How Does Data Storage Work?
A computer stores data in two ways: on its hard drive and in its RAM. The hard drive is much larger — easily 100 gigabytes — and much cheaper, so that’s the best place to dump huge amounts of data. The RAM is critical, however, because it’s where you take the data to work with it. A computer’s “virtual memory manager” chooses blocks of data to move back and forth between the hard drive and the RAM — even if you need just one piece of data, a whole block goes with it. Transferring these data blocks takes time, and creates a bottleneck in the program’s calculating speed. The best way to speed things up is to store and use data in an efficient order to minimize the number of blocks you need to transfer, and the number of times you need to transfer each one. To explain the scope of the computing challenge, Toma refers to an image that was taken of parts of Washington State. At a resolution of 33 feet, the image generated one billion points of data, each requiring at least 16 bytes of RAM (
