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VIRTUAL MACHINE OVERVIEW
PROBLEMS WITH TRADITIONAL COMPUTER SYSTEM
 Software compatibility
 Limitation by the need to support old interfaces
 Optimization across interfaces
 Hardware restriction
Virtual machine basics
 A virtual machine is a software implementation of a machine (computer) that executes programs like a real machine.
 Công việc cần làm:
 Mapping of virtual resources to hardware resources
 Using real machine instructions to carry out the actions specified by the VM instructions
Virtual machine applications
 Emulation
 Emulating one instruction set with another
Virtual machine applications
 Optimization
 Optimizing an existing application binary for the same instruction set
 Virtual machine applications
 Replication
 Replicating a virtual machine so that multiple Oses can be supported simultaneously
Virtual machine applications
 Sự kết hợp:
 Composing virtual machine software to form a more complex flexible system
 Virtual machine definition
 A virtual machine is a software implementation of a machine (computer) that executes programs like a real machine.
Process and system VM
 A process virtual machine is capable of supporting an individual process.
 A process virtual machine is created along with its guest process and terminates when the guest process terminates
 A system virtual machine provides a complete system enviroment.
 This enviroment can support multiple user processes: a file system, I/O devices, GUI…
Application binary interface
 ABI= User ISA + System Calls
 User ISA = set of all user instructions
 System calls
 Instruction set architecture interface
 ISA : major division between hardware and software