Storage unit

Details Storage unit Storage unit

2000-01-11

2003-02-18

Sniezek, Andrew L. (Department: 2651)

Dynamic magnetic information storage or retrieval

Automatic control of a recorder mechanism

Controlling the head

C360S055000

Reexamination Certificate

active

06522496

ABSTRACT:

FIELD OF THE INVENTION
The present invention relates to a storage unit for use as an external storage unit for a computer. More particularly this invention relates to a storage unit capable of improving the data transmission efficiency and reducing the seek time.
BACKGROUND OF THE INVENTION
As an external storage unit for computer, a storage unit employing a circular magnetic disk unit as a storage medium has been used. Upon read/write (R/W) operation in this storage unit, a seek operation for moving a read/write head to a desired track on the recording medium is necessary. Because it takes time for command processing until the read/write head actually moves since a seek command for instructing this seek operation is issued, a seamless seek operation can not be achieved. Further, because an inductance component is contained in a unit for driving the read/write head, there exists a voltage transition period. Thus, a delay time occurs until the read/write head actually moves since a voltage is supplied to this storage unit, and this delay time further prolongs the seek time. The above-mentioned decline in the data transmission efficiency and prolongation of the seek operation are important problems which obstruct increased density trend of the storage unit and therefore, a method for solving such a problem has been demanded.
FIG. 33
is a block diagram showing a structure of a conventional storage unit
2
. The storage unit
2
is connected to a host
1
such as computer through a small computer system interface (SCSI) bus and executes read/write to a recording medium (magnetic disk) (not shown) based on a read/write request command S
01
from this host
1
. Here, the aforementioned read/write request command S
01
contains target cylinder information for instructing a cylinder in the recording medium, target sector information for instructing a sector in the recording medium and head information for instructing a read/write head
13
using at the time of the read/write operation. A sector specified by the target cylinder information and the sector information is a region to be subjected to read/write.
In this storage unit
2
, a command/status processing section
3
, a position information conversion section
4
, a seek command issuing section
5
and a read/write control section
6
compose a upper level controller
7
. In this upper level controller
7
, the command/status processing section
3
carries out such processing as reception of a read/write request command S
01
from the host
1
and report of status of the storage unit
2
to the host
1
. The command/status processing section
3
outputs the target cylinder information, target sector information and target head information contained in the received read/write request command S
01
to the position information conversion section
4
as local block address (LBA) S
02
.
The position information conversion section
4
outputs the target cylinder information and head information of the target cylinder information, target sector information and head information obtained from the above LBA S
02
, as the position information S
03
to the seek command issuing section
5
and outputs the target sector information to the read/write control section
6
as the read/write object sector data S
07
. Here, the read/write control section
6
controls the read/write operation. The seek command issuing section
5
is triggered when a read/write completion report S
06
which indicates that a last read/write operation is completed is inputted from the read/write control section
6
so as to issue a seek command S
04
for carrying out the seek operation and this seek command is outputted to a detailed target position setting section
8
.
A head positioning control section
10
controls positioning of a read/write head
13
described later on a recording medium (not shown) and comprises the detailed target position setting section
8
and a seek command executing section
9
. The position of the read/write head
13
differs during reading and writing due to the influence of yaw angle. The detailed target position setting section
8
outputs target position to the seek command executing section
9
as the detailed target position information S
10
considering a correction corresponding to the difference in this yaw angle.
The detailed target position setting section
8
receives a feedback of the present position S
23
of the read/write head
13
which will be described later and then outputs a detailed target position information S
10
. The seek command executing section
9
outputs a voice coil motor (VCM) voltage S
11
based on the detailed target position information S
10
. A power amplifier
11
amplifies the aforementioned VCM voltage S
11
and supplies a VCM current S
12
which is a driving current to the VCM
12
.
A disk enclosure (DE)
16
includes the voice coil motor (VCM)
12
, the read/write head
13
, a preamplifier
14
and a position demodulator
15
in a sealed condition. The aforementioned VCM
12
moves the read/write head
13
in a radius direction between sectors during the seek operation and this motor is driven by the VCM current S
12
supplied from the power amplifier
11
. Here, the amount of movement of the read/write head
13
is controlled by changing the VCM current S
12
. The read/write head
13
writes read/write data S
19
(write data here) supplied from the read/write control section
6
on a recording medium using a magnetic field generated by a recording current amplified by a preamplifier
14
. The read/write head
13
reads out data recorded in the recording medium magnetically as a playback voltage and outputs it as the read/write data S
19
(read data here) to the read/write control section
6
through the preamplifier
14
.
The read/write head
13
detects a servo pattern for positioning recorded in the recording medium and the preamplifier
14
outputs this detection result to the position demodulator
15
as a servo signal S
13
. The position demodulator
15
demodulates the present position S
23
of the read/write head
13
from the aforementioned servo signal S
13
and outputs it to the detailed target position setting section
8
. Further, the position demodulator
15
obtains a number of a sector which the read/write head
13
currently tracks from the aforementioned demodulation result and outputs it to the read/write control section
6
as the present position sector number S
09
. Here, the read/write control section
6
determines whether or not the read/write operation is complete from the present position sector number S
09
and read/write data S
19
. If the read/write operation is complete, the read/write control section
6
outputs the read/write completion report S
06
to the command/status processing section
3
as well as to the seek command issuing section
5
. Then, the detailed target position setting section
8
determines whether or not the seek operation is complete based on the present position S
23
. If the seek operation is complete, the detailed target position setting section
8
outputs the seek completion report S
08
to the read/write control section
6
.
Next, with reference to
FIG. 34
, mainly the read/write operation and seek operation in the conventional storage unit
2
will be described. In the processing and operation of the storage unit
2
, as shown in the upper half of
FIG. 34
, command processing (
1
), seek operation, read/write operation and command processing (
2
), by which a single set is composed, are repeated in time series manner.
Here, the command processing (
1
) comprises a processing on the read/write request command S
01
in the command/status processing section
3
, target position information conversion processing in the position information conversion section
4
and an issuing processing of the seek command S
04
in the seek command issuing section
5
. Further, the seek operation is an operation for moving the read/write head
13
by the seek command executing section
9
, power amplifier
11
and VCM
12
. The read/write operation is a r

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