SECS program modules

Module Table I SECS Program Modules Description... 

With this overview let us now examine the components or modules of the SECS system shown in Figure 4. The executive is always present in memory together with one other module. This modular construction not only simplifies the program and makes it easy to maintain, but also allows us to keep memory requirements for execution of SECS below 48K 32 or 36 bit words. 

The simulation program comprises a number of modules, grouped in overlay phases. To save computation time the calculation of the matrix of total exchange areas was kept out of the inner iteration loop. This did not significantly affect the speed of convergence of the outer iteratioii cycle. With realistic starting estimates for Q. and T only 5 to 10 iterations were required. The CTP.U. time per iteration amounted to 50 sec on a Siemens 4004-150, a machine which is 14 times faster than the IBM 360-30 e.g. 

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