Data compression is a set of steps for packing data into a smaller space, while allowing for the original data to be seen again. Compression is a two-way process: a compression algorithm can be used to make a data package smaller, but it can also be run the other way, to decompress the package into its original form. Data compression is useful in computing to save disk space, or to reduce the bandwidth used when sending data (e.g., over the internet). 