I think he meant that Partition Magic was reading the Linux partition of the drive (he installed 'another OS' on the PS3), that's most likely what it picked up.
Right, but it must have a variable component to it as well (since the HDD/Mobo serial would be constant).
For example, I can take the same PS3 and format two HDDs, but if I try and put the first one back in, it doesn't pair up, meaning the PS3 either stores a single key to use time and time again (which is why it doesn't recognize the first HDD) or it incorporates a variable 'piece' of the key into each 'pairing' operation. At any rate, it needs to store this 'variable' info internally in order to recognize its matching HDD.
Going back to the idea of having the PS3 perform the same writing operation on multiple HDDs (or fake partitions), the pieces containing the HDD/mobo/etc serial should produce a familiar pattern each time, allowing the variable component to be isolated.
My thinking could be too much of a pie-in-the-sky idea though...
*Sorry, couldn't edit the post (I guess I was too late)
What I meant to say was not necessarily 'each time' but if it repeated a pattern more than once (say on the 20th time), then you could theoretically isolate the variable component by analyzing the difference between the two (the difference being the variable piece)