JPH01274229A - Fixed disk device - Google Patents

Abstract

PURPOSE:To recover a data file even when readout is impossible by providing a writable memory and a controller for the memory, and always performing the backup of directory data on the memory in a fixed disk. CONSTITUTION:When a central arithmetic processing unit 3 writes the data file generated in a main memory device 4 on a disk device 2, an instruction to read out the directory area 11 of a disk 7 to the main memory device is generated. Thereby, the directory data is read in. Next, it is judged whether or not the data file corresponding to a storage destination exists in read directory data. When no data exists, a null area in a data area 10 is searched, and the directory of the data file to be written from now is added on data read in the main memory device 4, and the instruction to write updated data on a disk controller 5 is generated.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a fixed disk device used as an auxiliary storage device of an electronic computer.

[Conventional technology]

FIG. 3 is a block diagram showing a conventional fixed disk device. In the figure, 1 is an electronic 1-L1 machine, 2 is a fixed disk device installed as an auxiliary storage device of this computer 1, and 3 is an electronic HE machine. 1 a central processing unit; 4 a main storage unit of the electronic computer 1; and 5 a fixed disk control unit in the computer 1 that controls the fixed disk unit 2 according to instructions from the central processing unit 3. It is. This fixed disk device 2 includes an interface circuit 6 consisting of a driver and a receiver, a magnetic disk 7 for storing data,
a read/write control device 8 that is connected to the interface circuit 6 and controls reading of data on the magnetic disk 7;
A magnetic head 9 is provided for reading and writing data on the magnetic disk 7 under the control of the read/write control device 8. The magnetic disk 7 is provided with a data area 10 and a directory area 11 indicating where in the data area 10 the data files of each part are located.

The interface circuit 6 transmits and receives control signals and data to and from the fixed disk controller 5.

Next, the operation will be explained. Central law 1 Jffi science equipment 3
When adding and writing data files generated in the main storage device 4 to the fixed disk mounted 2, and when reading data files stored in the fixed disk device 2 into the main storage device 4, the central processing The processing device 3 first issues a command to the fixed disk control device 5 to read the directory area 11 of the magnetic disk 7 to the host storage device 4.The fixed disk control device 5 decodes this command and sends it to the interface circuit. 6. When the read/write control device 8 receives this control signal through the interface circuit 6, it moves the magnetic head 9 to the directory area 11 and reads out the V directory data. The created directory data is transferred to the fixed disk controller 5 through the interface circuit 6.

The fixed disk controller 5 writes the received directory data to the main storage device 4.

Next, in the case of a read operation, the central processing unit 3 reads the address information of the data area "O" where the required data file exists from this directory data, and sends the data area 10 to the fixed disk controller 5. Generates a command to read the corresponding part of. As a result, the above-described operations are repeated, the magnetic head 9 moves to the data area 10, and the corresponding data file is read into the main storage device 4.

On the other hand, in the case of a write operation, the central processing unit 1! [Device 3
It is determined whether a data file corresponding to the storage location exists in the directory data read into the main storage device 4, and if the corresponding data file exists, its address information is read and the data is stored on the fixed disk. A command is issued to the control device 5 to write an additional data file to a corresponding location in the data area 1 or 10. Also, within this directory data, there is data corresponding to the storage location.
If the file does not exist, please
Device 3 is data area 1 based on the device directory data.
0 free space, add the new directory data of the data file to be written to the existing directory data, and send it to the fixed disk controller 5.
Add this updated directory to directory area 11.
Generates an instruction to make data obsolete. Fixed disk controller 5 decodes this command and generates a control signal to interface circuit 6. When the read/write control device 8 receives this control signal through the interface circuit 6, it moves the magnetic head 9 to the directory area 11 and updates the directory data. Only then does the central processing unit 3 issue a command to the fixed disk controller 5 to write an additional data file to the data area vi10. As a result, the above operations are repeated, the magnetic head 9 moves to the data area 10, and the corresponding data file is written in the data area 10.

(Problem to be Solved by the Invention) Conventional fixed disk devices are configured as described above, so when reading or writing data files, it is necessary to read the directory area, and considering the total capacity of the fixed disk, Once a small portion of the directory area is destroyed, whether by physical or software factors, important data files stored on the fixed disk will never be readable again, even if the data area is normal. There was a problem.

This invention was made in order to solve the above-mentioned problems, and provides a fixed disk device that can recover data even if the directory area is destroyed as long as the data area is not destroyed. With the goal.

[Means to solve the problem]

In this invention, in the fixed disk device 2 connected to the computing hall 1 and controlling the fixed disk 7, a readable/writable printer 21
and h in the directory area 11 provided on the fixed disk 7.
[The system is equipped with a mail control device 22 that detects directory data read and written by the computer 1 and controls the memory 21 to read the data.

[Effect]

A memory control device 22 always detects directory data read and written in a directory area 11 provided on a fixed disk 7, and always reads and stores them simultaneously in a memory 21. In response to a request from the training machine 1, the directory data on this memory 21 is read out by the memory control device 22 and sent out. Thereby, even if the contents of the directory area 11 on the fixed disk 7 are destroyed, the directory data can be restored.

(Example〕 An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 1, 1 is an electronic calculator, 2 is a fixed disk device as an auxiliary storage device, and the electronic h1 calculator 1 is a fixed disk that controls a central processing unit, a main storage device 4, and a fixed disk device 2. A control device 5 is provided.

The fixed disk device 2 includes an interface circuit 6 composed of a driver and a receiver, a magnetic disk 7 for storing data, and a read/write circuit connected to the interface circuit 6 and controlling reading and writing of data on the magnetic disk 7.
It includes a write control device 8 and a magnetic head 9 that reads and writes data on the magnetic disk 7 under the control of the read/write control device 8. The magnetic disk 7 has a data area 10 and data files are stored in this data area 10.
A directory area 11 indicating where the file exists is provided. The interface circuit 6 transmits and receives control signals and data to and from the fixed disk controller 5.

The fixed disk device 7 is also provided with a RAM memory 21, an interface circuit 6, and a memory control device 22 that is connected to the read/write control device 8 and controls the mail 21 according to the states of these devices.

As shown in FIG. 2, the memory control device 22 includes a step counter 23 that counts the current position of the head 9 based on a control signal from the read/write control device 8, and count data of the step counter 23. an address generation circuit 24 that generates an address of the memory 21 based on the
An MFM data modulation/demodulation circuit 25 that converts the MFM data signal from the interface circuit 6 into a digital signal or vice versa, and parallel data that supplies the serial data signal output from the MFM data modulation/demodulation circuit to the memory 21. A serial/parallel converter circuit 26 converts the read/parallel signal to the memory 21 based on the write signal and read signal from the interface circuit 6 and the carry signal output from the serial/parallel converter circuit 26.
Read/write signal generation circuit 27 that generates a write signal
It consists of

Next, the operation will be explained. When the central processing unit 3 outputs a data file generated in the main storage device 4 to the fixed disk head 2, the central processing unit 3 transfers the data file to the directory area 11 of the magnetic disk 7 to the fixed disk controller 5. A command is issued to read the data into the main memory device 4.

As a result, the fixed disk device 2 performs normal operation,
Directory data is read onto the main storage device 4.

Next, the central processing unit 3 determines whether a data file corresponding to the storage location exists in the directory data read into the main storage device 4. If the corresponding data file does not exist (for example, when creating a new data file), the central processing unit 3
searches for free space in the data area 10 of the magnetic disk 7 based on this directory data, adds the directory data of the data file that will become obsolete to the directory data read into the main storage device 4,
A command is issued to the fixed disk controller 5 to insert the updated fr (newly created) directory data into the directory area 11 of the magnetic disk. Fixed disk controller 5 decodes this command and generates a control signal to interface circuit 6. When the read/write control device 8 receives this control signal through the interface circuit 6,
The magnetic head 9 is moved to the directory area 11 of the magnetic disk 7.
, and update the directory data (create a new one).

At this time, the memory control device 22 operates as follows. The step signal and DI are always transmitted through the read/write control device 8.
When the step counter 23, which monitors the position of the magnetic head 9 based on the R signal, detects that the magnetic head 9 has moved to the directory gl area 11, the MFM data modulation/demodulation circuit 25 moves to the directory gl area. 11 is received through the interface circuit 6 and converted into digital serial data. At this time, the address generation circuit 24 generates an address on the memory 21 from the count data output from the step counter 23. Next, serial/parallel conversion circuit 2
6 converts the serial data output from this MFM data modulation/demodulation circuit 25 into parallel data.

At this time, the read/write signal generation circuit 27 detects from the carry signal output from the serial/parallel conversion circuit 26 that the data conversion has been completed, and as soon as the write signal is significant, Generate a light signal.

With the above steps, the directory data is written to the magnetic disk 7 and the mailbox 21, and the backup is completed.

Next, if it becomes impossible to read the directory area 11 due to some kind of failure, the central processing unit 3 instructs the fixed disk control unit 5 to read the contents of the memory 21 to the main storage unit 4. Occur. Fixed disk controller 5 decodes this command and generates a read signal to interface circuit 6. When the read/write signal generation circuit 27 receives this read signal through the interface circuit 6, it generates a read signal for the memory 21. Next, the serial/parallel conversion circuit 26 reads the backed up directory data at the relevant head position from the memory 21 and converts it into serial data. The MFM data modulation/demodulation circuit 25 uses this serial
The data is converted into MFM data, and this directory data is sent to the electronic rtll side through the interface circuit 6. The central performance IJ9u embedded device 3 reads the address information of the data area 10 in the magnetic disk 7 where the required data file exists from this directory data, and stores the data file from the corresponding location in the main storage device 4. I can read it. Also, this directory
It is possible to read all data from the memory 21 and record it on the magnetic disk 7 again.

Note that a CMOS memory backed up by a battery may be used as the memory 21 in the above embodiment, and in this case, there is an effect that the directory data can always be retained even if the power is cut off.

Note that the storage device is not limited to a magnetic disk, and may be a laser disk or other external storage device.

〔Effect of the invention〕

As explained above, according to the present invention, in a fixed disk device connected to a terminal device and controlling a fixed disk, a readable memory provided in the fixed disk device and a directory area provided in the fixed disk are Detects directory data read and written by computers,
It is equipped with a memory control device that controls the memory to read and write the data, and is configured to always back up the directory data on the memory, so even if the directory area becomes unreadable for some reason, the data will not be lost. - Files can be restored, ensuring a higher level of data security on fixed disk devices.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a fixed disk device according to an embodiment of the present invention, FIG. 2 is a block diagram showing the configuration of a memory control device, and FIG. 3 is a block diagram showing a conventional fixed disk device. 1 is an electronic sieve machine, 2 is a fixed disk device, and 3 is a central control unit.
A processing unit, 4 a main storage device, 5 a fixed disk control device, 6 an interface circuit, 7 a magnetic disk, 8 a read/write control device, 9 a magnetic head, 10 a data area, 11 a directory area, 21 is a memory, 22 is a memory control device, 23 is a step counter, 24 is an address generation circuit, 25 is an MFM data modulation/demodulation circuit,
26 is a serial/parallel conversion circuit, and 27 is a read/write signal generation circuit.

Claims (1)

[Scope of Claims] A fixed disk device connected to a computer and controlling a fixed disk, comprising: a readable/writable memory provided in the fixed disk device, and directory data read/written by the computer into a directory area provided in the fixed disk. A fixed disk device comprising: a memory control device that detects the data and controls the memory to read and write the data.