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| | Dr.Wily said: |
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| | TrekkiesUnite118 said: |
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TrekkiesUnite2018, Irimajiri's interview dates from October 2022. Irimajiri was not an engineer, so he was speaking from his vague memories. Same remark for Sato's most recent interview in 2018. Books, videos, documentaries have been written or made on the PlayStation success story for the last ten years. Don't you think SEGA chairmen or engineers just followed what they read or saw ? It was a good opportunity for them to disguise in a way the truth. For what reason ? I don't know. A cheque from Sony or a better visibility on PlayStation stores ? Everything is possible actually to arrange a potential truth to flatter even more Sony's image.
Dr.Wily, if we follow precisely what the topic given by fafling about the history of the SH-2 development (Nikkei Electronics Magazine, 22 September 1997, date which matches far better the context of the time) says, everything seems pretty clear even if you would possibly counterargue that the 2 SH-2 had to share the same bus (But is it really such a bottleneck ? That is the real question here...) :
A Request from the Research Lab
One day, the SH development group received a written message from Nobuyoshi Doumen, the head of the System Development Lab. It read, “Did anything ever come of the multiprocessor function that we discussed before?”
A few months prior, Doumen had requested the inclusion of a multiprocessor function in the SH-2. At that time, the lab was researching the development of a digital assistant for reading news articles code-named “Yajiuma Shimbun” and wanted to use the SH-2 in a multiprocessor configuration. However, the SH group did not want to include the function just for a research system and had been pretending to overlook the request.
When the second request came, they were unable to continue to ignore it. They were indebted to Doumen for a previous problem with the number of registers in the SH that he had helped them to overcome. They decided to include a rather simple circuit that would allow the SH-2 to be used in a multiprocessor configuration. “In my mind, I thought that certainly nobody would ever use that function,” Kawasaki recalled.
The Secret to Improved Performance
In the summer of 1993, a slight incident occurred. Sega stated that the performance of the SH-2 (25 MIPS) was insufficient for a next-generation home console (this was right around the time when Sega’s biggest rival Nintendo announced that they were including a 64-bit CPU as well as a graphics processor jointly developed with Silicon Graphics, Inc. in their next console, the Nintendo 64). They wanted to increase the performance of the SH-2 by raising the frequency. However, to do that, it would be necessary to re-examine the chip design, and the SH development group did not have the time remaining to do that.
The decision of what to do was left for the top-level meeting between Hitachi and Sega executives that took place in Hakone in September 1993. The SH group had prepared a secret plan to resolve the “performance improvement problem.” Their solution was stated as follows: “If we use the multiprocessor function that is included in the SH-2, we can operate two SH-2s linked together. This should satisfy the request for higher performance.” Nobody had expected that the multiprocessor function, which they had been reluctant to include, would prove to be this useful.
In this way, Sega’s next console, the Sega Saturn, came to be equipped with two SH-2s.
Furthermore, Hideki Sato said in his 2018 interview some trollesque remarks with a customer and wrong communication perspective to make the Saturn comparable to the coming N64 at the time, meaning that PlayStation was really out of the scope of SEGA. Just like we did these past ten years, Hideki Sato read SEGA added a processor because of the PlayStation and like a parrot, he repeats the same thing he would read in the past. Nintendo was the guy to beat, not Sony. Just like the SH-2 article quotes, the N64 is the first target SEGA would lock, as always :
Hideki Sato, 2018 interview :
It seemed like we were finally nearing completion. Then, the final PlayStation was revealed. It supported 300,000 polygons. Well, that was ultimately a bunch of lies, but… When you compared the Saturn with the PlayStation, we were completely missing something. The response that I chose was to add another SH processor, so we ended up with two SH-2s. By chance, the SH supported two-way cascaded data transfer. You could add a second processor and connect them in a cascade and get multi-CPU performance. When you get to about the PlayStation 3, multi-processors had become common, but the Saturn was the first home console to use multi-processors. So I added a second SH-2, but I felt that the ‘impact’ was still weak. Well, the SH-2 is a 32-bit processor, and we had two of them, so we could call the Saturn a 64-bit machine. It’s a dirty way of getting to 64-bits. But we revealed the CD-ROM-based Saturn using 64-bits as our sales point.
The two last lines show the former goal of the Saturn conception by SEGA, which was to reach in some way ("a dirty way of getting to 64-bits") the specs of the 64 bits machine made by Nintendo. Hideki Sato was counting on a fake advertising campaign to put the Saturn at the same level of the future Nintendo 64.
In the Nikkei electronics journal, we both have why there was one SH-2 planned originally and how they decided to put the second one. The circumstances might still be lacking of details or romanced but according to me, this is what we should rely on, not on Sato and Irimajiri's interviews which are full of inconsistencies because of the new recent context they were done with. |
