(19)

(11)

EP 0 527 792 A1

(12)

(43) Date of publication: 24.02.1993 Bulletin 1993/08 (21) Application number: 91908166.0 (22) Date of filing: 30.04.1991

(51) International Patent Classification (IPC):  G06F 9/ 44( . ) (86) International application number: PCT/GB1991/000687 (87) International publication number: WO 1991/017497 (14.11.1991 Gazette 1991/26)

(84) Designated Contracting States: DE FR GB (30) Priority: 30.04.1990 GB 19900009702 (71) Applicant: HEWLETT-PACKARD COMPANY Palo Alto, California 94304-1181 (US)	(72) Inventors: ROBSON, Christopher Stoke Gifford, Bristol BS12 6Q2 (GB) MOREL, William Paul Stoke Gifford, Bristol BS12 6Q2 (GB) DUGGAN, Hugh Stoke Gifford, Bristol BS12 6Q2 (GB) (74) Representative: Squibbs, Robert Francis  Hepworth, Lawrence, Bryer & Bizley, Lewins House, Lewins Mead Bristol BS1 2NN Bristol BS1 2NN (GB)