KR100217749B1 - Method for optimizing read channel of hard disk drive - Google Patents

Abstract

The present invention discloses a read channel optimization method for a hard disk drive. The hard disk drive lead channel optimization according to the present invention is performed when a user uses a host computer after shipping a hard disk drive product, and enters the lead channel optimization mode after a predetermined time elapses. If a command comes from the host computer during the read channel optimization mode, the read channel optimization operation is interrupted and the command is executed. Then, when the command finishes, the interrupted read channel optimization is performed again. If there is no command from the host computer until the read channel operation is completed, the read channel operation is completed to obtain the read channel optimization parameters and set the parameters to the read channel. This not only maintains the performance of the drive, but also obtains the optimal lead channel parameters that adapt to changes in the environment or the characteristics of the hard disk drive.

Description

How to Optimize Lead Channels for Hard Disk Drives

The present invention relates to a read channel optimization method of a hard disk drive (hereinafter referred to as an HDD), and more particularly, to a read channel optimization method capable of continuously maintaining the performance of a drive.

In general, when a HDD is manufactured, it usually goes through a process such as servolite → functional test → burn-in test. In the servo light process, the positional information is recorded on the disk. In the functional test process, it is determined whether the maintenance cylinder is defected and whether the data area can be read or written. In the burn-in test process, it is determined whether or not the data region is defective.

The burn-in test process includes a read channel optimization process for optimizing the read channel of the HDD. The read channel optimization process of the HDD is performed by a method consisting of the following steps. In this case, the read channel optimization may be performed by a controller of the HDD, for example, a CPU (Central Processing Unit), or may be performed by a test apparatus external to the HDD. The following process is an example of performing read channel optimization in the controller of the HDD.

1 Select a specific track on the disc that corresponds to the zone and head.

② Set the predetermined basic lead channel parameters to the lead channel of the read / write channel circuit.

3) Write a constant data pattern for the test to a specific track (the track selected for lead channel optimization) through the read / write channel circuit.

(4) The values of the basic lead channel parameters set in the lead channel are collectively changed and set in the lead channel of the read / write channel circuit (for example, set with the first parameter values). Typically, this batch parameter change is made at the time of multiple parameter optimization. The multi-parameter optimization is the opposite of single parameter optimization.

(5) A predetermined number of sectors in a specific track to which a constant data pattern is written are repeatedly read N times, and the number of errors for the parameter values is stored in the memory.

When step (5) is performed, the set parameter values are collectively changed again and set in the read channel of the read / write channel circuit (for example, set as the second parameter values). Then perform step ⑤.

⑦ If it proceeds up to N parameter values, which is the final parameter value, by repeating steps ④⑤⑥ above, proceed to step ⑧ below.

⑧ Select the lead channel parameter value (eg, the third parameter value) with the fewest error counts and store it in nonvolatile memory (disk, flash memory, etc.). Then use these parameter values as the basic parameters of the lead channel.

The parameter parameters of the read channel include, for example, a cutoff frequency, a group delay, a boost level, a data threshold, and the like. It should be understood that the above process of ①⑧ is performed for all zones and heads. That is, in the case where four zones exist on the disk and four heads are installed in the disk drive, the lead channel optimization is performed from the first zone to the fourth zone by first selecting the disk surface corresponding to the first head. do. Next, the disk surface corresponding to the second head is selected and performed from the first zone to the fourth zone. Then, the disk surface corresponding to the third head is selected and performed from the first zone to the fourth zone. Finally, the disk surface corresponding to the fourth head is selected and performed from the first zone to the fourth zone.

The lead channel optimization of the above-described method has a disadvantage in that it is not sufficient test because it has to be made within the time limit in the burn-in test process of the production process. More specifically, lead channel optimization in the burn-in test process uses a method that stresses the HDD more than normal (off-track) for maximum testing within a limited time. As a result, the error for a certain time is much more than the number of times an error occurs during a certain time under normal circumstances. Therefore, even in a limited time, the read channel parameter optimization can be performed using the error occurrence frequency. However, there is no guarantee that an optimized lead channel will have the optimized effect even under normal stress under HDD stress. This is due to factors that cannot be performed in the test process under normal circumstances, that is, changes in the surrounding environment (temperature, etc.) or mechanical characteristics change over time due to the characteristics of the HDD. Therefore, in order to solve these problems, a method for optimizing lead channels in a situation where a user is using a HDD as well as a production process was required.

An object of the present invention is to provide a read channel optimization method that can continuously maintain the performance of the drive.

Another object of the present invention is to provide a method for optimizing lead channel even when a user is using a hard disk drive.

It is still another object of the present invention to provide a read channel optimization method capable of obtaining an optimal read channel parameter according to a change in a surrounding environment or a change in characteristics of a hard disk drive.

1 is a block diagram of a HDD involved in performing read channel optimization according to an embodiment of the present invention.

2 illustrates a read channel optimization operation according to an embodiment of the present invention.

3 is a view illustrating a process in which lead channel optimization is performed from start to finish.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the embodiments of the present invention described below, many specific details such as the number of specific disks and heads, specific processing flows, etc. are shown to provide a more general understanding of the present invention. It will be apparent to those skilled in the art that the present invention may be practiced without these specific details. And a detailed description of known functions and configurations that may unnecessarily obscure the subject matter of the present invention will be omitted.

1 illustrates a block configuration of an HDD related to performing read channel optimization according to an embodiment of the present invention. Referring to the HDD according to FIG. 1, two disks 10 and four heads 12, a read / write channel circuit 14, a CPU 16, a ROM 18, a memory 20, and a disk controller ( 22) and a buffer ram 24. The CPU 16 reads a program mapped to the ROM 18 and performs various control operations. In the ROM 18, a program for controlling the operation of the HDD, a program for optimizing the read channel according to the embodiment of the present invention, a parameter table required for optimization, and the like are mapped. The disk 10 stores data in the form of a magnetic signal, which is read by the head 12 and applied to the read / write channel circuit 14. In the read channel of the read / write channel circuit 14, the signal is converted into encoded data and transmitted to the disc controller 22. In the write channel of the read / write channel circuit 14, the coded write data applied from the disc controller 22 is written onto the disc 10 through a predetermined head 12. The disk controller 22 temporarily stores the data to be transmitted to the host computer in the buffer RAM 24. The data received from the host computer is temporarily stored in the buffer RAM 24 and applied to the read / write channel circuit 14. It also interfaces the communication between the host computer and the CPU 16.

In addition to the user data area, the disc 10 according to the present invention is provided with an area for storing optimized lead channel parameters, and an area for copying and storing data in an optimized track.

It should be noted that the read channel optimization of the HDD according to the embodiment of the present invention is performed when the user uses the host computer after shipping the product. 2 is a diagram illustrating an operation of performing read channel optimization according to an embodiment of the present invention.

Referring now to Figures 1 and 2 the operation of the present invention will be described in more detail. The CPU 16 of FIG. 1 reads the optimized parameter OPMPR stored in the disk 10 and stores it in the memory 20 when the system is started as in step 100 of FIG. 2. After that, the flow proceeds to step 104 to initialize a timer for a predetermined time check. Then proceed to step 106.

Steps 106 through 114 of FIG. 2 are summarized as a process of entering a read channel optimization mode if a command is not received from the host computer for a predetermined time, and executing the command if the command comes. In step 106, it is determined whether a command exists from the host computer. If the command exists, the flow proceeds to step 108 to execute the command. However, if the command does not exist, the flow proceeds to step 110 to operate the timer. The timer accordingly starts a time count. In step 112, the CPU 16 determines whether the time count value has exceeded a predetermined reference value, that is, a predetermined predetermined time (10 sec as a preferred example). If the time count value does not exceed the preset reference value, the process returns to step 106 and the process from there is performed again. However, if the time count value exceeds the preset reference value, the process proceeds to step 114 to enter the read channel optimization mode. The lead channel optimization of the above-described method has a disadvantage in that it is not sufficient test because it has to be made within a time limit in the production process (ie burn-in test process). More specifically, lead channel optimization in the burn-in test process uses a method that stresses the HDD more than normal (off-track) for maximum testing within a limited time. As a result, the error for a certain time is much more than the number of times an error occurs during a certain time under normal circumstances. Therefore, even in a limited time, the read channel parameter optimization can be performed using the error occurrence frequency. However, there is no guarantee that an optimized lead channel will have the optimized effect even under normal stress conditions. This is due to factors that cannot be performed in the test process under normal circumstances, that is, changes in the surrounding environment (temperature, etc.) or mechanical characteristics change over time due to the characteristics of the HDD. Therefore, in order to solve these problems, a method for optimizing lead channels in a situation where a user is using a HDD as well as a production process was required.

The read channel optimization mode is from step 116 to step 132 of FIG. The CPU 16 determines whether the read channel optimization operation interrupted in step 116 is stopped. The read channel optimization operation is interrupted when a predetermined command comes from the host during the read channel optimization mode. When the work is interrupted, the work result and state up to that point are stored in the memory 20, and a flag indicating the work interruption is set. Therefore, the CPU 16 can know whether the interrupted read channel optimization operation is interrupted by checking the state of the flag indicating the interruption. If the operation is stopped, the process proceeds to step 118 to recover the suspended lead channel optimization operation and proceeds to step 120 to perform the lead channel optimization operation. However, if it is determined in step 116 that there is no interrupted work, the process proceeds directly to step 120 to perform lead channel optimization work from the beginning.

The process of performing the lead channel optimization operation from the beginning to the end is shown in FIG. 3. Referring to FIG. 3, the CPU 16 selects a head and a zone in step 200. In step 202, data recorded on a specific track of a corresponding zone is transferred to a storage area in the disk and stored. Thereafter, in step 204, the currently set lead channel optimal parameter is set to the lead channel. In operation 206, the test data pattern is written to the specific track, and in operation 208, the read channel parameters are changed and set, and the test data written in the specific track is read several times. The read channel parameters are stored in a parameter table mapped to the ROM 18, and the CPU 16 sets parameters in the read channel of the read / write channel circuit 14 using the parameter table. After performing step 208, the CPU 16 stores the changed parameters and the corresponding error count value in the memory 20. As an example, the memory 20 of FIG. 1 stores from the first parameter to the Nth parameter and the first error count value to the Nth error count value. After performing step 210, the CPU 16 finds the minimum error count value in the memory 20 and sets the read channel parameter corresponding thereto as the optimal read channel parameter. Therefore, in the read channel of the read / write channel circuit, the tested optimal read channel parameter is set. Thereafter, the data stored in the storage area in the disk 10 is moved again to store the specific track that was originally stored, the work result is stored in the memory 20, and the process ends.

While the read channel optimization operation is being performed, the CPU 16 continuously determines whether there is an instruction from the host as in step 122 of FIG. 2 until the operation is completed. If there is a command from the host computer during the read channel optimization, the process proceeds to step 124. In operation 124, the operation is stopped and the result and state of the operation up to that time are stored in the memory 20. And set a flag to indicate that the operation is stopped. Then proceed to step 128 to execute the command from the host computer. Then proceed to step 104 and perform the steps from there. However, if there is no command from the host computer until the operation is finished (check in step 130), the process proceeds to step 132 in which the optimal result is set in the memory 20 and the optimized read channel parameter storage area in the disk. Save and end the process.

According to the present invention as described above, since the lead channel optimization is performed when the user uses the host computer, the lead channel optimization can be performed regardless of time. Therefore, the lead channel optimization efficiency can be increased. In addition, continuous lead channel optimization is performed by the use of a host computer to maintain drive performance. It also has the advantage of obtaining optimal lead channel parameters that adapt to changes in the surrounding environment or changes in the characteristics of the hard disk drive.

Claims (6)

In the lead channel optimization method of the hard disk drive: A first step of entering a read channel optimization mode when no command is received from the host computer for a predetermined time; Performing a read channel optimization operation in the read channel optimization mode to obtain an optimal read channel parameter value and to store the read channel parameter value in a memory; And a third step of storing the result of execution of the work and the state until the command from the host computer during the second process, stopping the optimization and executing the command. . The read channel optimization method of claim 1, further comprising: restoring the optimization task that is interrupted because no instruction is received from the host computer for a predetermined time after the third process. The method of claim 1 or 2, wherein the optimal read channel parameter value is used as a basic parameter value of the read channel. The method of claim 3, wherein the predetermined predetermined time period is preferably 10 sec. In the lead channel optimization method of the hard disk drive: A first step of reading an optimization parameter previously stored in a disk according to a system startup, storing the optimized parameter in a memory, and initializing a timer; Determining whether there is a command from the host computer after initializing the timer, and performing a command if there is a command; A third step of operating a timer if there is no command and determining whether a count value of the timer exceeds a preset reference value; Performing a read channel optimization operation as the count value exceeds the reference value; A fifth step of stopping the work if there is a command from the host computer during the read channel optimization work and storing the work execution result and state so far in a memory and executing the command; A sixth step of storing, in a memory, an optimized read channel parameter value that is a result of performing a task if there is no command from the host computer until the read channel optimization operation is finished; Lead channel optimization method characterized in that. The method of claim 5, wherein the channel optimization operation in the fourth process; Entering the lead channel optimization mode; Determining whether the lead channel optimization work has been stopped; If there is an interrupted lead channel optimization, recover the interrupted optimization and do so afterwards, The lead channel optimization method comprising the step of performing the lead channel optimization operation from the beginning if there is no interrupted channel optimization operation.