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KriVa

737 DU refresh rate?

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While taking photos of the newest bird for Jetairfly today, I started wondering about something...What is the refresh rate of the DU's?I could go pretty high up in my shutter speeds and still not see the well known jagged edges you get when you take pictures from "normal" LCD screens.I don't know if this has been discussed before (I did try a search, which resulted in well... just about nothing).

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I read it as 80 Hz vertical ( I might be wrong, broken memory ), graphics capability of each DU graphics processor equivalent to an ATI 5850 or GTX 280, but this was since 90s when NG first came out. Do enlighten if you come up with something ...

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graphics capability of each DU graphics processor equivalent to an ATI 5850 or GTX 280

 

I very seriously doubt that's true - the DUs aren't rendering 3D graphics that require tons of fill rate and processing power. It's 2D bitmapping essentially. The NGs were designed in the early to mid 90s before 3D video cards like we have today really even existed. I bought my first 3D card (3dfx) sometime around 1996 or 1997 and that was extremely primitive - a modern card like the ones you listed has hundreds or even thousands of times the power that the very first ones did.

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I remember going through this when I was doing my research on which graphics card to buy suitable for FSX about 1.5 years back keeping the NGX and my budget in mind, I read in some technical write up for project magenta 737 home sim builders that the actual fill rate of a real NG DU is equivalent to that of a modern ATI 5850, thought was believable since each of the real ones end up costing like USD 10,000. never thought about 3D capability of the real NG DU, don't think it's of any use over there.

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I very seriously doubt that's true - the DUs aren't rendering 3D graphics that require tons of fill rate and procession power. It's 2D bitmapping essentially. The NGs were designed in the early to mid 90s before 3D video cards like we have today really even existed. I bought my first 3D card (3dfx) sometime around 1996 or 1997 and that was extremely primitive - a modern card like the ones you listed has hundreds or even thousands of times the power that the very first ones did.
Yeah, aircraft computers are extraordinarily primitive. The FMC has a 60 Mhz processor or something like that. I have a 95' Pentium 400 in my room that is better than what is found on most aircraft.

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Speaking of FMC processors, a friend of mine wondered if I ever saw a message saying something like "Syncronizing FMCs". I have never seen that in a sim, but apparently it happens all the time in real life. The FMCs computer is simply so slow that one have to wait for data to get syncronized between the various systems before new data can be entered. This was on the B744, I imagine that the NG FMCs are a bit quicker.

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Very primitive indeed:

The latest FMC – Model 2907C1' date=' has a Motorola 68040 processor running at 60MHz (30Mhz bus clock speed), with 4Mb static RAM and 32Mb for program & database[/quote']http://www.b737.org.uk/fmc.htm

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"Primitive" by the standards of todays latest-and-greatest, sure. Of course, the advantage of using such primitive technology is in part that the reliability and failure-rates of those processors has been well-established by operational experience, simply because they have been around for so long. Not only that, but the actual calculations required in a flight management system and the graphics displayed on the instrumentation are comparatively basic. As a side note: Most aviation geeks will be familiar with the often-quoted trivia that the Apollo moon missions were run on the equivalent of a few pocket calulators. It's essentially true, but it's worth remembering that in the 60's, that sort of computing power weighed almost as much as the Command and Lunar modules combined. They had to miniaturise it down into a briefcase-sized lightweight reliable device. "Moon Machines" is a fantastic doco series, with an episode dedicated solely to the navigation computer. Highly recommended!

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