Pro Tip: If you are downloading US Census summary files for use in PANDAS, it is a good idea to keep each summary file in a separate compressed ZIP file. PANDAS will automatically uncompress zip files on the fly if they have only one file inside, and it will cut your hard drive needs by roughly 90% over uncompressed — plus on modern computers ZIP decompression of a few megabyte zip file isn’t particularly slow, and chances are you only going to be processing a few segments at a time.