If a .zip file contains all of the information of the original, just in less space, why does it have to be unzipped to access any of it?

Question

If a .zip file contains all of the information of the original, just in less space, why does it have to be unzipped to access any of it?

In: 1276

Answer 1

Computers need data to be structured and aligned in exact lengths (say 32, 64… bits) and must be able to access it in random order. Compression algorithms are able to compress effectively only long chunks of data, making them inditinguishable from random gibberish. Current computer architectures cannot random access nor distinguish data in compressed format since structure is completely lost and depends on the data being compressed, so there is no general rule to be able to do that.