The first commercially used computer was the UNIVAC I, which weighed 16,000 lbs. The computer was released in 1951 and was designed for general purpose computing.
The UNIVAC I was a large machine of 25 feet by 50 feet in length. It was the first computer to use buffer memory and it was outfitted with a magnetic tape unit. J. Presper Eckert and John Mauchly designed the computer. It used 5,200 vacuum tubes was able to perform approximately 1.905 operations per second. The machine was used for payroll and other business purposes by many companies and it remained in use until 1970.