Multiple shift registers

Claim 1

A PLURALITY OF SHIFT REGISTERS EACH COMPRISING: A PAIR OF SECTOR OPPOSITELY DISPOSED ABOUT A TRACK OF A ROTATING MAGNETIC MEDIUM EACH SECTOR HAVING A CORRESPONDING NUMBER OF CELLS FOR STORING DATA; A MARKER TRACK STORING A PLURALITY OF MARKER PULSES ARRANGED IN PAIRS TO MARK THE BEGINNING AND END OF EACH SECTOR; A MEANS FOR READING SAID MARKER PULSES; A FIRST MEANS FOR READING DATA STORED IN SAID CELL OF A GIVEN SECTOR IN A GIVEN PAIR; A SECOND MEANS FOR WRITING DATA IN CELLS OF THE OTHER SECTOR OF SAID GIVEN PAIR; A FIRST GATED CHANNEL CONNECTING SAID FIRST MEANS AND SAID SECOND MEANS TO RECORD IN THE CELLS OF ONE SECTOR THE DATA READ FROM THE CORRESPONDING CELLS IN THE OTHER SECTOR; A SECOND GATED CHANNEL HAVING A DELAY MEANS CONNECTING SAID FIRST MEANS AND SAID SECOND MEANS TO CAUSE A BIT READ FROM A GIVEN CELL IN ONE SECTOR TO BE RECORDED IN A CELL OF THE SECOND SECTOR FOLLOWING THE CELL WHICH CORRESPONDS TO SAID GIVEN CELL; MEANS FOR SELECTIVELY ENABLING ONE OF SAID FIRST AND SECOND GATED CHANNELS AND MEANS FOR DISABLING BOTH OF SAID FIRST AND SECOND GATED CHANNELS IN RESPONSE TO SAID MARKER PULSE MARKING THE BEGINNING OF A GIVEN SECTOR BEING READ; AND A THIRD GATED CHANNEL CONNECTING SAID FIRST MEANS AND SAID SECOND MEANS, SAID MEANS FOR DISABLING BOTH SAID FIRST AND SAID SECOND GATED CHANNELS IN RESPONSE TO A MARKER PULSE ENABLING SAID THIRD CHANNEL, SAID THIRD CHANNEL INCLUDING MEANS FOR INTRODUCING A BIT FROM AN EXTERNAL SOURCE TO BE WRITTEN BY SAID SECOND MEANS AND INCLUDING MEANS FOR EXTRACTING A BIT READ BY SAID FIRST MEANS.