The mini-computer was a precursor to the personal computers that are ubiquitous today. Prior to the development of the mini-computer, scientists doing computer-intensive calculations shared mainframe computers that were expensive multi-user facilities the size of small houses. Mini-computers cost ten times less than mainframe computers, fit into a single room, and had sufficient computing power to solve numerical problems in physics and astronomy when fully dedicated to that purpose. When mini-computers first became available, many areas of scientific research blossomed, including the study of how structure formed in the universe.