The UNIVAC at Lawrence Livermore National Laboratory had a large console with a series of switches that could be set to address each of the machine's 1,000 words of memory. Once set, the contents of that memory location would be displayed on the console's oscilloscope. An electric typewriter could be used to direct the machine and was useful for debugging. The largest data system was a set of ten tape units, designed to read and write backwards and forwards. These served as an expanded main memory, allowing larger data volumes and even larger programs than would fit in the small amount of main memory. No photographer credited, circa 1950s.