| 摘要 |
1,139,207. Monitoring data on a magnetic tape or disc. INTERNATIONAL BUSINESS MACHINES CORP. 23 May, 1966 [2 July, 1965], No. 22822/66. Heading G5R. Signals from and to a computer 60 are recorded and/or sensed on a magnetic tape 10 which moves at a velocity V past write and read head gaps 61, 62 in a surface 31 separated from the tape by a spacing h which is controlled by varying the vacuum pressure in ports S1 to S6, by means of a variable pneumatic resistance 52. If there is an error in the signal read by head 42 it is sensed by an error check circuit 21 which causes computer 60 to respond in a particular programmed manner to control movement of the tape forward, backward or to stop it in order to write, read, backspace block, forward space block or rewind the tape. Circuit 21 also sets an error trigger 22 and a pneumatic control trigger 28 which reduces pneumatic resistance 52 and decreases spacing h. The error is corrected by continually rewriting and rereading that part of the tape on which the error occurs, with the tape 10 and surface 31 separated by the reduced spacing h. |
