Monday, February 7, 2011

Ultimate bit

How many bits of digital storage capacity humanity has right now in hard disks?

"How many computers?" I asked Wolfram Alpha search engine.

The answer came back as:

Estimated number of personal computers worldwide:

over 1 billion

Then I had to make a bold part guess of average storage per computer. Big fat machines that belong to governments and fortune 100 companies will have substantial capacity per computer. But there must still be many old machines around with small capacity as well. I estimated that 64 GB per machine would be too conservative as it was the benchmark 4-5 years ago. I thought 100GB would be a good figure.

So the number of bits came out as:

1 billion X 100 GB = 100 EB (exabytes) = 8 X 1020 bits

That is

800,000,000,000,000,000,000 bits

This number would be equal to eight times estimated information content of all human knowledge (10EB).

This means we have a growing memory surplus that we could meaningfully fill, also we still have no operational or economical capacity to store everything we know on hard disks.

I am not ignoring the fact that gene technology trends will require huge amount of storage to keep gigantic databases of gene sequences required by genetically modified food, bio-fuel research and so forth. But I still think it will lag behind available storage capacity as the global consumer market will always put huge pressure on reducing storage cost. Also the main problems in gene research seems to be indexing and CPU cycles rather than storage capacity.

So I estimate available storage will always be 10 times of human knowledge and at least 100 times of used storage.

Where is the most vulnerable of those useable bits that when flipped would cause the maximum catastrophic impact on humanity I wonder?

One nasty bit that its redundancy is incidentally non-existent.

Like all physical systems hard disks do fail. When hard disk fails software almost always fails.

On ageing nuclear missile sites?

On ageing GPS satellites?

One freak magnetic storm in space?


It would take just one bit to flip forever from 1 to 0 or from 0 to 1 out of 8,00,000,000,000,000,000,000.

I would like to buy a new notebook computer nowadays. I think I am going to pick a machine with a solid state drive (SSD).

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