Lesson plan
Vx32
The Vx32 virtual extension environment is an application-level virtual machine implemented as an ordinary user-mode library and designed to run native x86 code. Applications can link with and use Vx32 in order to create safe, OS-independent execution environments, in which to run untrusted plug-ins or other extensions written in any language that compiles to x86 code. From the host processor's viewpoint, plug-ins running under the Vx32 virtual machine monitor run in the context of the application process itself, but the Vx32 library uses dynamic recompilation to prevent the "guest" plug-in code from accessing memory or jumping to instructions outside its designated sandbox. The Vx32 library redirects any system calls the plug-in makes to the application itself rather than to the host operating system, thereby giving the application exclusive control over the API and security environment in which the plug-in code executes. Vx32 thus provides an application extension facility comparable in function to the Java virtual machine (JVM) or the Common Language Runtime (CLR), but with less overhead and with the ability to run code written in any language, safe or unsafe. Vx32's primary disadvantage is that it is more difficult to make it run on non-x86 host processors.
Article summary
The Vx32 virtual extension environment is an application-level virtual machine implemented as an ordinary user-mode library and designed to run native x86 code. Applications can link with and use Vx32 in order to create safe, OS-independent execution environments, in which to run untrusted plug-ins or other extensions written in any language that compiles to x86 code. From the host processor's viewpoint, plug-ins running under the Vx32 virtual machine monitor run in the context of the application process itself, but the Vx32 library uses dynamic recompilation to prevent the "guest" plug-in code from accessing memory or jumping to instructions outside its designated sandbox. The Vx32 library redirects any system calls the plug-in makes to the application itself rather than to the host operating system, thereby giving the application exclusive control over the API and security environment in which the plug-in code executes. Vx32 thus provides an application extension facility comparable in function to the Java virtual machine (JVM) or the Common Language Runtime (CLR), but with less overhead and with the ability to run code written in any language, safe or unsafe. Vx32's primary disadvantage is that it is more difficult to make it run on non-x86 host processors.
Key claims
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Discussion questions
- Summarise the article in your own words. Which single claim would you verify first, and why?
- Which claim in this article is most likely to be revised as the sources update? How would you check its current status?
- If two sources disagreed about one of these facts, what would you need in order to trust one over the other?
Bibliography
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Key claims and bibliography are generated from the same tracked claims and sources as the article page.