Dynamic information storage or retrieval – Specific detail of information handling portion of system – Radiation beam modification of or by storage medium
Reexamination Certificate
1998-12-03
2001-02-27
Huber, Paul W. (Department: 2753)
Dynamic information storage or retrieval
Specific detail of information handling portion of system
Radiation beam modification of or by storage medium
C369S053130
Reexamination Certificate
active
06195325
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an apparatus for and a method of recording data into a disc-like recording medium driven to spin at a constant speed.
2. Description of Related Art
The conventional apparatuses for recording data into a recording medium include one adapted to record data into sectors formed on a magnetooptic disc by regularly dividing concentric tracks on the disc circumferentially thereof, one adapted to record data into a magnetooptic disc at a constant frequency and a constant speed of disc spinning, and one adapted to record data into a phase-changing optical disc at a constant frequency and a constant speed of disc spinning.
The above-mentioned data recording apparatus adapted to record data into a magnetooptic disc having sectors formed thereon by regularly dividing concentric tracks circumferentially of the disc, adopts the well-known CLV (Constant Linear Velocity) method to attain a high surface density with a constant linear density by recording the data at a constant linear velocity. For recording data into a magnetooptic disc having wobbling data tracks, this data recording apparatus detects track wobbling modulated for data to be recorded onto all data tracks with a same linear density in order to record the data at a constant frequency.
On the other hand the above-mentioned data recording apparatus adapted to record data into a magnetooptic disc at a constant frequency and a constant speed of disc spinning adopts the well-known CAV (Constant Angular Velocity) method to record the data at a constant speed of disc spinning not only in the lead-in zone but in the lead-out zone on the magnetooptic disc.
The above-mentioned data recording apparatus adapted to record data into a phase-changing optical disc at a constant frequency and a constant speed of disc spinning, adopts the CAV method as in the data recording apparatus mentioned just above. This data recording apparatus is also adapted to generate a write frequency by detecting a fine clock mark in order to record the data.
In the above-mentioned data recording apparatus adopting the CAV method for data recording into a phase-changing optical disc, however, the linear density of recording on data tracks formed in the lead-out zone is lower than that on the data tracks in the lead-in zone since data is recorded at a constant speed of disc spinning and a constant frequency not only in the data tracks formed in the lead-in zone but also in the data tracks formed in the lead-in zone. Also, in a disc having track wobbles modulated for data to be recorded onto all data tracks with a same linear density, the CAV control is impossible for a quicker data access since it is necessary to lock write clocks precisely to the track wobbles.
SUMMARY OF THE INVENTION
Accordingly, the present invention overcomes the above-mentioned drawbacks of the prior art by providing a data recording apparatus and method adapted to record data into a disc-like recording medium without any lower linear density on data tracks in the lead-out zone even in the CAV mode.
The above goal can be attained by providing a data recording apparatus comprising, according to the present invention:
means for driving a disc-like recording medium having pre-formed thereon data tracks for data recording, the data tracks being wobbled with signals generated by modulating the frequency of a predetermined-frequency carrier correspondingly to an address information;
means for recording into the disc-like recording medium being driven to spin a data in sectors each consisting of a data block and a linking data next to the data block in such a manner that the linear density of recording is constant;
means for calculating a number of bits which are to be recorded into an n-th one of the sectors based on a following expression (1):
F
2
π
·
N
·
2
π
P
(
R
0
2
+
PL
π
(
n
+
1
)
-
R
0
2
+
PL
π
n
)
(
1
)
where
F: Write frequency, Hz
N: Spinning speed of the recording medium, s
−1
R
0
: Radius of innermost data track on which the bits are to be written, m
P: Track pitch of data tracks, m
L: Physical circumferential length of each sector, m; and
means for controlling the recording means so that the data is recorded in a number of bits having been calculated by the calculating means into each sector.
In the data recording apparatus according to the present invention, a number of bits to be recorded into each sector is calculated by the calculating means to record data in the calculated number of bits into each sector.
The above object can also be attained by providing a method of recording sectors each consisting of a data block and a linking data next to the data block into a disc-like recording medium having pre-formed thereon data tracks onto which data is to be recorded, the data tracks being wobbled with signals generated by modulating the frequency of a predetermined-frequency carrier correspondingly to an address information, comprising, according to the present invention, the steps of:
calculating a radial position on the recording medium of an n-th one of the sectors to generate a position information;
determining a write frequency based of the position information;
calculating a number of bits which are to be recorded into the n-th one of the sectors based on a following expression (1):
F
2
π
·
N
·
2
π
P
(
R
0
2
+
PL
π
(
n
+
1
)
-
R
0
2
+
PL
π
n
)
(
1
)
where
F: Write frequency, Hz
N: Spinning speed of the recording medium, s
−1
R
0
: Radius of innermost data track on which the bits are to be written, m
P: Track pitch of data tracks, m
L: Physical circumferential length of each sector, m; and
recording a data in the number of bits calculated based on the expression (1) into the recording medium on the basis of the write frequency.
For recording data into each sector by the data recording method according to the present invention, a position information indicative of a radial position of the sector is generated and a write frequency and a number of bits to be recorded into each sector are calculated based on the position information.
REFERENCES:
patent: 5815486 (1998-09-01), Kobayashi et al.
patent: 5991257 (1999-11-01), Kobayashi et al.
patent: 6067281 (2000-05-01), Kobayashi et al.
Huber Paul W.
Limbach & Limbach L.L.P.
Oh Seong-Kun
Sony Corporation
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