 The ZX80 was an immediate success , selling 20 @,@ 000 units over the following nine months . Science of Cambridge was producing <unk> at the rate of 9 @,@ 000 a month by the end of 1980 and within 18 months of its launch the company had sold 100 @,@ 000 units . The commercial success of the ZX80 made a follow @-@ up product inevitable . The company was renamed Sinclair Computers in November 1980 , reflecting its new focus , and became Sinclair Research in March 1981 . 
