Tustin, Backward or Forward

There are different methods of integration available in the discrete integrator blocks. What is the difference between these methods? Often software developers writing code for these blocks do not appreciate the differences between these. This Simulink model tries to bring out these differences and brings out the importance why the Software Requirement Document very clearly specifies the algorithm. Try these blocks with different sampling time.
The problem computes the solution to the differential equations dy/dt = -10 y(t), y(0) = 1.The exact mathematical solution exp(-10t). All the four are compared in this Simulink file. A similar exercise is done in the link provided.