Magnetic recording apparatus
AssigneeHitachi, Ltd.
InventorsYasutaka Nishida, Takehiko Hamaguchi, Hideki Sawaguchi
Life of this patent
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Abstract
A method of enhancing the thermal stability of gray codes is disclosed. The gray code block in a servo area is recorded with a combination of two different magnetization directions. When the two different magnetization directions are expressed as “+” and “−”, the information “1” is recorded as “++−−” or “−−++” with the information “0” recorded as “+−+−” or “−+−+”. Since the filter for gray code demodulation is provided with a perpendicular recording mode, the servo area does not use long-wavelength signals that are susceptible to thermal demagnetization. As a result, thermal stability is enhanced.
Claims9
A magnetic recording apparatus comprising:
- a magnetic head for recording and reproducing information,
- perpendicular magnetic recording media having a servo area for storing servo pattern recordings and a user data area for storing user data recordings, and
- a signal processing means for processing servo information or user data read by said magnetic head,
- wherein said servo area has a burst block in which burst patterns for positioning said magnetic head are recorded and a gray code block in which track information is recorded with patterns of “1” and “0” representing the information indicated by two different perpendicular magnetization directions, and
- wherein said information “1” and said information “0” are recorded respectively with a “++−−” pattern and a combination of “+−” patterns, or said information “1” and said information “0” are recorded respectively with a “−−++” pattern and a combination of “−+” patterns when said two different perpendicular magnetization directions are expressed as “+” and “−”.
A magnetic recording apparatus comprising:
- a magnetic head for recording and reproducing information,
- perpendicular magnetic recording media having a servo area for storing servo pattern recordings and a user data area for storing user data recordings, and
- a signal processing means for processing servo information or user data read by said magnetic head,
- wherein said servo area has a burst block in which burst patterns for positioning said magnetic head are recorded and a gray code block in which track information is recorded with patterns of “1” and “0” representing the information indicated by two different perpendicular magnetization directions, and
- wherein said information “1” and said information “0” are recorded respectively with a “++−−” pattern and a “+−+−” pattern, or said information “1” and said information “0” are recorded respectively with a “−−++” pattern and a “−+−+” pattern when said two different perpendicular magnetization directions are expressed as “+” and “−”.
Perpendicular magnetic recording media comprising:
- a servo area for storing servo pattern recordings and a user data area for storing user data recordings,
- wherein said servo area has a burst block in which burst patterns for positioning said magnetic head are recorded and a gray code block in which track information is recorded with patterns of “1” and “0” representing the information indicated by two different perpendicular magnetization directions, and
- wherein said gray code block records said information “1” and said information “0” respectively with a “++−−” pattern and a combination of “+−” patterns, or said information “1” and said information “0” respectively with a “−−++” pattern and a combination of “−+” patterns when said two different perpendicular magnetization directions are expressed as “+” and “−”.
Perpendicular magnetic recording media comprising:
- a servo area for storing servo pattern recordings and a user data area for storing user data recordings,
- wherein said servo area has a burst block in which burst patterns for positioning said magnetic head are recorded and a gray code block in which track information is recorded with patterns of “1” and “0” representing the information indicated by two different perpendicular magnetization directions, and
- wherein said gray code block records said information “1” and said information “0” respectively with a “++−−” pattern and a “+−+−” pattern, or said information “1” and said information “0” respectively with a “−−++” pattern and a “−+−+” pattern when said two different perpendicular magnetization directions are expressed as “+” and “−”.
Dependencies are inferred from the claim text.