| 摘要 |
1379355 Magnetic disc record INTERNATIONAL BUSINESS MACHINES CORP. 21 May 1973 [23 June 1972] 24039/73 Heading G5R A magnetic disc record 1 having only one recording surface 9 is formed with a centering aperture 3 and a second aperture 2 which is not symmetrical about a record radius whereby the record can only be positioned on the turntable 8, described in Specification 1,379,354 and provided with corresponding projections 5, 4, with its recording surface uppermost. |
