Linux.conf.au 2003 | Abstracts

Pretend Systems doing real Work

Dan Shearer

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Paper

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Simulated Systems let some things be done which are not easily possible using other means. Have you ever wanted to:

• fork an entire running system (where system = hardware + OS)
• so you can follow both branches during decisions in testing runs?
• build a simulated network starting from your existing firewall and server configurations?
• build a beowulf using just one computer?
• email your whole computer to a friend?
• set breakpoints on your hardware?
• write code for hardware that doesn't exist or you haven't got?
• boot your own personal 32-processor UltraSPARC, S/390 mainframe, Itanium or completely obsolete 16-bit architecture?
• create memory errors in your hardware and observe what the OS does?

There are some interesting problems and questions:

• what about preserving state when crossing over between real and pretend systems?
• licensing... some big companies get upset when free (and non-free) simulated systems are used to run their OS or other software
• how can we know if the simulated system is a good implementation of the original?