[Leica] Current State of Displays?

[Brian Reid]

There is an electronics/mathematics issue that factors into large 
displays. It's why I have an iMac and not an external display.

At any given time, the computer and electronics industry has some means 
that is the fastest for rapidly and reliably moving data over a cable. 
USB has never been in contention, but FireWire, Thunderbolt, DVI, and 
Fibre Channel have all been candidates for "the fastest and best" at one 
time or another. Ethernet, at any speed, has never been the fastest.

The 5K Retina display has about 15 million pixels. Each pixel can have 
about 10,000 different values (this number is a little soft). So one 
screen-shot on a 5K Retina display is 150 thousand million bits, about 
150 gigabits.

So to keep an iMac Retina display happy you have to feed it about 150 
gigabits for each screen refresh. People like 30 or 60 screen refreshes 
per second.

By putting some fast computing inside the display itself you can get 
away with not having to send the whole 150 gigabits every time. Which is 
a good thing, bdcause 150 gigabits sent 50 times per second is 7500 
gigabits per second.

If you try to send 7500 gigabits per second over a cable, you run into 
all manner of bad-ass electrical engineering issues. When good 
electrical engineers are speaking in hushed tones of the expertise of a 
master, they sometimes say "she can do terabit connections".

If you have an external display, then you have to have a cable that 
connects your computer to your display. That cable has to have at least 
one connector on it, so that it can plug into the computer. (Often the 
cable is permanently attached to the display to avoid having to use a 
connector there). Connectors are the black beast of high-speed signal 
transmission. They are much more difficult to design than cables, and 
cables themselves are hard.

In an iMac, the circuitry that generates the display signal is about 1 
inch away from the screen, and you can make multiple connections if you 
are tricky. That way you won't have to send the whole 7.5 terabits per 
second over one cable.

It's much easier to design and build the ultra-high-speed transmission 
capability in an all-in-1 design like the iMac than it is to design and 
build something that uses, say, an Eizo air traffic control display 
connected to a computer 5 feet away.

This is more or less why an iMac with a killer screen is just a few 
thousand dollars, while an air-traffic-control display system with 10 
good screens (though not as good as the iMac) is a few million dollars.