 One of the more bizarre software products for the ZX81 came about as a result of music companies attempting to capitalise on the popularity of Sinclair 's computers . In 1983 , EMI released a single by Chris Sievey that had a ZX81 program recorded on the B @-@ side . Island Records responded with XL1 by Buzzcocks frontman Pete Shelley , packaged with a program for the ZX Spectrum . 
