Octave tries to make every Matlab program run unmodified. A difficult goal, but that is the goal. Scilab doesn't try that exactly. They have their own syntax a

Octave tries to make every Matlab program run unmodified. A difficult goal, but that is the goal. Scilab doesn't try that exactly. They have their own syntax and some compatibility converter from Matlab code to Scilab code, but I don't thik it's as complete as Octave's. As a sibling comment mentions, Scilab has Xcos which tries to be a modelling helper like Simulink and Octave has nothing comparable.