As developers, we sometimes want to quickly test some software. Instead of installing it directly on our developer machine, it’s better to install it in a virtual machine (VM). But if you don’t have a VM ready, setting one up usally takes a lot of time – and there goes your productivity.

Fortunately, there is a solution: Vagrant

Vagrant is a free tool that lets you quickly spin-up fresh VMs out of thin air. It can even spin-up multiple VMs at the same time.

This article is step by step tutorial for getting from nothing to a multi-VM setup where the VMs can talk to each other.

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Security is hard. In a current project I saw some code that created some access tokens based on a random number generator – .NET’s Random class. The code used an instance of Random stored in static field and I got curious:

If you have such a long living Random instance, could you predict the random values after generating a few of them?

It turns out, it is possible. And you only need to read 56 55 “random” values to predict all future values.

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Recently, I wanted to try out the new .NET Core together with a Docker container. However, coming from programing .NET applications for the regular .NET Framework, there were some obstacles I encountered. This one is about NuGet packages.

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Update (2016-04-04): This article has been updated for Azure SDK 2.8 and SQL Server Developer Edition.

While developing for Windows Azure, I recently got lots of StorageExceptions reading “(500) Internal Server Error.”. This usually means that the SQL database that holds the table storage data is full. (SQL Server Express 2008 and sooner have a 4 GB limit; SQL Server Express 2012 and later have a 10 GB limit.)

Some time ago, Microsoft released its SQL Server Developer Edition for free. This edition doesn’t have a database size limit.

Here is how to use this SQL Server (or any SQL server instance) as storage for the table storage emulator:

1. Open Microsoft Azure Storage command line from the start menu.
2. cd "Storage Emulator"

3. (Re-)initialize the storage emulator (for the fully command-line reference see here):

   1. For the default SQL instance: AzureStorageEmulator.exe init -server .

   2. For a named SQL instance: AzureStorageEmulator.exe init -sqlinstance "MSSQLSERVER"

That’s it.

Note: If you use the “named SQL instance” option from above but the instance is actually the default instance, you will get this error:

Error: User-specified instance not found. Please correct this and re-run initialization.

Default instance or named instance ∞

You can run multi SQL Server instances on the same computer. Each instance has a name (e.g. MSSQLSERVER, SQLEXPRESS) and one of the instances will be the default instance. Depending on this, you need either to use option “default SQL instance” or “named SQL instance” above.

Unfortunately, I haven’t found a simple way to figure which instance is the default instance.

The one solution I found is to use Microsoft SQL Server Management Studio and try to connect to .\INSTANCENAME (e.g. .\MSSQLSERVER). If you can’t connect, than this instance is (most likely) the default instance.

How to get the name of the SQL instance ∞

The default SQL instance names are as follows:

SQL Server	MSSQLSERVER
SQL Server Express	SQLEXPRESS

You can list all instance names with the Sql Server Configuration Manager that should come with your SQL server installation.

It’ll give you something like this:

When you write software, you often/sometimes divide your project into several subprojects. This mini series describes how to do this with Visual C++ 2010 (but this first part also applies to earlier versions). We start with creating a library project in form of a DLL.

Related articles:

• Projects in Visual C++ 2010 – Part 2: Project Dependencies

• Projects in Visual C++ 2010 – Part 3: Precompiled Headers

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