How do PC files get compressed?

Question

How is it possible that a 10GB folder gets compressed into a 6GB exe or zip file?

In: Technology

Answer 1

Lots of clever mathy tricks depending on what compression algorithm is used. One way might be if a file has several repeating bits, say there’s 20 0 bits in a row, to replace them with a shorter pattern that describes the number of 0 bits that it replaced.

It might do the same with long repeating bit patterns, substituting them with a shorter patterns with a look up table to show what to replace when decompressing.

And lots of other ways to achieve the same thing: replacing lots of bits with fewer bits in a way that can somehow be restored when you want to uncompress the file.