 Like PL/I F, it is a multiple pass compiler with a 44 kilobyte design point, but it is an entirely new design.Unlike the F compiler, it has to perform compile time evaluation of constant expressions using the run-time library, reducing the maximum memory for a compiler phase to 28 kilobytes.A second-time around design, it succeeded in eliminating the annoyances of PL/I F such as cascading diagnostics.