[quote]The Forerunners had no way to know where the flood were at any given moment as the Burns were blocking their slipspace abilities which include their sensors.[/quote]Burns are just themas that had succumbed to the Flood. They don't produce any obstructing signals or energies. Mathematics is a surprisingly powerful tool. You'd be surprised with what you can calculate - and accurately too - despite having limited resources. That is true for both real life and Halo. One such example in Halo is the Carver findings, which were able to accurately model the dynamics of human civilization in the late 25th century and predict the coming insurrection. Another is that anyone with a clear view of the stars and radio equipment, as well as a basic understanding of math could locate human colonies (this one was mentioned in the adjunct of the Fall of Reach I believe). So for the Forerunners, who had MUCH more advanced technology, processing power, AI, and mathematics, it's not out of the realm of possibility they'd be able to accurately model the probability of the Flood accessing slipspace. Further than that, the IsoDidact literally says the Forerunners did this at the end of Silentium when they're beginning to make preparations to fire Halo. So even if you don't agree with its believability, it's canon. [quote]The flood were able to survive on the halo ring in Halo 1 for 100 thousand years with no bio matter.[/quote]That is because they were being purposely kept alive for research purposes.