4 ms·
If they have possible values: TGAC, why not convert everything into base4? Wouldn't you get astronomical gains in storage?
by slayed0 12y ago
If they have possible values: TGAC, why not convert everything into base4? Wouldn't you get astronomical gains in storage?
- Htsthbjig 12y agoI wondered the same question.
- FrankenPC 12y agoI was wondering the exact same thing. They may already be doing this.
- dzhu 12y agoThey chose to encode one bit per base (rather than two) to give them flexibility in encoding the binary values to avoid particularly tricky sequences for DNA synthesis or sequencing (such as ones that have many repeating bases, e.g. AAAAA, which are known as homopolymers, or ones that have high GC content).
- slayed0 12y agoGreat explanation, thank you
- elmin 12y agoNot astronomical gains. Ignoring the technical challenges of a biological system like DNA, base 4 can encode the same data in exactly half as many characters, so capacity would double.
- slayed0 12y agoI don't think that's right. Assuming we had 5 characters to encode data, with base2 we get 2^5 = 32 possible combinations with base4 we get 4^5 = 1024 possible combinations
- epistasis 12y agoBut storage length is the log of the number of possible combinations, so you're back to just double the amount of storage.
- slayed0 12y agoBoth functions (2^x and 4^x) have exponential growth, but their exponential growth is not linearly related. 2*(2^x) != (4^x)
- epistasis 12y agoWe are talking about data, which is the log of the number of combinations, like any measure of information. If this interests you, definitely look into basic information theory, and then move onto coding theory. Take, for example, 32bit integers vs 64bit integers (unsigned for simplicity). Two 32 bit integers can represent exactly the same number of combinations that a single 64 bit number can. Sure, there's an exponential number more combinations in a 64bit integer than a 32 bit, but the number of combinations is not how the storage capacity is measured.
- euphoria 12y agoThe difference is exponential. 1 quaternary digit can encode twice as much information as 1 bit, yes. But 2 digits can store 16 possible combinations, whereas 2 bits can store 4. X digits of binary vs quaternary can represent 2^x vs 4^x possibilities. Even at 10 digits, that is 2^10 = 1024 vs 4^10 = 1048576.
- skosuri 12y agoWe are doing things more dense now, especially w/ a new project w/ OK Go; but it would be a 2x gain in density, which isn't that big of a deal.