Handling defective frames on hard sectored magnetic tape

A method of operating a magnetic tape drive which transduces frames of information to and from magnetic tape, the method comprising:

• (1) reserving at least one reserved location on the tape for the re-recording of frames;
• (2) recording a frame at a first physical frame location on the tape during a recording mode;
• and
• (3) after the recording of step (2), checking whether the frame is readable or accurately recorded;
• (4) if the result of the checking of step (3) is negative, re-recording the frame at the reserved location and establishing in a memory a pairing of the first physical frame location with the reserved location;
• wherein the magnetic tape drive uses a head unit to transduce frames of information to and from tracks of the magnetic tape, wherein the frame is recorded at the first physical frame location on a first track, and wherein the at least one reserved location is on a reserved track which is not the first track;
• wherein the step of re-recording the frame at the reserved location comprises:
• moving a head unit to a bidirectional track, the bidirectional track having at least a first group of frame locations in which frames are recordable when the relative motion between the head unit and the tape occurs in a first direction and a second group of frame locations in which frames are recordable when the relative motion between the head unit and the tape occurs in a second direction, the second direction being opposite to the first direction;
• the recording of step (2) having been done in the first direction;
• transporting one of the head unit and the tape until the head unit is proximate the second group of frame locations;
• and
• re-recording the frame at an available one of the frame locations in the second group of frame locations.

A method of operating a magnetic tape drive to transduce frames of information from magnetic tape, the method comprising:

• (1) acquiring contents of a defect map from the tape, the defect map having a pairing of a frame original physical location on the tape with a frame re-recording physical location for a frame which is unreadable or erroneously recorded in its frame original physical location, the frame re-recording location being in a reserved portion of the tape;
• (2) reading non-defective frames from corresponding frame original physical locations on the tape;
• (3) when an original physical location is encountered on the tape for which there is a pairing in the defect map, obtaining the contents of a frame from a paired frame re-recording physical location;
• wherein the reading of step (2) occurs when relative movement between the head unit and the tape is in a first direction and wherein a track having the frame re-recording physical location is read when relative movement between the head unit and the tape is in a direction which is opposite the first direction.

A method of operating a magnetic tape drive to transduce frames of information from magnetic tape, the method comprising:

• (1) acquiring contents of a defect map from the tape, the defect map having a pairing of a frame original physical location on the tape with a frame re-recording physical location for a frame which is unreadable or erroneously recorded in its frame original physical location, the frame re-recording location being in a reserved portion of the tape;
• (2) reading non-defective frames from corresponding frame original physical locations on the tape;
• (3) when an original physical location is encountered on the tape for which there is a pairing in the defect map, obtaining the contents of a frame from a paired frame re-recording physical location;
• wherein the step of obtaining the contents of a frame from a paired frame re-recording physical location comprises:
• moving a head unit to a bidirectional track, the bidirectional track having at least a first group of frame locations in which frames are recordable when the relative motion between the head unit and the tape occurs in a first direction and a second group of frame locations in which frames are recordable when the relative motion between the head unit and the tape occurs in a second direction, the second direction being opposite to the first direction;
• the encountering of step (3) having been done in the first direction;
• transporting one of the head unit and the tape until the head unit is proximate the second group of frame locations;
• and
• reading the contents of a frame from the second group of frame locations in accordance with the defect map.

A magnetic tape drive comprising:

• a head unit which contains at least one head element for transducing information to or from tracks on the tape, the head unit including a write element for writing a frame to the tape during a write mode and a read element for reading back the frame from the tape during the write mode;
• a transport for moving the tape relative to the head unit;
• a controller which, when a frame is unable to be read back from its original physical location on a first track or is read back from its original physical location on the first track as a defective frame, causes the frame to be re-recorded at a reserved physical location on the tape and establishes in a memory a mapping of the frame's original physical location with the reserved physical location;
• wherein the first track is recorded or read when relative movement between the head unit and the tape is in a first direction and the reserved physical location is recorded or read when relative movement between the head unit and the tape is in a direction which is opposite the first direction.

A method of operating a magnetic tape drive having a head unit which transduces frames of information to and from magnetic tape, the method comprising:

• (1) recording a frame at a first physical frame location on the tape during a recording mode;
• and
• (2) after the recording of step (1), checking whether the frame is readable or accurately recorded;
• (3) if the result of the checking of step (2) is negative, re-recording the frame at a second physical frame location on the tape;
• wherein the frame is recorded at the first physical frame location when relative movement between the head unit and the tape is in a first direction and wherein the frame is recorded at the second physical frame location when relative movement between the head unit and the tape is in a second direction which is opposite the first direction.

A method of operating a magnetic tape drive having a head unit which transduces frames of information to and from magnetic tape, the method comprising:

• (1) recording a frame at a first physical frame location on the tape during a recording mode;
• and
• (2) after the recording of step (1), checking whether the frame is readable or accurately recorded;
• (3) if the result of the checking of step (2) is negative, re-recording the frame at a second physical frame location on the tape;
• wherein the re-recording of the frame at step (3) comprises:
• moving the head unit to a bidirectional track, the bidirectional track having at least a first group of frame locations in which frames are recordable when the relative motion between the head unit and the tape occurs in a first direction and a second group of frame locations in which frames are recordable when the relative motion between the head unit and the tape occurs in a second direction, the second direction being opposite to the first direction;
• the recording of step (1) having been done in the first direction;
• transporting one of the head unit and the tape until the head unit is proximate the second group of frame locations;
• and
• re-recording the frame at the second physical frame location in the second group of frame locations.