Dynamic magnetic information storage or retrieval – Automatic control of a recorder mechanism – Controlling the head
Reexamination Certificate
2001-02-22
2004-02-17
Hudspeth, David (Department: 2651)
Dynamic magnetic information storage or retrieval
Automatic control of a recorder mechanism
Controlling the head
C360S061000
Reexamination Certificate
active
06693765
ABSTRACT:
TECHNICAL FIELD
The present invention relates to information storage apparatuses and methods of controlling the same, and more particularly to an information storage apparatus which records information on a recording medium and a method of controlling the same.
BACKGROUND ART
In an information storage apparatus such as a magnetic disk unit or a magneto-optical disk unit, a variety of variable control parameters such as a threshold for signal detection and a light-emitting power of a laser beam are set to their optimum values at times of recording and reproduction. The light-emitting power of the laser beam is controlled based on the set parameters so that the recording and reproduction are performed in an optimum state. Here, a description will be given of a magnetic disk unit serving as an information storage apparatus.
FIG. 1
is a block diagram of a conventional magnetic disk unit.
According to a magnetic disk unit
1
, a magnetic head
4
opposes a magnetic disk
2
which is rotated by a spindle motor
3
, so that the magnetic disk
2
is magnetized by a magnetic field produced around the magnetic head
4
. Thereby, information is recorded on the magnetic disk
2
. On the other hand, information recorded on the magnetic disk
2
is reproduced by detecting variations in magnetization of the magnetic disk
2
.
The magnetic head
4
is supported at the tip of an arm
5
and opposes the magnetic disk
2
, the magnetic head
4
being floated slightly above the magnetic disk
2
by an air current produced by rotations of the magnetic disk
2
. The arm
5
is held so as to turn freely around a shaft
6
. The other end of the arm
5
is linked to a voice coil motor
7
. The voice coil motor
7
turns the arm
5
in a radial direction (direction indicated by arrow A) of the magnetic disk
2
around the shaft
6
.
The magnetic head
4
is connected to a head IC
8
. The head IC
8
amplifies a recording signal supplied to the magnetic head
4
and a reproduced signal reproduced by the magnetic head
4
.
The head IC
8
is connected to a read channel (RDC) IC
9
and to a servo information demodulation circuit
10
. The read channel IC
9
demodulates the reproduced signal supplied from the head IC
8
to its original data, and modulates recording data to be recorded on the magnetic disk
2
to generate the recording signal. The servo information demodulation circuit
10
extracts servo information from the reproduced signal supplied from the head IC
8
and demodulates the extracted servo information.
The reproduced data demodulated in the read channel IC
9
is supplied to a hard disk control IC (HDC)
11
. The hard disk control IC
11
retains the reproduced data in a memory
12
and transfers the retained reproduced data to a host computer via an interface. The hard disk control IC
11
temporarily stores in the memory
12
the recording data supplied from the host computer via the interface, and supplies the stored recording data to the read channel IC
9
.
The read channel IC
9
and the hard disk control IC
11
are connected to an MCU
14
. The servo information demodulation circuit
10
and a digital signal processor (DSP)
17
are connected to the MCU
14
via a gate array
16
.
The MCU
14
controls operations of the head IC
8
, the read channel IC
9
, the servo information demodulation circuit
10
, and the digital signal processor (DSP)
17
based on a control program and control parameters stored in a memory
15
.
A driver IC
18
is connected to the digital signal processing circuit
17
. The driver IC
18
generates, based on a control signal supplied from the digital signal processor
17
, driving signals which drive the voice coil motor
7
and the spindle motor
3
, respectively. The voice coil motor
7
is driven based on the driving signal supplied from the driver IC
18
to move the magnetic head
4
in the radial directions of the magnetic disk
2
, that is, in the direction indicated by the arrow A. The spindle motor
3
is driven by the driving signal supplied from the driver IC
18
to rotate the magnetic disk
2
on a shaft
19
.
A temperature sensor
20
is connected to the MCU
14
. The temperature sensor
20
detects an ambient temperature of the magnetic disk
2
. A temperature detected by the temperature sensor
20
is supplied to the DSP
17
via the gate array
16
. The MCU
14
controls the control parameters supplied to the read channel IC
9
, the head IC
4
, the servo information demodulation circuit
10
, and the DSP
17
based on, for instance, a generated error or the temperature detected by the temperature sensor
20
.
At this time, the control parameters supplied to the read channel IC
9
, the servo information demodulation circuit
10
, and the DSP
17
are stored in the memory
15
. When a write command and a read command are supplied to the MCU
14
from the host computer, the MCU
14
reads out the control parameters from the memory
15
based on the control program, and supplies the control parameters to the respective circuits. The main control parameters are a servo parameter and read and write parameters.
FIG. 2
is an operational flowchart of an MCU of the conventional magnetic disk unit at a time of a read/write operation.
When supplied with a write or read command from the host computer (step S
1
-
1
), the MCU
14
supplies servo parameters that are control parameters, one byte at a time, that is, one word at a time, from the memory
15
to the servo information demodulation circuit
10
and the digital signal processor
17
(steps S
1
-
2
and S
1
-
3
). The servo parameters are parameters that control a driving of the voice coil motor
7
and a reading of servo information at a time of, for instance, a tracking jump.
When the servo parameters are supplied to the servo information demodulation circuit
10
and to the digital signal processor
17
in step S
1
-
3
(steps S
1
-
4
and S
1
-
5
), the MCU
14
starts a seek operation to a head number X and a cylinder number Y specified by the write or read command supplied from the host computer (step S
1
-
6
).
When the seek operation to the given head number X and cylinder number Y is started in step S
1
-
6
, read or write (read/write) parameters that are control parameters are supplied to the read channel
9
one byte at a time, that is, one word at a time (step S
1
-
7
). The read/write parameters are parameters that control signal reading and writing states.
When the read/write parameters are set in the read channel IC
9
in step S
1
-
7
(steps S
1
-
8
and S
1
-
9
), and the seek operation to the head number X and cylinder number Y specified by the write or read command supplied from the host computer is completed (step S
1
-
10
), a read/write operation is performed (step S
1
-
11
).
In the conventional magnetic disk unit, the transfers of the control parameters and the seek operation of the above-described steps S
1
-
1
through S
1
-
11
are processed by firmware executed by the MCU.
In the case of transferring control parameters required for read/write control and servo control at a time of a read/write operation to a read/write control part and to a servo control part the transfer is performed by the MCU. Therefore, the MCU is prevented from performing other operations during the transfer of the control parameters, thus causing a problem of deterioration in the performance of the MCU.
FIG. 3
is a timing chart of signals in the conventional magnetic disk unit. FIG.
3
(A) shows a servo gate signal, FIG.
3
(B) shows a timing of a seek command, FIG.
3
(C) shows a timing of a parameter transfer, FIG.
3
(D) shows a timing of issuance of a seek command, and FIG.
3
(E) shows a timing of the start of processing the command.
As shown in
FIG. 3
, after the seek command is generated, parameters are transferred. At this time, it takes 50 &mgr;s to perform the parameter transfer by firmware. Therefore, as shown in FIG.
3
(A), the transfer of the parameters overlaps with a generation timing of the servo gate signal, so that the seek command is delayed by the parameter tra
Fujitsu Limited
Greer Burns & Crain Ltd.
Hudspeth David
Wong K.
LandOfFree
Information storage apparatus and method of controlling the... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Information storage apparatus and method of controlling the..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Information storage apparatus and method of controlling the... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3328614