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  • When open-sourcing a live Rails app, is it dangerous to leave the session key secret in source contr

    - by rspeicher
    I've got a Rails app that's been running live for some time, and I'm planning to open source it in the near future. I'm wondering how dangerous it is to leave the session key store secret in source control while the app is live. If it's dangerous, how do people usually handle this problem? I'd guess that it's easiest to just move the string to a text file that's ignored by the SCM, and read it in later. Just for clarity, I'm talking about this: # Your secret key for verifying cookie session data integrity. # If you change this key, all old sessions will become invalid! # Make sure the secret is at least 30 characters and all random, # no regular words or you'll be exposed to dictionary attacks. ActionController::Base.session = { :key => '_application_session', :secret => '(long, unique string)' } And while we're on the subject, is there anything else in a default Rails app that should be protected when open sourcing a live app?

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  • Need help on understanding Mobile First concept

    - by RhymeGuy
    So, I worked on responsive sites before but I'm on my way to build my first responsive site now. I opened some articles on the subject, and boom: Mobile First.. I have no idea how I skipped that concept till now. From the beginning I cant seem to understand whole thing (except that number of mobile devices will take out soon desktop computers) and here is why. How I'm supposed to know how my site will look for desktop version, if I design it for mobile first? I mean, on the smallest device I will have to eventually hide some content etc, how I'm supposed to know what to hide and move things, when I don't know how the site will look on bigger screen? Isn't stripping the things easier?!?! For me (right now), the Mobile First concept looks to me like building pyramid upside down.

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  • Easiest way to keep SSRS child elements in the same relative position when the parent is re-positioned?

    - by Mac
    I am trying to revise the layout of an SSRS report where I have several textboxes that are child elements of a rectangle. When I reposition the parent rectangle down by x, all of the child textboxes maintain the same absolute position. Their "Location" (defined relative to the parent) decreases by x. I then need to reposition the child textboxes. Additionally, if any of these ever has a negative "Location" then the parent rectangle is then repositioned back up by x. What is the easiest way to move everything in unison? I can Control-click everything and then drag them or use the arrow keys, but I want to position everything with precision and the "Location" field in the Properties window disappears when selecting more than one item. Is there a way I can avoid individually computing and typing in every "Location" value every time I have a small layout change? I am using SSRS (11.0.3360.12) within the Visual Studio 2012 Shell. Thanks!

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  • Neural network for aproximation function for board game

    - by Pax0r
    I am trying to make a neural network for aproximation of some unkown function (for my neural network course). The problem is that this function has very many variables but many of them are not important (for example in [f(x,y,z) = x+y] z is not important). How could I design (and learn) network for this kind of problem? To be more specific the function is an evaluation function for some board game with unkown rules and I need to somehow learn this rules by experience of the agent. After each move the score is given to the agent so actually it needs to find how to get max score. I tried to pass the neighborhood of the agent to the network but there are too many variables which are not important for the score and agent is finding very local solutions.

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  • how do I repaint an applet while moving a sprite?

    - by Nagrom_17
    I have a little java applet where I create 2 threads, one thread repaints and the other moves an image from a point to where the user clicks. The problem is that when I call the move function it loops until the image is where the user clicks but it wont repaint until I break out of the loop even though the thread doing the moving and the thread doing the painting are separate. shortened version of key points: my program is an applet using the paint() method I have 2 threads one moves an image and the other paints that image when I am moving the image it is in a while loop the painting thread is still calling repaint() but that is as far as the call goes, it never repaints thank you for your time.

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  • Create ordering in a MySQL table without using a number (because then it's hard to put something in

    - by user347256
    I have a long list of items (say, a few million items) in a mysql table, let's call it mytable and it has the field mytable.itemid. The items are given an order, and can be re=ordered by the user by drag and drop. If I add a field called mytable.order and just put numbers in them, it creates problems: what if I want to move an item between 2 other items? Then all the order fields have to be updated? That seems like a nightmare. Is there a (scalable) way to add order to a table that is different from just giving every item a number, order by that, and do loads of SQL queries everytime the order is changed?

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  • Copying just the data from one Database to another

    - by monksy
    I'm not sure if this is the site for this question or not [if so put in the comment or vote to move it] How can I copy only the data from one database to another within the same server on SQL Server 2005? The two databases have the same schema but not the same data. I'm trying to get the data from one database to another. I am not able to restore from a snapshot [that screws over the security settings on the database]. I'm not able to use the import data wizard, because that is trying to copy over schema data as well.

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  • I am requesting ideas on manipulating output from an array and parse to something useful

    - by Cyber Demon
    First I am new to PS scripting. Please be gentle. This simple script I have written is ok. $Iplist = Get-Content ips.txt foreach ($ip in $Iplist) { .\psping -h -n 3 -w 0 $ip >> results.csv } Move-Item "C:\ping\results.csv" ("C:\ping\aftermath\{0:yyyyMMddhhmm}.csv" -f (get-date)) The Output is as follows, as an example (I used www.google.com): Pinging 74.125.225.48 with 32 bytes of data: 3 iterations (warmup 0) ping test: Reply from 74.125.225.48: 54.14ms Reply from 74.125.225.48: 54.85ms Reply from 74.125.225.48: 54.48ms Ping statistics for 74.125.225.48: Sent = 3, Received = 3, Lost = 0 (0% loss), Minimum = 54.14ms, Maximum = 54.85ms, Average = 54.49ms Latency Count 54.14 1 54.17 0 54.21 0 54.25 0 54.29 0 54.32 0 54.36 0 54.4 0 54.44 0 54.47 1 54.51 0 54.55 0 54.59 0 54.62 0 54.66 0 54.7 0 54.74 0 54.77 0 54.81 0 54.85 1 What I'm looking for is something to show me the following as an output. ServerIP Name TimeStamp Results AverageResponseTime in milli-seconds www.google.com 2014-08-14T16:09:59 Up 53 Can you guide me?

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  • My company is a Rackspace Cloud client (provided to us for free) and I'm trying to find some way to set up version control

    - by Nick S.
    As the title says, my (small) business is provided a free Rackspace Cloud client account. We receive a decent amount of traffic but I haven't been able to put together a business case to move to our own server yet. However, we are developing some complex apps and I'm frustrated with not having the ability to even ssh into the remote server. Ultimately, I'd like to set up some sort of version control (at this point, I'll take anything, git or otherwise). I have control over databases, can FTP, set up cron jobs, and perform a few other basic functions. I can't think of any way to set up git or something similar without ssh access. A thought went through my mind that maybe some sort of PHP version control exists that I might be able to set up, but I haven't had any luck finding it yet. Do you guys have any ideas, thoughts, or advice?

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  • Path of the local directory

    - by Jayesh
    Hi, A rather simple question; how to find the path of the local directory in which my exe is placed? As-in I have an .exe and in the program I have to create a txt file in the directory where the exe is! [language - C#] So, if the exe is in C:/Temp and is started from there; my txt should be created in C:/Temp If the user wishes to move the exe to D:/Temp and runs from there; I should be able to create the txt file in D:/Temp I tried the Directory.GetCurrentDirectory() but that returns the directory of the execution of the program!

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  • Moving an item up and down in a WPF list box

    - by DommyCastles
    I have a list box with a bunch of values in it. I also have an UP button and a DOWN button. With these buttons, I would like to move the selected item in the list box up/down. I am having trouble doing this. Here is my code so far: private void btnDataUp_Click(object sender, RoutedEventArgs e) { int selectedIndex = listBoxDatasetValues.SelectedIndex; //get the selected item in the data list if (selectedIndex != -1 && selectedIndex != 0) //if the selected item is selected and not at the top of the list { //swap items here listBoxDatasetValues.SelectedIndex = selectedIndex - 1; //keep the item selected } } I do not know how to swap the values! Any help would be GREATLY appreciated!

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  • Using PHP OCI8 with 32-bit PHP on Windows 64-bit

    - by christopher.jones
    The world migration from 32-bit to 64-bit operating systems is gaining pace. However I've seen a couple of customers having difficulty with the PHP OCI8 extension and Oracle DB on Windows 64-bit platforms. The errors vary depending how PHP is run. They may appear in the Apache or PHP log: Unable to load dynamic library 'C:\Program Files (x86)\PHP\ext\php_oci8_11g.dll' - %1 is not a valid Win32 application. or Warning oci_connect(): OCIEnvNlsCreate() failed. There is something wrong with your system - please check that PATH includes the directory with Oracle Instant Client libraries Other than IIS permission issues a common cause seems to be trying to use PHP with libraries from an Oracle 64-bit database on the same machine. There is currently no 64-bit version of PHP on http://php.net/ so there is a library mismatch. A solution is to install Oracle Instant Client 32-bit and make sure that PHP uses these libraries, while not interferring with the 64-bit database on the same machine. Warning: The following hacky steps come untested from a Linux user: Unzip Oracle Instant Client 32-bit and move it to C:\WINDOWS\SYSWOW64\INSTANTCLIENT_11_2. You may need to do this in a console with elevated permissions. Edit your PATH environment variable and insert C:\WINDOWS\SYSTEM32\INSTANTCLIENT_11_2 in the directory list before the entry for the Oracle Home library. Windows makes it so all 32-bit applications that reference C:\WINDOWS\SYSTEM32 actually see the contents of the C:\WINDOWS\SYSWOW64 directory. Your 64-bit database won't find an Instant Client in the real, physical C:\WINDOWS\SYSTEM32 directory and will continue to use the database libraries. Some of our Windows team are concerned about this hack and prefer a more "correct" solution that (i) doesn't require changing the Windows system directory (ii) doesn't add to the "memory" burden about what was configured on the system (iii) works when there are multiple database versions installed. The solution is to write a script which will set the 64-bit (or 32-bit) Oracle libraries in the path as needed before invoking the relevant bit-ness application. This does have a weakness when the application is started as a service. As a footnote: If you don't have a local database and simply need to have 32-bit and 64-bit Instant Client accessible at the same time, try the "symbolic" link approach covered in the hack in this OTN forum thread. Reminder warning: This blog post came untested from a Linux user.

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  • Visual Studio 2010 SP1 Beta supports IIS Express

    - by DigiMortal
    Visual Studio 2010 SP1 Beta and ASP.NET MVC 3 RC2 were both announced today. I made a little test on one of my web applications to see how Visual Studio 2010 works with IIS Express. In this posting I will show you how to make your ASP.NET MVC 3 application work with IIS Express. Installing new stuff You can install IIS Express using Web Platform Installer. It is not part of WebMatrix anymore and you can just install IIS Express without WebMatrix. NB! You have to install IIS Express using Web Platform installer because IIS Express is not installed by SP1. After installing Visual Studio 2010 SP1 Beta on my machine (it took a long-long-long time to install) I installed also ASP.NET MVC 3 RC2. If you have Async CTP installed on your machine you have to uninstall it to get ASP.NET MVC 3 RC2 installed and run without problems. Screenshot on right shows what kinf of horrors my old laptop had to survive to get all new stuff installer. Setting IIS Express as server for web application Now, when you right-click on some web project you should see new menu item in context menu – Use IIS Express…. If you click on it you are asked for confirmation and if you say Yes then your web application is reconfigured to use IIS Express. After configuration you will see dialog box like this. And you are done. You can run your application now. Running web application When you run your application it is run on IIS Express. You can see IIS Express icon on taskbar and when you click it you can open IIS Express settings. If you closed your application in browser you can open it again from IIS Express icon. Modifying IIS Express settings for web application You can modify IIS Express settings for your application. Just open your project properties and move to Web tab. IIS and IIS Express are using same settings. The difference is if you make check to Use IIS Express checkbox or not. Switching back to Visual Studio Development Server If you don’t want or you can’t use IIS Express for some reason you can easily switch back to Visual Studio Development Server. Just right-click on your web application project and select Use Visual Studio Development Server from context menu. Conclusion IIS Express is more independent than full version of IIS and it can be also installed and run on machines where are very strict rules (some corporate and academic environments by example). IIS Express was previously part of WebMatrix package but now it is separate product and Visual Studio 2010 has very nice support for it thanks to SP1. You can easily make your web applications use IIS Express and if you want to switch back to development server it is also very easy.

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  • Grounded in Dublin

    - by Mike Dietrich
    Friday's hands-on workshop in the Oracle office in Dublin was quite good fun for everybody - except for Mick who has just recognized that his Ryanair flight back to Cork has been canceled (So I hope you've returned home well!) and me as my flights back to Munich via London City had been canceled as well. It's always good to have somebody in the workshop from Air Lingus so I've got hourly information what's going in in the Irish airspace (and now I know that the system dealing with such situations is an well prepared Oracle database which runs just like a switch watch - Thanks again for all your support!!! Was great to talk to you!!!). But to be honest, there are worse places to be grounded for a few days than Dublin. At least it gave me the chance to do something which I never had time enough before when visiting Oracle Ireland: a bit of sightseeing. When I've realized that nothing seems to move over the weekend I started organizing my travel back yesterday. It was no fun at all because there's no single system to book such a travel. Figuring out all possibilities and options going back to Munich was the first challange. Irish Ferries webpage was moaning with all the unexpected load (currently it's fully down). Hotel booking websites showed vacancies in Holyhead but didn't let me book. And calling them just reveiled that there are no rooms left. Haven't stayed overnight in a train station for quite a while ;-) The website of VirginTrains puzzled me with offering a seat at an enormous price for a train ride from Holyhead to London Euston (Thanks, Sir Richard Branson!) just to tell me after I booked a ticket that there are no seats left (but I traveled German railsways a few weeks ago from Düsseldorf to Frankfurt sitting on the floor as well). Eurostar's website let me choose tickets through the tunnel to tell me in the final step that the ticket cannot be confirmed as there are no seats left - but the next check again showed bookable seats - must be a database from some other vendor which has no proper row level locking ... hm ...?! Finally the TGV page for the speed train to Stuttgart and then the ICE to Munich was not allowing searches for quite a while - but ultimately ... after 4.5 hours of searching, waiting, sending credit card information again and again ... So if you have a few spare fingers please keep them crossed :-) And good luck to all my colleagues traveling back from the Exadata training in Berlin. As Mike Appleyard, my colleague from the UK presales team wrote: "Dublin and Berlin aren't too bad a place to get stuck... ;-)"

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  • Forbes Announcing The World’s Top 20 Billionaires

    - by Suganya
    Forbes company recently conducted a survey to figure out the world’s Billionaires list and has released it listing the top 20 names of the Billionaires. The company says that for the third time in the last three years the world has a new richest man for this year. So it means that Bill Gates was beaten up by someone else in world. Who is the new richest man in the world?   Forbes.Com announced the richest man in world and this time it is not Bill Gates. But it is Carlos Slim Helu who is into Telecom industry. Carlos lives in Mexico and he had the third richest man’s place last year. Having shown a Net worth of $ 53.5 Billion, Carlos has increased $18.5 Billion in a year. Carlos swooped on the privatization of Mexico’s national telephone service during the last decade and now has achieved the world’s first richest man. Following Carlos, in the second position is Bill Gates with the Nett worth of $53 Billion. As Bill Gates requires no great introduction, lets move on to the next place. The third place is occupied by Warren Buffett followed by Mukesh Ambani and Lakshmi Mittal in fourth and fifth places respectively. The top 20 names of world’s richest people, their occupation and the Nett worth that they hold are S.No Name Nett Worth (in $ Billion) Source of Income 1 Carlos Slim Helu 53.5 Telecom 2 Bill Gates 53 Microsoft 3 Warren Buffett 47 Investments 4 Mukesh Ambani 29 Petrochemical, Oil and Gas 5 Lakshmi Mittal 28.7 Steel 6 Lawrence Ellison 28 Oracle 7 Bernard Arnault 27.5 Luxury Goods 8 Eike Batista 27 Mining, Oil 9 Amancio Ortega 25 Fashion, Retail 10 Karl Albrecht 23.5 Supermarkets 11 Ingvar Kamprad and Family 23 IKEA 12 Christy Walton and Family 22.5 Wal-Mart 13 Stefan Persson 22.4 H & M 14 Li Ka-shing 21 Diversified 15 Jim C. Walton 20.7 Wal-Mart 16 Alice Walton 20.6 Wal-Mart 17 Liliane Bettencourt 20 L’Oreal 18 S. Robson Walton 19.8 Wal-Mart 19 Prince Alwaleed bin Talal Alsaud 19.4 Diversified 20 David Thomson and Family 19 Thomson Reuters   Source: Forbes and Image Credit : kevindooley Join us on Facebook to read all our stories right inside your Facebook news feed.

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  • The best, in the West

    - by Fatherjack
    As many of you know, I run the SQL South West user group and we are currently in full flow preparing to stage the UK’s second SQL Saturday. The SQL Saturday spotlight is going to fall on Exeter in March 2013. We have full-day session on Friday 8th with some truly amazing speakers giving their insights and experience into some vital areas of working with SQL Server: Dave Ballantyne and Dave Morrison – TSQL and internals Christian Bolton and Gavin Payne – Mission critical data platforms on Windows Server 2012 Denny Cherry – SQL Server Security André Kamman – Powershell 3.0 for SQL Server Administrators and Developers Mladen Prajdic – From SQL Traces to Extended Events – The next big switch. A number of people have claimed that the choice is too good and they’d have trouble selecting just one session to attend. I can see how this is a problem but hope that they make their minds up quickly. The venue is a bespoke conference suite in the centre of Exeter but has limited capacity so we are working on a first-come first-served basis. All the session details and booking and travel information can be found on our user group website. The Saturday will be a day of free, 50 minute sessions on all aspects SQL Server from almost 30 different speakers. If you would like to submit a session then get a move on as submissions close on 8th January 2013 (That’s less than a month away). We are really interested in getting new speakers started so we have a lightning talk session where you can come along and give a small talk (anywhere from 5 to 15 minutes long) about anything connected with SQL Server as a way to introduce you to what it’s like to be a speaker at an event. Details on registering to attend and to submit a session (Lightning talks need to be submitted too please) can be found on our SQL Saturday pages. This is going to be the biggest and best bespoke SQL Server conference to ever take place this far South West in the UK and we aim to give everyone who comes to either day a real experience of the South West so we have a few surprises for you on the day.

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  • Older SAS1 hardware Vs. newer SAS2 hardware

    - by user12620172
    I got a question today from someone asking about the older SAS1 hardware from over a year ago that we had on the older 7x10 series. They didn't leave an email so I couldn't respond directly, but I said this blog would be blunt, frank, and open so I have no problem addressing it publicly. A quick history lesson here: When Sun first put out the 7x10 family hardware, the 7410 and 7310 used a SAS1 backend connection to a JBOD that had SATA drives in it. This JBOD was not manufactured by Sun nor did Sun own the IP for it. Now, when Oracle took over, they had a problem with that, and I really can’t blame them. The decision was made to cut off that JBOD and it’s manufacturer completely and use our own where Oracle controlled both the IP and the manufacturing. So in the summer of 2010, the cut was made, and the 7410 and 7310 had a hardware refresh and now had a SAS2 backend going to a SAS2 JBOD with SAS2 drives instead of SATA. This new hardware had two big advantages. First, there was a nice performance increase, mostly due to the faster backend. Even better, the SAS2 interface on the drives allowed for a MUCH faster failover between cluster heads, as the SATA drives were the bottleneck on the older hardware. In September of 2010 there was a major refresh of the rest of the 7000 hardware, the controllers and the other family members, and that’s where we got today’s current line-up of the 7x20 series. So the 7x20 has always used the new trays, and the 7410 and 7310 have used the new SAS2 trays since last July of 2010. Now for the bad news. People who have the 7410 and 7310 from BEFORE the July 2010 cutoff have the models with SAS1 HBAs in them to connect to the older SAS1 trays. Remember, that manufacturer cut all ties with us and stopped making the JBOD, so there’s just no way to get more of them, as they don’t exist. There are some options, however. Oracle support does support taking out the SAS1 HBAs in the old 7410 and 7310 and put in newer SAS2 HBAs which can talk to the new trays. Hey, I didn’t say it was a great option, I just said it’s an option. I fully realize that you would then have a SAS1 JBOD full of SATA drives that you could no longer connect. I do know a client that did this, and took the SAS1 JBOD and connected it to another server and formatted the drives and is using it as a plain, non-7000 JBOD. This is not supported by Oracle support. The other option is to just keep it as-is, as it works just fine, but you just can’t expand it. Then you can get a newer 7x20 series, and use the built-in ZFSSA replication feature to move the data over. Now you can use the newer one for your production data and use the older one for DR, snaps and clones.

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  • Toorcon14

    - by danx
    Toorcon 2012 Information Security Conference San Diego, CA, http://www.toorcon.org/ Dan Anderson, October 2012 It's almost Halloween, and we all know what that means—yes, of course, it's time for another Toorcon Conference! Toorcon is an annual conference for people interested in computer security. This includes the whole range of hackers, computer hobbyists, professionals, security consultants, press, law enforcement, prosecutors, FBI, etc. We're at Toorcon 14—see earlier blogs for some of the previous Toorcon's I've attended (back to 2003). This year's "con" was held at the Westin on Broadway in downtown San Diego, California. The following are not necessarily my views—I'm just the messenger—although I could have misquoted or misparaphrased the speakers. Also, I only reviewed some of the talks, below, which I attended and interested me. MalAndroid—the Crux of Android Infections, Aditya K. Sood Programming Weird Machines with ELF Metadata, Rebecca "bx" Shapiro Privacy at the Handset: New FCC Rules?, Valkyrie Hacking Measured Boot and UEFI, Dan Griffin You Can't Buy Security: Building the Open Source InfoSec Program, Boris Sverdlik What Journalists Want: The Investigative Reporters' Perspective on Hacking, Dave Maas & Jason Leopold Accessibility and Security, Anna Shubina Stop Patching, for Stronger PCI Compliance, Adam Brand McAfee Secure & Trustmarks — a Hacker's Best Friend, Jay James & Shane MacDougall MalAndroid—the Crux of Android Infections Aditya K. Sood, IOActive, Michigan State PhD candidate Aditya talked about Android smartphone malware. There's a lot of old Android software out there—over 50% Gingerbread (2.3.x)—and most have unpatched vulnerabilities. Of 9 Android vulnerabilities, 8 have known exploits (such as the old Gingerbread Global Object Table exploit). Android protection includes sandboxing, security scanner, app permissions, and screened Android app market. The Android permission checker has fine-grain resource control, policy enforcement. Android static analysis also includes a static analysis app checker (bouncer), and a vulnerablity checker. What security problems does Android have? User-centric security, which depends on the user to grant permission and make smart decisions. But users don't care or think about malware (the're not aware, not paranoid). All they want is functionality, extensibility, mobility Android had no "proper" encryption before Android 3.0 No built-in protection against social engineering and web tricks Alternative Android app markets are unsafe. Simply visiting some markets can infect Android Aditya classified Android Malware types as: Type A—Apps. These interact with the Android app framework. For example, a fake Netflix app. Or Android Gold Dream (game), which uploads user files stealthy manner to a remote location. Type K—Kernel. Exploits underlying Linux libraries or kernel Type H—Hybrid. These use multiple layers (app framework, libraries, kernel). These are most commonly used by Android botnets, which are popular with Chinese botnet authors What are the threats from Android malware? These incude leak info (contacts), banking fraud, corporate network attacks, malware advertising, malware "Hackivism" (the promotion of social causes. For example, promiting specific leaders of the Tunisian or Iranian revolutions. Android malware is frequently "masquerated". That is, repackaged inside a legit app with malware. To avoid detection, the hidden malware is not unwrapped until runtime. The malware payload can be hidden in, for example, PNG files. Less common are Android bootkits—there's not many around. What they do is hijack the Android init framework—alteering system programs and daemons, then deletes itself. For example, the DKF Bootkit (China). Android App Problems: no code signing! all self-signed native code execution permission sandbox — all or none alternate market places no robust Android malware detection at network level delayed patch process Programming Weird Machines with ELF Metadata Rebecca "bx" Shapiro, Dartmouth College, NH https://github.com/bx/elf-bf-tools @bxsays on twitter Definitions. "ELF" is an executable file format used in linking and loading executables (on UNIX/Linux-class machines). "Weird machine" uses undocumented computation sources (I think of them as unintended virtual machines). Some examples of "weird machines" are those that: return to weird location, does SQL injection, corrupts the heap. Bx then talked about using ELF metadata as (an uintended) "weird machine". Some ELF background: A compiler takes source code and generates a ELF object file (hello.o). A static linker makes an ELF executable from the object file. A runtime linker and loader takes ELF executable and loads and relocates it in memory. The ELF file has symbols to relocate functions and variables. ELF has two relocation tables—one at link time and another one at loading time: .rela.dyn (link time) and .dynsym (dynamic table). GOT: Global Offset Table of addresses for dynamically-linked functions. PLT: Procedure Linkage Tables—works with GOT. The memory layout of a process (not the ELF file) is, in order: program (+ heap), dynamic libraries, libc, ld.so, stack (which includes the dynamic table loaded into memory) For ELF, the "weird machine" is found and exploited in the loader. ELF can be crafted for executing viruses, by tricking runtime into executing interpreted "code" in the ELF symbol table. One can inject parasitic "code" without modifying the actual ELF code portions. Think of the ELF symbol table as an "assembly language" interpreter. It has these elements: instructions: Add, move, jump if not 0 (jnz) Think of symbol table entries as "registers" symbol table value is "contents" immediate values are constants direct values are addresses (e.g., 0xdeadbeef) move instruction: is a relocation table entry add instruction: relocation table "addend" entry jnz instruction: takes multiple relocation table entries The ELF weird machine exploits the loader by relocating relocation table entries. The loader will go on forever until told to stop. It stores state on stack at "end" and uses IFUNC table entries (containing function pointer address). The ELF weird machine, called "Brainfu*k" (BF) has: 8 instructions: pointer inc, dec, inc indirect, dec indirect, jump forward, jump backward, print. Three registers - 3 registers Bx showed example BF source code that implemented a Turing machine printing "hello, world". More interesting was the next demo, where bx modified ping. Ping runs suid as root, but quickly drops privilege. BF modified the loader to disable the library function call dropping privilege, so it remained as root. Then BF modified the ping -t argument to execute the -t filename as root. It's best to show what this modified ping does with an example: $ whoami bx $ ping localhost -t backdoor.sh # executes backdoor $ whoami root $ The modified code increased from 285948 bytes to 290209 bytes. A BF tool compiles "executable" by modifying the symbol table in an existing ELF executable. The tool modifies .dynsym and .rela.dyn table, but not code or data. Privacy at the Handset: New FCC Rules? "Valkyrie" (Christie Dudley, Santa Clara Law JD candidate) Valkyrie talked about mobile handset privacy. Some background: Senator Franken (also a comedian) became alarmed about CarrierIQ, where the carriers track their customers. Franken asked the FCC to find out what obligations carriers think they have to protect privacy. The carriers' response was that they are doing just fine with self-regulation—no worries! Carriers need to collect data, such as missed calls, to maintain network quality. But carriers also sell data for marketing. Verizon sells customer data and enables this with a narrow privacy policy (only 1 month to opt out, with difficulties). The data sold is not individually identifiable and is aggregated. But Verizon recommends, as an aggregation workaround to "recollate" data to other databases to identify customers indirectly. The FCC has regulated telephone privacy since 1934 and mobile network privacy since 2007. Also, the carriers say mobile phone privacy is a FTC responsibility (not FCC). FTC is trying to improve mobile app privacy, but FTC has no authority over carrier / customer relationships. As a side note, Apple iPhones are unique as carriers have extra control over iPhones they don't have with other smartphones. As a result iPhones may be more regulated. Who are the consumer advocates? Everyone knows EFF, but EPIC (Electrnic Privacy Info Center), although more obsecure, is more relevant. What to do? Carriers must be accountable. Opt-in and opt-out at any time. Carriers need incentive to grant users control for those who want it, by holding them liable and responsible for breeches on their clock. Location information should be added current CPNI privacy protection, and require "Pen/trap" judicial order to obtain (and would still be a lower standard than 4th Amendment). Politics are on a pro-privacy swing now, with many senators and the Whitehouse. There will probably be new regulation soon, and enforcement will be a problem, but consumers will still have some benefit. Hacking Measured Boot and UEFI Dan Griffin, JWSecure, Inc., Seattle, @JWSdan Dan talked about hacking measured UEFI boot. First some terms: UEFI is a boot technology that is replacing BIOS (has whitelisting and blacklisting). UEFI protects devices against rootkits. TPM - hardware security device to store hashs and hardware-protected keys "secure boot" can control at firmware level what boot images can boot "measured boot" OS feature that tracks hashes (from BIOS, boot loader, krnel, early drivers). "remote attestation" allows remote validation and control based on policy on a remote attestation server. Microsoft pushing TPM (Windows 8 required), but Google is not. Intel TianoCore is the only open source for UEFI. Dan has Measured Boot Tool at http://mbt.codeplex.com/ with a demo where you can also view TPM data. TPM support already on enterprise-class machines. UEFI Weaknesses. UEFI toolkits are evolving rapidly, but UEFI has weaknesses: assume user is an ally trust TPM implicitly, and attached to computer hibernate file is unprotected (disk encryption protects against this) protection migrating from hardware to firmware delays in patching and whitelist updates will UEFI really be adopted by the mainstream (smartphone hardware support, bank support, apathetic consumer support) You Can't Buy Security: Building the Open Source InfoSec Program Boris Sverdlik, ISDPodcast.com co-host Boris talked about problems typical with current security audits. "IT Security" is an oxymoron—IT exists to enable buiness, uptime, utilization, reporting, but don't care about security—IT has conflict of interest. There's no Magic Bullet ("blinky box"), no one-size-fits-all solution (e.g., Intrusion Detection Systems (IDSs)). Regulations don't make you secure. The cloud is not secure (because of shared data and admin access). Defense and pen testing is not sexy. Auditors are not solution (security not a checklist)—what's needed is experience and adaptability—need soft skills. Step 1: First thing is to Google and learn the company end-to-end before you start. Get to know the management team (not IT team), meet as many people as you can. Don't use arbitrary values such as CISSP scores. Quantitive risk assessment is a myth (e.g. AV*EF-SLE). Learn different Business Units, legal/regulatory obligations, learn the business and where the money is made, verify company is protected from script kiddies (easy), learn sensitive information (IP, internal use only), and start with low-hanging fruit (customer service reps and social engineering). Step 2: Policies. Keep policies short and relevant. Generic SANS "security" boilerplate policies don't make sense and are not followed. Focus on acceptable use, data usage, communications, physical security. Step 3: Implementation: keep it simple stupid. Open source, although useful, is not free (implementation cost). Access controls with authentication & authorization for local and remote access. MS Windows has it, otherwise use OpenLDAP, OpenIAM, etc. Application security Everyone tries to reinvent the wheel—use existing static analysis tools. Review high-risk apps and major revisions. Don't run different risk level apps on same system. Assume host/client compromised and use app-level security control. Network security VLAN != segregated because there's too many workarounds. Use explicit firwall rules, active and passive network monitoring (snort is free), disallow end user access to production environment, have a proxy instead of direct Internet access. Also, SSL certificates are not good two-factor auth and SSL does not mean "safe." Operational Controls Have change, patch, asset, & vulnerability management (OSSI is free). For change management, always review code before pushing to production For logging, have centralized security logging for business-critical systems, separate security logging from administrative/IT logging, and lock down log (as it has everything). Monitor with OSSIM (open source). Use intrusion detection, but not just to fulfill a checkbox: build rules from a whitelist perspective (snort). OSSEC has 95% of what you need. Vulnerability management is a QA function when done right: OpenVas and Seccubus are free. Security awareness The reality is users will always click everything. Build real awareness, not compliance driven checkbox, and have it integrated into the culture. Pen test by crowd sourcing—test with logging COSSP http://www.cossp.org/ - Comprehensive Open Source Security Project What Journalists Want: The Investigative Reporters' Perspective on Hacking Dave Maas, San Diego CityBeat Jason Leopold, Truthout.org The difference between hackers and investigative journalists: For hackers, the motivation varies, but method is same, technological specialties. For investigative journalists, it's about one thing—The Story, and they need broad info-gathering skills. J-School in 60 Seconds: Generic formula: Person or issue of pubic interest, new info, or angle. Generic criteria: proximity, prominence, timeliness, human interest, oddity, or consequence. Media awareness of hackers and trends: journalists becoming extremely aware of hackers with congressional debates (privacy, data breaches), demand for data-mining Journalists, use of coding and web development for Journalists, and Journalists busted for hacking (Murdock). Info gathering by investigative journalists include Public records laws. Federal Freedom of Information Act (FOIA) is good, but slow. California Public Records Act is a lot stronger. FOIA takes forever because of foot-dragging—it helps to be specific. Often need to sue (especially FBI). CPRA is faster, and requests can be vague. Dumps and leaks (a la Wikileaks) Journalists want: leads, protecting ourselves, our sources, and adapting tools for news gathering (Google hacking). Anonomity is important to whistleblowers. They want no digital footprint left behind (e.g., email, web log). They don't trust encryption, want to feel safe and secure. Whistleblower laws are very weak—there's no upside for whistleblowers—they have to be very passionate to do it. Accessibility and Security or: How I Learned to Stop Worrying and Love the Halting Problem Anna Shubina, Dartmouth College Anna talked about how accessibility and security are related. Accessibility of digital content (not real world accessibility). mostly refers to blind users and screenreaders, for our purpose. Accessibility is about parsing documents, as are many security issues. "Rich" executable content causes accessibility to fail, and often causes security to fail. For example MS Word has executable format—it's not a document exchange format—more dangerous than PDF or HTML. Accessibility is often the first and maybe only sanity check with parsing. They have no choice because someone may want to read what you write. Google, for example, is very particular about web browser you use and are bad at supporting other browsers. Uses JavaScript instead of links, often requiring mouseover to display content. PDF is a security nightmare. Executible format, embedded flash, JavaScript, etc. 15 million lines of code. Google Chrome doesn't handle PDF correctly, causing several security bugs. PDF has an accessibility checker and PDF tagging, to help with accessibility. But no PDF checker checks for incorrect tags, untagged content, or validates lists or tables. None check executable content at all. The "Halting Problem" is: can one decide whether a program will ever stop? The answer, in general, is no (Rice's theorem). The same holds true for accessibility checkers. Language-theoretic Security says complicated data formats are hard to parse and cannot be solved due to the Halting Problem. W3C Web Accessibility Guidelines: "Perceivable, Operable, Understandable, Robust" Not much help though, except for "Robust", but here's some gems: * all information should be parsable (paraphrasing) * if not parsable, cannot be converted to alternate formats * maximize compatibility in new document formats Executible webpages are bad for security and accessibility. They say it's for a better web experience. But is it necessary to stuff web pages with JavaScript for a better experience? A good example is The Drudge Report—it has hand-written HTML with no JavaScript, yet drives a lot of web traffic due to good content. A bad example is Google News—hidden scrollbars, guessing user input. Solutions: Accessibility and security problems come from same source Expose "better user experience" myth Keep your corner of Internet parsable Remember "Halting Problem"—recognize false solutions (checking and verifying tools) Stop Patching, for Stronger PCI Compliance Adam Brand, protiviti @adamrbrand, http://www.picfun.com/ Adam talked about PCI compliance for retail sales. Take an example: for PCI compliance, 50% of Brian's time (a IT guy), 960 hours/year was spent patching POSs in 850 restaurants. Often applying some patches make no sense (like fixing a browser vulnerability on a server). "Scanner worship" is overuse of vulnerability scanners—it gives a warm and fuzzy and it's simple (red or green results—fix reds). Scanners give a false sense of security. In reality, breeches from missing patches are uncommon—more common problems are: default passwords, cleartext authentication, misconfiguration (firewall ports open). Patching Myths: Myth 1: install within 30 days of patch release (but PCI §6.1 allows a "risk-based approach" instead). Myth 2: vendor decides what's critical (also PCI §6.1). But §6.2 requires user ranking of vulnerabilities instead. Myth 3: scan and rescan until it passes. But PCI §11.2.1b says this applies only to high-risk vulnerabilities. Adam says good recommendations come from NIST 800-40. Instead use sane patching and focus on what's really important. From NIST 800-40: Proactive: Use a proactive vulnerability management process: use change control, configuration management, monitor file integrity. Monitor: start with NVD and other vulnerability alerts, not scanner results. Evaluate: public-facing system? workstation? internal server? (risk rank) Decide:on action and timeline Test: pre-test patches (stability, functionality, rollback) for change control Install: notify, change control, tickets McAfee Secure & Trustmarks — a Hacker's Best Friend Jay James, Shane MacDougall, Tactical Intelligence Inc., Canada "McAfee Secure Trustmark" is a website seal marketed by McAfee. A website gets this badge if they pass their remote scanning. The problem is a removal of trustmarks act as flags that you're vulnerable. Easy to view status change by viewing McAfee list on website or on Google. "Secure TrustGuard" is similar to McAfee. Jay and Shane wrote Perl scripts to gather sites from McAfee and search engines. If their certification image changes to a 1x1 pixel image, then they are longer certified. Their scripts take deltas of scans to see what changed daily. The bottom line is change in TrustGuard status is a flag for hackers to attack your site. Entire idea of seals is silly—you're raising a flag saying if you're vulnerable.

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  • WPF vs. WinForms - a Delphi programmer's perspective?

    - by Robert Oschler
    I have read most of the major threads on WPF vs. WinForms and I find myself stuck in the unfortunate ambivalence you can fall into when deciding between the tried and true previous tech (Winforms), and it's successor (WPF). I am a veteran Delphi programmer of many years that is finally making the jump to C#. My fellow Delphi programmers out there will understand that I am excited to know that Anders Hejlsberg, of Delphi fame, was the architect behind C#. I have a strong addiction to Delphi's VCL custom components, especially those involved in making multi-step Wizards and components that act as a container for child components. With that background, I am hoping that those of you that switched from Delphi to C# can help me with my WinForms vs. WPF decision for writing my initial applications. Note, I am very impatient when coding and things like full fledged auto-complete and proper debugger support can make or break a project for me, including being able to find readily available information on API features and calls and even more so, workarounds for bugs. The SO threads and comments in the early 2009 date range give me great concern over WPF when it comes to potential frustrations that could mar my C# UI development coding. On the other hand, spending an inordinate amount of time learning an API tech that is, even if it is not abandoned, soon to be replaced (WinForms), is equally troubling and I do find the GPU support in WPF tantalizing. Hence my ambivalence. Since I haven't learned either tech yet I have a rare opportunity to get a fresh start and not have to face the big "unlearning" curve I've seen people mention in various threads when a WinForms programmer makes the move to WPF. On the other hand, if using WPF will just be too frustrating or have other major negative consequences for an impatient RAD developer like myself, then I'll just stick with WinForms until WPF reaches the same level of support and ease of use. To give you a concrete example into my psychology as a programmer, I used VB and subsequently Delphi to completely avoid altogether the very real pain of coding with MFC, a Windows UI library that many developers suffered through while developing early Windows apps. I have never regretted my luck in avoiding MFC. It would also be comforting to know if Anders Hejlsberg had a hand in the architecture of WPF and/or WinForms, and if there are any disparities in the creative vision and ease of use embodied in either code base. Finally, for the Delphi programmers again, let me know how much "IDE schock" I'm in for when using WPF as opposed to WinForms, especially when it comes to debugger support. Any job market comments updated for 2011 would be appreciated too. -- roschler

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  • .NET Reflector Pro Coming…

    The very best software is almost always originally the creation of a single person. Readers of our 'Geek of the Week' will know of a few of them.  Even behemoths such as MS Word or Excel started out with one programmer.  There comes a time with any software that it starts to grow up, and has to move from this form of close parenting to being developed by a team.  This has happened several times within Red-Gate: SQL Refactor, SQL Compare, and SQL Dependency Tracker, not to mention SQL Backup, were all originally the work of a lone coder, who subsequently handed over the development to a structured team of programmers, test engineers and usability designers. Because we loved .NET Reflector when Lutz Roeder wrote and nurtured it, and, like many other .NET developers, used it as a development tool ourselves, .NET Reflector's progress from being the apple of Lutz's eye to being a Red-Gate team-based development  seemed natural.  Lutz, after all, eventually felt he couldn't afford the time to develop it to the extent it deserved. Why, then, did we want to take on .NET Reflector?  Different people may give you different answers, but for us in the .NET team, it just seemed a natural progression. We're always very surprised when anyone suggests that we want to change the nature of the tool since it seems right just as it is. .NET Reflector will stay very much the tool we all use and appreciate, although the new version will support .NET 4, and will have many improvements in the accuracy of its decompiling. Whilst we've made a lot of improvements to Reflector, the radical addition, which we hope you'll want to try out as well, is '.NET Reflector Pro'. This is an extension to .NET Reflector that allows the debugging of decompiled code using the Visual Studio debugger. It is an add-in, but we'll be charging for it, mainly because we prefer to live indoors with a warm meal, rather than outside in tents, particularly when the winter's been as cold as this one has. We're hoping (we're even pretty confident!) that you'll share our excitement about .NET Reflector Pro. .NET Reflector Pro integrates .NET Reflector into Visual Studio, allowing you to seamlessly debug into third-party code and assemblies, even if you don't have the source code for them. You can now treat decompiled assemblies much like your own code: you can step through them and use all the debugging techniques that you would use on your own code. Try the beta now. span.fullpost {display:none;}

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  • SSIS Lookup component tuning tips

    - by jamiet
    Yesterday evening I attended a London meeting of the UK SQL Server User Group at Microsoft’s offices in London Victoria. As usual it was both a fun and informative evening and in particular there seemed to be a few questions arising about tuning the SSIS Lookup component; I rattled off some comments and figured it would be prudent to drop some of them into a dedicated blog post, hence the one you are reading right now. Scene setting A popular pattern in SSIS is to use a Lookup component to determine whether a record in the pipeline already exists in the intended destination table or not and I cover this pattern in my 2006 blog post Checking if a row exists and if it does, has it changed? (note to self: must rewrite that blog post for SSIS2008). Fundamentally the SSIS lookup component (when using FullCache option) sucks some data out of a database and holds it in memory so that it can be compared to data in the pipeline. One of the big benefits of using SSIS dataflows is that they process data one buffer at a time; that means that not all of the data from your source exists in the dataflow at the same time and is why a SSIS dataflow can process data volumes that far exceed the available memory. However, that only applies to data in the pipeline; for reasons that are hopefully obvious ALL of the data in the lookup set must exist in the memory cache for the duration of the dataflow’s execution which means that any memory used by the lookup cache will not be available to be used as a pipeline buffer. Moreover, there’s an obvious correlation between the amount of data in the lookup cache and the time it takes to charge that cache; the more data you have then the longer it will take to charge and the longer you have to wait until the dataflow actually starts to do anything. For these reasons your goal is simple: ensure that the lookup cache contains as little data as possible. General tips Here is a simple tick list you can follow in order to tune your lookups: Use a SQL statement to charge your cache, don’t just pick a table from the dropdown list made available to you. (Read why in SELECT *... or select from a dropdown in an OLE DB Source component?) Only pick the columns that you need, ignore everything else Make the database columns that your cache is populated from as narrow as possible. If a column is defined as VARCHAR(20) then SSIS will allocate 20 bytes for every value in that column – that is a big waste if the actual values are significantly less than 20 characters in length. Do you need DT_WSTR typed columns or will DT_STR suffice? DT_WSTR uses twice the amount of space to hold values that can be stored using a DT_STR so if you can use DT_STR, consider doing so. Same principle goes for the numerical datatypes DT_I2/DT_I4/DT_I8. Only populate the cache with data that you KNOW you will need. In other words, think about your WHERE clause! Thinking outside the box It is tempting to build a large monolithic dataflow that does many things, one of which is a Lookup. Often though you can make better use of your available resources by, well, mixing things up a little and here are a few ideas to get your creative juices flowing: There is no rule that says everything has to happen in a single dataflow. If you have some particularly resource intensive lookups then consider putting that lookup into a dataflow all of its own and using raw files to pass the pipeline data in and out of that dataflow. Know your data. If you think, for example, that the majority of your incoming rows will match with only a small subset of your lookup data then consider chaining multiple lookup components together; the first would use a FullCache containing that data subset and the remaining data that doesn’t find a match could be passed to a second lookup that perhaps uses a NoCache lookup thus negating the need to pull all of that least-used lookup data into memory. Do you need to process all of your incoming data all at once? If you can process different partitions of your data separately then you can partition your lookup cache as well. For example, if you are using a lookup to convert a location into a [LocationId] then why not process your data one region at a time? This will mean your lookup cache only has to contain data for the location that you are currently processing and with the ability of the Lookup in SSIS2008 and beyond to charge the cache using a dynamically built SQL statement you’ll be able to achieve it using the same dataflow and simply loop over it using a ForEach loop. Taking the previous data partitioning idea further … a dataflow can contain more than one data path so why not split your data using a conditional split component and, again, charge your lookup caches with only the data that they need for that partition. Lookups have two uses: to (1) find a matching row from the lookup set and (2) put attributes from that matching row into the pipeline. Ask yourself, do you need to do these two things at the same time? After all once you have the key column(s) from your lookup set then you can use that key to get the rest of attributes further downstream, perhaps even in another dataflow. Are you using the same lookup data set multiple times? If so, consider the file caching option in SSIS 2008 and beyond. Above all, experiment and be creative with different combinations. You may be surprised at what works. Final  thoughts If you want to know more about how the Lookup component differs in SSIS2008 from SSIS2005 then I have a dedicated blog post about that at Lookup component gets a makeover. I am on a mini-crusade at the moment to get a BULK MERGE feature into the database engine, the thinking being that if the database engine can quickly merge massive amounts of data in a similar manner to how it can insert massive amounts using BULK INSERT then that’s a lot of work that wouldn’t have to be done in the SSIS pipeline. If you think that is a good idea then go and vote for BULK MERGE on Connect. If you have any other tips to share then please stick them in the comments. Hope this helps! @Jamiet Share this post: email it! | bookmark it! | digg it! | reddit! | kick it! | live it!

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  • The right way of using index.html

    - by Jeyekomon
    I have quite a lot of issues I'd like to hear your opinion on, so I hope I'll manage to explain it well enough. I should also note that I'm beginner equipped only with the knowledge of HTML and CSS so although I'm almost sure that there is a simple solution using powerful PHP, it won't help me. Let's say that I have my personal blog on the address example.com/blog.html and there are links to several sub-blogs example.com/blog/math.html, example.com/blog/coding.html etc. So my root folder contains blog.html and blog folder, the blog folder itself contains files math.html and coding.html. First of all, I learned (from Google Webmasters Tools) that for SEO and aesthetical purposes it's good to unify example.com.com and example.com/index.html by adding _rel="canonical"_ attribute into the source of the index.html. Using a couple of other tricks (like linking to ../ and ./) I got rid of the ugly index.html appearing in my web addresses. And now I wonder if this trick can be used not only for the root folder but for any folder? I mean, I would move my blog.html into the blog folder, rename it into the index.html and add rel="canonical" to unify example.com/blog/index.html with example.com/blog/. This trick would change the address of my blog from example.com/blog.html into example.com/blog/. Not finished! I'm also experiencing problems with the google robot indexing my folders. So when I type site:example.com/ into the google search, the link to my folder example.com/blog/ with raw files, icons etc. appears among the other results. I guess there are also other ways how to fix it, but IMHO the change mentioned above would do the trick too - the index.html in the blog folder would preserve the user from viewing the actual raw content of that folder, there would appear only the right link example.com/blog/ in the google search and (I hope that) _rel="canonical"_ would make the second, unwanted link example.com/blog/index.html not to appear in the search results. So my questions are: Is it a good practice to have the index.html file in every subfolder or is it intended to be only in the root folder? Are there any disadvantages or problems that may occur when using the second, "index in every folder" method? Which one of the two ways of structuring the website described above would you prefer?

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  • WPF vs. WinForms - a Delphi programmer's perspective?

    - by Robert Oschler
    Hello all. I have read most of the major threads on WPF vs. WinForms and I find myself stuck in the unfortunate ambivalence you can fall into when deciding between the tried and true previous tech (Winforms), and it's successor (WPF). I am a veteran Delphi programmer of many years that is finally making the jump to C#. My fellow Delphi programmers out there will understand that I am excited to know that Anders Hejlsberg, of Delphi fame, was the architect behind C#. I have a strong addiction to Delphi's VCL custom components, especially those involved in making multi-step Wizards and components that act as a container for child components. With that background, I am hoping that those of you that switched from Delphi to C# can help me with my WinForms vs. WPF decision for writing my initial applications. Note, I am very impatient when coding and things like full fledged auto-complete and proper debugger support can make or break a project for me, including being able to find readily available information on API features and calls and even more so, workarounds for bugs. The SO threads and comments in the early 2009 date range give me great concern over WPF when it comes to potential frustrations that could mar my C# UI development coding. On the other hand, spending an inordinate amount of time learning an API tech that is, even if it is not abandoned, soon to be replaced (WinForms), is equally troubling and I do find the GPU support in WPF tantalizing. Hence my ambivalence. Since I haven't learned either tech yet I have a rare opportunity to get a fresh start and not have to face the big "unlearning" curve I've seen people mention in various threads when a WinForms programmer makes the move to WPF. On the other hand, if using WPF will just be too frustrating or have other major negative consequences for an impatient RAD developer like myself, then I'll just stick with WinForms until WPF reaches the same level of support and ease of use. To give you a concrete example into my psychology as a programmer, I used VB and subsequently Delphi to completely avoid altogether the very real pain of coding with MFC, a Windows UI library that many developers suffered through while developing early Windows apps. I have never regretted my luck in avoiding MFC. It would also be comforting to know if Anders Hejlsberg had a hand in the architecture of WPF and/or WinForms, and if there are any disparities in the creative vision and ease of use embodied in either code base. Finally, for the Delphi programmers again, let me know how much "IDE schock" I'm in for when using WPF as opposed to WinForms, especially when it comes to debugger support. Any job market comments updated for 2011 would be appreciated too. -- roschler

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  • SQL SERVER – WRITELOG – Wait Type – Day 17 of 28

    - by pinaldave
    WRITELOG is one of the most interesting wait types. So far we have seen a lot of different wait types, but this log type is associated with log file which makes it interesting to deal with. From Book On-Line: WRITELOG Occurs while waiting for a log flush to complete. Common operations that cause log flushes are checkpoints and transaction commits. WRITELOG Explanation: This wait type is usually seen in the heavy transactional database. When data is modified, it is written both on the log cache and buffer cache. This wait type occurs when data in the log cache is flushing to the disk. During this time, the session has to wait due to WRITELOG. I have recently seen this wait type’s persistence at my client’s place, where one of the long-running transactions was stopped by the user causing it to roll back. In the future, I will see if I could re-create this situation once again on my machine to validate the relation. Reducing WRITELOG wait: There are several suggestions to reduce this wait stats: Move Transaction Log to Separate Disk from mdf and other files. Avoid cursor-like coding methodology and frequent committing of statements. Find the most active file based on IO stall time based on the script written over here. You can also use fn_virtualfilestats to find IO-related issues using the script mentioned over here. Check the IO-related counters (PhysicalDisk:Avg.Disk Queue Length, PhysicalDisk:Disk Read Bytes/sec and PhysicalDisk :Disk Write Bytes/sec) for additional details. Read about them over here. There are two excellent resources by Paul Randal, I suggest you understand the subject from those videos. The links to videos are here and here. Note: The information presented here is from my experience and there is no way that I claim it to be accurate. I suggest reading Book OnLine for further clarification. All the discussion of Wait Stats in this blog is generic and varies from system to system. It is recommended that you test this on a development server before implementing it to a production server. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: Pinal Dave, PostADay, SQL, SQL Authority, SQL Query, SQL Scripts, SQL Server, SQL Tips and Tricks, SQL Wait Stats, SQL Wait Types, T SQL, Technology

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  • Replacing “if”s with your own number system

    - by Michael Williamson
    During our second code retreat at Red Gate, the restriction for one of the sessions was disallowing the use of if statements. That includes other constructs that have the same effect, such as switch statements or loops that will only be executed zero or one times. The idea is to encourage use of polymorphism instead, and see just how far it can be used to get rid of “if”s. The main place where people struggled to get rid of numbers from their implementation of Conway’s Game of Life was the piece of code that decides whether a cell is live or dead in the next generation. For instance, for a cell that’s currently live, the code might look something like this: if (numberOfNeighbours == 2 || numberOfNeighbours == 3) { return CellState.LIVE; } else { return CellState.DEAD; } The problem is that we need to change behaviour depending on the number of neighbours each cell has, but polymorphism only allows us to switch behaviour based on the type of a value. It follows that the solution is to make different numbers have different types: public interface IConwayNumber { IConwayNumber Increment(); CellState LiveCellNextGeneration(); } public class Zero : IConwayNumber { public IConwayNumber Increment() { return new One(); } public CellState LiveCellNextGeneration() { return CellState.DEAD; } } public class One : IConwayNumber { public IConwayNumber Increment() { return new Two(); } public CellState LiveCellNextGeneration() { return CellState.LIVE; } } public class Two : IConwayNumber { public IConwayNumber Increment() { return new ThreeOrMore(); } public CellState LiveCellNextGeneration() { return CellState.LIVE; } } public class ThreeOrMore : IConwayNumber { public IConwayNumber Increment() { return this; } public CellState LiveCellNextGeneration() { return CellState.DEAD; } } In the code that counts the number of neighbours, we use our new number system by starting with Zero and incrementing when we find a neighbour. To choose the next state of the cell, rather than inspecting the number of neighbours, we ask the number of neighbours for the next state directly: return numberOfNeighbours.LiveCellNextGeneration(); And now we have no “if”s! If C# had double-dispatch, or if we used the visitor pattern, we could move the logic for choosing the next cell out of the number classes, which might feel a bit more natural. I suspect that reimplementing the natural numbers is still going to feel about the same amount of crazy though.

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