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Using QEMU 0.14.1 under Ubuntu 11.10 with kernel 3.0.0-17-generic, if I run qemu -cpu ? I get:

$ qemu -cpu ?
x86           [n270]
x86         [athlon]
x86       [pentium3]
x86       [pentium2]
x86        [pentium]
x86            [486]
x86        [coreduo]
x86          [kvm32]
x86         [qemu32]
x86          [kvm64]
x86       [core2duo]
x86         [phenom]
x86         [qemu64]
x86           [host]

...but when I run:

$ qemu -snapshot -m 256M -cpu x86 -hda live-usb.img 
Unable to find x86 CPU definition

I've tried x86, 486, x86-486 as well, with no success. So how do I actually use the CPU option?

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up vote 2 down vote accepted
qemu -M pc-0.14 -cpu core2duo -m 256 [-option argumentyouwant] live-usb.img

And x86 is cpu architecture is not an exact cpu... in cpu option u must use a cpu not architecture

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Perhaps you could point him out why it wasn't working as well? – Ivo Flipse Feb 17 '12 at 8:47
But -cpu 486 didn't work either. – detly Feb 17 '12 at 17:48
Okay, it worked today... I must've made a typo when I tried it. Oh well, if it works it works! – detly Feb 20 '12 at 3:15

You can use DOSBOX if you want a 486 computer with DOS, Or Virtualbox if you want a fast virtualisation.

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Alas neither — I need to boot an existing live USB image using a 586 (or similar) architecture. Virtualbox might still be able to help with the latter I suppose, but I won't be able to check until Monday. – detly Feb 18 '12 at 6:14
USB was generally absent in age of 586.... (There was USB 0.9 in FX mainboard, but that is no more considered USB) -cpu 486 works fine for me, i add -boot a/b/c/d to make it boot from "removable" device. Otherwise it uses -boot cad i.e looks for nonexistent CD and floppy first. – ZaB Feb 18 '12 at 10:00
the embedded system I'm using is a 586 (or maybe a 686) architecture, and has several USB ports available (including BIOS support for USB booting). – detly Feb 18 '12 at 11:53

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