done so. "I wasn't thinking of her - the Over-soul. I was thinking of it - the Index."
"It remembers everything," said Issib.
"How much of everything? The movements of every individual atom in the universe?"
Issib grinned at her. "Sometimes it seems like that. No, I meant everything about human history on Harmony."
"Forty million years," said Rasa. "Maybe two million generations of human beings. A world population of roughly a billion most of the time. Two quadrillion lives, with thousands of meaningful events in every life."
"That's right," said Issib. "And then add to those biographies the histories of every human community, starting with families and including those as large as nations and language groups and as small as childhood friends and casual sexual liaisons. And then include all natural events that impinged on human history. And then include every word that humans ever wrote and the map of every city we ever built and the plans for every building we ever constructed..."
"There wouldn't be room to contain all the information," said Rasa. "Not if the whole planet were devoted to nothing but storing it. We should be tripping over the Oversoul's data storage with every step."
"Not really," said Issib. "The Oversoul's memory isn't stored in the cheap and bulky memory we use for ordinary computers. Our computers are all binary, for one thing - every memory location can carry only two possible meanings."
"On or off," said Rasa. "Yes or no."
"It's read electrically," said Issib. "And we can only fit a few trillion bits of information into each computer before they start getting too bulky to carry around. And the space we waste inside our computers - just to represent simple numbers. For instance, in two bits we can only hold four numbers."
"A-1, B-1, A-2, and B-2," said Rasa. "I did teach the basic computer theory course in my little school, you know."
"But now imagine," said Issib, "that instead of only being able to represent two states at each location, on or off, you could represent five states. Then in two bits - "
"Twenty-five possible values," said Rasa. "A-l, B-l, V-1, G-1, D-1, and so on to D-5."
Chapter 6
"Now imagine that each memory location can have thousands of possible states."
"That certainly does make the memory more efficient at containing meaning."
"Not really," said Issib. "Not yet anyway. The increase is only geometric, not exponential. And it would have a vicious limitation on it, in that each single location could only convey one state at a time. Even if there were a billion possible messages that a single location could deliver, each location could only deliver one of those at a time."
"But if they were paired, that problem disappears, since between them any two locations could deliver millions of possible meanings," said Rasa.
"But still only one meaning at any one time."
"Well, you can't very well use the same memory location to store contradictory information. Both G-9 and D-9."
"It depends on how the information is stored. For the Over-soul, each memory location is the interior edge of a circle - a very tiny, tiny circle - and that inside edge is fractally complex. That is, thousands of states can be represented by protrusions, like the points on a mechanical key, or the teeth on a comb - in each location it's either got a protrusion or it doesn't."
"But then the memory location is the tooth, and not the circle," said Rasa, "and we're back to binary."
"But it can stick out farther or not as far," said Issib. "The Oversoul's memory is capable of distinguishing hundreds of different degrees of protrusion at each location around the inside of the circle."
"Still a geometric increase, then," said Rasa.
"But now," said Issib, "you must include the fact that the Oversoul can also detect teeth on each protrusion - hundreds of different values from each of hundreds of teeth. And on each tooth, hundreds of barbs, each reporting hundreds of possible values. And on each barb, hundreds of thorns. And on each thorn, hundreds of hairs. And on each hair - "
"I get the idea," said Rasa.
"And then the meanings can change depending on where on the circle you start reading - at the north or the east or south-southeast. You see, Mother, at every memory location the Oversoul can store trillions of different pieces of information at once," said Issib. "We have nothing in our computers that can begin to compare to it."