CoreCLR
CoreCLR provides the common language runtime environment for .NET Core applications, and manages the execution of the complete application life cycle. It performs various operations when the program is running. Operations such as memory allocation, garbage collection, exception handling, type safety, thread management, and security are part of CoreCLR.
.NET Core's runtime provides the same Garbage Collection (GC) as .NET Framework and a new Just In Time (JIT) compiler that is more optimized, codenamed RyuJIT. When .NET Core was first released, it was only supported for 64-bit platforms, but with the release of .NET Core 2.0, it is now available for 32-bit platforms as well. However, the 32-bit version is only supported by Windows operating systems.