[lispm]

One of the main differences is that much of Mathematica is written in C++ (for example the UI). The Mathematica language then itself is a slow language (term rewriting, is not a really good low-level language).

Medley is written is largely written in Interlisp (and a bit of Common Lisp), including its UI. Interlisp (originally as BBN Lisp) was originally developed as an integrated development environment with complete source management (similar what Smalltalk later did). In the 70s it was then moved to the metal on early workstations (again, similar what Smalltalk did) -> it was its own OS. It does memory management, networking, graphics, all in Interlisp, ... Its purpose was to be a development environment for Lisp (here Interlisp).

Mathematica's purpose is to be an integrated tool in the mathematics domains, including applied mathematics in physics, chemistry, visualization, biology, ...

The nearest system to Interlisp-D is/was Smalltalk 80.

[7thaccount]

Oh I agree that a Lisp machine or Smalltalk machine is turtles all the way down. The only problem is that it seems like there isn't really a good modern option with fully modern libraries and all that. Mathematica is a nice tool for exploring all kinds of computations in a manner that is kind of similar to lisp with brackets if you squint. That may or may not be of use to some on here. I only mention it as I don't think many in the CS field get exposed to it.

[lispm]

> I only mention it as I don't think many in the CS field get exposed to it.

Because it is a specialized commercial offering.

> Oh I agree that a Lisp machine or Smalltalk machine is turtles all the way down.

Many non-Lisp-Machine Lisps are also mostly written in itself. Implementations like SBCL provide a wide spectrum of performance.