RIOTS―95: a MATLAB toolbox for solving general optimal control problems and its applications to chemical processes RIOTS―95 is a group of programs and utilities, written mostly in C, Fortran and M-file scripts and designed as a toolbox for MATLAB, that provides an interactive environment for solving a very broad class of optimal control problems (OCP’s). RIOTS 95 comes pre-compiled for use with the Windows 95/98/2000 or Windows NT operating systems. The user’s OCP can be prepared via either M-file or C-file interface. For M-file interface, no compiler is needed to compile the user-provided codes. This chapter describes the use and operation of RIOTS―95 together with two demonstrative examples in solving OCP’s, one of which is for a fed-batch fermenter. Detailed codes related to M-File and C-file interfaces are given in two appendices.