Important era of Computer invention By UMER Period: 1947 to 1947 Silicon transistor Bell's Lab Period: 1951 to 1951 Memory device Random access magnetic core store by J forster Period: 1954 to 1954 Transistorized Computer First Transistorized Computer Period: 1957 to 1957 Hard drive IBM introduced the Hard drive of 5MB Period: 1958 to 1958 Semiconductor Integrated Circuit First Semiconductor Integrated Circuit was invented by Jack S. Kilby