Patent ID: 7245575
Filing Date: 2007-07-17
Classification: B82Y,G11B

Abstract:
1. A method for overwriting data in a storage device, wherein data bits are represented by at least one of a presence and an absence of pits formed at a plurality of bit positions on a storage surface, the plurality of bit positions being spaced such that writing a pit at each bit position can cause a previously-written pit within r bit positions to be erased, where r is a predetermined number 1, the method comprising: coding data such that successive bits of a value x in a coded bit sequence are separated by at least d bits of value reading an amount of an old bit sequence to be overwritten by the coded bit sequence sufficient to locate at least one excess pit, wherein each excess pit is a pit not within r bit positions of a bit position where a coded bit of the value x is to be recorded; writing, at respective bit positions, each pit required to erase each excess pit in the old bit sequence; and writing, at respective bit positions, each pit required to maintain a pit at each bit position where the coded bit of the value x is to be recorded.