according to intels documentation, once disabled cpuid serial number function can not be used without restarting the system.
I use eax,1 , cpuid -> test bit 18 of edx and get refused (bit18=0).
is there any way of manualy or programatically enabling the serial number feature (winXp)?  If not what is the use of it except systems programming?
Posted on 2006-09-26 10:47:36 by Confusius
PSN (Processor Serial Number) was kinda 'mistake' on some PIIIs. It's no longer supported and you're supposed "not to depend on it".
Posted on 2006-09-26 16:20:20 by ti_mo_n
Whether you meant the CPUID or Processor Serial Number, here is a LINK to some information on obtaining the CPUID.
Posted on 2006-09-26 18:40:49 by SpooK
Once disabled, the serial number can't be re-enabled except by a reset... and then the BIOS will control whether to enable or disable it. And that's a good thing.

Same goes for other features that can be turned off, like the VMX instruction set: once disabled, it can't be re-enabled except by reset.
Posted on 2006-09-27 05:36:52 by f0dder
does anybody know another way (like Volume Serial Number, mac Nr) to identify a unique machine
Posted on 2006-09-27 08:28:21 by Confusius
Volume serial number or NIC MAC address, or a combination. Just think long and hard about this if it's for copy protection, you don't want to punish users too much...
Posted on 2006-09-27 08:50:42 by f0dder