Contributor: SWAG SUPPORT TEAM { MR> I have started playing With Borland Turbo Pascal 7.0 and I have a MR> problem. The Random routine is not the same as the one in TP 6.0. MR> Using the same RandSeed, they generate different series of numbers. MR> I have a couple of applications that depend upon the number series MR> generated by the TP 6.0 version. Can anyone supply me With the MR> algorithm used in the TP 6.0 Random routine? or maybe point me in MR> the right direction? I want to Construct my own TP 7 Random routine MR> that will behave as the one in TP 6. The way both generators work is to update System.Randseed, then calculate the new random value from that one. There have been several different ways to calculate the value; I think TP 6 is different from TP 5.5, and TP 7 is different again. The update algorithm has been pretty Constant. As I recall, you can simulate the TP 6 Random(N) Function in TP 7 as follows: } Function TP6Random(N:Word):Word; Var junk : Word; myrandseed : Record lo, hi : Word end Absolute system.randseed; begin junk := Random(0); { Update Randseed } TP6Random := myrandseed.hi mod N; end; { You might want to keep the following around in Case the update algorithm gets changed sometime in the future: Demonstration Program to show how the TP 6.0 random number generator updates System.Randseed. Allows the seed to be cycled backwards. } Procedure CycleRandseed(cycles:Integer); { For cycles > 0, mimics cycles calls to the TP random number generator. For cycles < 0, backs it up the given number of calls. } Var i : Integer; begin if cycles > 0 then For i := 1 to cycles do system.randseed := system.randseed*134775813 + 1 else For i := -1 downto cycles do system.randseed := (system.randseed-1)*(-649090867); end; Var i : Integer; begin randomize; Writeln('Forwards:'); For i:=1 to 5 do Writeln(random); Writeln('Backwards:'); For i:=1 to 5 do begin CycleRandseed(-1); { Back to previous value } Writeln(random); { Show it } CycleRandseed(-1); { Back up over it again } end; end.