6.7 KiB
Information
Information wants to be free.
Information (from Latin informare: shape/describe/represent) is knowledge that can be used for making decisions. Information is interpreted data, i.e. while data itself may not give us any information, e.g. if they're encrypted and we don't know the key or if we simply don't know what the data signifies or implies, information emerges once we make sense of the data. Information is contained e.g in books, on the Internet, in nature, and we access it through our senses. Computers can be seen as machines for processing information and since the computer revolution information has become the focus of our society; we often encounter terms such as information technology, informatics, information war, information age etc. Information theory is a scientific field studying information.
Information wants to be free, i.e. it is free naturally unless we decide to limit its spread with shit like intellectual property laws. What does "free" mean? It is the miraculous property of information that allows us to duplicate it basically without any cost. Once we have certain information, we may share it with others without having to give up our own knowledge of the information. A file on a computer can be copied to another computer without deleting the file on the original computer. This is unlike with physical products which if we give to someone, we lose them ourselves. Imagine if you could make a piece of bread and then duplicate it infinitely for the whole world -- information works like this! We see it as a crime to want to restrict such a miracle. We may also very nicely store information in our heads. For all this information is beautiful. It is sometimes discussed whether information is created or discovered -- if a mathematician comes up with an equation, is it his creation or simply his discovery of something that belongs to the nature and that has always been there? This question isn't so important because whatever terms we use, we at LRS decide to create, spread and freely share information without limiting it in any way, i.e. neither discovery nor invention should give rise to any kind of property.
In computer science the basic unit of information amount is 1 bit (for binary digit), also known as shannon. It represents a choice of two possible options, for example an answer to a yes/no question (with each answer being equally likely), or one of two binary digits: 0 or 1. From this we derive higher units such as bytes (8 bits), kilobytes (1000 bytes) etc. Other units of information include nat or hart. With enough bits we can encode any information including text, sounds and images. For this we invent various formats and encodings with different properties: some encodings may for example contain redundancy to ensure the encoded information is preserved even if the data is partially lost. Some encodings may try to hide the contained information (see encryption, obfuscation, steganography). For processing information we create algorithms which we usually execute with computers. We may store information (contained in data) in physical media such as books, computer memory or computer storage media such as CDs, or even with traditional potentially analog media such as photographs.
Keep in mind that the amount of physically present bits doesn't have to equal the amount of information because, as mentioned above, data that takes N bits may e.g. utilize redundancy and so store less information that would theoretically be possible with N bits. It may happen that the stored bits are correlated for any reason or different binary values convey the same information (e.g. in some number encodings there are two values for number zero: positive and negative). All this means that the amount of information we receive in N bit data may be lower (but never higher) than N bits, i.e. if we e.g. store a file on a 1 GB flash drive, the actual theoretical information contained may be lower -- the exact size of such theoretical information depends on probabilities of what can really appear in the file and MAY CHANGE with the knowledge we posses, i.e. the amount of information stored on the flash drive may change by simply us coming to know that the file stored on the drive is a movie about cats which rules out many combinations of bits that can be stored there. Imagine a simplified case when there is file which says whether there exists infinitely many prime numbers -- to a mathematician who already knows the answer the file gives zero information, while to someone who doesn't know the answer the file provides 1 bit of information. However in practice we often make the simplification of equating the amount of physically present bits to the contained "information".
Information is related to information entropy (also Shannon entropy, similar to but distinct from the concept of thermodynamic entropy in physics); they're both measured in same units (usually bits) but entropy measures a kind of "uncertainty" or average information received from a certain event when we know its probability distribution -- in a sense information and entropy can be seen as opposites: before we receive information we lack the information but there exists entropy, once we receive the information there is information but no entropy.
In signal theory information is also often used as a synonym for signal, however a distinction can be made: signal is the function that carries information. Here we also encounter the term noise which means an unwanted signal mixed in with the desired signal which may make it harder to extract the information carried by the signal, or even obscure some or all of the information so that it can't be retrieved.
According to the theory of relativity information can never travel faster than light -- even if some things may move faster than light, such as a shadow, so called "spooky action at a distance" (usually associated with quantum entanglement) or even matter due to the expansion of space, by our best knowledge we can never use this to transfer information faster than light. For this it seems our communication technology will always be burdened by lag, no matter how sophisticated.