Application Programming Interfaces (APIs) are where you have to be. It's not a matter of if as much as a matter of which.

Application Programming Interfaces (APIs) are where you have to be. It's not a matter of if as much as a matter of which.
If you have written solid code, you have accomplished one half of the objective. Solid code is the protagonist, or hero, of our story, but testing is the more sedate side kick that often saves the day after the hubris of the hero has almost certainly lead to calamity.
Is some of your business logic in code and some in SQL Server? Then, just call the SQL from the .NET framework and the .NET framework from SQL with CLR integration. Here are all the steps you need to get started.
Memory mapped files use the system's memory manager and lets you treat large files as if they were in-memory objects, supporting extremely large file access, faster access, and multiple, simultaneous processes accessing the same file.
Learn how to enumerate the files and folders on a computer with LINQ, managing access exceptions along the way.
Encryption and keeping secrets depends on large prime numbers that are too big to crack by brute force. .NET framework 4.0 introduces the BigInteger that has no theoretical upper and lower bounds.