The VMware Solution: Full Virtualization of x86 Hardware
In 1999, VMware introduced virtualization to x86 systems as a means to efficiently address many of these challenges and to transform x86 systems into general purpose, shared hardware infrastructure that offers full isolation, mobility and operating system choice for application environments.
Challenges & Obstacles to x86 Virtualization
Unlike mainframes, x86 machines were not designed to support full virtualization, and VMware had to overcome formidable challenges to create virtual machines out of x86 computers.
The basic function of most CPUs, both in mainframes and in PCs, is to execute a sequence of stored instructions (ie, a software program). In x86 processors, there are 17 specific instructions that create problems when virtualized, causing the operating system to display a warning, terminate the application, or simply crash altogether. As a result, these 17 instructions were a significant obstacle to the initial implementation of virtualization on x86 computers.
To handle the problematic instructions in the x86 architecture, VMware developed an adaptive virtualization technique that “traps” these instructions as they are generated and converts them into safe instructions that can be virtualized, while allowing all other instructions to be executed without intervention. The result is a high-performance virtual machine that matches the host hardware and maintains total software compatibility. VMware pioneered this technique and is today the undisputed leader in virtualization technology. |