type without incrementing the GC allocation counter (except as above where it’s a struct with a reference type in it that is allocated by the constructor, but there are no .NET Framework or XNA Framework value types that do this so it would have to be a struct you created or that was in some third-party library you were using for that to even become an issue). The following is a list of most all of value types you are likely to use in a generic XNA game: AudioCategory (used with XACT; not available on WP7) AvatarExpression (Xbox 360 only, but exposed on Windows to ease Xbox development) bool BoundingBox BoundingSphere byte char Color DateTime decimal double any enum (System.Enum itself is a class, but all enums are value types such that there are no GC allocations for enums) float GamePadButtons GamePadCapabilities GamePadDPad GamePadState GamePadThumbSticks GamePadTriggers GestureSample int IntPtr (rarely but occasionally used in XNA) KeyboardState long Matrix MouseState nullable structs (anytime you see, e.g. int? something, that ‘?’ denotes a nullable struct, also called a nullable type) Plane Point Quaternion Ray Rectangle RenderTargetBinding sbyte (though I’ve never seen it used since most people would just use a short) short TimeSpan TouchCollection TouchLocation TouchPanelCapabilities uint ulong ushort Vector2 Vector3 Vector4 VertexBufferBinding VertexElement VertexPositionColor VertexPositionColorTexture VertexPositionNormalTexture VertexPositionTexture Viewport So there you have it. That’s not quite a complete list, mind you. For example: There are various structs in the .NET framework you might make use of. I left out everything from the Microsoft.Xna.Framework.Graphics.PackedVector namespace, since everything in there ventures into the realm of advanced XNA programming anyway (n.b. every single instantiable thing in that namespace is a struct and thus a value type; there are also two interfaces but interfaces cannot be instantiated at all and thus don’t figure in to this discussion). There are so many enums you’re likely to use (PlayerIndex, SpriteSortMode, SpriteEffects, SurfaceFormat, etc.) that including them would’ve flooded the list and reduced its utility. So I went with “any enum” and trust that you can figure out what the enums are (and it’s rare to use ‘new’ with an enum anyway). That list also doesn’t include any of the pre-defined static instances of some of the classes (e.g. BlendState.AlphaBlend, BlendState.Opaque, etc.) which are already allocated such that using them doesn’t cause any new allocations and therefore doesn’t increase that 1 MB counter. That list also has a few misleading things. VertexElement, VertexPositionColor, and all the other vertex types are structs. But you’re only likely to ever use them as an array (for use with VertexBuffer or DynamicVertexBuffer), and all arrays are reference types (even arrays of value types such as VertexPositionColor[ ] or int[ ]). * So that’s it for now. The note below may be a bit confusing (it deals with how the GC works and how arrays are managed in .NET). If so, you can probably safely ignore it for now but feel free to ask any questions regardless. * Arrays of value types (where the value type doesn’t contain any reference type members) are much faster for the GC to examine than arrays of reference types, so there is a definite benefit to using arrays of value types where it makes sense. But creating arrays of value types does cause the GC’s allocation counter to increase. Indeed, allocating a large array of a value type is one of the quickest ways to increment the allocation counter since a .NET array is a sequential block of memory. An array of reference types is just a sequential block of references (typically 4 bytes each) while an array of value types is a sequential block of instances of that type. So for an array of Vector3s it would be 12 bytes each since each float is 4 bytes and there are 3 in a Vector3; for an array of VertexPositionNormalTexture structs it would typically be 32 bytes each since it has two Vector3s and a Vector2. (Note that there are a few additional bytes taken up in the creation of an array, typically 12 but sometimes 16 or possibly even more, which depend on the implementation details of the array type on the particular platform the code is running on).

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  • DBCC CHECKDB (BatmanDb, REPAIR_ALLOW_DATA_LOSS) &ndash; Are you Feeling Lucky?

    - by David Totzke
    I’m currently working for a client on a PowerBuilder to WPF migration.  It’s one of those “I could tell you, but I’d have to kill you” kind of clients and the quick-lime pits are currently occupied by the EMC tech…but I’ve said too much already. At approximately 3 or 4 pm that day users of the Batman[1] application here in Gotham[1] started to experience problems accessing the application.  Batman[2] is a document management system here that also integrates with the ERP system.  Very little goes on here that doesn’t involve Batman in some way.  The errors being received seemed to point to network issues (TCP protocol error, connection forcibly closed by the remote host etc…) but the real issue was much more insidious. Connecting to the database via SSMS and performing selects on certain tables underlying the application areas that were having problems started to reveal the issue.  You couldn’t do a SELECT * FROM MyTable without it bombing and giving the same error noted above.  A run of DBCC CHECKDB revealed 14 tables with corruption.  One of the tables with issues was the Document table.  Pretty central to a “document management” system.  Information was obtained from IT that a single drive in the SAN went bad in the night.  A new drive was in place and was working fine.  The partition that held the Batman database is configured for RAID Level 5 so a single drive failure shouldn’t have caused any trouble and yet, the database is corrupted.  They do hourly incremental backups here so the first thing done was to try a restore.  A restore of the most recent backup failed so they worked backwards until they hit a good point.  This successful restore was for a backup at 3AM – a full day behind.  This time also roughly corresponds with the time the SAN started to report the drive failure.  The plot thickens… I got my hands on the output from DBCC CHECKDB and noticed a pattern.  What’s sad is that nobody that should have noticed the pattern in the DBCC output did notice.  There was a rush to do things to try and recover the data before anybody really understood what was wrong with it in the first place.  Cooler heads must prevail in these circumstances and some investigation should be done and a plan of action laid out or you could end up making things worse[3].  DBCC CHECKDB also told us that: repair_allow_data_loss is the minimum repair level for the errors found by DBCC CHECKDB Yikes.  That means that the database is so messed up that you’re definitely going to lose some stuff when you repair it to get it back to a consistent state.  All the more reason to do a little more investigation into the problem.  Rescuing this database is preferable to having to export all of the data possible from this database into a new one.  This is a fifteen year old application with about seven hundred tables.  There are TRIGGERS everywhere not to mention the referential integrity constraints to deal with.  Only fourteen of the tables have an issue.  We have a good backup that is missing the last 24 hours of business which means we could have a “do-over” of yesterday but that’s not a very palatable option either. All of the affected tables had TEXT columns and all of the errors were about LOB data types and orphaned off-row data which basically means TEXT, IMAGE or NTEXT columns.  If we did a SELECT on an affected table and excluded those columns, we got all of the rows.  We exported that data into a separate database.  Things are looking up.  Working on a copy of the production database we then ran DBCC CHECKDB with REPAIR_ALLOW_DATA_LOSS and that “fixed” everything up.   The allow data loss option will delete the bad rows.  This isn’t too horrible as we have all of those rows minus the text fields from out earlier export.  Now I could LEFT JOIN to the exported data to find the missing rows and INSERT them minus the TEXT column data. We had the restored data from the good 3AM backup that we could now JOIN to and, with fingers crossed, recover the missing TEXT column information.  We got lucky in that all of the affected rows were old and in the end we didn’t lose anything.  :O  All of the row counts along the way worked out and it looks like we dodged a major bullet here. We’ve heard back from EMC and it turns out the SAN firmware that they were running here is apparently buggy.  This thing is only a couple of months old.  Grrr…. They dispatched a technician that night to come and update it .  That explains why RAID didn’t save us. All-in-all this could have been a lot worse.  Given the root cause here, they basically won the lottery in not losing anything. Here are a few links to some helpful posts on the SQL Server Engine blog.  I love the title of the first one: Which part of 'REPAIR_ALLOW_DATA_LOSS' isn't clear? CHECKDB (Part 8): Can repair fix everything? (in fact, read the whole series) Ta da! Emergency mode repair (we didn’t have to resort to this one thank goodness)   Dave Just because I can…   [1] Names have been changed to protect the guilty. [2] I'm Batman. [3] And if I'm the coolest head in the room, you've got even bigger problems...

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  • Why is my external USB hard drive sometimes completely inaccessible?

    - by Eliah Kagan
    I have an external USB hard drive, consisting of an 1 TB SATA drive in a Rosewill RX35-AT-SU SLV Aluminum 3.5" Silver USB 2.0 External Enclosure, plugged into my SONY VAIO VGN-NS310F laptop. It is plugged directly into the computer (not through a hub). The drive inside the enclosure is a 7200 rpm Western Digital, but I don't remember the exact model. I can remove the drive from the enclosure (again), if people think it's necessary to know that detail. The drive is formatted ext4. I mount it dynamically with udisks on my Lubuntu 11.10 system, usually automatically via PCManFM. (I have had Lubuntu 12.04 on this machine, and experienced all this same behavior with that too.) Every once in a while--once or twice a day--it becomes inaccessible, and difficult to unmount. Attempting to unmount it with sudo umount ... gives an error message saying the drive is in use and suggesting fuser and lsof to find out what is using it. Killing processes found to be using the drive with fuser and lsof is sometimes sufficient to let me unmount it, but usually isn't. Once the drive is unmounted or the machine is rebooted, the drive will not mount. Plugging in the drive and turning it on registers nothing on the computer. dmesg is unchanged. The drive's access light usually blinks vigorously, as though the drive is being accessed constantly. Then eventually, after I keep the drive off for a while (half an hour), I am able to mount it again. While the drive doesn't work on this machine for a while, it will work immediately on another machine running the same version of Ubuntu. Sometimes bringing it back over from the other machine seems to "fix" it. Sometimes it doesn't. The drive doesn't always stop being accessible while mounted, before becoming unmountable. Sometimes it works fine, I turn off the computer, I turn the computer back on, and I cannot mount the drive. Currently this is the only drive with which I have this problem, but I've had problems that I think are the same as this, with different drives, on different Ubuntu machines. This laptop has another external USB drive plugged into it regularly, which doesn't have this problem. Unplugging that drive before plugging in the "problem" drive doesn't fix the problem. I've opened the drive up and made sure the connections were tight in the past, and that didn't seem to help (any more than waiting the same amount of time that it took to open and close the drive, before attempting to remount it). Does anyone have any ideas about what could be causing this, what troubleshooting steps I should perform, and/or how I could fix this problem altogether? Update: I tried replacing the USB data cable (from the enclosure to the laptop), as Merlin suggested. I should've tried that long ago, since it fits the symptoms perfectly (the drive works on another machine, which would make sense because the cable would be bent at a different angle, possibly completing a circuit of frayed wires). Unfortunately, though, this did not help--I have the same problem with the new cable. I'll try to provide additional detailed information about the drive inside the enclosure, next time I'm able to get the drive working. (At the moment I don't have another machine available to attach it.) Major Update (28 June 2012) The drive seems to have deteriorated considerably. I think this is so, because I've attached it to another machine and gotten lots of errors about invalid characters, when copying files from it. I am less interested in recovering data from the drive than I am in figuring out what is wrong with it. I specifically want to figure out if the problem is the drive or the enclosure. Now, when I plug the drive into the original machine where I was having the problems, it still doesn't appear (including with sudo fdisk -l), but it is recognized by the kernel and messages are added to dmesg. Most of the message consist of errors like this, repeated many times: [ 7.707593] sd 5:0:0:0: [sdc] Unhandled sense code [ 7.707599] sd 5:0:0:0: [sdc] Result: hostbyte=invalid driverbyte=DRIVER_SENSE [ 7.707606] sd 5:0:0:0: [sdc] Sense Key : Medium Error [current] [ 7.707614] sd 5:0:0:0: [sdc] Add. Sense: Unrecovered read error [ 7.707621] sd 5:0:0:0: [sdc] CDB: Read(10): 28 00 00 00 00 00 00 00 08 00 [ 7.707636] end_request: critical target error, dev sdc, sector 0 [ 7.707641] Buffer I/O error on device sdc, logical block 0 Here are all the lines from dmesg starting with when the drive is recognized. Please note that: I'm back to running Lubuntu 12.04 on this machine (and perhaps that's a factor in better error messages). Now that the drive has been plugged into another machine and back into this one, and also now that this machine is back to running 12.04, the drive's access light doesn't blink as I had described. Looking at the drive, it would appear as though it is working normally, with low or no access. This behavior (the errors) occurs when rebooting the machine with the drive plugged in, and also when manually plugging in the drive. A few of the messages are about /dev/sdb. That drive is working fine. The bad drive is /dev/sdc. I just didn't want to edit anything out from the middle.

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  • Goodbye XML&hellip; Hello YAML (part 2)

    - by Brian Genisio's House Of Bilz
    Part 1 After I explained my motivation for using YAML instead of XML for my data, I got a lot of people asking me what type of tooling is available in the .Net space for consuming YAML.  In this post, I will discuss a nice tooling option as well as describe some small modifications to leverage the extremely powerful dynamic capabilities of C# 4.0.  I will be referring to the following YAML file throughout this post Recipe: Title: Macaroni and Cheese Description: My favorite comfort food. Author: Brian Genisio TimeToPrepare: 30 Minutes Ingredients: - Name: Cheese Quantity: 3 Units: cups - Name: Macaroni Quantity: 16 Units: oz Steps: - Number: 1 Description: Cook the macaroni - Number: 2 Description: Melt the cheese - Number: 3 Description: Mix the cooked macaroni with the melted cheese Tooling It turns out that there are several implementations of YAML tools out there.  The neatest one, in my opinion, is YAML for .NET, Visual Studio and Powershell.  It includes a great editor plug-in for Visual Studio as well as YamlCore, which is a parsing engine for .Net.  It is in active development still, but it is certainly enough to get you going with YAML in .Net.  Start by referenceing YamlCore.dll, load your document, and you are on your way.  Here is an example of using the parser to get the title of the Recipe: var yaml = YamlLanguage.FileTo("Data.yaml") as Hashtable; var recipe = yaml["Recipe"] as Hashtable; var title = recipe["Title"] as string; In a similar way, you can access data in the Ingredients set: var yaml = YamlLanguage.FileTo("Data.yaml") as Hashtable; var recipe = yaml["Recipe"] as Hashtable; var ingredients = recipe["Ingredients"] as ArrayList; foreach (Hashtable ingredient in ingredients) { var name = ingredient["Name"] as string; } You may have noticed that YamlCore uses non-generic Hashtables and ArrayLists.  This is because YamlCore was designed to work in all .Net versions, including 1.0.  Everything in the parsed tree is one of two things: Hashtable, ArrayList or Value type (usually String).  This translates well to the YAML structure where everything is either a Map, a Set or a Value.  Taking it further Personally, I really dislike writing code like this.  Years ago, I promised myself to never write the words Hashtable or ArrayList in my .Net code again.  They are ugly, mostly depreciated collections that existed before we got generics in C# 2.0.  Now, especially that we have dynamic capabilities in C# 4.0, we can do a lot better than this.  With a relatively small amount of code, you can wrap the Hashtables and Array lists with a dynamic wrapper (wrapper code at the bottom of this post).  The same code can be re-written to look like this: dynamic doc = YamlDoc.Load("Data.yaml"); var title = doc.Recipe.Title; And dynamic doc = YamlDoc.Load("Data.yaml"); foreach (dynamic ingredient in doc.Recipe.Ingredients) { var name = ingredient.Name; } I significantly prefer this code over the previous.  That’s not all… the magic really happens when we take this concept into WPF.  With a single line of code, you can bind to the data dynamically in the view: DataContext = YamlDoc.Load("Data.yaml"); Then, your XAML is extremely straight-forward (Nothing else.  No static types, no adapter code.  Nothing): <StackPanel> <TextBlock Text="{Binding Recipe.Title}" /> <TextBlock Text="{Binding Recipe.Description}" /> <TextBlock Text="{Binding Recipe.Author}" /> <TextBlock Text="{Binding Recipe.TimeToPrepare}" /> <TextBlock Text="Ingredients:" FontWeight="Bold" /> <ItemsControl ItemsSource="{Binding Recipe.Ingredients}" Margin="10,0,0,0"> <ItemsControl.ItemTemplate> <DataTemplate> <StackPanel Orientation="Horizontal"> <TextBlock Text="{Binding Quantity}" /> <TextBlock Text=" " /> <TextBlock Text="{Binding Units}" /> <TextBlock Text=" of " /> <TextBlock Text="{Binding Name}" /> </StackPanel> </DataTemplate> </ItemsControl.ItemTemplate> </ItemsControl> <TextBlock Text="Steps:" FontWeight="Bold" /> <ItemsControl ItemsSource="{Binding Recipe.Steps}" Margin="10,0,0,0"> <ItemsControl.ItemTemplate> <DataTemplate> <StackPanel Orientation="Horizontal"> <TextBlock Text="{Binding Number}" /> <TextBlock Text=": " /> <TextBlock Text="{Binding Description}" /> </StackPanel> </DataTemplate> </ItemsControl.ItemTemplate> </ItemsControl> </StackPanel> This nifty XAML binding trick only works in WPF, unfortunately.  Silverlight handles binding differently, so they don’t support binding to dynamic objects as of late (March 2010).  This, in my opinion, is a major lacking feature in Silverlight and I really hope we will see this feature available to us in Silverlight 4 Release.  (I am not very optimistic for Silverlight 4, but I can hope for the feature in Silverlight 5, can’t I?) Conclusion I still have a few things I want to say about using YAML in the .Net space including de-serialization and using IronRuby for your YAML parser, but this post is hopefully enough to see how easy it is to incorporate YAML documents in your code. Codeplex Site for YAML tools Dynamic wrapper for YamlCore

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  • Sea Monkey Sales & Marketing, and what does that have to do with ERP?

    - by user709270
    Tier One Defined By Lyle Ekdahl, Oracle JD Edwards Group Vice President and General Manager  I recently became aware of the latest Sea Monkey Sales & Marketing tactic. Wait now, what is Sea Monkey Sales & Marketing and what does that have to do with ERP? Well if you grew up in USA during the 50’s, 60’s and maybe a bit in the early 70’s there was a unifying media of culture known as the comic book. I was a big Iron Man fan. I always liked the troubled hero aspect of Tony Start and hey he was a technologist. This is going somewhere, just hold on. Of course comic books like most media contained advertisements. Ninety pound weakling transformed by Charles Atlas in just 15 minutes per day. Baby Ruth, Juicy Fruit Gum and all assortments of Hostess goodies were on display. The best ad was for the “Amazing Live Sea-Monkeys – The real live fun-pets you grow yourself!” These ads set the standard for exaggeration and half-truth; “…they love attention…so eager to please, they can even be trained…” The cartoon picture on the ad is of a family of royal looking sea creatures – daddy, mommy, son and little sis – sea monkey? There was a disclaimer at the bottom in fine print, “Caricatures shown not intended to depict Artemia.” Ok what ten years old knows what the heck artemia is? Well you grow up fast once you’ve been separated from your buck twenty five plus postage just to discover that it is brine shrimp. Really dumb brine shrimp that don’t take commands or do tricks. Unfortunately the technology industry is full of sea monkey sales and marketing. Yes believe it or not in some cases there is subterfuge and obfuscation used to secure contracts. Hey I get it; the picture on the box might not be the actual size. Make up what you want about your product, but here is what I don’t like, could you leave out the obvious falsity when it comes to my product, especially the negative stuff. So here is the latest one – “Oracle’s JD Edwards is NOT tier one”. Really? Definition please! Well a whole host of googleable and reputable sources confirm that a tier one vendor is large, well known, and enjoys national and international recognition. Let me see large, so thousands of customers? Oh and part of the world’s largest business software and hardware corporation? Check and check JD Edwards has that and that. Well known, enjoying national and international recognition? Oracle’s JD Edwards EnterpriseOne is available in 21 languages and is directly localized in 33 countries that support some of the world’s largest multinationals and many midsized domestic market companies. Something on the order of half the JD Edwards customer base is outside North America. My passport is on its third insert after 2 years and not from vacations. So if you don’t mind I am going to mark national and international recognition in the got it column. So what else is there? Well let me offer a few criteria. Longevity – The JD Edwards products benefit from 35+ years of intellectual property development; through booms, busts, mergers and acquisitions, we are still here Vision & innovation – JD Edwards is the first full suite ERP to run on the iPad as just one example Proven track record of execution – Since becoming part of Oracle, JD Edwards has released to the market over 20 deliverables including major release, point releases, new apps modules, tool releases, integrations…. Solid, focused functionality with a flexible, interoperable, extensible underlying architecture – JD Edwards offers solid core ERP with specialty modules for verticals all delivered on a well defined independent tools layer that helps enable you to scale your business without an ERP reimplementation A continuation plan – Oracle’s JD Edwards offers our customers a 6 year roadmap as well as interoperability with Oracle’s next generation of applications Oh I almost forgot that the expert sources agree on one additional thing, tier one may be a preferred vendor that offers product and services to you with appealing value. You should check out the TCO studies of JD Edwards. I think you will see what the thousands of customers that rely on these products to run their businesses enjoy – that is the tier one solution with the lowest TCO. Oh and if you get an offer to buy an ERP for no license charge, remember the picture on the box might not be the actual size. 

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  • NDepend 4 – First Steps

    - by Ricardo Peres
    Introduction Thanks to Patrick Smacchia I had the chance to test NDepend 4. I can only say: awesome! This will be the first of a series of posts on NDepend, where I will talk about my discoveries. Keep in mind that I am just starting to use it, so more experienced users may find these too basic, I just hope I don’t say anything foolish! I must say that I am in no way affiliated with NDepend and I never actually met Patrick. Installation No installation program – a curious decision, I’m not against it -, just unzip the files to a folder and run the executable. It will optionally register itself with Visual Studio 2008, 2010 and 11 as well as RedGate’s Reflector; also, it automatically looks for updates. NDepend can either be used as a stand-alone program (with or without a GUI) or from within Visual Studio or Reflector. Getting Started One thing that really pleases me is the Getting Started section of the stand-alone, with links to pages on NDepend’s web site, featuring detailed explanations, which usually include screenshots and small videos (<5 minutes). There’s also an How do I with hierarchical navigation that guides us to through the major features so that we can easily find what we want. Usage There are two basic ways to use NDepend: Analyze .NET solutions, projects or assemblies; Compare two versions of the same assembly. I have so far not used NDepend to compare assemblies, so I will first talk about the first option. After selecting a solution and some of its projects, it generates a single HTML page with an highly detailed report of the analysis it produced. This includes some metrics such as number of lines of code, IL instructions, comments, types, methods and properties, the calculation of the cyclomatic complexity, coupling and lots of others indicators, typically grouped by type, namespace and assembly. The HTML also includes some nice diagrams depicting assembly dependencies, type and method relative proportions (according to the number of IL instructions, I guess) and assembly analysis relating to abstractness and stability. Useful, I would say. Then there’s the rules; NDepend tests the target assemblies against a set of more than 120 rules, grouped in categories Code Quality, Object Oriented Design, Design, Architecture and Layering, Dead Code, Visibility, Naming Conventions, Source Files Organization and .NET Framework Usage. The full list can be configured on the application, and an explanation of each rule can be found on the web site. Rules can be validated, violated and violated in a critical manner, and the HTML will contain the violated rules, their queries – more on this later - and results. The HTML uses some nice JavaScript effects, which allow paging and sorting of tables, so its nice to use. Similar to the rules, there are some queries that display results for a number (about 200) questions grouped as Object Oriented Design, API Breaking Changes (for assembly version comparison), Code Diff Summary (also for version comparison) and Dead Code. The difference between queries and rules is that queries are not classified as passes, violated or critically violated, just present results. The queries and rules are expressed through CQLinq, which is a very powerful LINQ derivative specific to code analysis. All of the included rules and queries can be enabled or disabled and new ones can be added, with intellisense to help. Besides the HTML report file, the NDepend application can be used to explore all analysis results, compare different versions of analysis reports and to run custom queries. Comparison to Other Analysis Tools Unlike StyleCop, NDepend only works with assemblies, not source code, so you can’t expect it to be able to enforce brackets placement, for example. It is more similar to FxCop, but you don’t have the option to analyze at the IL level, that is, other that the number of IL instructions and the complexity. What’s Next In the next days I’ll continue my exploration with a real-life test case. References The NDepend web site is http://www.ndepend.com/. Patrick keeps an updated blog on http://codebetter.com/patricksmacchia/ and he regularly monitors StackOverflow for questions tagged NDepend, which you can find on http://stackoverflow.com/questions/tagged/ndepend. The default list of CQLinq rules, queries and statistics can be found at http://www.ndepend.com/DefaultRules/webframe.html. The syntax itself is described at http://www.ndepend.com/Doc_CQLinq_Syntax.aspx and its features at http://www.ndepend.com/Doc_CQLinq_Features.aspx.

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  • Top Reasons You Need A User Engagement Platform

    - by Michael Snow
    Guest post by: Amit Sircar, Senior Sales Consultant, Oracle Deliver complex enterprise functionality through a simple intuitive and unified User Interface (UI) The modern enterprise contains a wide range of applications that are used to manage the business and drive competitive advantages. Organizations respond by creating a complex structure that results in a functional and management grouping of users. Each of these groups of users requires access to multiple applications and information sources in order to perform their job functions. This leads to the lack of a unified view of enterprise information, inconsistent user interfaces and disjointed security. To be effective, portals must be designed from the end-user perspective, enabling the user to accomplish as many tasks as possible while visiting the fewest number of portals. This requires rethinking the way that portals are built, moving from a functional business unit perspective to a user-focused, process-oriented point of view. Oracle WebCenter provides the Common User Experience Architecture that allows organizations to seamlessly present a unified view of enterprise information tailored to a particular user’s role and preferences. This architecture provides the best practices, design patterns and delivery mechanism for myriad services, applications, and data sources.  In order to serve as a primary system of access, Oracle WebCenter also provides access to unstructured content and to other users via integrated search, service-oriented artifacts, content management, and collaboration tools. Provide a modern and engaging experience without modifying the core business application Web 2.0 technologies such as blogs, wikis, forums or social media sites are having a profound impact in the public internet.  These technologies can be leveraged by enterprises to add significant value to the business. Organizations need to integrate these technologies directly into their business applications while continuing to meet their security and governance needs. To deliver richer connections and become a more agile and intelligent business, WebCenter provides an enterprise portal platform that contains pre-integrated, standards-based Enterprise 2.0 services. These Enterprise 2.0 services can be easily accessed, integrated and utilized by users. By giving users the ability to use and integrate Enterprise 2.0 services such as tags, links, wikis, activities, blogs or social networking directly with their portals and applications, they are empowered to make richer connections, optimize their productivity, and ultimately increase the value of their applications. Foster a collaborative experience The organizational workplace has undergone a major change in the last decade. With increasing globalization and a distributed workforce, project teams may be physically separated by large distances. Online collaboration technologies are becoming a critical resource to enable virtual teams to share information and work together effectively. Oracle WebCenter delivers dynamic business communities with rich Services to empower teams to quickly and efficiently manage their information, applications, projects, and people without requiring IT assistance. It brings together the latest technology around Enterprise 2.0 and social computing, communities, personal productivity, and ad-hoc team interactions without any development effort. It enables the sharing and collaboration on team content, focusing an organization’s valuable resources on solving business problems, tapping into new ideas, and reducing time-to-market. Mobile Support The traditional workplace dynamics that required employees to access their work applications from their desktops have undergone a fundamental shift. Employees were used to primarily working from company offices and utilized an IT-issued computer for performing their job functions. With the introduction of flexible work hours and the growth of remote workers, more and more employees need the ability to remain productive even when they do not have access to a computer via the use of tablets and smartphones.  In addition, customers and citizens have come to expect 24x7 access to resources and websites from wherever they are located. Tablets and smartphones have empowered everyone to quickly access services they need anytime and from any place.  WebCenter provides out of the box capabilities to deliver the mobile experience in a seamless manner. Seeded device profiles and toolkits within WebCenter can be used to render the same web pages into multiple target devices such iPads, iPhones and android devices. Web designers can preview the portal using the built in simulator, make necessary updates and then deploy their UI design for the targeted device. Conclusion The competitive economy and resource constraints facing organizations today require them to find ways to make their applications, portals and Web sites more agile and intelligent and their knowledge workers more productive no matter where they are located. Organizations need to provide faster access to relevant information and resources, enhance existing applications and business processes with rich Enterprise 2.0 services, and seamlessly deliver content to mobile platforms. Oracle WebCenter successfully meets these challenges by providing the modern user experience platform for the enterprise and the Web.

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  • A Semantic Model For Html: TagBuilder and HtmlTags

    - by Ryan Ohs
    In this post I look into the code smell that is HTML literals and show how we can refactor these pesky strings into a friendlier and more maintainable model.   The Problem When I started writing MVC applications, I quickly realized that I built a lot of my HTML inside HtmlHelpers. As I did this, I ended up moving quite a bit of HTML into string literals inside my helper classes. As I wanted to add more attributes (such as classes) to my tags, I needed to keep adding overloads to my helpers. A good example of this end result is the default html helpers that come with the MVC framework. Too many overloads make me crazy! The problem with all these overloads is that they quickly muck up the API and nobody can remember exactly what order the parameters go in. I've seen many presenters (including members of the ASP.NET MVC team!) stumble before realizing that their view wasn't compiling because they needed one more null parameter in the call to Html.ActionLink(). What if instead of writing Html.ActionLink("Edit", "Edit", null, new { @class = "navigation" }) we could do Html.LinkToAction("Edit").Text("Edit").AddClass("navigation") ? Wouldn't that be much easier to remember and understand?  We can do this if we introduce a semantic model for building our HTML.   What is a Semantic Model? According to Martin Folwer, "a semantic model is an in-memory representation, usually an object model, of the same subject that the domain specific language describes." In our case, the model would be a set of classes that know how to render HTML. By using a semantic model we can free ourselves from dealing with strings and instead output the HTML (typically via ToString()) once we've added all the elements and attributes we desire to the model. There are two primary semantic models available in ASP.NET MVC: MVC 2.0's TagBuilder and FubuMVC's HtmlTags.   TagBuilder TagBuilder is the html builder that is available in ASP.NET MVC 2.0. I'm not a huge fan but it gets the job done -- for simple jobs.  Here's an overview of how to use TagBuilder. See my Tips section below for a few comments on that example. The disadvantage of TagBuilder is that unless you wrap it up with our own classes, you still have to write the actual tag name over and over in your code. eg. new TagBuilder("div") instead of new DivTag(). I also think it's method names are a little too long. Why not have AddClass() instead of AddCssClass() or Text() instead of SetInnerText()? What those methods are doing should be pretty obvious even in the short form. I also don't like that it wants to generate an id attribute from your input instead of letting you set it yourself using external conventions. (See GenerateId() and IdAttributeDotReplacement)). Obviously these come from Microsoft's default approach to MVC but may not be optimal for all programmers.   HtmlTags HtmlTags is in my opinion the much better option for generating html in ASP.NET MVC. It was actually written as a part of FubuMVC but is available as a stand alone library. HtmlTags provides a much cleaner syntax for writing HTML. There are classes for most of the major tags and it's trivial to create additional ones by inheriting from HtmlTag. There are also methods on each tag for the common attributes. For instance, FormTag has an Action() method. The SelectTag class allows you to set the default option or first option independent from adding other options. With TagBuilder there isn't even an abstraction for building selects! The project is open source and always improving. I'll hopefully find time to submit some of my own enhancements soon.   Tips 1) It's best not to have insanely overloaded html helpers. Use fluent builders. 2) In html helpers, return the TagBuilder/tag itself (not a string!) so that you can continue to add attributes outside the helper; see my first sample above. 3) Create a static entry point into your builders. I created a static Tags class that gives me access all the HtmlTag classes I need. This way I don't clutter my code with "new" keywords. eg. Tags.Div returns a new DivTag instance. 4) If you find yourself doing something a lot, create an extension method for it. I created a Nest() extension method that reads much more fluently than the AddChildren() method. It also accepts a params array of tags so I can very easily nest many children.   I hope you have found this post helpful. Join me in my war against HTML literals! I’ll have some more samples of how I use HtmlTags in future posts.

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  • College Courses through distance learning

    - by Matt
    I realize this isn't really a programming question, but didn't really know where to post this in the stackexchange and because I am a computer science major i thought id ask here. This is pretty unique to the programmer community since my degree is about 95% programming. I have 1 semester left, but i work full time. I would like to finish up in December, but to make things easier i like to take online classes whenever I can. So, my question is does anyone know of any colleges that offer distance learning courses for computer science? I have been searching around and found a few potential classes, but not sure yet. I would like to gather some classes and see what i can get approval for. Class I need: Only need one C SC 437 Geometric Algorithms C SC 445 Algorithms C SC 473 Automata Only need one C SC 452 Operating Systems C SC 453 Compilers/Systems Software While i only need of each of the above courses i still need to take two more electives. These also have to be upper 400 level classes. So i can take multiple in each category. Some other classes I can take are: CSC 447 - Green Computing CSC 425 - Computer Networking CSC 460 - Database Design CSC 466 - Computer Security I hoping to take one or two of these courses over the summer. If not, then online over the regular semester would be ok too. Any help in helping find these classes would be awesome. Maybe you went to a college that offered distance learning. Some of these classes may be considered to be graduate courses too. Descriptions are listed below if you need. Thanks! Descriptions Computer Security This is an introductory course covering the fundamentals of computer security. In particular, the course will cover basic concepts of computer security such as threat models and security policies, and will show how these concepts apply to specific areas such as communication security, software security, operating systems security, network security, web security, and hardware-based security. Computer Networking Theory and practice of computer networks, emphasizing the principles underlying the design of network software and the role of the communications system in distributed computing. Topics include routing, flow and congestion control, end-to-end protocols, and multicast. Database Design Functions of a database system. Data modeling and logical database design. Query languages and query optimization. Efficient data storage and access. Database access through standalone and web applications. Green Computing This course covers fundamental principles of energy management faced by designers of hardware, operating systems, and data centers. We will explore basic energy management option in individual components such as CPUs, network interfaces, hard drives, memory. We will further present the energy management policies at the operating system level that consider performance vs. energy saving tradeoffs. Finally we will consider large scale data centers where energy management is done at multiple layers from individual components in the system to shutting down entries subset of machines. We will also discuss energy generation and delivery and well as cooling issues in large data centers. Compilers/Systems Software Basic concepts of compilation and related systems software. Topics include lexical analysis, parsing, semantic analysis, code generation; assemblers, loaders, linkers; debuggers. Operating Systems Concepts of modern operating systems; concurrent processes; process synchronization and communication; resource allocation; kernels; deadlock; memory management; file systems. Algorithms Introduction to the design and analysis of algorithms: basic analysis techniques (asymptotics, sums, recurrences); basic design techniques (divide and conquer, dynamic programming, greedy, amortization); acquiring an algorithm repertoire (sorting, median finding, strong components, spanning trees, shortest paths, maximum flow, string matching); and handling intractability (approximation algorithms, branch and bound). Automata Introduction to models of computation (finite automata, pushdown automata, Turing machines), representations of languages (regular expressions, context-free grammars), and the basic hierarchy of languages (regular, context-free, decidable, and undecidable languages). Geometric Algorithms The study of algorithms for geometric objects, using a computational geometry approach, with an emphasis on applications for graphics, VLSI, GIS, robotics, and sensor networks. Topics may include the representation and overlaying of maps, finding nearest neighbors, solving linear programming problems, and searching geometric databases.

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  • Kendo UI Mobile with Knockout for Master-Detail Views

    - by Steve Michelotti
    Lately I’ve been playing with Kendo UI Mobile to build iPhone apps. It’s similar to jQuery Mobile in that they are both HTML5/JavaScript based frameworks for buildings mobile apps. The primary thing that drew me to investigate Kendo UI was its innate ability to adaptively render a native looking app based on detecting the device it’s currently running on. In other words, it will render to look like a native iPhone app if it’s running on an iPhone and it will render to look like a native Droid app if it’s running on a Droid. This is in contrast to jQuery Mobile which looks the same on all devices and, therefore, it can never quite look native for whatever device it’s running on. My first impressions of Kendo UI were great. Using HTML5 data-* attributes to define “roles” for UI elements is easy, the rendering looked great, and the basic navigation was simple and intuitive. However, I ran into major confusion when trying to figure out how to “correctly” build master-detail views. Since I was already very family with KnockoutJS, I set out to use that framework in conjunction with Kendo UI Mobile to build the following simple scenario: I wanted to have a simple “Task Manager” application where my first screen just showed a list of tasks like this:   Then clicking on a specific task would navigate to a detail screen that would show all details of the specific task that was selected:   Basic navigation between views in Kendo UI is simple. The href of an <a> tag just needs to specify a hash tag followed by the ID of the view to navigate to as shown in this jsFiddle (notice the href of the <a> tag matches the id of the second view):   Direct link to jsFiddle: here. That is all well and good but the problem I encountered was: how to pass data between the views? Specifically, I need the detail view to display all the details of whichever task was selected. If I was doing this with my typical technique with KnockoutJS, I know exactly what I would do. First I would create a view model that had my collection of tasks and a property for the currently selected task like this: 1: function ViewModel() { 2: var self = this; 3: self.tasks = ko.observableArray(data); 4: self.selectedTask = ko.observable(null); 5: } Then I would bind my list of tasks to the unordered list - I would attach a “click” handler to each item (each <li> in the unordered list) so that it would select the “selectedTask” for the view model. The problem I found is this approach simply wouldn’t work for Kendo UI Mobile. It completely ignored the click handlers that I was trying to attach to the <a> tags – it just wanted to look at the href (at least that’s what I observed). But if I can’t intercept this, then *how* can I pass data or any context to the next view? The only thing I was able to find in the Kendo documentation is that you can pass query string arguments on the view name you’re specifying in the href. This enabled me to do the following: Specify the task ID in each href – something like this: <a href=”#taskDetail?id=3></a> Attach an “init method” (via the “data-show” attribute on the details view) that runs whenever the view is activated Inside this “init method”, grab the task ID passed from the query string to look up the item from my view model’s list of tasks in order to set the selected task I was able to get all that working with about 20 lines of JavaScript as shown in this jsFiddle. If you click on the Results tab, you can navigate between views and see the the detail screen is correctly binding to the selected item:   Direct link to jsFiddle: here.   With all that being done, I was very happy to get it working with the behavior I wanted. However, I have no idea if that is the “correct” way to do it or if there is a “better” way to do it. I know that Kendo UI comes with its own data binding framework but my preference is to be able to use (the well-documented) KnockoutJS since I’m already familiar with that framework rather than having to learn yet another new framework. While I think my solution above is probably “acceptable”, there are still a couple of things that bug me about it. First, it seems odd that I have to loop through my items to *find* my selected item based on the ID that was passed on the query string - normally, with Knockout I can just refer directly to my selected item from where it was used. Second, it didn’t feel exactly right that I had to rely on the “data-show” method of the details view to set my context – normally with Knockout, I could just attach a click handler to the <a> tag that was actually clicked by the user in order to set the “selected item.” I’m not sure if I’m being too picky. I know there are many people that have *way* more expertise in Kendo UI compared to me – I’d be curious to know if there are better ways to achieve the same results.

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  • 7 Reasons for Abandonment in eCommerce and the need for Contextual Support by JP Saunders

    - by Tuula Fai
    Shopper confidence, or more accurately the lack thereof, is the bane of the online retailer. There are a number of questions that influence whether a shopper completes a transaction, and all of those attributes revolve around knowledge. What products are available? What products are on offer? What would be the cost of the transaction? What are my options for delivery? In general, most online businesses do a good job of answering basic questions around the products as the shopper engages in the online journey, navigating the product catalog and working through the checkout process. The needs that are harder to address for the shopper are those that are less concerned with product specifics and more concerned with deciding whether the transaction met their needs and delivered value. A recent study by the Baymard Institute [1] finds that more than 60% of ecommerce site visitors will abandon their shopping cart. The study also identifies seven reasons for abandonment out of the commerce process [2]. Most of those reasons come down to poor usability within the commerce experience. Distractions. External distractions within the shopper’s external environment (TV, Children, Pets, etc.) or distractions on the eCommerce page can drive shopper abandonment. Ideally, the selection and check-out process should be straightforward. One common distraction is to drive the shopper away from the task at hand through pop-ups or re-directs. The shopper engaging with support information in the checkout process should not be directed away from the page to consume support. Though confidence may improve, the distraction also means abandonment may increase. Poor Usability. When the experience gets more complicated, buyer’s remorse can set in. While knowledge drives confidence, a lack of understanding erodes it. Therefore it is important that the commerce process is streamlined. In some cases, the number of clicks to complete a purchase is lengthy and unavoidable. In these situations, it is vital to ensure that the complexity of your experience can be explained with contextual support to avoid abandonment. If you can illustrate the solution to a complex action while the user is engaged in that action and address customer frustrations with your checkout process before they arise, you can decrease abandonment. Fraud. The perception of potential fraud can be enough to deter a buyer. Does your site look credible? Can shoppers trust your brand? Providing answers on the security of your experience and the levels of protection applied to profile information may play as big a role in ensuring the sale, as does the support you provide on the product offerings and purchasing process. Does it fit? If it is a clothing item or oversized furniture item, another common form of abandonment is for the shopper to question whether the item can be worn by the intended user. Providing information on the sizing applied to clothing, physical dimensions, and limitations on delivery/returns of oversized items will also assist the sale. A photo alone of the item will help, as it answers some of those questions, but won’t assuage all customer concerns about sizing and fit. Sometimes the customer doesn’t want to buy. Prospective buyers might be browsing through your catalog to kill time, or just might not have the money to purchase the item! You are unlikely to provide any information in contextual support to increase the likelihood to buy if the shopper already has no intentions of doing so. The customer will still likely abandon. Ensuring that any questions are proactively answered as they browse through your site can only increase their likelihood to return and buy at a future date. Can’t Buy. Errors or complexity at checkout can be another major cause of abandonment. Good contextual support is unlikely to help with severe errors caused by technical issues on your site, but it will have a big impact on customers struggling with complexity in the checkout process and needing a question answered prior to completing the sale. Embedded support within the checkout process to patiently explain how to complete a task will help increase conversion rates. Additional Costs. Tax, shipping and other costs or duties can dramatically increase the cost of the purchase and when unexpected, can increase abandonment, particularly if they can’t be adequately explained. Again, a lack of knowledge erodes confidence in the purchase, and cost concerns in particular, erode the perception of your brand’s trustworthiness. Again, providing information on what costs are additive and why they are being levied can decrease the likelihood that the customer will abandon out of the experience. Knowledge drives confidence and confidence drives conversion. If you’d like to understand best practices in providing contextual customer support in eCommerce to provide your shoppers with confidence, download the Oracle Cloud Service and Oracle Commerce - Contextual Support in Commerce White Paper. This white paper discusses the process of adding customer support, including a suggested process for finding where knowledge has the most influence on your shoppers and practical step-by-step illustrations on how contextual self-service can be added to your online commerce experience. Resources: [1] http://baymard.com/checkout-usability [2] http://baymard.com/blog/cart-abandonment

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  • Take Advantage of Oracle's Ongoing Assurance Effort!

    - by eric.maurice
    Hi, this is Eric Maurice again! A few years ago, I posted a blog entry, which discussed the psychology of patching. The point of this blog entry was that a natural tendency existed for systems and database administrators to be reluctant to apply patches, even security patches, because of the fear of "breaking" the system. Unfortunately, this belief in the principle "if it ain't broke, don't fix it!" creates significant risks for organizations. Running systems without applying the proper security patches can greatly compromise the security posture of the organization because the security controls available in the affected system may be compromised as a result of the existence of the unfixed vulnerabilities. As a result, Oracle continues to strongly recommend that customers apply all security fixes as soon as possible. Most recently, I have had a number of conversations with customers who questioned the need to upgrade their highly stable but otherwise unsupported Oracle systems. These customers wanted to know more about the kind of security risks they were exposed to, by running obsolete versions of Oracle software. As per Oracle Support Policies, Critical Patch Updates are produced for currently supported products. In other words, Critical Patch Updates are not created by Oracle for product versions that are no longer covered under the Premier Support or Extended Support phases of the Lifetime Support Policy. One statement used in each Critical Patch Update Advisory is particularly important: "We recommend that customers upgrade to a supported version of Oracle products in order to obtain patches. Unsupported products, releases and versions are not tested for the presence of vulnerabilities addressed by this Critical Patch Update. However, it is likely that earlier versions of affected releases are also affected by these vulnerabilities." The purpose of this warning is to inform Oracle customers that a number of the vulnerabilities fixed in each Critical Patch Update may affect older versions of a specific product line. In other words, each Critical Patch Update provides a number of fixes for currently supported versions of a given product line (this information is listed for each bug in the Risk Matrices of the Critical Patch Update Advisory), but the unsupported versions in the same product line, while they may be affected by the vulnerabilities, will not receive the fixes, and are therefore vulnerable to attacks. The risk assumed by organizations wishing to remain on unsupported versions is amplified by the behavior of malicious hackers, who typically will attempt to, and sometimes succeed in, reverse-engineering the content of vendors' security fixes. As a result, it is not uncommon for exploits to be published soon after Oracle discloses vulnerabilities with the release of a Critical Patch Update or Security Alert. Let's consider now the nature of the vulnerabilities that may exist in obsolete versions of Oracle software. A number of severe vulnerabilities have been fixed by Oracle over the years. While Oracle does not test unsupported products, releases and versions for the presence of vulnerabilities addressed by each Critical Patch Update, it should be assumed that a number of the vulnerabilities fixed with the Critical Patch Update program do exist in unsupported versions (regardless of the product considered). The most severe vulnerabilities fixed in past Critical Patch Updates may result in full compromise of the targeted systems, down to the OS level, by remote and unauthenticated users (these vulnerabilities receive a CVSS Base Score of 10.0) or almost as critically, may result in the compromise of the affected systems (without compromising the underlying OS) by a remote and unauthenticated users (these vulnerabilities receive a CVSS Base Score of 7.5). Such vulnerabilities may result in complete takeover of the targeted machine (for the CVSS 10.0), or may result in allowing the attacker the ability to create a denial of service against the affected system or even hijacking or stealing all the data hosted by the compromised system (for the CVSS 7.5). The bottom line is that organizations should assume the worst case: that the most critical vulnerabilities are present in their unsupported version; therefore, it is Oracle's recommendation that all organizations move to supported systems and apply security patches in a timely fashion. Organizations that currently run supported versions but may be late in their security patch release level can quickly catch up because most Critical Patch Updates are cumulative. With a few exceptions noted in Oracle's Critical Patch Update Advisory, the application of the most recent Critical Patch Update will bring these products to current security patch level and provide the organization with the best possible security posture for their patch level. Furthermore, organizations are encouraged to upgrade to most recent versions as this will greatly improve their security posture. At Oracle, our security fixing policies state that security fixes are produced for the main code line first, and as a result, our products benefit from the mistakes made in previous version(s). Our ongoing assurance effort ensures that we work diligently to fix the vulnerabilities we find, and aim at constantly improving the security posture our products provide by default. Patch sets include numerous in-depth fixes in addition to those delivered through the Critical Patch Update and, in certain instances, important security fixes require major architectural changes that can only be included in new product releases (and cannot be backported through the Critical Patch Update program). For More Information: • Mary Ann Davidson is giving a webcast interview on Oracle Software Security Assurance on February 24th. The registration link for attending this webcast is located at http://event.on24.com/r.htm?e=280304&s=1&k=6A7152F62313CA09F77EBCEEA9B6294F&partnerref=EricMblog • A blog entry discussing Oracle's practices for ensuring the quality of Critical patch Updates can be found at http://blogs.oracle.com/security/2009/07/ensuring_critical_patch_update_quality.html • The blog entry "To patch or not to patch" is located at http://blogs.oracle.com/security/2008/01/to_patch_or_not_to_patch.html • Oracle's Support Policies are located at http://www.oracle.com/us/support/policies/index.html • The Critical Patch Update & Security Alert page is located at http://www.oracle.com/technetwork/topics/security/alerts-086861.html

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  • Interview with Ronald Bradford about MySQL Connect

    - by Keith Larson
    Ronald Bradford,  an Oracle ACE Director has been busy working with  database consulting, book writing (EffectiveMySQL) while traveling and speaking around the world in support of MySQL. I was able to take some of his time to get an interview on this thoughts about theMySQL Connect conference. Keith Larson: What where your thoughts when you heard that Oracle was going to provide the community the MySQL Conference ?Ronald Bradford: Oracle has already been providing various different local community events including OTN Tech Days and  MySQL community days. These are great for local regions both in the US and abroad.  In previous years there has been an increase of content at Oracle Open World, however that benefits the Oracle community far more then the MySQL community.  It is good to see that Oracle is realizing the benefit in providing a large scale dedicated event for the MySQL community that includes speakers from the MySQL development teams, invested companies in the ecosystem and other community evangelists.I fully expect a successful event and look forward to hopefully seeing MySQL Connect at the upcoming Brazil and Japan OOW conferences and perhaps an event on the East Coast.Keith Larson: Since you are part of the content committee, what did you think of the submissions that were received during call for papers?Ronald Bradford: There was a large number of quality submissions to the number of available presentation sessions. As with the previous years as a committee member for the annual MySQL conference, there is always a large variety of common cornerstone MySQL features as well as new products and upcoming companies sharing their MySQL experiences. All of the usual major players in the ecosystem will in presenting at MySQL Connect including Facebook, Twitter, Yahoo, Continuent, Percona, Tokutek, Sphinx and Amazon to name a few.  This is ensuring the event will have a large number of quality speakers and a difficult time in choosing what to attend. Keith Larson: What sessions do you look forwarding to attending? Ronald Bradford: As with most quality conferences you can only be in one place at one time, so with multiple tracks per session it is always difficult to decide. The continued work and success with MySQL Cluster, and with a number of sessions I am sure will be popular. The features that interest me the most are around the optimizer, where there are several sessions on new features, and on the importance of backups. There are three presentations in this area to choose from.Keith Larson: Are you going to cover any of the content in your books at your MySQL Connect sessions?Ronald Bradford: I will be giving two presentations at MySQL Connect. The first will include the techniques available for creating better indexes where I will be touching on some aspects of the first Effective MySQL book on Optimizing SQL Statements.  In my second presentation from experiences of managing 500+ AWS MySQL instances, I will be touching on areas including SQL tuning, backup and recovery and scale out with replication.   These are the key topics of the initial books in the Effective MySQL series that focus on performance, scalability and business continuity.  The books however cover a far greater amount of detail then can be presented in a 1 hour session. Keith Larson: What features of MySQL 5.6 do you look forward to the most ?Ronald Bradford: I am very impressed with the optimizer trace feature. The ability to see exposed information is invaluable not just for MySQL 5.6, but to also apply information discerned for optimizing SQL statements in earlier versions of MySQL.  Not everybody understands that it is easy to deploy a MySQL 5.6 slave into an existing topology running an older version if MySQL for evaluation of many new features.  You can use the new mysqlbinlog streaming feature for duplicating master binary logs on an older version with a MySQL 5.6 slave.  The improvements in instrumentation in the Performance Schema are exciting.   However, as with my upcoming Replication Techniques in Depth title, that will be available for sale at MySQL Connect, there are numerous replication features, some long overdue with provide significant management benefits. Crash Save Slaves, Global transaction Identifiers (GTID)  and checksums just to mention a few.Keith Larson: You have been to numerous conferences, what would you recommend for people at the conference? Ronald Bradford: Make the time to meet and introduce yourself to the speakers that cover the topics that most interest you. The MySQL ecosystem has a very strong community.  The relationships you build with presenters, developers and architects in MySQL can be invaluable, however they are created over time. Get to know these people, interact with them over time.  This is the opportunity to learn more then just the content from a 1 hour session. Keith Larson: Any additional tips to handling the long hours ? Ronald Bradford: Conferences can be hard, especially with all the post event drinking.  This is a two day event and I am sure will include additional events on Friday and Saturday night so come well prepared, and leave work behind. Take the time to learn something new.   You can always catchup on sleep later. Keith Larson: Thank you so much for taking some time to do this I look forward to seeing you at the MySQL Connect conference.  Please stay tuned here for more updates on MySQL. 

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  • SQLAuthority News – Great Time Spent at Great Indian Developers Summit 2014

    - by Pinal Dave
    The Great Indian Developer Conference (GIDS) is one of the most popular annual event held in Bangalore. This year GIDS is scheduled on April 22, 25. I will be presented total four sessions at this event and each session is very different from each other. Here are the details of four of my sessions, which I presented there. Pluralsight Shades This event was a great event and I had fantastic fun presenting a technology over here. I was indeed very excited that along with me, I had many of my friends presenting at the event as well. I want to thank all of you to attend my session and having standing room every single time. I have already sent resources in my newsletter. You can sign up for the newsletter over here. Indexing is an Art I was amazed with the crowd present in the sessions at GIDS. There was a great interest in the subject of SQL Server and Performance Tuning. Audience at GIDS I believe event like such provides a great platform to meet and share knowledge. Pinal at Pluralsight Booth Here are the abstract of the sessions which I had presented. They were recorded so at some point in time they will be available, but if you want the content of all the courses immediately, I suggest you check out my video courses on the same subject on Pluralsight. Indexes, the Unsung Hero Relevant Pluralsight Course Slow Running Queries are the most common problem that developers face while working with SQL Server. While it is easy to blame SQL Server for unsatisfactory performance, the issue often persists with the way queries have been written, and how Indexes has been set up. The session will focus on the ways of identifying problems that slow down SQL Server, and Indexing tricks to fix them. Developers will walk out with scripts and knowledge that can be applied to their servers, immediately post the session. Indexes are the most crucial objects of the database. They are the first stop for any DBA and Developer when it is about performance tuning. There is a good side as well evil side to indexes. To master the art of performance tuning one has to understand the fundamentals of indexes and the best practices associated with the same. We will cover various aspects of Indexing such as Duplicate Index, Redundant Index, Missing Index as well as best practices around Indexes. SQL Server Performance Troubleshooting: Ancient Problems and Modern Solutions Relevant Pluralsight Course Many believe Performance Tuning and Troubleshooting is an art which has been lost in time. However, truth is that art has evolved with time and there are more tools and techniques to overcome ancient troublesome scenarios. There are three major resources that when bottlenecked creates performance problems: CPU, IO, and Memory. In this session we will focus on High CPU scenarios detection and their resolutions. If time permits we will cover other performance related tips and tricks. At the end of this session, attendees will have a clear idea as well as action items regarding what to do when facing any of the above resource intensive scenarios. Developers will walk out with scripts and knowledge that can be applied to their servers, immediately post the session. To master the art of performance tuning one has to understand the fundamentals of performance, tuning and the best practices associated with the same. We will discuss about performance tuning in this session with the help of Demos. Pinal Dave at GIDS MySQL Performance Tuning – Unexplored Territory Relevant Pluralsight Course Performance is one of the most essential aspects of any application. Everyone wants their server to perform optimally and at the best efficiency. However, not many people talk about MySQL and Performance Tuning as it is an extremely unexplored territory. In this session, we will talk about how we can tune MySQL Performance. We will also try and cover other performance related tips and tricks. At the end of this session, attendees will not only have a clear idea, but also carry home action items regarding what to do when facing any of the above resource intensive scenarios. Developers will walk out with scripts and knowledge that can be applied to their servers, immediately post the session. To master the art of performance tuning one has to understand the fundamentals of performance, tuning and the best practices associated with the same. You will also witness some impressive performance tuning demos in this session. Hidden Secrets and Gems of SQL Server We Bet You Never Knew Relevant Pluralsight Course SQL Trio Session! It really amazes us every time when someone says SQL Server is an easy tool to handle and work with. Microsoft has done an amazing work in making working with complex relational database a breeze for developers and administrators alike. Though it looks like child’s play for some, the realities are far away from this notion. The basics and fundamentals though are simple and uniform across databases, the behavior and understanding the nuts and bolts of SQL Server is something we need to master over a period of time. With a collective experience of more than 30+ years amongst the speakers on databases, we will try to take a unique tour of various aspects of SQL Server and bring to you life lessons learnt from working with SQL Server. We will share some of the trade secrets of performance, configuration, new features, tuning, behaviors, T-SQL practices, common pitfalls, productivity tips on tools and more. This is a highly demo filled session for practical use if you are a SQL Server developer or an Administrator. The speakers will be able to stump you and give you answers on almost everything inside the Relational database called SQL Server. I personally attended the session of Vinod Kumar, Balmukund Lakhani, Abhishek Kumar and my favorite Govind Kanshi. Summary If you have missed this event here are two action items 1) Sign up for Resource Newsletter 2) Watch my video courses on Pluralsight Reference: Pinal Dave (http://blog.sqlauthority.com)Filed under: MySQL, PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, SQLAuthority Author Visit, SQLAuthority News, T SQL Tagged: GIDS

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  • Goals for 2010 Retrospective

    - by Brian Jackett
    As we approach the end of 2010 I’d like to take a  few minutes to reflect back on this past year and revisit the goals that I set for myself at the beginning of the year (click here to see those goals).  I feel it is important to track your goals not only to see if you accomplished them but also to see what new directions in life you pursued.  Once we enter into 2011 I’ll follow up with a new post on goals for the new year. Professional Blog – This year I intended to write at least 2 posts a month.  Looking back I far surpassed that goal by writing 47 posts (this one being my 48th).  As with many things in life, quantity does not mean quality.  A good example is a number of my posts announcing upcoming speaking engagements and providing links to presentation slides and scripts.  That aside, I like to at least keep content relatively fresh on this blog  which I was able to accomplish.  At the same time I’ve gotten much more comfortable in my blogging style and it has become much easier to write. Speaking – I didn’t define a clear goal for speaking engagements, but had a rough idea of wanting to speak at 2-3 events.  Once again I far exceeded that number by speaking at 10 separate events and delivering 12+ presentations.  I’m very thankful for all of the opportunities that I was given and all of the wonderful people I have met as a result. Volunteering – This year I intended to help out with the COSPUG (now Buckeye SPUG) steering committee and Stir Trek conference.  I fulfilled both goals and as well as taking on lead organizer duties for the first ever SharePoint Saturday Columbus.  Each of these events and groups turned out to be successful and I was glad to be a part of them all.  I look forward to continuing to volunteer with each next year in some capacity. Android Development – My goal for getting into Android development was a late addition, but one I didn’t necessarily fulfill.  I spent a couple nights downloading the tools, configuring my environment, and going through some “simple” tutorials.  I say “simple” because in my opinion the tutorials were not laid out very well, took a long time to get running properly, and confused me more than helped.  After about a week I was frustrated with the process and didn’t think it was a good use of my time.  On a side note, I’ve dabbled in Windows Phone 7 development over the past few months and have been very excited by how easy and intuitive it was to get started and develop some proof of concepts. Personal Getting in Shape – I had intended to play on recreational sports leagues and work out on a semi-regular basis.  For the most part I fulfilled this goal by playing on various softball and volleyball leagues as well as using the gym.  At the same time I had some major setbacks.  In the spring I badly sprained my ankle and got hit in the knee with a softball which kept me inactive for almost 2 months.  More recently I broke my knuckle (click here to read about it) which I am still recovering from. Volunteering – On the volunteering front I kept my commitments at my parish’s high school youth group.  As for other volunteering opportunities I got involved with a great organization called Columbus Gives Back (website).  I’ve volunteered with them a few times and really enjoy their goal to provide opportunities to people with busy schedules.  They  offer a variety of events typically after work hours and spread out around Columbus with no set commitments on time you need to put in.  If you have the time or motivation I highly recommend them. House/Condo – I had been thinking of buying a house or condo this past summer, but decided to extend my apartment lease for another year instead.  I have begun the search for a place in the past few weeks and am excited begin the process of owning a home. Conclusion     This year I was able to set and achieve many of my goals.  For next year I’ll try to put more specific numbers to all of my goals.  If any of you readers set goals for 2011 feel free to send me a link as I’d love to see what you are aiming to accomplish.  Have a great end of 2010 and best wishes for the start of 2011!       -Frog Out

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  • How to get javascript object references or reference count?

    - by Tauren
    How to get reference count for an object Is it possible to determine if a javascript object has multiple references to it? Or if it has references besides the one I'm accessing it with? Or even just to get the reference count itself? Can I find this information from javascript itself, or will I need to keep track of my own reference counters. Obviously, there must be at least one reference to it for my code access the object. But what I want to know is if there are any other references to it, or if my code is the only place it is accessed. I'd like to be able to delete the object if nothing else is referencing it. If you know the answer, there is no need to read the rest of this question. Below is just an example to make things more clear. Use Case In my application, I have a Repository object instance called contacts that contains an array of ALL my contacts. There are also multiple Collection object instances, such as friends collection and a coworkers collection. Each collection contains an array with a different set of items from the contacts Repository. Sample Code To make this concept more concrete, consider the code below. Each instance of the Repository object contains a list of all items of a particular type. You might have a repository of Contacts and a separate repository of Events. To keep it simple, you can just get, add, and remove items, and add many via the constructor. var Repository = function(items) { this.items = items || []; } Repository.prototype.get = function(id) { for (var i=0,len=this.items.length; i<len; i++) { if (items[i].id === id) { return this.items[i]; } } } Repository.prototype.add = function(item) { if (toString.call(item) === "[object Array]") { this.items.concat(item); } else { this.items.push(item); } } Repository.prototype.remove = function(id) { for (var i=0,len=this.items.length; i<len; i++) { if (items[i].id === id) { this.removeIndex(i); } } } Repository.prototype.removeIndex = function(index) { if (items[index]) { if (/* items[i] has more than 1 reference to it */) { // Only remove item from repository if nothing else references it this.items.splice(index,1); return; } } } Note the line in remove with the comment. I only want to remove the item from my master repository of objects if no other objects have a reference to the item. Here's Collection: var Collection = function(repo,items) { this.repo = repo; this.items = items || []; } Collection.prototype.remove = function(id) { for (var i=0,len=this.items.length; i<len; i++) { if (items[i].id === id) { // Remove object from this collection this.items.splice(i,1); // Tell repo to remove it (only if no other references to it) repo.removeIndxe(i); return; } } } And then this code uses Repository and Collection: var contactRepo = new Repository([ {id: 1, name: "Joe"}, {id: 2, name: "Jane"}, {id: 3, name: "Tom"}, {id: 4, name: "Jack"}, {id: 5, name: "Sue"} ]); var friends = new Collection( contactRepo, [ contactRepo.get(2), contactRepo.get(4) ] ); var coworkers = new Collection( contactRepo, [ contactRepo.get(1), contactRepo.get(2), contactRepo.get(5) ] ); contactRepo.items; // contains item ids 1, 2, 3, 4, 5 friends.items; // contains item ids 2, 4 coworkers.items; // contains item ids 1, 2, 5 coworkers.remove(2); contactRepo.items; // contains item ids 1, 2, 3, 4, 5 friends.items; // contains item ids 2, 4 coworkers.items; // contains item ids 1, 5 friends.remove(4); contactRepo.items; // contains item ids 1, 2, 3, 5 friends.items; // contains item ids 2 coworkers.items; // contains item ids 1, 5 Notice how coworkers.remove(2) didn't remove id 2 from contactRepo? This is because it was still referenced from friends.items. However, friends.remove(4) causes id 4 to be removed from contactRepo, because no other collection is referring to it. Summary The above is what I want to do. I'm sure there are ways I can do this by keeping track of my own reference counters and such. But if there is a way to do it using javascript's built-in reference management, I'd like to hear about how to use it.

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  • CSM DX11 issues

    - by KaiserJohaan
    I got CSM to work in OpenGL, and now Im trying to do the same in directx. I'm using the same math library and all and I'm pretty much using the alghorithm straight off. I am using right-handed, column major matrices from GLM. The light is looking (-1, -1, -1). The problem I have is twofolds; For some reason, the ground floor is causing alot of (false) shadow artifacts, like the vast shadowed area you see. I confirmed this when I disabled the ground for the depth pass, but thats a hack more than anything else The shadows are inverted compared to the shadowmap. If you squint you can see the chairs shadows should be mirrored instead. This is the first cascade shadow map, in range of the alien and the chair: I can't figure out why this is. This is the depth pass: for (uint32_t cascadeIndex = 0; cascadeIndex < NUM_SHADOWMAP_CASCADES; cascadeIndex++) { mShadowmap.BindDepthView(context, cascadeIndex); CameraFrustrum cameraFrustrum = CalculateCameraFrustrum(degreesFOV, aspectRatio, nearDistArr[cascadeIndex], farDistArr[cascadeIndex], cameraViewMatrix); lightVPMatrices[cascadeIndex] = CreateDirLightVPMatrix(cameraFrustrum, lightDir); mVertexTransformPass.RenderMeshes(context, renderQueue, meshes, lightVPMatrices[cascadeIndex]); lightVPMatrices[cascadeIndex] = gBiasMatrix * lightVPMatrices[cascadeIndex]; farDistArr[cascadeIndex] = -farDistArr[cascadeIndex]; } CameraFrustrum CalculateCameraFrustrum(const float fovDegrees, const float aspectRatio, const float minDist, const float maxDist, const Mat4& cameraViewMatrix) { CameraFrustrum ret = { Vec4(1.0f, 1.0f, -1.0f, 1.0f), Vec4(1.0f, -1.0f, -1.0f, 1.0f), Vec4(-1.0f, -1.0f, -1.0f, 1.0f), Vec4(-1.0f, 1.0f, -1.0f, 1.0f), Vec4(1.0f, -1.0f, 1.0f, 1.0f), Vec4(1.0f, 1.0f, 1.0f, 1.0f), Vec4(-1.0f, 1.0f, 1.0f, 1.0f), Vec4(-1.0f, -1.0f, 1.0f, 1.0f), }; const Mat4 perspectiveMatrix = PerspectiveMatrixFov(fovDegrees, aspectRatio, minDist, maxDist); const Mat4 invMVP = glm::inverse(perspectiveMatrix * cameraViewMatrix); for (Vec4& corner : ret) { corner = invMVP * corner; corner /= corner.w; } return ret; } Mat4 CreateDirLightVPMatrix(const CameraFrustrum& cameraFrustrum, const Vec3& lightDir) { Mat4 lightViewMatrix = glm::lookAt(Vec3(0.0f), -glm::normalize(lightDir), Vec3(0.0f, -1.0f, 0.0f)); Vec4 transf = lightViewMatrix * cameraFrustrum[0]; float maxZ = transf.z, minZ = transf.z; float maxX = transf.x, minX = transf.x; float maxY = transf.y, minY = transf.y; for (uint32_t i = 1; i < 8; i++) { transf = lightViewMatrix * cameraFrustrum[i]; if (transf.z > maxZ) maxZ = transf.z; if (transf.z < minZ) minZ = transf.z; if (transf.x > maxX) maxX = transf.x; if (transf.x < minX) minX = transf.x; if (transf.y > maxY) maxY = transf.y; if (transf.y < minY) minY = transf.y; } Mat4 viewMatrix(lightViewMatrix); viewMatrix[3][0] = -(minX + maxX) * 0.5f; viewMatrix[3][1] = -(minY + maxY) * 0.5f; viewMatrix[3][2] = -(minZ + maxZ) * 0.5f; viewMatrix[0][3] = 0.0f; viewMatrix[1][3] = 0.0f; viewMatrix[2][3] = 0.0f; viewMatrix[3][3] = 1.0f; Vec3 halfExtents((maxX - minX) * 0.5, (maxY - minY) * 0.5, (maxZ - minZ) * 0.5); return OrthographicMatrix(-halfExtents.x, halfExtents.x, -halfExtents.y, halfExtents.y, halfExtents.z, -halfExtents.z) * viewMatrix; } And this is the pixel shader used for the lighting stage: #define DEPTH_BIAS 0.0005 #define NUM_CASCADES 4 cbuffer DirectionalLightConstants : register(CBUFFER_REGISTER_PIXEL) { float4x4 gSplitVPMatrices[NUM_CASCADES]; float4x4 gCameraViewMatrix; float4 gSplitDistances; float4 gLightColor; float4 gLightDirection; }; Texture2D gPositionTexture : register(TEXTURE_REGISTER_POSITION); Texture2D gDiffuseTexture : register(TEXTURE_REGISTER_DIFFUSE); Texture2D gNormalTexture : register(TEXTURE_REGISTER_NORMAL); Texture2DArray gShadowmap : register(TEXTURE_REGISTER_DEPTH); SamplerComparisonState gShadowmapSampler : register(SAMPLER_REGISTER_DEPTH); float4 ps_main(float4 position : SV_Position) : SV_Target0 { float4 worldPos = gPositionTexture[uint2(position.xy)]; float4 diffuse = gDiffuseTexture[uint2(position.xy)]; float4 normal = gNormalTexture[uint2(position.xy)]; float4 camPos = mul(gCameraViewMatrix, worldPos); uint index = 3; if (camPos.z > gSplitDistances.x) index = 0; else if (camPos.z > gSplitDistances.y) index = 1; else if (camPos.z > gSplitDistances.z) index = 2; float3 projCoords = (float3)mul(gSplitVPMatrices[index], worldPos); float viewDepth = projCoords.z - DEPTH_BIAS; projCoords.z = float(index); float visibilty = gShadowmap.SampleCmpLevelZero(gShadowmapSampler, projCoords, viewDepth); float angleNormal = clamp(dot(normal, gLightDirection), 0, 1); return visibilty * diffuse * angleNormal * gLightColor; } As you can see I am using depth bias and a bias matrix. Any hints on why this behaves so wierdly?

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  • How to Save Hundreds or Thousands of Dollars on Cell Phone Service

    - by Chris Hoffman
    Cell phone contracts are bad. You get a seemingly cheap phone up front, but you more than pay for the cost of the phone over two years. Prepaid phone plans are surging in North America for a reason. Prepaid phone plans will be cheaper and more flexible than traditional contracts with big carriers for many people. However much you use your phone, there’s a good chance you can save money with a prepaid service. No More Contracts Here’s how cell phone service typically works in North America: You get a subsidized phone for “free”, $99, or $199. You sign up for a two-year contract and more than pay back the cost of that phone over the length of the contract. This is similar to leasing something or purchasing it on a credit card and paying it back over two years — you spend less up front, but you’re paying more in the long run. But this isn’t the only option. You could opt for a cheaper prepaid service that doesn’t lock you into a contract. If you don’t use your phone much, you could just pay for what you use and avoid the hefty cell phone bills. If you use your phone a lot, you could get a cheaper plan, too. Now, this certainly isn’t for everyone. If you want the latest iPhone or Galaxy smartphone every two years and require a 4G data connection, prepaid services may not be for you. On the other hand, if you don’t need the latest phone, you can save money here. You can also save a huge amount of money if you don’t use your phone much. Phone Options When you choose your prepaid or contract-free service, you’ll often be able to purchase a phone from them. You’ll generally be able to find dirt-cheap dumbphones and the cheapest, slowest Android phones for not very much money. If you are able to buy a top-of-the-line smartphone, you’ll have to pay the full, unsubsidized price. That’s $649 for either an iPhone 5S or Samsung Galaxy S4. Whatever phones the service provider offers, you could always buy a phone elsewhere — for example, you could buy an unsubsidized iPhone direct from Apple and then take it to your cell phone service of choice. Most services will allow you to get a SIM card and pop it into your existing phone rather than purchasing a phone. If you can get a hand-me-down smartphone, you can often save quite a bit of money. For example, you may have a family member upgrading from an iPhone 4S to an iPhone 5S. You could take their phone to a prepaid carrier and have a nicer phone on a cheap cell phone plan. If you brought an old smartphone to a big carrier like AT&T or Verizon, they wouldn’t give you a discount on your monthly plan. You’d have to pay the same amount of money every month as if you had gotten a subsidized phone. Google’s Nexus phones are also great options for people looking to buy smartphones and pay up-front. Google’s Nexus 4 offered a modern, almost top-of-the-line Android smartphone experience at $299 or $349 when it came out last year. Google will soon be releasing the Nexus 5 and it’s expected to be priced at $349. That’s certainly a lot more than a cheap phone, but it’s a fairly high-end smartphone at almost half the price of an iPhone 5S or Galaxy S4. Nexus phones can be purchased online from Google’s Play Store. Service Options When choosing a service, you need to consider what you actually use. If you’re someone who only uses your phone rarely, you can get plans that will allow you to pay as little as a few dollars per month. If you’re someone who’s usually in range of Wi-Fi, you may not need much data at all. If you want a plan with unlimited talk, texting, and data usage, you can get it for much cheaper than you’d pay on a major carrier like AT&T. The options here range from pay-as-you-go plans, like the ones offered by T-Mobile, which allow you to put a certain amount of money in and only drain that balance when you actually use minutes, texts, or data. If you only make a few calls and send a few texts per month, you’d only pay a few bucks. On the other end, Walmart’s Straight Talk service is a popular option that offers unlimited talk, texting, and data at $45 per month. Which service is right for you depends on a lot of things, including your usage and what each network’s coverage is like in your area. You’ll want to do some research of your own before choosing a service. Prepaid services also offer you even more flexibility after you choose one. If you’re not happy or a better deal comes along, you can switch — you’re not locked into your service for two years and you won’t pay an early termination fee. Image Credit: Intel Free Press on Flickr, Jon Fingas on Flickr, John Karakatsanis on Flickr, kendalkinggroup on Flickr     

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