Tobe: During development when we were talking about what sort of graphics performance could be expected of the VAIO SZ, it was estimated that we could achieve roughly double that of the VAIO S benchmark. If we doubled battery life as well, it would surely be an amazing product. Now the previous VAIO S had an external graphics controller and a battery life of 3.5 hours. — Could you explain exactly how the hybrid graphics system works? Koide: Picture two graphics chips, mounted together on the same motherboard so you can switch between them. It's literally a hybrid system. — What was most difficult? Hayashi: First, when the decision was made to go with hybrid graphics, people just wouldn't believe that this would extend battery life. But Tobe-san did the calculations and proved that it really would work. Only then did everyone appreciate what it could do for battery life. But the actual development went quite smoothly, I think, from the implementation onwards, thanks to the fact that we had worked out all the details very thoroughly in the early stages. Kawata: We had several meetings and then, when we reached the point of deciding on the general layout, we used breadboards to see if it would work. And it did! I was genuinely impressed. Koide: One talks about switching, but it's not as simple as that. We had to go through a series of processes, checking that each idea, which worked in principle, actually worked in practice. The process of trial and error was repeated, and at one point we seemed to be groping in the dark, looking for some kind of bright idea. There were some wrong turns along the way, but somehow we gradually made progress. We had a good tool to work with — the breadboard — and since we had made an early start, we were able to find the time and eventually succeed. Tobe: In actual fact, just getting the pair of graphics controllers to work was not so difficult. But we spent a lot of time working on such things as the appropriate interface for delivering the output of the two controllers to the same display device; how to ensure, when outputting to a CRT, that part would be invisible to the user; how best to enable the user to switch between internal and external; and how the interface should be presented. Also, when the external graphics controller isn't being used, power will be wasted if the supply isn't shut off, and since extending battery life is, after all, the point of the exercise, it's necessary to shut off power to the graphics controller that is not being used. It was quite a difficult task solving these various issues associated with the use of hybrid graphics in order to create a product that actually benefited from this approach. Nishino: It was a long journey. At first, many ideas were put forward for the actual switching, including snapping back and forth between controllers while the computer is in actual use. But we faced a technical obstacle. " Well then, let's take a different approach — say, rebooting. You could use one controller when out of the office, and the other when at your desk — that way, you'd enjoy the advantages of the hybrid system." We thought about it, and thought about it, and then checked to see if it was really doable. This whole process was very tiring, but, after we had proved it would work, the rest was relatively easy. Rather than the actual implementation, what was most difficult was this process of testing and discussing that led up to the final decision on the type of approach we would adopt. Kawata: Ideally, the user would simply be able to switch between controllers as needed, but there was a technical reason why we couldn't do this, and rebooting was the only solution. Nevertheless, to facilitate switching to suit different situations — in the office, or on a business trip, say — we developed a convenient utility.