JPS62256268A - Magnetic disk device - Google Patents

Abstract

PURPOSE:To improve the reliability by recording an address having the prescribed number of times or over of data error in a recording medium so as to prevent a data from being written in a defective location on the medium. CONSTITUTION:A check bit is added (3) to a serial data being the result of conversion of a parallel data recorded onto a recording medium from a host computer CP 1 by a P/S conversion circuit 11 and required information such as an address is added by a controller CT 4 and fed to a driver 5. A binarized, data (8) read from a magnetic head from which an undesired component such as a clock is separated (9) is subject to check by a check circuit 10 via the CT 4. When the circuit 10 detects an error, the address written with the erroneous data is written in an error address recording means 14. When no access request comes from the CP 1, a CPU 12 accesses the means 14 and when the read data includes still an error, the number of times of the error is written in an error number recording means 15. When the number of times of error of the means 15 is a prescribed number or over, the CPU 12 detects the address as a defective address and makes a driver 13 write the data in an alternate address.

Description

[Detailed description of the invention] [Purpose of the invention] (Industrial application field) The present invention relates to a magnetic disk device.

(Prior Art) Generally, magnetic recording media (LA disks) used in magnetic disk devices always have defects, although the degree of defects may vary due to manufacturing problems. There is an extremely high probability that the stored data will not be read out correctly later.

For this reason, conventionally, when a magnetic disk drive is assembled at the factory, work has been done to identify the defective locations, and based on the information obtained through this work, data is not recorded in the defective locations. Countermeasures are being taken.

However, it is impossible for the factory to completely identify defective locations, and defects often appear in new locations on the user's side.

Furthermore, even if the defect is of a low level and is not discovered at the factory, it may grow on the user's side and later appear as an obvious defect, but no countermeasures have been taken against such defects. However, there was a problem that it could interfere with data recording.

(Problems to be Solved by the Invention) The present invention was made due to the above circumstances, and in a magnetic disk device, not only defects that have already appeared on the recording medium but also defects that have appeared later. The purpose is to dramatically increase data reliability by preventing data from being written to defective locations.

[Effects of the Invention] (Means for Solving Problems) The magnetic disk device of the present invention has check picks 1 to 1 that add check picks 1 to each data when writing data.
Data error detection means for detecting whether an error has occurred using the additional check bit, and an address record for recording the address from which the data was input or output when an error occurs in the read data. and a data error method that accesses the address where the data in which the error has occurred is written when there is no access request, and detects whether an error has occurred again in the read data. redetection means;
When an error occurs a predetermined number of times in reading the failed data (), a data write control means is provided which designates the address as a defective address and records data at an alternative address.

(Function) Even when the magnetic eye disk device of the present invention is used on the second side, it can detect errors in data while a data access request is being made. Since the defective address can be specified at any time, the use of the defective address is always avoided.

(Example) Hereinafter, details of an example of the present invention will be described based on the drawings.

In the figure, 1 is a host combination coater, 2 is a parallel-to-serial conversion circuit (consisting of j1 shift 1 to register 1, and boss), which converts parallel data output from the computer 1 to serial data, and 3 is a parallel-to-serial conversion circuit. A check pit adding circuit adds check bits for code error detection to serial data; 4 is a data controller 1 roller that controls data input/output; and 5 is a read/write driver that provides write data to the magnetic head.

Further, 6 is an amplifier that amplifies the analog waveform data signal read from the recording medium by the magnetic head, 7 is a low-pass filter that removes noise components in the data signal, and 8 is the analog waveform data signal that is converted into a digital waveform data signal. 9 is a data separator that removes the clock signal included in the data signal; 10 is an error check detection circuit that checks whether an error has occurred in the data signal; 11 is serial data This is a serial-to-parallel conversion circuit that converts data into parallel data.

Furthermore, 12 is a CPtJ on the controller 1 to roller side, 13 is a receiver/driver that is an interface with the post computer 1, 14 is an error address recording means for recording the address where an error has occurred in the read data, and 15 is an error address recording means for recording the address where an error has occurred in the read data. This is an error number recording means for recording the number of errors at each error address.

In the apparatus of this embodiment, the host computer coater 1 first sends out data to be recorded on a recording medium as parallel data.

This data is input to the parallel-serial conversion circuit 2 to become serial data, or after that, the check picks 1 to 1 are added in the check pick 1 to addition circuit 3.

FIG. 2 shows the above-mentioned ticks 1 to 1 in this embodiment device.
This is a diagram showing the data structure after addition, and in the diagram CRC/FC
The part marked C corresponds to check picks 1~.

The data with the check bit added is ]n 1 to roller 4.
After adding necessary information such as an address mark, the data is sent to the input/output driver 5.

On the other hand, the data read by the magnetic head is transmitted to the amplifier 6.
The signal is amplified, passed through a low-pass filter 7 to remove noise, converted into a digital waveform signal by a binarization circuit 8, and further removed by a data separator 9 from unnecessary components such as clock signals.

In the apparatus of this embodiment, the CPU 12 can know the contents of the read data by using the DECRON 1 to the roller 4. After the error detection circuit 10 determines whether or not there is an error in the read data, the process shown in FIG. 3 is performed.

First, the CPU 124 (J: data controller 1 to L1-4) reads the address of the data content (step A), and stores the read atto1nos in an internal register (step B).

Since the error check circuit 10 has a function of determining whether or not there is an error in the read data and correcting the error, the CPU
12 reads the presence or absence of data errors from the error check circuit 10 (step C).

Step D
), if an R error has occurred, move the internally provided address-only counter and set it to 1 or higher (step [)]. Furthermore, the count value is compared with a constant value (N>) in step ``), and if it is smaller than the constant value, the corresponding address IFt3 is stored in the memory (step G).

Such processing is repeated when there is no request from the host computer 1 to access the magnetic disk device.

That is, the address recorded at the error address is accessed, the data is read out, and the error check circuit 10 is checked to see if the error occurs again.

Then, specify the error count value for successive occurrences at the same address or a certain value (if N> or more, define that address as a defective address (step 1-1), specify an alternative address, and then proceed to that address from now on. Avoid recording data.

10) As mentioned above, the device of this embodiment can be used even if a data error that was not detected on the factory side appears on the NIA side.
When the degree of the problem becomes significant, it can be treated as a defective address.

FIG. 4 is a block diagram showing the configuration of an embodiment (112) of the present invention, and parts common to those in FIG. 1 are given the same reference numerals.

In this circuit, the constituent elements 1 to 17 are the same as those in FIG. 1, and therefore their explanation will be omitted.

In the device of this embodiment, the number of newly designated defective addresses is
A defective address number recording means 18 is provided which notifies the host computer 1 when the number exceeds a certain value.

FIG. 5 is a diagram showing the flow of processing carried out in the apparatus of this embodiment.

First, the CPU 12 reads data content and its address from the data controller 4 (step A) and stores the read address in an internal register (step B).

Since the error check circuit 10 has a function of determining whether or not there is an error in the read data and correcting the error, the CPU
12 reads the presence or absence of data errors from the error check circuit 10 (step C).

Step D to recognize whether an error has occurred or not.
> If an error has occurred, an internally provided address-only counter is operated to run from 1 (step E). The current value is roughly compared with a constant value (N) in step [), and if it is smaller than the constant value, the address value is stored in the memory (step G).

Such processing is repeated when there is no request from the host computer 1 to access the magnetic disk device.

That is, the address recorded as an error address is accessed and data is read out, and the error check circuit 10 checks whether the error occurs again or not.

If the error count value when reading at the same address exceeds a certain value (N), that address is defined as a defective address (step 1-1), an alternative address is specified, and subsequent attempts to that address are made. Avoid recording data.

The processing up to this point is the same as that of the previous embodiment, but the apparatus of this embodiment subsequently performs the following processing.

First, when a defective address is defined, an internal defective address counter is operated and counted (step I). Then, the callan 1 to value is compared with a constant value N (step J), and when the total number of defective addresses exceeds a constant value (E), the host computer is notified (step K).

That is, in the device of this embodiment, when the total number of newly found defective addresses exceeds a certain value, this is notified to the host computer 1, and at that stage, the host computer 1
Data protection is prioritized by taking measures such as discontinuing the use of devices. This further improves the reliability of the data.

[Effects of the Invention] As explained above, in the magnetic disk drive of the present invention, an address where a data error occurs a certain number of times or more is recorded on a recording medium, and the address is determined to be a defective address and an alternative address is used. The reliability of the data is dramatically improved because the control work is performed automatically.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of a device according to an embodiment of the present invention, FIG. 2 is a diagram showing the structure of data from check pin 1 to addition in the same embodiment device, and FIG. FIG. 4 is a block diagram showing the configuration of an apparatus according to another embodiment of the present invention, and FIG. 5 is a diagram showing the flow of processing in the same embodiment. 1...Host computer 2...
...Parallel-serial conversion circuit 3...
...Check bit addition circuit 4...Data controller 5...Write driver 6...Amplifier 7... Low pass fill 8...
... Binarization circuit 9 ...... Data separator 10 ...
...Error checking circuit 11... Serial-to-parallel conversion circuit 12...CPt
J 13...Receiver/driver 14...
...Error address recording means 15...
Error count recording means 16...Positioning control circuit 17...Carriage drive circuit 1B.
...Applicant for defective address number recording means
Toshiba Corporation Toshiba Computer Engineering Corporation

Claims (1)

[Claims] (1) Check bit adding means for adding check bits to each data when writing data, and data error detection for detecting whether an error has occurred using the check bits when reading the data. an address recording means for recording an address at which the data was written when an error occurred in the read data; and an address recording means for recording the address at which the data was written when an error occurred in the read data; data error re-detection means for accessing the address where the error occurred and detecting whether an error has occurred again in the read data;
When the data is read multiple times and an error occurs a certain number of times,
1. A magnetic disk drive comprising: data write control means that designates the address as a defective address and causes data to be written to an alternative address.