YDL 4

[Longman, Bill]

> For context, 5 exabytes is enough storage to encode every word ever 
> spoken by a human being throughout history. The next big jump up in 
> processing power, 128-bits, is 3.4 x 10^34 bits (which has no 
> name). A 
> memory "card" of such a size, if made entirely of hydrogen 
> atoms, would 
> weigh about 567 million metric tons (again, if I have done 
> the math right).

How much would it weigh if it were made of holes?

One thing that's a limit to memory is the address bus width. That's the
bottleneck between the CPU and the memory. With a 32 bit address bus width,
the addressable memory limit is 4GB. Most newer CPUs have a 36 bit address
bus giving them direct access to 64GB of RAM (G4s and most i686s). The G5
has a 42 bit address bus. We leave the calculation to Clint, who'll probably
compare the sheer size of this number to acres of bacteria....