How and when are generics realized as real code?

Questions often come up regarding .Net 2.0's generics; how much code is shared, when are the specialized versions created, and how much does it cost? While I want to repeat the refrain I often use—You don't really need to know this—it is useful information. The short version:

• There is one copy of the generic IL
• The JIT creates specializations as they are needed
• All reference-type specializations share one JITted copy
• Each value-type spawns a separate specialization

For more information, please refer to this excellent post from Ognjen Bajić