When Dennis Nedry was first hired by InGen to work on Isla Nublar, he was surprised by the sheer size of the database. Originally hired to work on the park’s database, his initial parameters were to create a database with three billion fields. He worked under a non-disclosure agreement, and had to build the mainframe for the database without being told what the real purpose of the park was. Meeting with a colleague, Barney Fellows, he stated that his job was mostly to reserve storage and memory for the whole system.
Barney Fellows speculated that the large size of the database could be due to working with DNA, a speculation which would prove correct. Nedry’s first vision was of the Human Genome Project as a potentially comparable thing that InGen could be working on, because they had attempted to analyze the entire human DNA strand. He dismissed that notion because the Project had taken ten years of project with laboratories worldwide working on it. He guessed a private company would never attempt something as ambitious as that, which he compared to the Manhattan Project (which had produced the first atomic bomb).
Barney suggested that perhaps InGen was being optimistic in designing their system, just to ensure that they had enough space. He postulated that RAM intensive algorithms that ate up a lot of memory space. Nedry and his team spent more then an year working on the system. However, he felt gradually frustrated as his design parameters were intentionally made vague by InGen in order to preserve secrecy.
The real reason why the database had required three billion fields was because InGen was using the system to process a whole DNA molecule. The strand contained three billion of the bases (adenine, thymine, guanine, and cytosine) of the DNA strand. The complexity of the system was required in order to analyze and select any point in the strand at will, making the genetic engineering of the dinosaurs an easier task.
Jurassic Park by Michael Crichton page 101, 103-104 (First Edition, Thirty Fourth printing)