# How much storage does a Mind (from The Culture series) have in today's computer storage terms?

The Mind had an image to illustrate its information capacity. It liked to imagine the contents of its memory store written out on cards; little slips of paper with tiny writing on them, big enough for a human to read. If the characters were a couple of millimetres tall and the paper about ten centimetres square and written on both sides, then ten thousand characters could be squeezed onto each card. In a metre-long drawer of such cards maybe one thousand of them – ten million pieces of information – could be stored. In a small room a few metres square, with a corridor in the middle just wide enough to pull a tray out into, you could keep perhaps a thousand trays arranged in close-packed cabinets: ten billion characters in all.

A square kilometre of these cramped cells might contain as many as one hundred thousand rooms; a thousand such floors would produce a building two thousand metres tall with a hundred million rooms. If you kept building those squat towers, squeezed hard up against each other until they entirely covered the surface of a largish standard-G world – maybe a billion square kilometres – you would have a planet with one trillion square kilometres of floor space, one hundred quadrillion paper-stuffed rooms, thirty light years of corridors and a number of potential stored characters sufficiently large to boggle just about anybody’s mind.

In base 10 that number would be a 1 followed by twenty-seven zeros, and even that vast figure was only a fraction of the capacity of the Mind. To match it you would need a thousand such worlds; systems of them, a clusterful of information-packed globes…. and that vast a capacity was physically contained within a space smaller than a single one of those tiny rooms, inside the Mind...

How big would that be in gigabytes/petabytes, assuming the 'written text' on the notecards is plain, ascii-encoded text? The reason for that assumption is that if you had `1100001` written on a notecard, it represents the number `97` in base 10, but in ascii it's a lower-case `a`.

• Hi, welcome to SF&F. I think the quote is simply intended to give a sense of the vast scale of the Mind; rendering it in real-world terms... First, I'm not sure it's really on-topic here; but even if it is, if the character set is {0,1} then there is about 5 orders of magnitude difference in the information storage capacity between that and if the alphabet is the full Chinese character set. (i.e. the difference could be 10e30 bits vs. 10e47 bits.) Feb 21, 2020 at 17:56
• This is pretty borderline on not being on-topic. Feb 21, 2020 at 19:03