user11326: For example, could modern Stockfish theoretically, with the hardware at the time, be entered into the 1974 World Computer Chess Championship?  If so, would it be grandmaster level?

user825: Stockfish is a C++ source code chess engine, so it will work if you can compile it. However, the C++ language was invented after the 1974 World Championship, so it wouldn't work even if you had the source code back in 1974.
No. Nothing would play at a grandmaster level on the 1974 hardware. Don't believe me? Limit your Stockfish to 100 nodes per move, and see what happens.

user4418: 
could modern Stockfish theoretically, with the hardware at the time,
  be entered into the 1974 World Computer Chess Championship?

No. Modern Stockfish is not compatible with 1974 computer architecture.
Modern engines which can run on 64-bit Linux should be able to run on an early 90's Digital Equipment Corporation 64 bit Alpha PC running Unix with a suitable recompile and perhaps tweak of the code.

11326: <p>For example, could modern Stockfish theoretically, with the hardware at the time, be entered into the 1974 World Computer Chess Championship?  If so, would it be grandmaster level?</p>
 825: <p>Stockfish is a C++ source code chess engine, so it will work if you can compile it. However, the C++ language was invented <strong>after</strong> the 1974 World Championship, so it wouldn't work even if you had the source code back in 1974.</p>

<p>No. Nothing would play at a grandmaster level on the 1974 hardware. Don't believe me? Limit your Stockfish to 100 nodes per move, and see what happens.</p>
 4418: <blockquote>
  <p>could modern Stockfish theoretically, with the hardware at the time,
  be entered into the 1974 World Computer Chess Championship?</p>
</blockquote>

<p>No. Modern Stockfish is not compatible with 1974 computer architecture.</p>

<p>Modern engines which can run on 64-bit Linux should be able to run on an early 90's Digital Equipment Corporation 64 bit Alpha PC running Unix with a suitable recompile and perhaps tweak of the code.</p>
