Some historians, however, count as the first "true" portable the "Osborne 1". It was created in 1981 by Adam Osborne who was also a former book publisher. He was the founder of Osborne Computer. His portable computer weighed 11 kg (24 pounds) and had a five-inch (13 cm) screen, a serial port and two floppy disk drives. Several programs were included with the Osborne 1. Customers could also buy a 1-hour battery pack.