Search Results

Search found 16385 results on 656 pages for 'fusion applications'.

Page 622/656 | < Previous Page | 618 619 620 621 622 623 624 625 626 627 628 629  | Next Page >

  • career advice for PhD scientist seeking to program?

    - by C SD
    I'm largely a self-taught programmer. In fact, I first started programming about half way through biophysics grad school, and even though I think I've done some pretty nice work, I've never worked as part of a 'serious' development team that had more than one or two other developers (and I wouldn't hesitate to call them equally inexperienced in software development as a profession). After finishing my PhD I applied to Google, on a lark, since I had some confidence in my abilities, if not necessarily my experience, and I was hoping to maybe slip in and absorb all the experience and talent I'd be surrounded with and become productive enough, quickly enough, that they wouldn't immediately regret their decision. I was excited to actually get invited to interview up at Mountain View (this was ~ mid 2008). Overall, my memory of the interview was very positive, but after close to a three month wait (is that normal?) they ended up turning me down. I wasn't too surprised or disappointed (aside from the uncomfortably long wait) given my unusual background and admitted lack of experience. I decided to continue as a postdoc, but focus on improving my skills rather than doing research. I've done about three years of that, and my honest assessment is that I've learned a ton more, but I really need more of a peer group to maintain or accelerate my growth. Google invited me to interview again about eight months ago, and the interview process went even better than the first time around (I thought), though they again declined to give me an offer. I have to admit this second rejection was much more discouraging. They had insisted I interview even after I mentioned to them that a move on my part was unlikely given that I had bought a house, gotten married, etc. since the first interview. I guess I was hoping they'd at least give me an offer that I could parlay into a more conventional, but still interesting, programming position close to home. So here I am, going on my third year out of grad school, a glorified postdoc and I'm starting to get pretty discouraged. Even though I could technically get 'back-on-track' for a career in science, I have been focusing the vast majority of this time on gaining programming experience rather than on research and publications. The problem is, whenever I look, most job listings have requirements that seem impossibly grandiose and I hesitate to apply. That, or the job/project seems incredibly dull. Ironically, applying to Google struck me as less intimidating. I suspect that either most people are just a lot less realistic than I am when it comes to assessing how long it will take for them to get up to speed, or they don't care; my fear is that I'm just woefully unqualified for any interesting, well paying work. IE: I'm confident I could switch fully back into C++ mode with a couple weeks work (I mostly use C,Python,C# daily) but I don't list myself as being 'proficient' in C++ on my CV, or applying for jobs that 'require' such knowledge. The few applications for which I did feel I was a legitimately good match have not elicited a response. I suspect the following things are potential problems with my application/CV and I would like feedback on: I don't have a CS degree. My BS was in biochemistry and molecular biology, my PhD in biophysics. I took a undergrad and grad level CS course at UCSD and completely killed them, but I don't know how to translate that to my CV effectively. I have a PhD, but it's not in CS... I've been debating if I should remove it from my CV, and wether or not it would then be misleading to list at least some of those years as some kind of 'programming' job (in many respects it was). I think there are sometimes strong stigmas associated with 'self-taught' programmers. I am certainly one of those. I even recognize that some of those stigmas hold a hint of truth, but I really do want to be an asset to a team. How do I communicate that even though I have been largely self-directing for ~8 years I can still take marching orders when needed? Do I just say so outright? Should I just become a lot less scrupulous about the whole process? anecdote: I have a friend who applied for positions where he completely fudged his qualifications to get past the first culling. He was much more honest and forthcoming about his actual qualifications when contacted and he still managed to get invited to a couple of interviews and even got some offers. His balls are larger than mine though.

    Read the article

  • Coherence Warnings in WLS

    - by john.graves(at)oracle.com
    With 11g (10.3.4 WLS), coherence is now built into many applications.  I’ve been noticing errors in my OSB logs like these:####<10/03/2011 10:45:40 AM EST> <Warning> <Coherence> <osb-jeos> <osb_server1> <Logger@324239121 3.6.0.4> <<anonymous>> <> <583c1 0bfdbd326ba:-8c38159:12e9d02c829:-8000-0000000000000003> <1299714340643> <BEA-000000> <Oracle Coherence 3.6.0.4 (member=n/a): Unic astUdpSocket failed to set receive buffer size to 714 packets (1023KB); actual size is 12%, 89 packets (127KB). Consult your OS do cumentation regarding increasing the maximum socket buffer size. Proceeding with the actual value may cause sub-optimal performanc e.> ####<10/03/2011 10:45:40 AM EST> <Warning> <Coherence> <osb-jeos> <osb_server1> <Logger@324239121 3.6.0.4> <<anonymous>> <> <583c1 0bfdbd326ba:-8c38159:12e9d02c829:-8000-0000000000000003> <1299714340650> <BEA-000000> <Oracle Coherence 3.6.0.4 (member=n/a): Pref erredUnicastUdpSocket failed to set receive buffer size to 1428 packets (1.99MB); actual size is 6%, 89 packets (127KB). Consult y our OS documentation regarding increasing the maximum socket buffer size. Proceeding with the actual value may cause sub-optimal p erformance.> ####<10/03/2011 10:45:40 AM EST> <Warning> <Coherence> <osb-jeos> <osb_server1> <Logger@324239121 3.6.0.4> <<anonymous>> <> <583c1 0bfdbd326ba:-8c38159:12e9d02c829:-8000-0000000000000003> <1299714340659> <BEA-000000> <Oracle Coherence 3.6.0.4 (member=n/a): Mult icastUdpSocket failed to set receive buffer size to 714 packets (1023KB); actual size is 12%, 89 packets (127KB). Consult your OS documentation regarding increasing the maximum socket buffer size. Proceeding with the actual value may cause sub-optimal performa nce.> I was able to “fix” this on my ubuntu system by adding the following lines to the /etc/sysctl.conf file:# Setup networking for coherence # maximum receive socket buffer size, default 131071 net.core.rmem_max = 2000000 # maximum send socket buffer size, default 131071 net.core.wmem_max = 1000000 # default receive socket buffer size, default 65535 net.core.rmem_default = 2524287 # default send socket buffer size, default 65535 net.core.wmem_default = 2524287 .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; }   .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; }

    Read the article

  • Telerik is First to Announce Support for Microsoft Silverlight Analytics Framework

    Yesterday at MIX 10 conference Microsoft announced the Microsoft Silverlight Analytics Framework Beta. The Silverlight Analytics Framework (SAF) is a new open-source framework to allow designers and developers to integrate web analytics into Silverlight applications in a consistent manner. Supporting out-of-browser and offline scenarios, Microsoft built this framework in conjunction with a number of web analytics services and control vendors to support multiple analytics services simultaneously without degrading application performance. Because the SAF is enabled as a set of behaviors in Microsoft Expression Blend, designers and developers can visually instrument their designs and configure A/B testing rapidly without writing any code. Telerik is proud to be the first control vendor to support the Silverlight Analytics Framework. RadControls for Silverlight can be used with the framework out of the box. The suite offers Silverlight Analytics Framework handlers and behavior, helping developers to fine tune the values sent to the analytics providers. Because the analytics framework is using the Managed Extensibility Framework (MEF) for composition, you don't need to change the way you use the controls to benefit from the Telerik handlers. Just add a reference to the Telerik assemblies that contains the handlers. Here is the code that you need to declare to use RadTreeView: <UserControl x:Class="Telerik.SLAF.MainPage"         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"         xmlns:i="clr-namespace:System.Windows.Interactivity;assembly=System.Windows.Interactivity"         xmlns:ga="clr-namespace:Google.WebAnalytics;assembly=Google.WebAnalytics"         xmlns:sa="clr-namespace:Microsoft.WebAnalytics.Behaviors;assembly=Microsoft.WebAnalytics.Behaviors"         xmlns:ic="clr-namespace:Microsoft.Expression.Interactivity.Core;assembly=Microsoft.Expression.Interactions"         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"         xmlns:telerikNavigation="clr-namespace:Telerik.Windows.Controls;assembly=Telerik.Windows.Controls.Navigation">        <Grid x:Name="LayoutRoot">         <i:Interaction.Behaviors>             <ga:GoogleAnalytics ProfileId="--Your GA ProfileId" Category="Demo" />         </i:Interaction.Behaviors>         <telerikNavigation:RadTreeView>             <i:Interaction.Triggers>                 <i:EventTrigger EventName="SelectionChanged">                     <sa:TrackAction />                 </i:EventTrigger>             </i:Interaction.Triggers>             <telerikNavigation:RadTreeViewItem Header="Item1">             </telerikNavigation:RadTreeViewItem>             <telerikNavigation:RadTreeViewItem Header="Item2" />             <telerikNavigation:RadTreeViewItem Header="Item3" />         </telerikNavigation:RadTreeView>     </Grid> </UserControl> Download the Telerik Microsoft Silverlight Analytics Framework Handlers and the sample project. This is our first Beta release - please drop us a line with any feedback you have or even better if you are at MIX10 - come visit us at the booth in the "Commons" hall so we can discuss it in person. Did you know that DotNetSlackers also publishes .net articles written by top known .net Authors? We already have over 80 articles in several categories including Silverlight. Take a look: here.

    Read the article

  • Rkhunter 122 suspect files; do I have a problem?

    - by user276166
    I am new to ubuntu. I am using Xfce Ubuntu 14.04 LTS. I have ran rkhunter a few weeks age and only got a few warnings. The forum said that they were normal. But, this time rkhunter reported 122 warnings. Please advise. casey@Shaman:~$ sudo rkhunter -c [ Rootkit Hunter version 1.4.0 ] Checking system commands... Performing 'strings' command checks Checking 'strings' command [ OK ] Performing 'shared libraries' checks Checking for preloading variables [ None found ] Checking for preloaded libraries [ None found ] Checking LD_LIBRARY_PATH variable [ Not found ] Performing file properties checks Checking for prerequisites [ Warning ] /usr/sbin/adduser [ Warning ] /usr/sbin/chroot [ Warning ] /usr/sbin/cron [ OK ] /usr/sbin/groupadd [ Warning ] /usr/sbin/groupdel [ Warning ] /usr/sbin/groupmod [ Warning ] /usr/sbin/grpck [ Warning ] /usr/sbin/nologin [ Warning ] /usr/sbin/pwck [ Warning ] /usr/sbin/rsyslogd [ Warning ] /usr/sbin/useradd [ Warning ] /usr/sbin/userdel [ Warning ] /usr/sbin/usermod [ Warning ] /usr/sbin/vipw [ Warning ] /usr/bin/awk [ Warning ] /usr/bin/basename [ Warning ] /usr/bin/chattr [ Warning ] /usr/bin/cut [ Warning ] /usr/bin/diff [ Warning ] /usr/bin/dirname [ Warning ] /usr/bin/dpkg [ Warning ] /usr/bin/dpkg-query [ Warning ] /usr/bin/du [ Warning ] /usr/bin/env [ Warning ] /usr/bin/file [ Warning ] /usr/bin/find [ Warning ] /usr/bin/GET [ Warning ] /usr/bin/groups [ Warning ] /usr/bin/head [ Warning ] /usr/bin/id [ Warning ] /usr/bin/killall [ OK ] /usr/bin/last [ Warning ] /usr/bin/lastlog [ Warning ] /usr/bin/ldd [ Warning ] /usr/bin/less [ OK ] /usr/bin/locate [ OK ] /usr/bin/logger [ Warning ] /usr/bin/lsattr [ Warning ] /usr/bin/lsof [ OK ] /usr/bin/mail [ OK ] /usr/bin/md5sum [ Warning ] /usr/bin/mlocate [ OK ] /usr/bin/newgrp [ Warning ] /usr/bin/passwd [ Warning ] /usr/bin/perl [ Warning ] /usr/bin/pgrep [ Warning ] /usr/bin/pkill [ Warning ] /usr/bin/pstree [ OK ] /usr/bin/rkhunter [ OK ] /usr/bin/rpm [ Warning ] /usr/bin/runcon [ Warning ] /usr/bin/sha1sum [ Warning ] /usr/bin/sha224sum [ Warning ] /usr/bin/sha256sum [ Warning ] /usr/bin/sha384sum [ Warning ] /usr/bin/sha512sum [ Warning ] /usr/bin/size [ Warning ] /usr/bin/sort [ Warning ] /usr/bin/stat [ Warning ] /usr/bin/strace [ Warning ] /usr/bin/strings [ Warning ] /usr/bin/sudo [ Warning ] /usr/bin/tail [ Warning ] /usr/bin/test [ Warning ] /usr/bin/top [ Warning ] /usr/bin/touch [ Warning ] /usr/bin/tr [ Warning ] /usr/bin/uniq [ Warning ] /usr/bin/users [ Warning ] /usr/bin/vmstat [ Warning ] /usr/bin/w [ Warning ] /usr/bin/watch [ Warning ] /usr/bin/wc [ Warning ] /usr/bin/wget [ Warning ] /usr/bin/whatis [ Warning ] /usr/bin/whereis [ Warning ] /usr/bin/which [ OK ] /usr/bin/who [ Warning ] /usr/bin/whoami [ Warning ] /usr/bin/unhide.rb [ Warning ] /usr/bin/mawk [ Warning ] /usr/bin/lwp-request [ Warning ] /usr/bin/heirloom-mailx [ OK ] /usr/bin/w.procps [ Warning ] /sbin/depmod [ Warning ] /sbin/fsck [ Warning ] /sbin/ifconfig [ Warning ] /sbin/ifdown [ Warning ] /sbin/ifup [ Warning ] /sbin/init [ Warning ] /sbin/insmod [ Warning ] /sbin/ip [ Warning ] /sbin/lsmod [ Warning ] /sbin/modinfo [ Warning ] /sbin/modprobe [ Warning ] /sbin/rmmod [ Warning ] /sbin/route [ Warning ] /sbin/runlevel [ Warning ] /sbin/sulogin [ Warning ] /sbin/sysctl [ Warning ] /bin/bash [ Warning ] /bin/cat [ Warning ] /bin/chmod [ Warning ] /bin/chown [ Warning ] /bin/cp [ Warning ] /bin/date [ Warning ] /bin/df [ Warning ] /bin/dmesg [ Warning ] /bin/echo [ Warning ] /bin/ed [ OK ] /bin/egrep [ Warning ] /bin/fgrep [ Warning ] /bin/fuser [ OK ] /bin/grep [ Warning ] /bin/ip [ Warning ] /bin/kill [ Warning ] /bin/less [ OK ] /bin/login [ Warning ] /bin/ls [ Warning ] /bin/lsmod [ Warning ] /bin/mktemp [ Warning ] /bin/more [ Warning ] /bin/mount [ Warning ] /bin/mv [ Warning ] /bin/netstat [ Warning ] /bin/ping [ Warning ] /bin/ps [ Warning ] /bin/pwd [ Warning ] /bin/readlink [ Warning ] /bin/sed [ Warning ] /bin/sh [ Warning ] /bin/su [ Warning ] /bin/touch [ Warning ] /bin/uname [ Warning ] /bin/which [ OK ] /bin/kmod [ Warning ] /bin/dash [ Warning ] [Press <ENTER> to continue] Checking for rootkits... Performing check of known rootkit files and directories 55808 Trojan - Variant A [ Not found ] ADM Worm [ Not found ] AjaKit Rootkit [ Not found ] Adore Rootkit [ Not found ] aPa Kit [ Not found ] Apache Worm [ Not found ] Ambient (ark) Rootkit [ Not found ] Balaur Rootkit [ Not found ] BeastKit Rootkit [ Not found ] beX2 Rootkit [ Not found ] BOBKit Rootkit [ Not found ] cb Rootkit [ Not found ] CiNIK Worm (Slapper.B variant) [ Not found ] Danny-Boy's Abuse Kit [ Not found ] Devil RootKit [ Not found ] Dica-Kit Rootkit [ Not found ] Dreams Rootkit [ Not found ] Duarawkz Rootkit [ Not found ] Enye LKM [ Not found ] Flea Linux Rootkit [ Not found ] Fu Rootkit [ Not found ] Fuck`it Rootkit [ Not found ] GasKit Rootkit [ Not found ] Heroin LKM [ Not found ] HjC Kit [ Not found ] ignoKit Rootkit [ Not found ] IntoXonia-NG Rootkit [ Not found ] Irix Rootkit [ Not found ] Jynx Rootkit [ Not found ] KBeast Rootkit [ Not found ] Kitko Rootkit [ Not found ] Knark Rootkit [ Not found ] ld-linuxv.so Rootkit [ Not found ] Li0n Worm [ Not found ] Lockit / LJK2 Rootkit [ Not found ] Mood-NT Rootkit [ Not found ] MRK Rootkit [ Not found ] Ni0 Rootkit [ Not found ] Ohhara Rootkit [ Not found ] Optic Kit (Tux) Worm [ Not found ] Oz Rootkit [ Not found ] Phalanx Rootkit [ Not found ] Phalanx2 Rootkit [ Not found ] Phalanx2 Rootkit (extended tests) [ Not found ] Portacelo Rootkit [ Not found ] R3dstorm Toolkit [ Not found ] RH-Sharpe's Rootkit [ Not found ] RSHA's Rootkit [ Not found ] Scalper Worm [ Not found ] Sebek LKM [ Not found ] Shutdown Rootkit [ Not found ] SHV4 Rootkit [ Not found ] SHV5 Rootkit [ Not found ] Sin Rootkit [ Not found ] Slapper Worm [ Not found ] Sneakin Rootkit [ Not found ] 'Spanish' Rootkit [ Not found ] Suckit Rootkit [ Not found ] Superkit Rootkit [ Not found ] TBD (Telnet BackDoor) [ Not found ] TeLeKiT Rootkit [ Not found ] T0rn Rootkit [ Not found ] trNkit Rootkit [ Not found ] Trojanit Kit [ Not found ] Tuxtendo Rootkit [ Not found ] URK Rootkit [ Not found ] Vampire Rootkit [ Not found ] VcKit Rootkit [ Not found ] Volc Rootkit [ Not found ] Xzibit Rootkit [ Not found ] zaRwT.KiT Rootkit [ Not found ] ZK Rootkit [ Not found ] [Press <ENTER> to continue] Performing additional rootkit checks Suckit Rookit additional checks [ OK ] Checking for possible rootkit files and directories [ None found ] Checking for possible rootkit strings [ None found ] Performing malware checks Checking running processes for suspicious files [ None found ] Checking for login backdoors [ None found ] Checking for suspicious directories [ None found ] Checking for sniffer log files [ None found ] Performing Linux specific checks Checking loaded kernel modules [ OK ] Checking kernel module names [ OK ] [Press <ENTER> to continue] Checking the network... Performing checks on the network ports Checking for backdoor ports [ None found ] Checking for hidden ports [ Skipped ] Performing checks on the network interfaces Checking for promiscuous interfaces [ None found ] Checking the local host... Performing system boot checks Checking for local host name [ Found ] Checking for system startup files [ Found ] Checking system startup files for malware [ None found ] Performing group and account checks Checking for passwd file [ Found ] Checking for root equivalent (UID 0) accounts [ None found ] Checking for passwordless accounts [ None found ] Checking for passwd file changes [ Warning ] Checking for group file changes [ Warning ] Checking root account shell history files [ None found ] Performing system configuration file checks Checking for SSH configuration file [ Not found ] Checking for running syslog daemon [ Found ] Checking for syslog configuration file [ Found ] Checking if syslog remote logging is allowed [ Not allowed ] Performing filesystem checks Checking /dev for suspicious file types [ Warning ] Checking for hidden files and directories [ Warning ] [Press <ENTER> to continue] System checks summary ===================== File properties checks... Required commands check failed Files checked: 137 Suspect files: 122 Rootkit checks... Rootkits checked : 291 Possible rootkits: 0 Applications checks... All checks skipped The system checks took: 5 minutes and 11 seconds All results have been written to the log file (/var/log/rkhunter.log)

    Read the article

  • Silverlight Relay Commands

    - by George Evjen
    v\:* {behavior:url(#default#VML);} o\:* {behavior:url(#default#VML);} w\:* {behavior:url(#default#VML);} .shape {behavior:url(#default#VML);} Normal 0 false false false false EN-US X-NONE X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;} I am fairly new at Silverlight development and I usually have an issue that needs research every day. Which I enjoy, since I like the idea of going into a day knowing that I am  going to learn something new. The issue that I am currently working on centers around relay commands. I have a pretty good handle on Relay Commands and how we use them within our applications. <Button Command="{Binding ButtonCommand}" CommandParameter="NewRecruit" Content="New Recruit" /> Here in our xaml we have a button. The button has a Command and a CommandParameter. The command binds to the ButtonCommand that we have in our ViewModel RelayCommand _buttonCommand;         /// <summary>         /// Gets the button command.         /// </summary>         /// <value>The button command.</value>         public RelayCommand ButtonCommand         {             get             {                 if (_buttonCommand == null)                 {                     _buttonCommand = new RelayCommand(                         x => x != null && x.ToString().Length > 0 && CheckCommandAvailable(x.ToString()),                         x => ExecuteCommand(x.ToString()));                 }                 return _buttonCommand;             }         }   In our relay command we then do some checks with a lambda expression. We check if the command  parameter is null, is the length greater than 0 and we have a CheckCommandAvailable method that will tell  us if the button is even enabled. After we check on these three items we then pass the command parameter to an action method. This is all pretty straight forward, the issue that we solved a few days ago centered around having a control that needed to use a Relay Command and this control was a nested control and was using a different DataContext. The example below illustrates how we handled this scenario. In our xaml usercontrol we had to set a name to this control. <Controls3:RadTileViewItem x:Class="RecruitStatusTileView"     xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"     xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"     xmlns:d="http://schemas.microsoft.com/expression/blend/2008"     xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"      xmlns:Controls1="clr-namespace:Telerik.Windows.Controls;assembly=Telerik.Windows.Controls"      xmlns:Controls2="clr-namespace:Telerik.Windows.Controls;assembly=Telerik.Windows.Controls.Input"      xmlns:Controls3="clr-namespace:Telerik.Windows.Controls;assembly=Telerik.Windows.Controls.Navigation"      mc:Ignorable="d" d:DesignHeight="400" d:DesignWidth="800" Header="{Binding Title,Mode=TwoWay}" MinimizedHeight="100"                             x:Name="StatusView"> Here we are using a telerik RadTileViewItem. We set the name of this control to “StatusView”. In our button control we set our command parameters and commands different than the example above. <HyperlinkButton Content="{Binding BigBoardButtonText, Mode=TwoWay}" CommandParameter="{Binding 'Position.PositionName'}" Command="{Binding ElementName=StatusView, Path=DataContext.BigBoardCommand, Mode=TwoWay}" /> This hyperlink button lives in a ListBox control and this listbox has an ItemSource of PositionSelectors. The Command Parameter is binding to the Position.Position property of that PositionSelectors object. This again is pretty straight forward again. What gets a bit tricky is the Command property in the hyperlink. It is binding to the element name we created in the user control (StatusView) Because this hyperlink is in a listbox and is in the item template it doesn’t have a direct handle on the DataContext that the RadTileViewItem has so we have to make sure it does. We do that by binding to the element name of status view then set the path to DataContext.BigBoardCommand. BigBoardCommand is the name of the RelayCommand in the view model. private RelayCommand _bigBoardCommand = null;         /// <summary>         /// Gets the big board command.         /// </summary>         /// <value>The big board command.</value>         public RelayCommand BigBoardCommand         {             get             {                 if (_bigBoardCommand == null)                 {                     _bigBoardCommand = new RelayCommand(x => true, x => AddToBigBoard(x.ToString()));                 }                 return _bigBoardCommand;             }         } From there we check for true again and then call the action and pass in the parameter that we had as the command parameter. What we are working on now is a bit trickier than this second example. In the above example we are only creating this TileViewItem with this name “StatusView” once. In another part of our application we are generating multiple TileViewItems, so we cannot set the name in the control as we cant have multiple controls with the same name. When we run the application we get an error that reads that the value is out of expected range. My searching has led me to think we cannot have multiple controls with the same name. This is today’s problem and Ill post the solution to this once it is found.

    Read the article

  • About Solaris 11 and UltraSPARC II/III/IV/IV+

    - by nospam(at)example.com (Joerg Moellenkamp)
    I know that I will get the usual amount of comments like "Oh, Jörg ? you can't be negative about Oracle" for this article. However as usual I want to explain the logic behind my reasoning. Yes ? I know that there is a lot of UltraSPARC III, IV and IV+ gear out there. But there are some very basic questions: Does your application you are currently running on this gear stops running just because you can't run Solaris 11 on it? What is the need to upgrade a system already in production to Solaris 11? I have the impression, that some people think that the systems get useless in the moment Oracle releases Solaris 11. I know that Sun sold UltraSPARC IV+ systems until 2009. The Sun SF490 introduced 2004 for example, that was a Sun SF480 with UltraSPARC IV and later with UltraSPARC IV+. And yes, Sun made some speedbumps. At that time the systems of the UltraSPARC III to IV+ generations were supported on Solaris 8, on Solaris 9 and on Solaris 10. However from my perspective we sold them to customers, which weren't able to migrate to Solaris 10 because they used applications not supported on Solaris 9 or who just didn't wanted to migrate to Solaris 10. Believe it or not ? I personally know two customers that migrated core systems to Solaris 10 in ? well 2008/9. This was especially true when the M3000 was announced in 2008 when it closed the darned single socket gap. It may be different at you site, however that's what I remember about that time when talking with customers. At first: Just because there is no Solaris 11 for UltraSPARC III, IV and IV+, it doesn't mean that Solaris 10 will go away anytime soon. I just want to point you to "Expect Lifetime Support - Hardware and Operating Systems". It states about Premier Support:Maintenance and software upgrades are included for Oracle operating systems and Oracle VM for a minimum of eight years from the general availability date.GA for Solaris 10 was in 2005. Plus 8 years ? 2013 ? at minimum. Then you can still opt for 3 years of "Extended Support" ? 2016 ? at minimum. 2016 your systems purchased in 2009 are 7 years old. Even on systems purchased at the very end of the lifetime of that system generation. That are the rules as written in the linked document. I said minimum The actual dates are even further in the future: Premier Support for Solaris 10 ends in 2015, Extended support ends 2018. Sustaining support ? indefinite. You will find this in the document "Oracle Lifetime Support Policy: Oracle Hardware and Operating Systems".So I don't understand when some people write, that Oracle is less protective about hardware investments than Sun. And for hardware it's the same as with Sun: Service 5 years after EOL as part of Premier Support. I would like to write about a different perspective as well: I have to be a little cautious here, because this is going in the roadmap area, so I will mention the public sources here: John Fowler told last year that we have to expect at at least 3x the single thread performance of T3 for T4. We have 8 cores in T4, as stated by Rick Hetherington. Let's assume for a moment that a T4 core will have the performance of a UltraSPARC core (just to simplify math and not to disclosing anything about the performance, all existing SPARC cores are considered equal). So given this pieces of information, you could consolidate 8 V215, 4 or 8 V245, 2 full blown V445,2 full blown 490, 2 full blown M3000 on a single T4 SPARC processor. The Fowler roadmap prezo talked about 4-socket systems with T4. So 32 V215, 16 to 8 V245, 8 fullblown V445, 8 full blown V490, 8 full blown M3000 in a system image. I think you get the idea. That said, most of the systems we are talking about have already amortized and perhaps it's just time to invest in new systems to yield other advantages like reduced space consumptions, like reduced power consumption, like some of the neat features sun4v gives you, and yes ? reduced number of processor licenses for Oracle and less money for Oracle HW/SW support. As much as I dislike it myself that my own UltraSPARC III and UltraSPARC II based systems won't run on Solaris 11 (and I have quite a few of them in my personal lab), I really think that the impact on production environments will be much less than most people think now. By the way: The reason for this move is a quite significant new feature. I will tell you that it was this feature, when it's out. I assume, telling just a word more could lead to much more time to blog.

    Read the article

  • Converting LINQ to Twitter to Twitter API v1.1

    - by Joe Mayo
    Twitter recently updated their API to v1.1 (Current status: API v1.1). Naturally, LINQ to Twitter  needed to be updated too. This blog post outlines the changes made to LINQ to Twitter during this conversion and highlights important features that LINQ to Twitter developers will want to know. Overall Impact Generally speaking, Twitter API v1.1 is semantically very much the same as it’s predecessor. The base URL changed and so did a few resource segments, but the resources themselves are still intact. The good news is that LINQ to Twitter has always shielded the developer from this plumbing, so the entities, types, and filters didn’t change much at all.  The following sections describe what did  change. Authentication In Twitter API v1.0 authentication was not required for some resources, such as user timelines and search. However, that’s all changed because *all* queries must be authenticated in Twitter API v1.1. LINQ to Twitter has various types of authorizers you can use, supporting whatever OAuth options are available via Twitter.  You can see the LINQ to Twitter documentation, Securing Your Applications, for more info on OAuth support. The New Search One of the larger changes to the API was Search. To be more specific, the Search entity now contains a List<Status>, named Statuses, to hold results.  Additionally, any meta-data associated with the search is now in a property named SearchMetaData. The change to the Search entity and responses is the big change, but the good news is that your Search query syntax doesn’t change. Different Rate Limits The issue of rate limits itself is contentious, but this discussion is focused on the coding experience and I’ll leave the politics to those who prefer to engage in that activity. What’s important here is that both headers and resources have changed. You should review Twitter’s Rate Limit documentation to understand what the changes mean.  A quick explanation is that rate limits are applied individually to each resource in 15 minute time intervals. In LINQ to Twitter these changes surface on the Help entity, via HelpType.RateLimits. The RateLimits query has a Resources filter where you can specify a comma-separated list of categories to return rate limit info for.  The results materialize in the RateLimits dictionary, keyed on category. The Help entity also has a RateLimitsAuthorizationContext, holding the Access Token for the user performing queries – and to whom the rate limits apply. In addition to the new RateLimits query, there are new RateLimit headers that appear in the query response, whose HTTP header name is of the form X-Rate-Limit… which is different from the previous header name. LINQ to Twitter surfaces these headers via the existing properties of the TwitterContext instance. For anyone who retrieved rate limit information via the Headers property of TwitterContext, you should be aware of the new header names.  I haven’t done anything with Feature rate limit properties yet, but they appear to no longer be available – this will require more follow-up. Error Handling Twitter API v1.1 has a new format for Error Codes & Responses. LINQ to Twitter wraps these messages in the TwitterQueryException, which has been updated appropriately. The Message property of TwitterQueryException now reflects the Twitter error message, when available. There’s also a new ErrorCode that’s populated with the message error code. Parameters Most parameters stayed the same, but one of interest is Include Entities (different from LINQ to Twitter data object entities). Entities are metadata hanging off tweets, that provide start/end position in the tweet and other information for mentions, urls, hash tags, and media. Entities used to not be included unless you specified you wanted them. Now, in v1.1, entities are included by default for all APIs that return a Status.  If you were always setting IncludeEntities to true, then you won’t see a change. However, be aware that you’ll now be receiving additional data in your response from Twitter, which will explain a sudden increase in bandwidth utilization. This might or might not  matter to you  depending on the requirements of your application, but you should be aware of it. Everything Else There might be small changes here and there that I haven’t mentioned, but these were the ones you should be most aware of.  Streams didn’t change, but Twitter will be deprecating username/password authentication on public streams, in favor of OAuth, so you’ll be seeing me make that change some time in the future.  Also, Twitter will continue to evolve the API and you can expect that LINQ to Twitter will change accordingly. Summary The big changes to Twitter API were Authentication, Search, Rate Limits, and Error Handling. All API calls must be authenticated. You’ll need to change your code to read Search results differently, but the query is much the same as you use now. There’s a new RateLimits API, one of the Help queries.  Also, the new error messages are integrated into TwitterQueryException. Besides these changes, I expect  most others to be small or affect a smaller percentage of developers.  You can get the latest version of LINQ to Twitter from NuGet or visit the LINQ to Twitter download page at CodePlex.com.   @JoeMayo

    Read the article

  • .NET Security Part 4

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

    Read the article

  • Career guidance/advice for Junior-level Software Engineer [closed]

    - by John Do
    I have quite a few questions on my mind, so please bare with me. Please don't feel obligated to answer all of them, any as you choose will do. I'd appreciate if you could share some insight on any of these. Before I begin, some context: I currently have almost two years of professional experience as a Software Engineer, mainly developing software in Java. At this point, I feel that I have reached the peak in my career growth at the current company I am at and therefore I am looking for a new job, ideally again, as a Software Engineer. I have been interviewing for the past few months casually but have not had luck with companies I have a passion for. So, in no particular order - 1) In general, what are your thoughts on having graduate degrees in CS / Software Engineering. How much does it influence a salary increase, and do you think it's beneficial when working on real-world problems? I get the sense that a graduate degree in the field is trivial unless you really have a passion for research. 2) In general, in professional practice, how often had you have to write your own data structures and "complex" algorithms from scratch? In my own work, I have found myself relying mainly on third-party frameworks and the Java standard library to implement solutions as per business requirements. What are your thoughts on this? 3) In terms of resume, I feel the most ambivalent here. I want to be able to "blemish" my resume to a certain extent so that it stands out from others', but at the same time I do not want to over-exagerate my abilities. How do you strike a balance here? For example: I say that I am proficient in Java with data structures and algorithms. This is obviously a subjective and relative statement. I've taken the classes in my undergrad, and I've applied it in my work experience. What I feel as "prociency" can be seen as junior-level to others. How do you know what to say? Most of the time, recruiters (with no technical background) will be looking for keywords that stand out. This leads me to my next question (4). 4) Just from interviewing for the past few months (and getting plenty of rejections), I've come to realize that I may not be as proficient in data structures and algorithms as I thought I was. Do you think it's a good idea to remove the "proficient in java/data structure and algorithms"? I feel that being too hoenst on the resume will impede me from scoring opportunities to even have an interview with top-notch companies. What are your thoughts? 5) What is the absolute "must-have" knowledge going into a technical interview? I've been practicing several algorithmic and data sturcture problems now, and I feel that my abilities to solve arbitrary problems efficiently has not gotten significantly better. Do you think these abilities are something innate - it's either you have in you, or you don't? How can you teach yourself to learn, if you will? 6) How easy is it to go from industry/function to the next? I work mainly with backend technologies and I'm now interested in working with the frontend, i.e javascript,jquery,php or even mobile development. In your own experience, how did you not get pidgeon holed in your career? I feel that the choices you make now ultimately decide your future. As cliche as it sounds, I think it may be true. Here's what I mean: you've worked mainly as a backend engineer, people are interested in you doing the same thing since you've already accumulated experience in that function. How do get experience in a new function if people won't accept you because you don't already have it? It's a catch 22, you see... Are side projects the only real way to help you move from one function to another that you're truly interested in? For example: I could start writing my own mobile applications, even though I've worked mainly on the backend. Thanks so much for the long read. As a relatively new engineer to the real world, I am very humble and would like those who are experienced to shed some light. Thank you so much.

    Read the article

  • VS2010 crashes when opening a vsp generated using VS 2012

    - by Tarun Arora
    I recently profiled some web applications using Visual Studio 2012, a vsp (Visual Studio Profile) file was generated as a result of the profiling session. I could successfully open the vsp file in Visual Studio 2012 as expected but when I tried to open the vsp file in Visual Studio 2010 the VS2010 IDE crashed. As a responsible citizen I raised bug # 762202 on Microsoft Connect site using the Microsoft Visual Studio 2012 Feedback Client. Note – In case you didn’t already know, VSP generated in Visual Studio 2012 is not backward compatible. Please refer below for the steps to reproduce the issue and the resolution of the connect bug. 1. Behaviour and Steps to Reproduce the Issue Description I have generated a vsp file by using the Visual Studio 2012 Standalone profiler. When I try and open the vsp file in Visual Studio 2010 the IDE crashes. I understand that a vsp generated by using VS 2012 cannot be opened in VS 2010, but the IDE crashing is not the behaviour I would expect to see. Steps to Reproduce the Issue 1. Pick up the Stand lone profiler from the VS 2012 installation media. The folder has both x 64 and x86 installer, since the machine I am using is x64 bit. I have installed the x64 version of the standalone profiler. 2. I have configured the system path by setting the 'environment variable' path to where the profiler is installed. In my case this is, C:\Program Files (x86)\Microsoft Visual Studio 11.0\Team Tools\Performance Tools 3. Created a new environment variable _NT_SYMBOL_PATH and set its value to CACHE*C:\SYMBOLSCACHE;SRV*C:\SYMBOLSCACHE*HTTP://MSDL.MICROSOFT.COM/DOWNLOAD/SYMBOLS;\\FOO\BUILD1234 4. Open up CMD as an administrator and run 'VSPerfASPNETCmd /tip http://localhost:56180/ /o:C:\Temp\SampleEISK.vsp' 5. This generates the following message on the cmd       Microsoft (R) VSPerf ASP.NET Command, Version 11.0.0.0     Copyright (C) Microsoft Corporation. All rights reserved.     Configuring and attaching to ASP.NET process. Please wait.     Setting up profiling environment.     Starting monitor.     Launching ASP.NET service.     Attaching Monitor to process.     Launching Internet Explorer.     The profiler is attached to ASP.net. Please run your application scenario now.     Press Enter to stop data collection...   6. I perform certain actions and then I come back to the cmd and hit enter to shut down the profiling. Once I do this, the following message is written to the cmd, Press Enter to stop data collection... Profiling now shut down. Report file "C:\Temp\SampleEISK.vsp" was generated. Running VsPerfReport, packing symbols into the .VSP. Shutting down profiling and restarting ASP.NET. Please wait. Restarting w3wp.exe.   7. I look in the C:\Temp folder and I can see the SampleEISK.vsp file generated. I can successfully open this file in Visual Studio 2012. 8. When I am trying to open the vsp file in VS 2010 the VS 2010 IDE crashes. Kaboooom! What I would expect to happen I expect to receive a message "VS 2010 does not support the vsp file generated by VS 2012". What actually happened The VS 2010 IDE crashed 2. Resolution This is a valid bug! However, there isn’t much value in releasing a hotfix for this issue. Refer below to the resolution provided by the Visual Studio Profiler Team.  Thank you for taking the time to report this issue. We completely agree that Visual Studio 2010 should not crash. However in this particular case this is not a bug we are going to retroactively release a fix to 2010 for at this point. Given that a fix would not unblock the scenario of opening a 2012 created file on Visual Studio 2010, and there is not an active update channel for Visual Studio 2010 other than manually locating and installing hot fixes, we will not be fixing this particular issue. Best Regards, Visual Studio Profiler Team   Though it would be great to improve the behaviour however, this is not a defect that would stop you from progressing in any way. It’s important to note however that VSP files generated by Visual Studio 2012 are not backward compatible so you should refrain from opening these files in Visual Studio 2010.

    Read the article

  • Unexpected advantage of Engineered Systems

    - by user12244672
    It's not surprising that Engineered Systems accelerate the debugging and resolution of customer issues. But what has surprised me is just how much faster issue resolution is with Engineered Systems such as SPARC SuperCluster. These are powerful, complex, systems used by customers wanting extreme database performance, app performance, and cost saving server consolidation. A SPARC SuperCluster consists or 2 or 4 powerful T4-4 compute nodes, 3 or 6 extreme performance Exadata Storage Cells, a ZFS Storage Appliance 7320 for general purpose storage, and ultra fast Infiniband switches.  Each with its own firmware. It runs Solaris 11, Solaris 10, 11gR2, LDoms virtualization, and Zones virtualization on the T4-4 compute nodes, a modified version of Solaris 11 in the ZFS Storage Appliance, a modified and highly tuned version of Oracle Linux running Exadata software on the Storage Cells, another Linux derivative in the Infiniband switches, etc. It has an Infiniband data network between the components, a 10Gb data network to the outside world, and a 1Gb management network. And customers can run whatever middleware and apps they want on it, clustered in whatever way they want. In one word, powerful.  In another, complex. The system is highly Engineered.  But it's designed to run general purpose applications. That is, the physical components, configuration, cabling, virtualization technologies, switches, firmware, Operating System versions, network protocols, tunables, etc. are all preset for optimum performance and robustness. That improves the customer experience as what the customer runs leverages our technical know-how and best practices and is what we've tested intensely within Oracle. It should also make debugging easier by fixing a large number of variables which would otherwise be in play if a customer or Systems Integrator had assembled such a complex system themselves from the constituent components.  For example, there's myriad network protocols which could be used with Infiniband.  Myriad ways the components could be interconnected, myriad tunable settings, etc. But what has really surprised me - and I've been working in this area for 15 years now - is just how much easier and faster Engineered Systems have made debugging and issue resolution. All those error opportunities for sub-optimal cabling, unusual network protocols, sub-optimal deployment of virtualization technologies, issues with 3rd party storage, issues with 3rd party multi-pathing products, etc., are simply taken out of the equation. All those error opportunities for making an issue unique to a particular set-up, the "why aren't we seeing this on any other system ?" type questions, the doubts, just go away when we or a customer discover an issue on an Engineered System. It enables a really honed response, getting to the root cause much, much faster than would otherwise be the case. Here's a couple of examples from the last month, one found in-house by my team, one found by a customer: Example 1: We found a node eviction issue running 11gR2 with Solaris 11 SRU 12 under extreme load on what we call our ExaLego test system (mimics an Exadata / SuperCluster 11gR2 Exadata Storage Cell set-up).  We quickly established that an enhancement in SRU12 enabled an 11gR2 process to query Infiniband's Subnet Manager, replacing a fallback mechanism it had used previously.  Under abnormally heavy load, the query could return results which were misinterpreted resulting in node eviction.  In several daily joint debugging sessions between the Solaris, Infiniband, and 11gR2 teams, the issue was fully root caused, evaluated, and a fix agreed upon.  That fix went back into all Solaris releases the following Monday.  From initial issue discovery to the fix being put back into all Solaris releases was just 10 days. Example 2: A customer reported sporadic performance degradation.  The reasons were unclear and the information sparse.  The SPARC SuperCluster Engineered Systems support teams which comprises both SPARC/Solaris and Database/Exadata experts worked to root cause the issue.  A number of contributing factors were discovered, including tunable parameters.  An intense collaborative investigation between the engineering teams identified the root cause to a CPU bound networking thread which was being starved of CPU cycles under extreme load.  Workarounds were identified.  Modifications have been put back into 11gR2 to alleviate the issue and a development project already underway within Solaris has been sped up to provide the final resolution on the Solaris side.  The fixed SPARC SuperCluster configuration greatly aided issue reproduction and dramatically sped up root cause analysis, allowing the correct workarounds and fixes to be identified, prioritized, and implemented.  The customer is now extremely happy with performance and robustness.  Since the configuration is common to other customers, the lessons learned are being proactively rolled out to other customers and incorporated into the installation procedures for future customers.  This effectively acts as a turbo-boost to performance and reliability for all SPARC SuperCluster customers.  If this had occurred in a "home grown" system of this complexity, I expect it would have taken at least 6 months to get to the bottom of the issue.  But because it was an Engineered System, known, understood, and qualified by both the Solaris and Database teams, we were able to collaborate closely to identify cause and effect and expedite a solution for the customer.  That is a key advantage of Engineered Systems which should not be underestimated.  Indeed, the initial issue mitigation on the Database side followed by final fix on the Solaris side, highlights the high degree of collaboration and excellent teamwork between the Oracle engineering teams.  It's a compelling advantage of the integrated Oracle Red Stack in general and Engineered Systems in particular.

    Read the article

  • java.util.zip.ZipException: Error opening file When Deploying an Application to Weblogic Server

    - by lmestre
    The latest weeks we had a hard time trying to solve a deployment issue.* WebLogic Server 10.3.6* Target: WLS Cluster<21-10-2013 05:29:40 PM CLST> <Error> <Console> <BEA-240003> <Console encountered the following error weblogic.management.DeploymentException:        at weblogic.servlet.internal.WarDeploymentFactory.findOrCreateComponentMBeans(WarDeploymentFactory.java:69)        at weblogic.application.internal.MBeanFactoryImpl.findOrCreateComponentMBeans(MBeanFactoryImpl.java:48)        at weblogic.application.internal.MBeanFactoryImpl.createComponentMBeans(MBeanFactoryImpl.java:110)        at weblogic.application.internal.MBeanFactoryImpl.initializeMBeans(MBeanFactoryImpl.java:76)        at weblogic.management.deploy.internal.MBeanConverter.createApplicationMBean(MBeanConverter.java:89)        at weblogic.management.deploy.internal.MBeanConverter.createApplicationForAppDeployment(MBeanConverter.java:67)        at weblogic.management.deploy.internal.MBeanConverter.setupNew81MBean(MBeanConverter.java:315)        at weblogic.deploy.internal.targetserver.operations.ActivateOperation.compatibilityProcessor(ActivateOperation.java:81)        at weblogic.deploy.internal.targetserver.operations.AbstractOperation.setupPrepare(AbstractOperation.java:295)        at weblogic.deploy.internal.targetserver.operations.ActivateOperation.doPrepare(ActivateOperation.java:97)        at weblogic.deploy.internal.targetserver.operations.AbstractOperation.prepare(AbstractOperation.java:217)        at weblogic.deploy.internal.targetserver.DeploymentManager.handleDeploymentPrepare(DeploymentManager.java:747)        at weblogic.deploy.internal.targetserver.DeploymentManager.prepareDeploymentList(DeploymentManager.java:1216)        at weblogic.deploy.internal.targetserver.DeploymentManager.handlePrepare(DeploymentManager.java:250)        at weblogic.deploy.internal.targetserver.DeploymentServiceDispatcher.prepare(DeploymentServiceDispatcher.java:159)        at weblogic.deploy.service.internal.targetserver.DeploymentReceiverCallbackDeliverer.doPrepareCallback(DeploymentReceiverCallbackDeliverer.java:171)        at weblogic.deploy.service.internal.targetserver.DeploymentReceiverCallbackDeliverer.access$000(DeploymentReceiverCallbackDeliverer.java:13)        at weblogic.deploy.service.internal.targetserver.DeploymentReceiverCallbackDeliverer$1.run(DeploymentReceiverCallbackDeliverer.java:46)        at weblogic.work.SelfTuningWorkManagerImpl$WorkAdapterImpl.run(SelfTuningWorkManagerImpl.java:545)        at weblogic.work.ExecuteThread.execute(ExecuteThread.java:256)        at weblogic.work.ExecuteThread.run(ExecuteThread.java:221)Caused by: java.util.zip.ZipException: Error opening file - C:\Oracle\Middleware\user_projects\domains\MyDomain\servers\MyServer\stage\myapp\myapp.war Message - error in opening zip file        at weblogic.servlet.utils.WarUtils.existsInWar(WarUtils.java:87)        at weblogic.servlet.utils.WarUtils.isWebServices(WarUtils.java:76)        at weblogic.servlet.internal.WarDeploymentFactory.findOrCreateComponentMBeans(WarDeploymentFactory.java:61) So the first idea you have with that error is that the war file is corrupted or has incorrect privileges.        We tried:1. Unzipping the  war file, the file was perfect.2. Checking the size, same size as in other environments.3. Checking the ownership of the file, same as in other environments.4. Checking the permissions of the file, same as other applications.Then we accepted the file was fine, so we tried enabling some deployment debugs, but no clues.We also tried:1. Delete all contents of <MyDomain/servers/<MyServer>/tmp> a and <MyDomain/servers/<MyServer>/cache> folders, the issue persisted.2. When renaming the application the deployment was sucessful3. When targeting to the Admin Server, deployment was also working.4. Using 'Copy this application onto every target for me' didn't help either.Finally, my friend 'Test Case' solved the issue again.I saw this name in the config.xml<jdbc-system-resource>    <name>myapp</name>    <target></target>    <descriptor-file-name>jdbc/myapp-jdbc.xml</descriptor-file-name>  </jdbc-system-resource> So, it turned out that customer had created a DataSource with the same name as the application 'myapp' in the above example.By deleting the datasource and created another exact DataSource with a different name the issue was solved.At this point, Do you know Why 'java.util.zip.ZipException: Error opening file' was occurring?Because all names is WebLogic Server need to be unique.References: http://docs.oracle.com/cd/E23943_01/web.1111/e13709/setup.htm"Assigning Names to WebLogic Server ResourcesMake sure that each configurable resource in your WebLogic Server environment has a unique name. Each, domain, server, machine, cluster, JDBC data source, virtual host, or other resource must have a unique name." Enjoy!

    Read the article

  • Windows for IoT, continued

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

    Read the article

  • XBRL - Moving from Production to Consumption

    - by jmorourke
    Here's an update on what’s new with XBRL and how it can actually benefit your organization versus adding extra time and costs to financial reporting.  On February 29th (leap day) of 2012 I attended the XBRL and Financial Analysis Technology Conference at Baruch College in NYC.  The event, which attracted over 300 XBRL gurus and fans was presented by XBRL US, The New York Society of Security Analysts’ Improved Corporate Reporting Committee, and Baruch College’s Robert Zicklin Center for Corporate Integrity.  The event featured keynotes from the U.S. Securities and Exchange Commission (SEC), and the CFA Institute as well as panels covering alternative research tools and data, corporate reporting to stakeholders and a demonstration of XBRL analysis tools.  The program culminated in a presentation of the finalists and the winner of the $20,000 XBRL Challenge.    Some of the key points made in the sessions included: The focus of XBRL tools is moving from production to consumption. As of February 2012, over 9000 companies are reporting in XBRL, with over 10 million facts filed to date XBRL taxonomy extensions have dropped from 27% to 11% making comparisons easier The SEC reports that XBRL makes it easier to analyze disclosures, focus on accounting issues XBRL is helping standards-setters like the FASB speed their analysis of impacts of proposed accounting rule changes Companies like Thomson Reuters report that XBRL is helping speed the delivery of data to clients The most interesting part of the program though, was the session highlighting the 5 finalists in the XBRL Challenge competition and the winning solution.  The XBRL Challenge was launched in 2011 as a means of spurring the development of more end-user tools to help with the consumption of XBRL-based financial information.       Over an 8-month process handled by 5 judges, there were 84 registrants, 15 completed submissions, 5 finalists and one winner of the challenge.  All of the solutions are open-sourced tools and most of them focus on consuming XBRL-based data.  The 5 finalists included: Advanced XBRL Processing from Oxide solutions – XBRL viewer for taxonomies, filings and company data with peer comparison capabilities. Arrelle – API for XBRL processes, supports SEC Validations, RSS Feeds to access filings etc. Calcbench – XBRL data analysis tool that can be embedded in other web applications.  This tool can combine XBRL filings with real-time market data. XBRL to XL – allows the importing of XBRL data into Microsoft Excel for analysis, comparisons.  Users start on the web and populate Excel with XBRL data. XBurble – allows users to search and view XBRL filings, export to Excel, merge for comparison, and includes a workflow interface. The winner of the $20,000 XBRL Challenge prize was CalcBench.  More information about the XBRL Challenge and the finalists can be found at www.XBRLUS.org/challenge XBRL for Sustainability Reporting – other recent news on the XBRL front was the announcement by the Global Reporting Initiative (GRI) of an XBRL taxonomy for Sustainability Reporting.  This taxonomy was co-developed by the GRI and Deloitte and is designed to make the consumption of data found in Sustainability Reports much easier.  Although there is no government mandate to file Sustainability Reports in XBRL format, organizations that do use the GRI guidelines for Sustainability Reporting are encouraged to tag and submit their data voluntarily to the GRI – who will populate a database with Sustainability Reporting data and make this available to the public.  For more information about this initiative, you can go to the GRI web site:  www.globalreporting.org. So how does all of this benefit corporate filers and investors?  Since its introduction, the consensus in the market is that XBRL has mainly benefited the regulators and investment analysts who need to consume and analyze large volumes of financial data.  But with the emergence of more end-user tools for consuming and analyzing XBRL-based data, and the ability to perform quick comparisons of one company versus its peers and competitors in an industry group, will soon accelerate the benefits to corporate finance staff, as well as individual investors.  This could apply to financial results tagged in XBRL, as well as non-financial information such as Sustainability Reporting – which over the long-term will likely be integrated with financial reporting.   And as multiple regulators and agencies in a country adopt the XBRL standard for corporate filings, more benefits will accrue as companies will be able to leverage one set of XBRL-based financial data for multiple regulatory filings.     For more information about the latest developments in XBRL, check out the XBRL US or XBRL International web sites:  www.xbrl.org, www.xbrlus.org. For more information about what Oracle is doing to support XBRL, here are some links: http://www.oracle.com/us/solutions/ent-performance-bi/disclosure-management-065892.html http://www.oracle.com/technetwork/database/features/xmldb/index-087631.html Feel free to contact me if you have any questions or need more information:  [email protected]

    Read the article

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

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

    Read the article

  • Best Practices - Dynamic Reconfiguration

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

    Read the article

  • Is Data Science “Science”?

    - by BuckWoody
    I hold the term “science” in very high esteem. I grew up on the Space Coast in Florida, and eventually worked at the Kennedy Space Center, surrounded by very intelligent people who worked in various scientific fields. Recently a new term has entered the computing dialog – “Data Scientist”. Since it’s not a standard term, it has a lot of definitions, and in fact has been disputed as a correct term. After all, the reasoning goes, if there’s no such thing as “Data Science” then how can there be a Data Scientist? This argument has been made before, albeit with a different term – “Computer Science”. In Peter Denning’s excellent article “Is Computer Science Science” (April  2005/Vol. 48, No. 4 COMMUNICATIONS OF THE ACM) there are many points that separate “science” from “engineering” and even “art”.  I won’t repeat the content of that article here (I recommend you read it on your own) but will leverage the points he makes there. Definition of Science To ask the question “is data science ‘science’” then we need to start with a definition of terms. Various references put the definition into the same basic areas: Study of the physical world Systematic and/or disciplined study of a subject area ...and then they include the things studied, the bodies of knowledge and so on. The word itself comes from Latin, and means merely “to know” or “to study to know”. Greek divides knowledge further into “truth” (episteme), and practical use or effects (tekhne). Normally computing falls into the second realm. Definition of Data Science And now a more controversial definition: Data Science. This term is so new and perhaps so niche that the major dictionaries haven’t yet picked it up (my OED reference is older – can’t afford to pop for the online registration at present). Researching the term's general use I created an amalgam of the definitions this way: “Studying and applying mathematical and other techniques to derive information from complex data sets.” Using this definition, data science certainly seems to be science - it's learning about and studying some object or area using systematic methods. But implicit within the definition is the word “application”, which makes the process more akin to engineering or even technology than science. In fact, I find that using these techniques – and data itself – part of science, not science itself. I leave out the concept of studying data patterns or algorithms as part of this discipline. That is actually a domain I see within research, mathematics or computer science. That of course is a type of science, but does not seek for practical applications. As part of the argument against calling it “Data Science”, some point to the scientific method of creating a hypothesis, testing with controls, testing results against the hypothesis, and documenting for repeatability.  These are not steps that we often take in working with data. We normally start with a question, and fit patterns and algorithms to predict outcomes and find correlations. In this way Data Science is more akin to statistics (and in fact makes heavy use of them) in the process rather than starting with an assumption and following on with it. So, is Data Science “Science”? I’m uncertain – and I’m uncertain it matters. Even if we are facing rampant “title inflation” these days (does anyone introduce themselves as a secretary or supervisor anymore?) I can tolerate the term at least from the intent that we use data to study problems across a wide spectrum, rather than restricting it to a single domain. And I also understand those who have worked hard to achieve the very honorable title of “scientist” who have issues with those who borrow the term without asking. What do you think? Science, or not? Does it matter?

    Read the article

  • C# Open Source software that is useful for learning Design Patterns

    - by Fathom Savvy
    In college I took a class in Expert Systems. The language the book taught (CLIPS) was esoteric - Expert Systems: Principles and Programming, Fourth Edition. I remember having a tough time with it. So, after almost failing the class, I needed to create the most awesome Expert System for my final presentation. I chose to create an expert system that would calculate risk analysis for a person's retirement portfolio. In short, the system would provide the services normally performed by one's financial adviser. In other words, based on personality, age, state of the macro economy, and other factors, should one's portfolio be conservative, moderate, or aggressive? In the appendix of the book (or on the CD-ROM), there was this in-depth example program for something unrelated to my presentation. Over my break, I read and re-read every line of that program until I understood it to the letter. Even though it was unrelated, I learned more than I ever could by reading all of the chapters. My presentation turned out to be pretty damn good and I received praises from my professor and classmates. So, the moral of the story is..., by understanding other people's code, you can gain greater insight into a language/paradigm than by reading canonical examples. Still, to this day, I am having trouble with everyday design patterns such as the Factory Pattern. I would like to know if anyone could recommend open source software that would help me understand the Gang of Four design patterns, at the very least. I have read the books, but I'm having trouble writing code for the concepts in the real world. Perhaps, by studying code used in today's real world applications, it might just "click". I realize a piece of software may only implement one kind of design pattern. But, if the pattern is an implementation you think is good for learning, and you know what pattern to look for within the source, I'm hoping you can tell me about it. For example, the System.Linq.Expressions namespace has a good example of the Visitor Pattern. The client calls Expression.Accept(new ExpressionVisitor()), which calls ExpressionVisitor (VisitExtension), which calls back to Expression (VisitChildren), which then calls Expression (Accept) again - wooah, kinda convoluted. The point to note here is that VisitChildren is a virtual method. Both Expression and those classes derived from Expression can implement the VisitChildren method any way they want. This means that one type of Expression can run code that is completely different from another type of derived Expression, even though the ExpressionVisitor class is the same in the Accept method. (As a side note Expression.Accept is also virtual). In the end, the code provides a real world example that you won't get in any book because it's kinda confusing. To summarize, If you know of any open source software that uses a design pattern implementation you were impressed by, please list it here. I'm sure it will help many others besides just me. public class VisitorPatternTest { public void Main() { Expression normalExpr = new Expression(); normalExpr.Accept(new ExpressionVisitor()); Expression binExpr = new BinaryExpression(); binExpr.Accept(new ExpressionVisitor()); } } public class Expression { protected internal virtual Expression Accept(ExpressionVisitor visitor) { return visitor.VisitExtension(this); } protected internal virtual Expression VisitChildren(ExpressionVisitor visitor) { if (!this.CanReduce) { throw Error.MustBeReducible(); } return visitor.Visit(this.ReduceAndCheck()); } public virtual Expression Visit(Expression node) { if (node != null) { return node.Accept(this); } return null; } public Expression ReduceAndCheck() { if (!this.CanReduce) { throw Error.MustBeReducible(); } Expression expression = this.Reduce(); if ((expression == null) || (expression == this)) { throw Error.MustReduceToDifferent(); } if (!TypeUtils.AreReferenceAssignable(this.Type, expression.Type)) { throw Error.ReducedNotCompatible(); } return expression; } } public class BinaryExpression : Expression { protected internal override Expression Accept(ExpressionVisitor visitor) { return visitor.VisitBinary(this); } protected internal override Expression VisitChildren(ExpressionVisitor visitor) { return CreateDummyExpression(); } protected internal Expression CreateDummyExpression() { Expression dummy = new Expression(); return dummy; } } public class ExpressionVisitor { public virtual Expression Visit(Expression node) { if (node != null) { return node.Accept(this); } return null; } protected internal virtual Expression VisitExtension(Expression node) { return node.VisitChildren(this); } protected internal virtual Expression VisitBinary(BinaryExpression node) { return ValidateBinary(node, node.Update(this.Visit(node.Left), this.VisitAndConvert<LambdaExpression>(node.Conversion, "VisitBinary"), this.Visit(node.Right))); } }

    Read the article

  • Data management in unexpected places

    - by Ashok_Ora
    Normal 0 false false false EN-US X-NONE X-NONE Data management in unexpected places When you think of network switches, routers, firewall appliances, etc., it may not be obvious that at the heart of these kinds of solutions is an engine that can manage huge amounts of data at very high throughput with low latencies and high availability. Consider a network router that is processing tens (or hundreds) of thousands of network packets per second. So what really happens inside a router? Packets are streaming in at the rate of tens of thousands per second. Each packet has multiple attributes, for example, a destination, associated SLAs etc. For each packet, the router has to determine the address of the next “hop” to the destination; it has to determine how to prioritize this packet. If it’s a high priority packet, then it has to be sent on its way before lower priority packets. As a consequence of prioritizing high priority packets, lower priority data packets may need to be temporarily stored (held back), but addressed fairly. If there are security or privacy requirements associated with the data packet, those have to be enforced. You probably need to keep track of statistics related to the packets processed (someone’s sure to ask). You have to do all this (and more) while preserving high availability i.e. if one of the processors in the router goes down, you have to have a way to continue processing without interruption (the customer won’t be happy with a “choppy” VoIP conversation, right?). And all this has to be achieved without ANY intervention from a human operator – the router is most likely to be in a remote location – it must JUST CONTINUE TO WORK CORRECTLY, even when bad things happen. How is this implemented? As soon as a packet arrives, it is interpreted by the receiving software. The software decodes the packet headers in order to determine the destination, kind of packet (e.g. voice vs. data), SLAs associated with the “owner” of the packet etc. It looks up the internal database of “rules” of how to process this packet and handles the packet accordingly. The software might choose to hold on to the packet safely for some period of time, if it’s a low priority packet. Ah – this sounds very much like a database problem. For each packet, you have to minimally · Look up the most efficient next “hop” towards the destination. The “most efficient” next hop can change, depending on latency, availability etc. · Look up the SLA and determine the priority of this packet (e.g. voice calls get priority over data ftp) · Look up security information associated with this data packet. It may be necessary to retrieve the context for this network packet since a network packet is a small “slice” of a session. The context for the “header” packet needs to be stored in the router, in order to make this work. · If the priority of the packet is low, then “store” the packet temporarily in the router until it is time to forward the packet to the next hop. · Update various statistics about the packet. In most cases, you have to do all this in the context of a single transaction. For example, you want to look up the forwarding address and perform the “send” in a single transaction so that the forwarding address doesn’t change while you’re sending the packet. So, how do you do all this? Berkeley DB is a proven, reliable, high performance, highly available embeddable database, designed for exactly these kinds of usage scenarios. Berkeley DB is a robust, reliable, proven solution that is currently being used in these scenarios. First and foremost, Berkeley DB (or BDB for short) is very very fast. It can process tens or hundreds of thousands of transactions per second. It can be used as a pure in-memory database, or as a disk-persistent database. BDB provides high availability – if one board in the router fails, the system can automatically failover to another board – no manual intervention required. BDB is self-administering – there’s no need for manual intervention in order to maintain a BDB application. No need to send a technician to a remote site in the middle of nowhere on a freezing winter day to perform maintenance operations. BDB is used in over 200 million deployments worldwide for the past two decades for mission-critical applications such as the one described here. You have a choice of spending valuable resources to implement similar functionality, or, you could simply embed BDB in your application and off you go! I know what I’d do – choose BDB, so I can focus on my business problem. What will you do? /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin-top:0in; mso-para-margin-right:0in; mso-para-margin-bottom:10.0pt; mso-para-margin-left:0in; line-height:115%; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin;}

    Read the article

  • MERGE gives better OUTPUT options

    - by Rob Farley
    MERGE is very cool. There are a ton of useful things about it – mostly around the fact that you can implement a ton of change against a table all at once. This is great for data warehousing, handling changes made to relational databases by applications, all kinds of things. One of the more subtle things about MERGE is the power of the OUTPUT clause. Useful for logging.   If you’re not familiar with the OUTPUT clause, you really should be – it basically makes your DML (INSERT/DELETE/UPDATE/MERGE) statement return data back to you. This is a great way of returning identity values from INSERT commands (so much better than SCOPE_IDENTITY() or the older (and worse) @@IDENTITY, because you can get lots of rows back). You can even use it to grab default values that are set using non-deterministic functions like NEWID() – things you couldn’t normally get back without running another query (or with a trigger, I guess, but that’s not pretty). That inserted table I referenced – that’s part of the ‘behind-the-scenes’ work that goes on with all DML changes. When you insert data, this internal table called inserted gets populated with rows, and then used to inflict the appropriate inserts on the various structures that store data (HoBTs – the Heaps or B-Trees used to store data as tables and indexes). When deleting, the deleted table gets populated. Updates get a matching row in both tables (although this doesn’t mean that an update is a delete followed by an inserted, it’s just the way it’s handled with these tables). These tables can be referenced by the OUTPUT clause, which can show you the before and after for any DML statement. Useful stuff. MERGE is slightly different though. With MERGE, you get a mix of entries. Your MERGE statement might be doing some INSERTs, some UPDATEs and some DELETEs. One of the most common examples of MERGE is to perform an UPSERT command, where data is updated if it already exists, or inserted if it’s new. And in a single operation too. Here, you can see the usefulness of the deleted and inserted tables, which clearly reflect the type of operation (but then again, MERGE lets you use an extra column called $action to show this). (Don’t worry about the fact that I turned on IDENTITY_INSERT, that’s just so that I could insert the values) One of the things I love about MERGE is that it feels almost cursor-like – the UPDATE bit feels like “WHERE CURRENT OF …”, and the INSERT bit feels like a single-row insert. And it is – but into the inserted and deleted tables. The operations to maintain the HoBTs are still done using the whole set of changes, which is very cool. And $action – very convenient. But as cool as $action is, that’s not the point of my post. If it were, I hope you’d all be disappointed, as you can’t really go near the MERGE statement without learning about it. The subtle thing that I love about MERGE with OUTPUT is that you can hook into more than just inserted and deleted. Did you notice in my earlier query that my source table had a ‘src’ field, that wasn’t used in the insert? Normally, this would be somewhat pointless to include in my source query. But with MERGE, I can put that in the OUTPUT clause. This is useful stuff, particularly when you’re needing to audit the changes. Suppose your query involved consolidating data from a number of sources, but you didn’t need to insert that into the actual table, just into a table for audit. This is now very doable, either using the INTO clause of OUTPUT, or surrounding the whole MERGE statement in brackets (parentheses if you’re American) and using a regular INSERT statement. This is also doable if you’re using MERGE to just do INSERTs. In case you hadn’t realised, you can use MERGE in place of an INSERT statement. It’s just like the UPSERT-style statement we’ve just seen, except that we want nothing to match. That’s easy to do, we just use ON 1=2. This is obviously more convoluted than a straight INSERT. And it’s slightly more effort for the database engine too. But, if you want the extra audit capabilities, the ability to hook into the other source columns is definitely useful. Oh, and before people ask if you can also hook into the target table’s columns... Yes, of course. That’s what deleted and inserted give you.

    Read the article

  • Identity Globe Trotters (Sep Edition): The Social Customer

    - by Tanu Sood
    Welcome to the inaugural edition of our monthly series - Identity Globe Trotters. Starting today, the last Friday of every month, we will explore regional commentary on Identity Management. We will invite guest contributors from around the world to share their opinions and experiences around Identity Management and highlight regional nuances, specific drivers, solutions and more. Today's feature is contributed by Michael Krebs, Head of Business Development at esentri consulting GmbH, a (SOA) specialized Oracle Gold Partner based in Ettlingen, Germany. In his current role, Krebs is dealing with the latest developments in Enterprise Social Networking and the Integration of Social Media within business processes.  By Michael Krebs The relevance of "easy sign-on" in the age of the "Social Customer" With the growth of Social Networks, the time people spend within those closed "eco-systems" is growing year by year. With social networks looking to integrate search engines, like Facebook announced some weeks ago, their relevance will continue to grow in contrast to the more conventional search engines. This is one of the reasons why social network accounts of the users are getting more and more like a virtual fingerprint. With the growing relevance of social networks the importance of a simple way for customers to get in touch with say, customer care or contract departments, will be crucial for sales processes in critical markets. Customers want to have one single point of contact and also an easy "login-method" with no dedicated usernames, passwords or proprietary accounts. The golden rule in the future social media driven markets will be: The lower the complexity of the initial contact, the better a company can profit from social networks. If you, for example, can generate a smart way of how an existing customer can use self-service portals, the cost in providing phone support can be lowered significantly. Recruiting and Hiring of "Digital Natives" Another particular example is "social" recruiting processes. The so called "digital natives" don´t want to type in their profile facts and CV´s in proprietary systems. Why not use the actual LinkedIn profile? In German speaking region, the market in the area of professional social networks is dominated by XING, the equivalent to LinkedIn. A few weeks back, this network also opened up their interfaces for integrating social sign-ons or the usage of profile data for recruiting-purposes. In the European (and especially the German) employment market, where the number of young candidates is shrinking because of the low birth rate in the region, it will become essential to use social-media supported hiring processes to find and on-board the rare talents. In fact, you will see traditional recruiting websites integrated with social hiring to attract the best talents in the market, where the pool of potential candidates has decreased dramatically over the years. Identity Management as a key factor in the Customer Experience process To create the biggest value for customers and also future employees, companies need to connect their HCM or CRM-systems with powerful Identity management solutions. With the highly efficient Oracle (social & mobile enabling) Identity Management solution, enterprises can combine easy sign on with secure connections to the backend infrastructure. This combination enables a "one-stop" service with personalized content for customers and talents. In addition, companies can collect valuable data for the enrichment of their CRM-data. The goal is to enrich the so called "Customer Experience" via all available customer channels and contact points. Those systems have already gained importance in the B2C-markets and will gradually spread out to B2B-channels in the near future. Conclusion: Central and "Social" Identity management is key to Customer Experience Management and Talent Management For a seamless delivery of "Customer Experience Management" and a modern way of recruiting the best talent, companies need to integrate Social Sign-on capabilities with modern CX - and Talent management infrastructure. This lowers the barrier for existing and future customers or employees to get in touch with sales, support or human resources. Identity management is the technology enabler and backbone for a modern Customer Experience Infrastructure. Oracle Identity management solutions provide the opportunity to secure Social Applications and connect them with modern CX-solutions. At the end, companies benefit from "best of breed" processes and solutions for enriching customer experience without compromising security. About esentri: esentri is a provider of enterprise social networking and brings the benefits of social network communication into business environments. As one key strength, esentri uses Oracle Identity Management solutions for delivering Social and Mobile access for Oracle’s CRM- and HCM-solutions. …..End Guest Post…. With new and enhanced features optimized to secure the new digital experience, the recently announced Oracle Identity Management 11g Release 2 enables organizations to securely embrace cloud, mobile and social infrastructures and reach new user communities to help further expand and develop their businesses. Additional Resources: Oracle Identity Management 11gR2 release Oracle Identity Management website Datasheet: Mobile and Social Access (pdf) IDM at OOW: Focus on Identity Management Facebook: OracleIDM Twitter: OracleIDM We look forward to your feedback on this post and welcome your suggestions for topics to cover in Identity Globe Trotters. Last Friday, every month!

    Read the article

  • Top Questions and Answers for Pluging into Oracle Database as a Service

    - by David Swanger
    Yesterday we hosted a comprehensive online forum that shared a comprehensive path to help your organization design, deploy, and deliver a Database as a Service cloud. If you missed the online forum, you can watch it on demand by registering here. We received numerous questions.  Below are highlights of the most informative: DBaaS requires a lengthy and careful design efforts. What is the minimum requirements of setting up a scaled-down environment and test it out? You should have an OEM 12c environment for DBaaS administration and then a target database deployment platform that has the key characteristics of what your production environment will look like. This could be a single server or it could be a small pool of hosts if your production DBaaS will be larger and you want to test a more robust / real world configuration with Zones and Pools or DR capabilities for example. How does this benefit companies having their own data center? This allows companies to transform their internal IT to a service delivery model for the database. The benefits to the company are significant cost savings, improved business agility and reduced risk. The benefits to the consumers (internal) of services if much fast provisioning, and response to change in business requirements. From a deployment perspective, is DBaaS's job solely DBA's job? The best deployment model enables the DBA (or end-user) to control the entire process. All resources required to deploy the service are pre-provisioned, and there are no external dependencies (on network, storage, sysadmins teams). The service is created either via a self-service portal or by the DBA. The purpose of self service seems to be that the end user does not rely on the DBA. I just need to give him a template. He decides how much AMM he needs. Why shall I set it one by one. That doesn't seem to be the purpose of self service. Most customers we have worked with define a standardized service catalog, with a few (2 to 5) different classes of service. For each of these classes, there is a pre-defined deployment template, and the user has the ability to select from some pre-defined service sizes. The administrator only has to create this catalog once. Each user then simply selects from the options offered in the catalog.  Looking at DBaaS service definition, it seems to be no different from a service definition provided by a well defined DBA team. Why do you attribute it to DBaaS? There are a couple of perspectives. First, some organizations might already be operating with a high level of standardization and a higher level of maturity from an ITIL or Service Management perspective. Their journey to DBaaS could be shorter and their Service Definition will evolve less but they still might need to add capabilities such as Self Service and Metering/Chargeback. Other organizations are still operating in highly siloed environments with little automation and their formal Service Definition (if they have one) will be a lot less mature today. Therefore their future state DBaaS will look a lot different from their current state, as will their Service Definition. How database as a service impact or help with "Click to Compute" or deploying "Database in cloud infrastructure" DBaaS enables Click to Compute. Oracle DBaaS can be implemented using three architecture models: Oracle Multitenant 12c, native consolidation using Oracle Database and consolidation using virtualization in infrastructure cloud. As Deploy session showed, you get higher consolidating density and efficiency using Multitenant and higher isolation using infrastructure cloud. Depending upon your business needs, DBaaS can be implemented using any of these models. How exactly is the DBaaS different from the traditional db? Storage/OS/DB all together to 'transparently' provide service to applications? Will there be across-databases access by application/user. Some key differences are: 1) The services run on a shared platform. 2) The services can be rapidly provisioned (< 15 minutes). 3) The services are dynamic and can be relocated, grown, shrunk as needed to meet business needs without disruption and rapidly. 4) The user is able to provision the services directly from a standardized service catalog.. With 24x7x365 databases its difficult to find off peak hrs to do basic admin tasks such as gathering stats, running backups, batch jobs. How does pluggable database handle this and different needs/patching downtime of apps databases might be serving? You can gather stats in Oracle Multitenant the same way you had been in regular databases. Regarding patching/upgrading, Oracle Multitenant makes patch/upgrade very efficient in that you can pre-provision a new version/patched multitenant db in a different ORACLE_HOME and then unplug a PDB from its CDB and plug it into the newer/patched CDB in seconds.  Thanks for all the great questions!  If you'd like to learn more and missed the online forum, you can watch it on demand here.

    Read the article

  • CPU Usage in Very Large Coherence Clusters

    - by jpurdy
    When sizing Coherence installations, one of the complicating factors is that these installations (by their very nature) tend to be application-specific, with some being large, memory-intensive caches, with others acting as I/O-intensive transaction-processing platforms, and still others performing CPU-intensive calculations across the data grid. Regardless of the primary resource requirements, Coherence sizing calculations are inherently empirical, in that there are so many permutations that a simple spreadsheet approach to sizing is rarely optimal (though it can provide a good starting estimate). So we typically recommend measuring actual resource usage (primarily CPU cycles, network bandwidth and memory) at a given load, and then extrapolating from those measurements. Of course there may be multiple types of load, and these may have varying degrees of correlation -- for example, an increased request rate may drive up the number of objects "pinned" in memory at any point, but the increase may be less than linear if those objects are naturally shared by concurrent requests. But for most reasonably-designed applications, a linear resource model will be reasonably accurate for most levels of scale. However, at extreme scale, sizing becomes a bit more complicated as certain cluster management operations -- while very infrequent -- become increasingly critical. This is because certain operations do not naturally tend to scale out. In a small cluster, sizing is primarily driven by the request rate, required cache size, or other application-driven metrics. In larger clusters (e.g. those with hundreds of cluster members), certain infrastructure tasks become intensive, in particular those related to members joining and leaving the cluster, such as introducing new cluster members to the rest of the cluster, or publishing the location of partitions during rebalancing. These tasks have a strong tendency to require all updates to be routed via a single member for the sake of cluster stability and data integrity. Fortunately that member is dynamically assigned in Coherence, so it is not a single point of failure, but it may still become a single point of bottleneck (until the cluster finishes its reconfiguration, at which point this member will have a similar load to the rest of the members). The most common cause of scaling issues in large clusters is disabling multicast (by configuring well-known addresses, aka WKA). This obviously impacts network usage, but it also has a large impact on CPU usage, primarily since the senior member must directly communicate certain messages with every other cluster member, and this communication requires significant CPU time. In particular, the need to notify the rest of the cluster about membership changes and corresponding partition reassignments adds stress to the senior member. Given that portions of the network stack may tend to be single-threaded (both in Coherence and the underlying OS), this may be even more problematic on servers with poor single-threaded performance. As a result of this, some extremely large clusters may be configured with a smaller number of partitions than ideal. This results in the size of each partition being increased. When a cache server fails, the other servers will use their fractional backups to recover the state of that server (and take over responsibility for their backed-up portion of that state). The finest granularity of this recovery is a single partition, and the single service thread can not accept new requests during this recovery. Ordinarily, recovery is practically instantaneous (it is roughly equivalent to the time required to iterate over a set of backup backing map entries and move them to the primary backing map in the same JVM). But certain factors can increase this duration drastically (to several seconds): large partitions, sufficiently slow single-threaded CPU performance, many or expensive indexes to rebuild, etc. The solution of course is to mitigate each of those factors but in many cases this may be challenging. Larger clusters also lead to the temptation to place more load on the available hardware resources, spreading CPU resources thin. As an example, while we've long been aware of how garbage collection can cause significant pauses, it usually isn't viewed as a major consumer of CPU (in terms of overall system throughput). Typically, the use of a concurrent collector allows greater responsiveness by minimizing pause times, at the cost of reducing system throughput. However, at a recent engagement, we were forced to turn off the concurrent collector and use a traditional parallel "stop the world" collector to reduce CPU usage to an acceptable level. In summary, there are some less obvious factors that may result in excessive CPU consumption in a larger cluster, so it is even more critical to test at full scale, even though allocating sufficient hardware may often be much more difficult for these large clusters.

    Read the article

  • Rebuilding CoasterBuzz, Part IV: Dependency injection, it's what's for breakfast

    - by Jeff
    (Repost from my personal blog.) This is another post in a series about rebuilding one of my Web sites, which has been around for 12 years. I hope to relaunch soon. More: Part I: Evolution, and death to WCF Part II: Hot data objects Part III: The architecture using the "Web stack of love" If anything generally good for the craft has come out of the rise of ASP.NET MVC, it's that people are more likely to use dependency injection, and loosely couple the pieces parts of their applications. A lot of the emphasis on coding this way has been to facilitate unit testing, and that's awesome. Unit testing makes me feel a lot less like a hack, and a lot more confident in what I'm doing. Dependency injection is pretty straight forward. It says, "Given an instance of this class, I need instances of other classes, defined not by their concrete implementations, but their interfaces." Probably the first place a developer exercises this in when having a class talk to some kind of data repository. For a very simple example, pretend the FooService has to get some Foo. It looks like this: public class FooService {    public FooService(IFooRepository fooRepo)    {       _fooRepo = fooRepo;    }    private readonly IFooRepository _fooRepo;    public Foo GetMeFoo()    {       return _fooRepo.FooFromDatabase();    } } When we need the FooService, we ask the dependency container to get it for us. It says, "You'll need an IFooRepository in that, so let me see what that's mapped to, and put it in there for you." Why is this good for you? It's good because your FooService doesn't know or care about how you get some foo. You can stub out what the methods and properties on a fake IFooRepository might return, and test just the FooService. I don't want to get too far into unit testing, but it's the most commonly cited reason to use DI containers in MVC. What I wanted to mention is how there's another benefit in a project like mine, where I have to glue together a bunch of stuff. For example, when I have someone sign up for a new account on CoasterBuzz, I'm actually using POP Forums' new account mailer, which composes a bunch of text that includes a link to verify your account. The thing is, I want to use custom text and some other logic that's specific to CoasterBuzz. To accomplish this, I make a new class that inherits from the forum's NewAccountMailer, and override some stuff. Easy enough. Then I use Ninject, the DI container I'm using, to unbind the forum's implementation, and substitute my own. Ninject uses something called a NinjectModule to bind interfaces to concrete implementations. The forum has its own module, and then the CoasterBuzz module is loaded second. The CB module has two lines of code to swap out the mailer implementation: Unbind<PopForums.Email.INewAccountMailer>(); Bind<PopForums.Email.INewAccountMailer>().To<CbNewAccountMailer>(); Piece of cake! Now, when code asks the DI container for an INewAccountMailer, it gets my custom implementation instead. This is a lot easier to deal with than some of the alternatives. I could do some copy-paste, but then I'm not using well-tested code from the forum. I could write stuff from scratch, but then I'm throwing away a bunch of logic I've already written (in this case, stuff around e-mail, e-mail settings, mail delivery failures). There are other places where the DI container comes in handy. For example, CoasterBuzz does a number of custom things with user profiles, and special content for paid members. It uses the forum as the core piece to managing users, so I can ask the container to get me instances of classes that do user lookups, for example, and have zero care about how the forum handles database calls, configuration, etc. What a great world to live in, compared to ten years ago. Sure, the primary interest in DI is around the "separation of concerns" and facilitating unit testing, but as your library grows and you use more open source, it starts to be the glue that pulls everything together.

    Read the article

  • Think before you animate

    - by David Paquette
    Animations are becoming more and more common in our applications.  With technologies like WPF, Silverlight and jQuery, animations are becoming easier for developers to use (and abuse).  When used properly, animation can augment the user experience.  When used improperly, animation can degrade the user experience.  Sometimes, the differences can be very subtle. I have recently made use of animations in a few projects and I very quickly realized how easy it is to abuse animation techniques.  Here are a few things I have learned along the way. 1) Don’t animate for the sake of animating We’ve all seen the PowerPoint slides with annoying slide transitions that animate 20 different ways.  It’s distracting and tacky.  The same holds true for your application.  While animations are fun and becoming easy to implement, resist the urge to use the technology just because you think the technology is amazing.   2) Animations should (and do) have meaning I recently built a simple Windows Phone 7 (WP7) application, Steeped (download it here).  The application has 2 pages.  The first page lists a number of tea types.  When the user taps on one of the tea types, the application navigates to the second page with information about that tea type and some options for the user to choose from.       One of the last things I did before submitting Steeped to the marketplace was add a page transition between the 2 pages.  I choose the Slide / Fade Out transition.  When the user selects a tea type, the main page slides to the left and fades out.  At the same time, the details page slides in from the right and fades in.  I tested it and thought it looked great so I submitted the app.  A few days later, I asked a friend to try the app.  He selected a tea type, and I was a little surprised by how he used the app.  When he wanted to navigate back to the main page, instead of pressing the back button on the phone, he tried to use a swiping gesture.  Of course, the swiping gesture did nothing because I had not implemented that feature.  After thinking about it for a while, I realized that the page transition I had chosen implied a particular behaviour.  As a user, if an action I perform causes an item (in this case the page) to move, then my expectation is that I should be able to move it back.  I have since added logic to handle the swipe gesture and I think the app flows much better now. When using animation, it pays to ask yourself:  What story does this animation tell my users?   3) Watch the replay Some animations might seem great initially but can get annoying over time.  When you use an animation in your application, make sure you try using it over and over again to make sure it doesn’t get annoying.  When I add an animation, I try watch it at least 25 times in a row.  After watching the animation repeatedly, I can make a more informed decision whether or not I should keep the animation.  Often, I end up shortening the length of the animations.   4) Don’t get in the users way An animation should never slow the user down.  When implemented properly, an animation can give a perceived bump in performance.  A good example of this is a the page transitions in most of the built in apps on WP7.  Obviously, these page animations don’t make the phone any faster, but they do provide a more responsive user experience.  Why?  Because most of the animations begin as soon as the user has performed some action.  The destination page might not be fully loaded yet, but the system responded immediately to user action, giving the impression that the system is more responsive.  If the user did not see anything happen until after the destination page was fully loaded, the application would feel clumsy and slow.  Also, it is important to make sure the animation does not degrade the performance (or perceived performance) of the application.   Jut a few things to consider when using animations.  As is the case with many technologies, we often learn how to misuse it before we learn how to use it effectively.

    Read the article

< Previous Page | 618 619 620 621 622 623 624 625 626 627 628 629  | Next Page >