Thoughts on machine identity
One of the things my earlier entry got me thinking about was how differently people can see the issue of machine identity. Or, to make it more concrete, when do you give something a new name (even if the name is only in your head, not related to the OS-level hostname)?
(I could try to justify it by talking about how it shows something about how people think about their computers, but really it's just the kind of thing that satisfies my wandering curiosity, like discussions of computer naming schemes and pictures of people's desktops.)
One view is the physical one: a machine is its hardware, and new hardware means a new name. This is especially appealing for things like laptops, where a lot of the personality of the machine is in things like how the keyboard feels or the screen looks. It's also things like licensing software tend to think about it, famously including Microsoft's Windows activation stuff.
(Like all views of identity, things get fuzzy around the edges; for example, how many parts can you upgrade and replace (at once or spread out over time) before it's a different machine?)
I tend to a more abstract view of machine identity; as best I can describe it, machine identity is more or less tied to continuity of data and capabilities (somewhat in combination with the machine's role), not directly to hardware. As long as the hardware and the OS retain more or less the same capabilities, especially the ability to run my current software, it is the same machine.
This gets fuzzy around the edges for things like my current transition to Fedora Core 5 and the x86_64 architecture; a number of programs are falling off and my environment is changing a fair bit, although I have continuity of data and of a lot of programs. I'm not sure I still think of this as 'the same machine', and I certainly find myself wishing I could leave the old machine up with a reference copy of the old environment.
(I complicate my life by mostly assigning hostnames to roles instead of machine identities; for example, my main office machine is called 'hawkwind', regardless of what machine it is at the time. I do this because I tend to like my names too much to give them up just because I happen to have replaced the machine.)