(19)

(11)

EP 0 151 129 A1

(12)

(43) Date of publication: 14.08.1985 Bulletin 1985/33 (21) Application number: 84902211.0 (22) Date of filing: 25.05.1984

(51) International Patent Classification (IPC):  G11B 5/ 10( . ) G11B 15/ 675( . ) G11B 15/ 62( . ) (86) International application number: PCT/GB1984/000184 (87) International publication number: WO 1984/004842 (06.12.1984 Gazette 1984/28)

(84) Designated Contracting States: AT BE CH DE FR GB LI LU NL SE (30) Priority: 27.05.1983 GB 19830014688 (71) Applicant: SINCLAIR RESEARCH LIMITED Cambridge CB1 2AQ (GB)	(72) Inventor: SOUTHWARD, David, Connor Cottenham Cambridge CB4 4QF (GB)