emulation & virtualisation

Back to basics: emulation and virtualisation

When it comes to server virtualisation, consolidating and securing a data centre is often our first thought. In fact, we typically overlook one of the first applications that enabled virtualisation solutions to take off in the past few years: computer emulators.

What is emulation?
Emulation is when one information system operates like another system by taking on functions for which it was not originally designed. A common example of emulation involves running old video game consoles (e.g., NES, SNES, Sega Mega Drive) on an x86 architecture (PC).

When we talk about emulation, several principles of virtualisation apply:
  • Independence. The emulated structure is independent of the material platform, with the emulator acting as a bridge between the two machines.
  • Isolation. The emulated structure is isolated from other structures. This separation ensures that the entire physical and logical platform is not affected in the event of a malfunction.
  • Comparability. Emulation places significant demands on system resources. The performance of an application running on an emulated platform versus a physical proprietary environment will not necessarily be the same. A number of parameters can affect performance, including the quality of the emulator.

Emulation at work

That's nice but, apart from nostalgia, where's the value in emulating old video game consoles in a professional context? In fact, emulation offers several distinct advantages that can help businesses tackle a number of tough problems.

A few years ago, noted developer Fabrice Bellard invented QEMU, a VirtualBox hypervisor that is capable of emulating several different types of processors. With QEMU, it's possible to operate VMs using an x86 machine with a CPU that's x86-, PPC- or SPARC-compatible. The immediate advantage for businesses is that critical equipment, which is old and beyond repair, can be replaced without compromising software availability.

IBM subsidiary Transitive took the idea one step further, offering the chance to run applications developed on SPARC architecture in VMware or HyperV (x86 infrastructure) virtual machines without changing the code at all. When we consider the difference in price between a SUN SPARC machine and x86 servers, things really get interesting.

Beyond dollars and cents, we can see the next-generation data
centre (NGDC) model taking shape before our eyes. Tomorrow's businesses will use virtualisation technologies to create a unified, shared platform that is capable of running applications designed for all types of infrastructure. It's the principle of independence taken to the extreme on the material level.
Olivier Domy

I work around the concepts related to the rationalization of infrastructure information systems and particularly on user environments transformation projects.