The big difference between FORTH and other stack machines (e.g., the JVM) is the runtime. FORTH doesn't have one to speak of. No dynamic memory management, no

The big difference between FORTH and other stack machines (e.g., the JVM) is the runtime. FORTH doesn't have one to speak of. No dynamic memory management, no garbage collection. It's about as bare-bones as you can get. PostScript, the JVM, the CLR and so forth are all backed by runtimes with powerful functionality.