if you're willing to write a plugin here's a native snippet of C/ObjC  
you can use to get the serial number.

     io_service_t platformExpert = IOServiceGetMatchingService(
         kIOMasterPortDefault,
         IOServiceMatching("IOPlatformExpertDevice"));

     if (platformExpert) {
         CFTypeRef serialNumberAsCFString =
             IORegistryEntryCreateCFProperty(platformExpert,
                                              
CFSTR(kIOPlatformSerialNumberKey),
                                             kCFAllocatorDefault, 0);
         IOObjectRelease(platformExpert);
     }

hth,

--Marc

On Apr 23, 2008, at 11:28 AM, tim Rowledge wrote:

>
> On 23-Apr-08, at 10:35 AM, Norbert Hartl wrote:
>
>> On Wed, 2008-04-23 at 15:00 +0200, Javier Reyes wrote:
>>> Hi Edgar,
>>>
>>> It's for a licensing server. I think I've found a way to do it using
>>> the ethernet physical ID trough:
>>>
>>> Applescript doIt: 'do shell script "ifconfig en0"'.
>>>
>>> And then filtering the physical address.
>>>
>> This won't work. Usually the MAC address shown is only a copy
>> of the number stored on the device. You can alter this address
>> easily.
> I assume simply replacing the ethernet card - or even just adding  
> one and reassigning which is en0 - would mess it up pretty badly.
>
> Many CPus have an actual unique ID that is findable somewhere. Even  
> there you're in trouble if the cpu has to be replaced due to failure  
> of upgrade.
>
>
> tim
> --
> tim Rowledge; tim at rowledge.org; http://www.rowledge.org/tim
> The next generation of computers will have a "Warranty Expired"  
> interrupt.
>
>
>