A single Turing machine can perfectly emulate any number of independent concurrently running Turing machines (including an unbounded number), so I’m not sure that the distinction for abstract machines is relevant.
In the physical realm, it is certainly true that modern computers actually contain many different physical computers. Though again, one physical computer can also emulate multiple physical computers so the distinction isn’t all that great there either.
I do think that most of the apparent limitation is actually a human limitation. My computer at the moment is doing at least half a dozen different top-level tasks (i.e. not just housekeeping or support tasks), but most of them are not constantly competing for my limited human attention on the physical screen at once.
Thanks for the clarity, it is helpful. Although of course a turing machine simulating unbounded concurrent turing macchines would be slower than the machines running independently.
A single Turing machine can perfectly emulate any number of independent concurrently running Turing machines (including an unbounded number), so I’m not sure that the distinction for abstract machines is relevant.
In the physical realm, it is certainly true that modern computers actually contain many different physical computers. Though again, one physical computer can also emulate multiple physical computers so the distinction isn’t all that great there either.
I do think that most of the apparent limitation is actually a human limitation. My computer at the moment is doing at least half a dozen different top-level tasks (i.e. not just housekeeping or support tasks), but most of them are not constantly competing for my limited human attention on the physical screen at once.
Thanks for the clarity, it is helpful. Although of course a turing machine simulating unbounded concurrent turing macchines would be slower than the machines running independently.