PHP versus ASP.NET – Windows versus Linux

How does IMPLEMENTATION Performance Compare ?

Usually, when someone creates benchmarks, they are trying to prove that their thing is faster than someone else's thing.

I’m PAID by Microsoft to write BOTH PHP and ASP.NET Code. I was doing PHP before .NET shipped. I love them both.

This makes it hard for me to say anything good about either one. When I confer a preference for something in PHP, my Microsoft peers send me flame mail and when I confer a preference for something in ASP.NET, my PHP friends come out of the woodwork to call me a Microsoft shill.

I started building and running these tests because everyone had opinions about comparative PHP performance (Windows versus Linux & 5.2 versus 5.3), but no one had any solid data.

So, I decided to collect some empirical evidence of my own.

Before you look at them, let m e provide some method details and context.

All tests were run on the SAME Machine.

A Toshiba Tecra M5 with 4 Gig of ram and a 60 Gig 7200 RPM Hard Drive.

Ubuntu 9 and Windows Server 2008 Standard were natively installed on 2 separate (but identical) hard drives.

The web servers were Apache2 on Linux and IIS 7 on Windows.

Both operating systems were fully patched / updated.

No Operating System or Development Runtime performance enhancements were added.

I wasn’t investigating how much speed an expert could custom tailor the tests to on a specific platform.

Yes, I could implement PHP Byte Caching, or for ASP.NET I could use Page Caching, Partial Page Caching, SQL Cache Dependency, Multi Threading, etc.

Both Windows and Linux Implementations of PHP will benefit from PHP Byte Code caching.

My goal was to determine the relative speed of THE IMPLEMENTATION.

I found the results both interesting and unexpected.

PHP on Linux Versus PHP on Windows…..

I really though one would just be faster than the other, but I was wrong. Some things are faster on Windows, other are faster on Linux.

• RAW statement execution seems faster on Windows.
• Function Calls were faster on Windows
• Object Creation / Access was faster on Linux with PHP 5.2 but faster on Windows with 5.3
• Library calls were faster on Linux. (Example: Encryption 3-5 times faster on Ubuntu.)
• File Access is faster on Linux by a small percentage, except for file copy operations which was as much as 60% slower on Windows probably due to the ACL advanced security.
• MySQL access with Linux is faster by more than a little and on Windows, MySQL access deteriorates in version 5.3 (This seems to be poor implementation, see PostgreSQL below.)
• PostgreSQL performance is very close on both platforms (within 6/100 of a second for 1000 Operations) – It’s faster on Windows and faster still on Windows with PHP 5.3
• MS SQL Server access from PHP 5.2 on Windows is marginally slower than MySQL access on Linux. (PHP 5.3 not yet supported at the time of this writing.)

So what does all that mean ?

• We can probably say that in terms of raw execution – performance on Linux versus Windows is probably a wash (more or less equivalent) so that the performance of PHP itself becomes a moot factor in choosing Linux or Windows for PHP application deployment.
• If you are building an application, or running an application that supports it, PostgreSQL might be a better database choice since it performs pretty much the same on Windows and Linux.
• If you are running an application that locks you in to Sun Microsystems’ MySQL and you want to run it on Windows, your should do scale planning. (My personal guess is that it’s unlikely that Sun will markedly improve MySQL performance on Windows. )
• Version 1 of the PHP Driver for SQL Server (V2 is in the works) is somewhat slower than MySQL or PostpreSQL but probably not enough to discourage use where diverse developer access is desired. (v2 ot the driver will improve performance. )

By and large I think the PHP team and the Microsoft IIS team have accomplished good raw performance equivalence across platforms. (Now we just need to get the Open Source Application teams (Drupal, WordPress, Joomle, etc.) to do performance optimization on both !)

PHP versus ASP.NET Raw Performance …..

By now you have cheated and looked at the spread sheet.

Yes, ASP.NET is universally faster than PHP (on Windows and on Linux) with the exceptions of File Copy and Attribute operations.

MySQL Access from PHP on Linux is a TINY bit faster than SQL Server access on Windows (assuming common data types and SELECT statements) but probably not enough to matter.

ASP.NET (C#) operations, object use, library calls, etc. are SIGNIFICANTLY faster that the PHP equivalents.

I know my PHP friends and the Linux dudes (and dude-etts) will probably come out of the wood work to refute my tests and results :)

I’ve always thought that if high end performance options were part of your needs requirements,  then .NET programming has some advanced options “out of the box” like multi-threading, asynchronous requests, and a number of caching options.

NOTE – I’m not saying “ASP.NET is Faster so you shouldn't choose PHP !!!!  I’ve always contended that the affable simplicity of PHP had some drawbacks for certain advanced applications. (Just as the early learning complexity of ASP.NET can have it’s drawbacks. )

To me (your mileage may vary) the exciting thing about PHP is not the language / platform so much as it is what thousands of clever PHP Developers have done with it (Drupal, Joomla, Wordpress, PHPBB, Nuke, etc.)

In any event, it’s nice to now have some data that PHP performance on Windows and Linux are “in the same ballpark”.

Now I can start writing those Windows specific PHP  libraries I’ve been dreaming about for years !!

COMMENT WARNING

• I know some will be incensed by these tests. You are welcome to comment and disagree, but if you can't be polite I’ll simply delete your comments and block your IP address.
• If you dislike the results and want to refute them – DO THE WORK. Accompany your dissent with DATA. Take my code or write your own and argue with FACTS.

Posted in: General asp.net | Tags: asp.net php windows linux implementation performance compare windows versus linux sql server postgresql ms sql server mysql

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C# Interview Questions and Answers

1. What’s the implicit name of the parameter that gets passed into the class’ set method?
   Value, and its datatype depends on whatever variable we’re changing.
2. How do you inherit from a class in C#?
   Place a colon and then the name of the base class. Notice that it’s double colon in C++.
3. Does C# support multiple inheritance?
   No, use interfaces instead.
4. When you inherit a protected class-level variable, who is it available to?
   Classes in the same namespace.
5. Are private class-level variables inherited?
   Yes, but they are not accessible, so looking at it you can honestly say that they are not inherited. But they are.
6. Describe the accessibility modifier protected internal.
   It’s available to derived classes and classes within the same Assembly (and naturally from the base class it’s declared in).
7. C# provides a default constructor for me. I write a constructor that takes a string as a parameter, but want to keep the no parameter one. How many constructors should I write? Two. Once you write at least one constructor, C# cancels the freebie constructor, and now you have to write one yourself, even if there’s no implementation in it.
8. What’s the top .NET class that everything is derived from?
   System.Object.
9. How’s method overriding different from overloading?
   When overriding, you change the method behavior for a derived class. Overloading simply involves having a method with the same name within the class.
10. What does the keyword virtual mean in the method definition?
    The method can be over-ridden.
11. Can you declare the override method static while the original method is non-static?
    No, you can’t, the signature of the virtual method must remain the same, only the keyword virtual is changed to keyword override.
12. Can you override private virtual methods?
    No, moreover, you cannot access private methods in inherited classes, have to be protected in the base class to allow any sort of access.
13. Can you prevent your class from being inherited and becoming a base class for some other classes?
    Yes, that’s what keyword sealed in the class definition is for. The developer trying to derive from your class will get a message: cannot inherit from Sealed class WhateverBaseClassName. It’s the same concept as final class in Java.
14. Can you allow class to be inherited, but prevent the method from being over-ridden?
    Yes, just leave the class public and make the method sealed.
15. What’s an abstract class?
    A class that cannot be instantiated. A concept in C++ known as pure virtual method. A class that must be inherited and have the methods over-ridden. Essentially, it’s a blueprint for a class without any implementation.
16. When do you absolutely have to declare a class as abstract (as opposed to free-willed educated choice or decision based on UML diagram)?
    When at least one of the methods in the class is abstract. When the class itself is inherited from an abstract class, but not all base abstract methods have been over-ridden.
17. What’s an interface class?
    It’s an abstract class with public abstract methods all of which must be implemented in the inherited classes.
18. Why can’t you specify the accessibility modifier for methods inside the interface?
    They all must be public. Therefore, to prevent you from getting the false impression that you have any freedom of choice, you are not allowed to specify any accessibility, it’s public by default.
19. Can you inherit multiple interfaces?
    Yes, why not.
20. And if they have conflicting method names?
    It’s up to you to implement the method inside your own class, so implementation is left entirely up to you. This might cause a problem on a higher-level scale if similarly named methods from different interfaces expect different data, but as far as compiler cares you’re okay.
21. What’s the difference between an interface and abstract class?
    In the interface all methods must be abstract; in the abstract class some methods can be concrete. In the interface no accessibility modifiers are allowed, which is ok in abstract classes.
22. How can you overload a method?
    Different parameter data types, different number of parameters, different order of parameters.
23. If a base class has a bunch of overloaded constructors, and an inherited class has another bunch of overloaded constructors, can you enforce a call from an inherited constructor to an arbitrary base constructor?
    Yes, just place a colon, and then keyword base (parameter list to invoke the appropriate constructor) in the overloaded constructor definition inside the inherited class.
24. What’s the difference between System.String and System.StringBuilder classes?
    System.String is immutable; System.StringBuilder was designed with the purpose of having a mutable string where a variety of operations can be performed.
25. What’s the advantage of using System.Text.StringBuilder over System.String?
    StringBuilder is more efficient in the cases, where a lot of manipulation is done to the text. Strings are immutable, so each time it’s being operated on, a new instance is created.
26. Can you store multiple data types in System.Array?
    No.
27. What’s the difference between the System.Array.CopyTo() and System.Array.Clone()?
    The first one performs a deep copy of the array, the second one is shallow.
28. How can you sort the elements of the array in descending order?
    By calling Sort() and then Reverse() methods.
29. What’s the .NET datatype that allows the retrieval of data by a unique key?
    HashTable.
30. What’s class SortedList underneath?
    A sorted HashTable.
31. Will finally block get executed if the exception had not occurred?
    Yes.
32. What’s the C# equivalent of C++ catch (…), which was a catch-all statement for any possible exception?
    A catch block that catches the exception of type System.Exception. You can also omit the parameter data type in this case and just write catch {}.
33. Can multiple catch blocks be executed?
    No, once the proper catch code fires off, the control is transferred to the finally block (if there are any), and then whatever follows the finally block.
34. Why is it a bad idea to throw your own exceptions?
    Well, if at that point you know that an error has occurred, then why not write the proper code to handle that error instead of passing a new Exception object to the catch block? Throwing your own exceptions signifies some design flaws in the project.
35. What’s a delegate?
    A delegate object encapsulates a reference to a method. In C++ they were referred to as function pointers.
36. What’s a multicast delegate?
    It’s a delegate that points to and eventually fires off several methods.
37. How’s the DLL Hell problem solved in .NET?
    Assembly versioning allows the application to specify not only the library it needs to run (which was available under Win32), but also the version of the assembly.
38. What are the ways to deploy an assembly?
    An MSI installer, a CAB archive, and XCOPY command.
39. What’s a satellite assembly?
    When you write a multilingual or multi-cultural application in .NET, and want to distribute the core application separately from the localized modules, the localized assemblies that modify the core application are called satellite assemblies.
40. What namespaces are necessary to create a localized application?
    System.Globalization, System.Resources.
41. What’s the difference between // comments, /* */ comments and /// comments?
    Single-line, multi-line and XML documentation comments.
42. How do you generate documentation from the C# file commented properly with a command-line compiler?
    Compile it with a /doc switch.
43. What’s the difference between <c> and <code> XML documentation tag?
    Single line code example and multiple-line code example.
44. Is XML case-sensitive?
    Yes, so <Student> and <student> are different elements.
45. What debugging tools come with the .NET SDK?
    CorDBG – command-line debugger, and DbgCLR – graphic debugger. Visual Studio .NET uses the DbgCLR. To use CorDbg, you must compile the original C# file using the /debug switch.
46. What does the This window show in the debugger?
    It points to the object that’s pointed to by this reference. Object’s instance data is shown.
47. What does assert() do?
    In debug compilation, assert takes in a Boolean condition as a parameter, and shows the error dialog if the condition is false. The program proceeds without any interruption if the condition is true.
48. What’s the difference between the Debug class and Trace class? Documentation looks the same.
    Use Debug class for debug builds, use Trace class for both debug and release builds.
49. Why are there five tracing levels in System.Diagnostics.TraceSwitcher?
    The tracing dumps can be quite verbose and for some applications that are constantly running you run the risk of overloading the machine and the hard drive there. Five levels range from None to Verbose, allowing to fine-tune the tracing activities.
50. Where is the output of TextWriterTraceListener redirected?
    To the Console or a text file depending on the parameter passed to the constructor.
51. How do you debug an ASP.NET Web application?
    Attach the aspnet_wp.exe process to the DbgClr debugger.
52. What are three test cases you should go through in unit testing?
    Positive test cases (correct data, correct output), negative test cases (broken or missing data, proper handling), exception test cases (exceptions are thrown and caught properly).
53. Can you change the value of a variable while debugging a C# application?
    Yes, if you are debugging via Visual Studio.NET, just go to Immediate window.
54. Explain the three services model (three-tier application).
    Presentation (UI), business (logic and underlying code) and data (from storage or other sources).
55. What are advantages and disadvantages of Microsoft-provided data provider classes in ADO.NET?
    SQLServer.NET data provider is high-speed and robust, but requires SQL Server license purchased from Microsoft. OLE-DB.NET is universal for accessing other sources, like Oracle, DB2, Microsoft Access and Informix, but it’s a .NET layer on top of OLE layer, so not the fastest thing in the world. ODBC.NET is a deprecated layer provided for backward compatibility to ODBC engines.
56. What’s the role of the DataReader class in ADO.NET connections?
    It returns a read-only dataset from the data source when the command is executed.
57. What is the wildcard character in SQL? Let’s say you want to query database with LIKE for all employees whose name starts with La.
    The wildcard character is %, the proper query with LIKE would involve ‘La%’.
58. Explain ACID rule of thumb for transactions.
    Transaction must be Atomic (it is one unit of work and does not dependent on previous and following transactions), Consistent (data is either committed or roll back, no “in-between” case where something has been updated and something hasn’t), Isolated (no transaction sees the intermediate results of the current transaction), Durable (the values persist if the data had been committed even if the system crashes right after).
59. What connections does Microsoft SQL Server support?
    Windows Authentication (via Active Directory) and SQL Server authentication (via Microsoft SQL Server username and passwords).
60. Which one is trusted and which one is untrusted?
    Windows Authentication is trusted because the username and password are checked with the Active Directory, the SQL Server authentication is untrusted, since SQL Server is the only verifier participating in the transaction.
61. Why would you use untrusted verificaion?
    Web Services might use it, as well as non-Windows applications.
62. What does the parameter Initial Catalog define inside Connection String?
    The database name to connect to.
63. What’s the data provider name to connect to Access database?
    Microsoft.Access.
64. What does Dispose method do with the connection object?
    Deletes it from the memory.
65. What is a pre-requisite for connection pooling?
    Multiple processes must agree that they will share the same connection, where every parameter is the same, including the security settings.

C# developer interview questions

A representative of a high-tech company in United Kingdom sent this in today noting that the list was used for interviewing a C# .NET developer. Any corrections and suggestions would be forwarded to the author. I won’t disclose the name of the company, since as far as I know they might still be using this test for prospective employees. Correct answers are in green color.

1) The C# keyword .int. maps to which .NET type?

1. System.Int16

2. System.Int32

3. System.Int64

4. System.Int128

2) Which of these string definitions will prevent escaping on backslashes in C#?

1. string s = #.n Test string.;

2. string s = ..n Test string.;

3. string s = @.n Test string.;

4. string s = .n Test string.;

3) Which of these statements correctly declares a two-dimensional array in C#?

1. int[,] myArray;

2. int[][] myArray;

3. int[2] myArray;

4. System.Array[2] myArray;

4) If a method is marked as protected internal who can access it?

1. Classes that are both in the same assembly and derived from the declaring class.

2. Only methods that are in the same class as the method in question.

3. Internal methods can be only be called using reflection.

4. Classes within the same assembly, and classes derived from the declaring class.

5) What is boxing?

a) Encapsulating an object in a value type.

b) Encapsulating a copy of an object in a value type.

c) Encapsulating a value type in an object.

d) Encapsulating a copy of a value type in an object.

6) What compiler switch creates an xml file from the xml comments in the files in an assembly?

1. /text

2. /doc

3. /xml

4. /help

7) What is a satellite Assembly?

1. A peripheral assembly designed to monitor permissions requests from an application.

2. Any DLL file used by an EXE file.

3. An assembly containing localized resources for another assembly.

4. An assembly designed to alter the appearance or .skin. of an application.

8) What is a delegate?

1. A strongly typed function pointer.

2. A light weight thread or process that can call a single method.

3. A reference to an object in a different process.

4. An inter-process message channel.

9) How does assembly versioning in .NET prevent DLL Hell?

1. The runtime checks to see that only one version of an assembly is on the machine at any one time.

2. .NET allows assemblies to specify the name AND the version of any assemblies they need to run.

3. The compiler offers compile time checking for backward compatibility.

4. It doesn.t.

10) Which .Gang of Four. design pattern is shown below?

public class A {

    private A instance;

    private A() {

    }

    public
static A Instance {

        get

        {

            if ( A == null )

                A = new A();

            return instance;

        }

    }

}

1. Factory

2. Abstract Factory

3. Singleton

4. Builder

11) In the NUnit test framework, which attribute must adorn a test class in order for it to be picked up by the NUnit GUI?

1. TestAttribute

2. TestClassAttribute

3. TestFixtureAttribute

4. NUnitTestClassAttribute

12) Which of the following operations can you NOT perform on an ADO.NET DataSet?

1. A DataSet can be synchronised with the database.

2. A DataSet can be synchronised with a RecordSet.

3. A DataSet can be converted to XML.

4. You can infer the schema from a DataSet.

13) In Object Oriented Programming, how would you describe encapsulation?

1. The conversion of one type of object to another.

2. The runtime resolution of method calls.

3. The exposition of data.

4. The separation of interface and implementation.

Posted in: Interview Questions | Tags: interview questions and answers questions interview answers q&a .net c# c sharp sql server private derive overloading definition static abstract interface base inherited inherit variable acid trusted immediate window data provider ado.net

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Web Packaging in visual studio 2010

Visual Studio 2010 uses the MSDeploy tool to create a compressed (.zip) file for your application, which is referred to as a Web package. The package file contains metadata about your application plus the following content:

· IIS settings, which includes application pool settings, error page settings, and so on.

· The actual Web content, which includes Web pages, user controls, static content (images and HTML files), and so on.

· SQL Server database schemas and data.

· Security certificates, components to install in the GAC, registry settings, and so on.

A Web package can be copied to any server and then installed manually by using IIS Manager. Alternatively, for automated deployment, the package can be installed by using command-line commands or by using deployment APIs.

VS 2010 provides built in MSBuild tasks and targets to create Web packages. For more information, see 10 + 20 reasons why you should create a Web Package on Vishal Joshi’s blog.

Posted in: software asp.net | Tags: sql server vs 2010 visual studio 2010 msdeploy iis schema security certificates msbuild

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