Data processing apparatus

Claim 1

INFORMATION STORAGE APPARATUS FOR STORING A PLURALITY OF BINARY DIGITS IN SUCCESSION, INCLUDING AN ANISOTROPIC MAGNETIC THIN FILM ELEMENT HAVING MUTUALLY PERPENDICULAR EASY AND HARD AXES OF MAGNETISATION AND BEING SWITCHABLE TO A FIRST STATE IN WHICH THE MAGNETISATION IS ALIGNED IN ONE DIRECTION SUBSTANTIALLY ALONG THE EASY AXIS TO WRITE A DIGIT OF FIRST BINARY SIGNIFICANCE INTO THE ELEMENT, AND TO A SECOND STATE IN WHICH THE MAGNETISATION IS ALIGNED IN THE OPPOSITE DIRECTION SUBSTANTIALLY ALONG THE EASY AXIS TO WRITE A DIGIT OF SECOND BINARY SIGNIFICANCE INTO THE ELEMENT; MEANS OPERABLE, IN A SUCCESSION OF WRITE-READ CYCLES IN EACH OF WHICH A SUCCESSIVE DIGIT IS WRITTEN INTO THE ELEMENT IN A WRITING PHASE AND READ-OUT FROM THE ELEMENT IN A READING PHASE, TO APPLY TO THE ELEMENT A FIRST MAGNETIC FIELD SUBSTANTIALLY ALIGNED WITH THE HARD AXIS, SAID FIRST FIELD BEING APPLIED FOR EACH WRITING PHASE AND REAPPLIED FOR EACH READING PHASE; AND MEANS OPERABLE TO APPLY TO SAID ELEMENT, AT THE BEGINNING OF A WRITE-READ CYCLE, A SECOND MAGNETIC FIELD SUBSTANTIALLY ALIGNED WITH THE EASY AXIS TO CAUSE, IN COMBINATION WITH SAID FIRST FIELD, A DIGIT OF ONE BINARY SIGNIFICANCE TO BE WRITTEN INTO THE ELEMENT, AND TO MAINTAIN THE APPLICATION OF SAID SECOND FIELD UNTIL THE BEGINNING OF THAT NEXT OCCURRING WRITE-READ CYCLE IN WHICH A DIGIT OF THE OTHER BINARY SIGNIFICANCE IS TO BE WRITTEN INTO THE ELEMENT.