by Paul Ducklin

If you’re a fan of retro gaming, you’ve probably used an emulator, which is a software program that runs on computer hardware of one sort, and pretends to be a computer system of its own, possibly of a completely different sort.
That’s how your latest-model Mac, which has an Intel x64 CPU, can run original, unaltered software that was written for a computer such as the Apple ][ or the Nintendo GameBoy.
One advantage of emulators is that even though the running program thinks it’s running exactly as it would in real life, it isn’t – everything it does is controlled, instrumented, regimented and mitigated by the emulator software.
When your 1980s Sinclair Spectrum game accidentally corrupts system memory and crashes the whole system, it doesn’t really crash anything at the hardware level, and the crashed pseudo-computer doesn’t affect the operating system or the hardware on which the emulator is running.
Similarly, if you’re an anti-virus program “running” some sort of malicious code inside an emulator, you get to watch what it does every step of the way, and even to egg it on to show its hand…
…without letting it actually do anything dangerous in real life, because it’s not accessing the real operating system, the real computer hardware or the real network at all.

Another advantage of emulators is that you can run several copies of the emulator at the same time, thus turning one real computer into several pseudo-computers.
For example, if you want to analyse multiple new viruses at the same time, all without putting the real computer – the host system – in any danger, you can run each sample simultaneously in its own instance of the emulator.
One disadvantage of true emulators – those that simulate via …

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Author: Paul Ducklin

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