How many of you like HP41C calculators?

There are several architectures for computers, with all being the equal of the Turing machine. Frankly, the Turing machine is the definition of a computer, so any similarity with physical hardware implementations is either, purely coincidental, or (and this is the more likely option), it too is a computer. The writing of self-modifying code (a specialty for me) does require that the data path have access to the code store, and not all processors support such access. So, it is not possible to construct run-time self-modifying code for all processors. Nevertheless, for all systems of computation, there is the possibility of self-modification of code which is accessible through other means, typically in the form of a file. Also, remember the features of some languages, like APL, which will operate on von Neumann and Harvard architectures, and which APL code might include the execute operator, which facilitates run-time code generation and execution. Data processing in inherently a task of translation. William R. Buckley