This VM provide a virtual environment at the program or process level. This allow program compiled for one system to run in a different system. Program are compiled, distributed and stored as executable binaries that conforms to a specific ABI which include hardware instruction set and OS interface.
Process VM contains the following components:
(1) Loader writes the guest code and data into a region of memory and loads the runtime code.
(2) Loader passes control to the initialization block which allocates memory space for code cache and other tables used during emulation. It also involves host OS to establish signal handlers for all trap conditions.
(3) Emulation engine uses interpretation or binary translation to emulate guest instructions.
(4) Code cache manager to maintain the cache
(5) Profile database contains dynamically collected program information that is used to guide optimization during translation.
(6) When guest program performs a system call, the OS call emulator translates the OS call into approapriate calls to the host OS and handles any associated information returned as a result.
(7) The runtime must also handle traps that may occur and interrupt that is directed at the guest process using exception emulator
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