A disc cassette includes a curved portion configured to hold multiple discs. A platform portion abuts the curved portion. A movable bale is configured to maintain discs securely in the disc cassette except when rotated off the discs.

A disc cassette includes a curved portion configured to hold multiple discs. A platform portion abuts the curved portion. A movable bale is configured to maintain discs securely in the disc cassette except when rotated off the discs.

A disc cassette includes a curved portion configured to hold multiple discs. The disc cassette further includes a bottom side including track connectors configured to position the disc cassette relative to one or more track portions that hold the disc cassette in place. The disc cassette is slideable along the one or more track portions.

A disc cassette includes a curved portion configured to hold multiple discs. The disc cassette further includes a bottom side including track connectors configured to position the disc cassette relative to one or more track portions that hold the disc cassette in place. The disc cassette is slideable along the one or more track portions.

Implementations generally relate to storage systems. In one implementation, a system includes a plurality of storage libraries that store a plurality of removable media units. The system also includes a plurality of head units for reading and writing to one or more of the removable media units. The system also includes a plurality of robots that transfer one or more of the removable media units between one or more of the storage libraries and one or more of the head units. The system also includes enabling one or more of the robots to recover a set of data from two or more of the removable media units if a failure occurs in association with at least one of the other removable media units.

An operating method of a disc pick-and-place device is provided. Discs can be picked up when each flexible rod is driven to rotate and make the disc pick-and-place device enter a first operating state and then a second operating state in which the first carrying portion is located at the disc releasing position and then at the disc holding position, and the second carrying portion is located at the disc releasing position in the first and second operating states. Discs can be unloaded when each flexible rod is driven to rotate and make the disc pick-and-place device enter a third operating state and then a fourth operating state in which the first carrying portion is located at the disc holding position and then at the disc releasing position, and the second carrying portion is located at the disc holding position in the third and fourth operating states.

An operating method of a disc pick-and-place device is provided. Discs can be picked up when each flexible rod is driven to rotate and make the disc pick-and-place device enter a first operating state and then a second operating state in which the first carrying portion is located at the disc releasing position and then at the disc holding position, and the second carrying portion is located at the disc releasing position in the first and second operating states. Discs can be unloaded when each flexible rod is driven to rotate and make the disc pick-and-place device enter a third operating state and then a fourth operating state in which the first carrying portion is located at the disc holding position and then at the disc releasing position, and the second carrying portion is located at the disc holding position in the third and fourth operating states.

A disc pick-and-place device including a disc pick-and-place body and a quantity sensing unit is provided. The disc pick-and-place body is for clamping and unloading at least one disc. The quantity sensing unit is disposed on the disc pick-and-place body for sensing the quantity of the at least one disc clamped on the disc pick-and-place body. The quantity sensing unit includes a movable piece and an optical distance measuring device. The movable piece leans on at least one disc and moves as the quantity of the at least one disc changes. The optical distance measuring device is for emitting a beam and receiving the beam reflected from the movable piece to detect the quantity of the at least one disc.

A disc pick-and-place device including a disc pick-and-place body and a quantity sensing unit is provided. The disc pick-and-place body is for clamping and unloading at least one disc. The quantity sensing unit is disposed on the disc pick-and-place body for sensing the quantity of the at least one disc clamped on the disc pick-and-place body. The quantity sensing unit includes a movable piece and an optical distance measuring device. The movable piece leans on at least one disc and moves as the quantity of the at least one disc changes. The optical distance measuring device is for emitting a beam and receiving the beam reflected from the movable piece to detect the quantity of the at least one disc.

A disc pick-and-place device including a disc pick-and-place body and a quantity sensing unit is provided. The disc pick-and-place body is for clamping and unloading at least one disc. The quantity sensing unit is disposed on the disc pick-and-place body for sensing the quantity of the at least one disc clamped on the disc pick-and-place body. The quantity sensing unit includes a movable piece and an optical distance measuring device. The movable piece leans on at least one disc and moves as the quantity of the at least one disc changes. The optical distance measuring device is for emitting a beam and receiving the beam reflected from the movable piece to detect the quantity of the at least one disc.