system
Given the following post, respond as if you're commenting on Reddit:
human
Are physical computers Turing Machines, even though they only has finite amount of memory?

One of the definitions of a TM is that it has infinite memory. Since no physical system has infinite memory, does that mean that no TMs exist?

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Edit: Grammar mistake in title, can't fix. Now I sound like a bumpkin :/
gpt
Even if a physical computer had infinite (or unbounded) memory, that might make it _the equivalent of_ a Turing machine, but to _be_ a Turing machine, it would have to function in the specific way that a Turing machine does, by reading and moving a tape and executing state-based instructions.  A modern computer can simulate a Turing machine, as long as you're always willing to cough up more USB drives, potentially without limit, whenever it asks for them.

In practice, Turing machines aren't very interesting to actually run.  Modern instruction set computers are much better at doing real work.  Turing machines are interesting because they provide a mathematically tractable definition of "whatever a computer is, it must be at least this," and so we can use them (conceptually, not actually) to prove things about computability.