Microsoft .Net Framework 3.5 vs .Net Framework 4.0
The .Net framework from Microsoft is like a virtual machine where applications run on top of each other. .Net framework 3.5 and .Net framework 4.0 are two sequential versions of this software framework, and the latter should eventually replace the former. The main difference between them is availability as .Net framework 3.5 is already built in to Windows 7, Microsoft’s latest operating system. If you need .Net framework 4.0, you have no choice but to download it online from Microsoft’s site or let the updater install it for you.
The biggest improvement in .Net framework 4.0 is its optimization for running on a computer with multiple cores. .Net framework 3.5 was not optimized for multi-core operation, and it cannot take as much advantage when deployed in a computer with 2 or more cores. The inclusion of PLINQ (Parallel LINQ) instead of the LINQ used by .Net framework 3.5 means that .Net framework 4.0 can subdivide its operation into multiple threads that can be assigned to different cores for more even loading.
Another improvement in .Net framework 4.0 is the added support for code contracts. Code contracts allow the expression of coding assumptions without truly knowing the underlying language used in the code. There are several advantageous consequences of this, not the least of which is easier and more reliable checking of the code during or even before runtime.
In order to support complex math operations, .Net framework adds new math data structures. The BigInteger structure is to be used in arbitrary precision arithmetic. This is useful in generating keys for public key cryptography, a security mechanism used by many software. The Complex structure is to be used when dealing with complex numbers. There are many real-world applications where complex numbers are used; for example, complex numbers are used to represent the capacitive and inductive elements of an electrical or electronic network.
It was stated above that .Net framework 4.0 should replace .Net framework 3.5. But, in reality, the two coexist in a system, and the software runs on either depending on which one it was coded for. Eventually, the majority if not all of the software would be coded for .Net framework 4.0, and the older version would be simply made obsolete.
Summary:
1..Net framework 3.5 is built into Windows 7 while .Net framework 4.0 isn’t.
2..Net framework 4.0 is optimized for multiple cores while .Net framework 3.5 isn’t.
3..Net framework 4.0 supports code contracts while .Net framework 3.5 doesn’t.
4..Net framework 4.0 adds new data structures for advanced mathematical operations not supported by .Net framework 3.5.