Abstract: A method and encoding/decoding apparatus that achieves an increase in the amount of data stored in or on a recording medium by utilizing the polarities as well as the locations within the cells to minimally double the recording density of that medium. This encoding is effected by the recording of two or more digits in the same transition with the direction and position of the recording indicating its contents. The respective cells include two or more timing boundaries that are used in the encoding process. The boundaries are used to encode based on location of transitions within the cell. The number of boundaries (b) needed to provide a unique identity for all encoding options within the cell is b=2n?1 where “n” is the number of bits to be encoded by each cell. The direction of transition of a reference bit may also be used to uniquely identify the bit encoding to provide a second tier of encoding and a level of data compression.

Abstract: Improved systems and methods for storing data, wherein data stored on one or more disks of a first capacity is mirrored to one or more disks of a second, larger capacity. According to the invention, one or more disk drives of a first capacity may be coupled to create a virtual volume. One or more disks of a second, larger capacity are then used to provide a single larger volume or multiple larger volumes that serve as the mirroring drive or drives for the array of smaller drives. Data from the smaller drives is stacked in stripes sequentially across the larger drive(s). Alternately, data from the smaller drives may be striped in zones across the larger drive(s). In yet another embodiment, the asymmetric nature of the mirroring technique of the present invention can be used in reverse, wherein an array of smaller capacity drives serve as the mirror for one or more larger capacity drives.