Electrical computers and digital processing systems: memory – Storage accessing and control – Specific memory composition
Reexamination Certificate
1998-07-13
2004-04-13
Kim, Matthew (Department: 2186)
Electrical computers and digital processing systems: memory
Storage accessing and control
Specific memory composition
C711S167000
Reexamination Certificate
active
06721844
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method for starting an operation of a data storage unit equipped with an actuator arm which supports a flexible cable for data transfer connected between the transducer and the control circuit of the data storage unit. More particularly, the invention relates to a start method which makes it possible to execute early the access tension which a flexible cable gives to an actuator arm.
2. Description of Related Art
In a quest of user friendliness, the computer system in recent years is even further shortening the time needed to use of the computer system after power is turned on. In such environment, magnetic disk drives are used as the secondary data storage unit of the computer system and store an operating system and various application programs which are used in the computer system. Access to the magnetic disk drive has been recognized as a specific problem in shortening the time needed to use a host computer after power is turned on.
FIG. 1
is a plan view of a general magnetic disk drive. The magnetic disk drive
10
is a data storage unit which includes a rotary type magnetic disk
11
with concentric data tracks on which data is stored, a transducer (not shown) for reading or writing data from or to various tracks, a slider
12
with the transducer attached thereto, a suspension arm
13
having the slider
12
attached thereto so that bias force is applied in a direction in which the slider
12
approaches the surface of the magnetic disk
11
, an actuator arm
14
and a voice coil motor (VCM) section
15
for locking the suspension arm
13
and for moving the transducer over a desired track position and maintaining it over the longitudinal center line of the track during read and write operations, a flexible cable
16
connected at one end thereof to the transducer and supported by the actuator arm
14
, and a board
20
mounted with a control circuit section
17
connected to the other end of the flexible cable
16
.
The magnetic disk
11
has a plurality of magnetic disks fastened to a spindle
19
and stacked at predetermined intervals. The magnetic disks
11
are rotated together with the spindle
19
by a spindle motor (not shown). A plurality of actuator sets each consisting of the transducer, the slider
12
, the suspension arm
13
, and the actuator arm
14
are stacked in correspondence with the respective surfaces of the magnetic disks
11
and constitute an actuator assembly
21
. The actuator sets are integrally rotated over magnetic disk surfaces in directions of arrow A with stacked magnetic disks on which data can be read out or written to with the transducer are often called cylinders.
In order to position the transducer over a predetermined cylinder, a predetermined driving torque needs to be generated in the VCM section
15
to move the actuator assembly
21
. The driving torque is computed from the relationship between the current cylinder position of the transducer and the cylinder position to which the converter is to be moved. Although the flexible cable
16
is connected to both the transducer supported by the actuator arm
14
and the board
20
, it does not interfere with the rotation of the actuator assembly in the directions of arrow A. The flexible cable always gives the actuator assembly
21
tension in a direction of arrow B. Therefore, the driving torque for the actuator assembly
21
, which is generated in the VCM section, needs to be set to a value compensating for the tension of the flexible cable
16
.
However, the value of the tension of the flexible cable does not only vary with a cylinder position on the magnetic disk
11
, but it also varies due to various major factors, such as operating conditions (temperature, humidity, voltage, etc.), elapsed years, and operating time. Therefore, the tension applied to the actuator assembly
21
by the flexible cable
16
needs to be successively corrected. In current magnetic disk drives, tension data is generated each time power is turned on.
Until a magnetic disk drive will be able to accept access from a host computer after power to the magnetic disk drive is turned on, there is always a need to perform a predetermined start operation.
FIG. 2
is a flowchart showing a conventional procedure for starting the magnetic disk drive of FIG.
1
. In step
50
, power to the magnetic disk drive is turned on. Then, in step
51
, an internal diagnostic program is executed to confirm whether there is anything abnormal in the function of the magnetic disk drive. After it has been confirmed that there is nothing abnormal in step
51
, it is confirmed in step
52
that the spindle motor has been rotated and has reached a predetermined rotational speed. Next, in step
53
, microcode which is stored on the magnetic disk for controlling the magnetic disk drive is read out to a memory. After the procedure in step
53
has ended, the actuator assembly is positioned over each cylinder to correct the tension data of the flexible cable (hereinafter referred to as tension data). Then the corrected tension data is stored on memory to form a table (step
54
). After the procedure has been completed (step
54
), the computer is at last able to have access to the magnetic disk drive to read out or write data (step
55
). In a typical example of 3.5-inch magnetic disk drives, the start preparation from step
51
to step
53
takes 8 seconds and the generation of corrected tension data in step
54
takes 2 seconds, so that the host computer cannot have access to the magnetic disk drive for 10 seconds after power is turned on.
The object of the present invention is to provide a method of early use of a data storage unit which allows a computer system to be used as early as possible after turning on power to the computer system, including the data storage unit.
SUMMARY OF THE INVENTION
The principles of the present invention involve the use of the tension data of a flexible cable generated at the time of fabrication (hereinafter referred to as shipping-time tension data), to allow a host computer to have early access to a data storage unit. After power has been turned on, the host computer executes a diagnostic program. In order to complete the start operation early, the host computer requires early access to a data storage unit. On the other hand, during the start sequence of the data storage unit, generation of the corrected tension data of the flexible cable is always needed. However, at the stage immediately after power is turned on, the corrected tension data does not always have to be generated prior to the access of the host computer. Therefore, in the present invention, the start sequence of the data storage unit which must be executed prior to access by the host computer is first executed. After the start sequence has been completed, the host computer is allowed to have access to the data storage unit, and generation of corrected tension data is executed in parallel with the execution of the start sequence of the host computer.
In an embodiment of the present invention, after a start operation excluding generation of corrected tension data has been completed, if there is an access command from a host computer, it will be processed. The start operation excluding generation of corrected tension data is an operation that is always performed before accepting access commands, such as execution of an internal diagnostic program, start of a spindle motor, and reading of microcode to a memory.
In another embodiment of the present invention, previously generated tension data is stored on a non-volatile storage medium and read to memory during a start operation before generation of corrected tension data. When an access command is sent from a host computer before corrected tension data is generated, the torque which is generated in a voice coil motor (VCM) for positioning of a transducer is set by using the previously generated tension data. The previously generated tension data may be tension data generated at the time of shipment o
Fukushima Yukio
Kakihara Toshio
Okutsu Kazushige
Ueda Tetsuo
Anderson Matthew
Hitachi Global Storage Technologies - Netherlands B.V.
Kim Matthew
Martin Robert B.
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