JPS6381663A - Magnetic disk data check method - Google Patents

Abstract

PURPOSE:To improve the reliability of read data by securely reading objective data in a disk and checking read data. CONSTITUTION:If a CPU 1 outputs a read instruction to a disk controller 2 and designates a sector address, the controller 2 retrieves the ID part of the sector for the designated sector address, reads data in the sector retrieval area of a first bite in a data part, and transfers read data from the controller 2 to the CPU 1. The CPU 1 checks whether read and transferred data coincides with an objective sector number or not. If they coincide, the CPU 1 judges it to be normal reading and proceeds to a next processing. If they do not coicide, it repeats checking for prescribed times, and if they do not coincide still, displays them on a display device as an error processing.

Description

[Detailed Description of the Invention] Technical Field The present invention relates to a data checking method for a magnetic disk.
In particular, the present invention relates to a data check method suitable for reliably reading data written on a magnetic disk.

Prior Art Conventionally, a magnetic disk device 4, for example, a hard disk device (
In the HDD (hereinafter referred to as HDD), the hard disk controller (hereinafter referred to as HDC) formats the ID magnetic disk medium and writes the ID part and data part (a certain pattern, for example, E5, etc.). . As shown in FIG. 3, a sector of a magnetic disk medium formatted in this manner has an ID field in which information indicating the start and address of the sector is recorded, and a data field in which data is recorded. Gaps are placed before and after these to protect data from rotational fluctuations, mechanical dimensional errors, erase gate delays, and timing errors. The ID field above is a sink field,
It is divided into a missing clock (A l ) and an ID information area, and the ID information area further contains a cylinder number (track number).

The head number, sector number, and sector length are stored.

When reading the data section of a magnetic disk medium formatted as described above, the HDC reads the ID information in the ID section shown in Figure 3, decodes it itself, and then determines whether it is the target sector or not. Was.

FIG. 2 shows an example of a system configured by connecting the aforementioned HDD as an external storage device to a host system. Here, 1 is a host system including memory etc. (e.g. CPU
), 2 is an HD (disk drive device) that controls data writing/reading and data transfer, and an HDC 13 is an H'D that records data on a magnetic disk medium. CPU ID
A read command (one sector read) is issued to the HDC2, and the HDC2 receives the command and goes to read the disk medium of the HD3.The reading method at that time is, for example, reading O cylinder, 0 head, 0 sector. case.

First, when the HDC 2 detects the index shown in Fig. 3 (a pulse that occurs once per revolution of the disk plate of the HD 3), it searches the ID section, and the information written there is 0 cylinder, 0 Determine whether the head is 0 sector or not, and then read the data section. To explain in more detail, before reading the ID section, the IDVFO circuit (this is
(assumed to be inside DC2), and synchronize VF○
At the same time, a 5YNC signal is given to HDC2 from the VFO circuit. HDC2 given 5YNC signal
When the HDC 2 learns that the ID section has started, it next reads data A1°, determines that the following data is ID information, and reads the ID information. The same operation is performed for the data field, but to determine whether it is the data field or the ID field, the data following "A1" is "F8".
It is decided whether or not.

In such a read operation, the ID of the target 0 sector
Even if the part can be decoded, the 5YNC of the data part in Figure 3
IDVFO for uneven hard disk rotation, noise, etc.
If the circuits are not synchronized, the data portion of the 0 sector will be skipped because the 5YNC signal is not given to the HDC 2 even though the target data portion of the O sector has arrived. Next comes 5YNC of the ID part of one sector, but even if the VFO circuit is synchronized and the 5YNC signal is given to HDC2, the data following "Al" is not F8'. , HDC
2 is not the data section, and waits for the next 5YNC. ■
When synchronization is achieved at 5YNC of the data section of the sector, the HD
C2 is A1'.

Check F8', read the data, and as a result, the data of 1 sector is converted to C instead of the data of the target O sector.
It will be transferred to PU.

However, with this method, the CPU cannot judge whether the data transferred from the HDC2 is the data of the target sector or not, so the IDVF○ circuit lacks tracking accuracy due to uneven rotation and noise of the HDA itself. HDC2
Even if the CPU erroneously determines that the sector is normal and transfers data other than the target sector, the CPU has no choice but to process the data as the target sector data.

Purpose The purpose of the present invention is to solve such conventional problems and provide a magnetic disk data check method that can reliably read target data in a magnetic disk device and improve the reliability of read data. It is about providing.

Configuration In order to achieve the above object, the magnetic disk data check method of the present invention uses ID=
a magnetic disk formatted into an ID field for recording l# information and a data field for recording data;
In a magnetic disk device having a control means for writing data to the magnetic disk, reading data from the magnetic disk, and transferring data, read data is stored in a data field in addition to the ID information in the ID field. After formatting a search area for the higher-level device to judge whether or not it is a sector, the same number as the sector number of the ID information is set in the search area, and the data given from the higher-level device is received and the above control is performed. The feature is that when the means reads data in the search area and transfers the read data to a host device, the host device compares and checks the data in the search area and the data given by the host device. .

Hereinafter, the configuration of the present invention will be explained with reference to embodiments.

Since the overall configuration to which this embodiment is applied is the same as that shown in FIG. 2, this embodiment will be described below with reference to FIG. 2.

FIG. 4 is a comparison diagram of the flow of disk formatting of a magnetic disk medium according to the embodiment of the present invention and the conventional flow. Here, (a) shows the conventional flow, and (
b) shows the flow of this embodiment.

As shown in FIG. 4(a), conventionally, formatting of one track of the ID magnetic disk medium is performed on the HDC 2 (301), and the final cylinder (track) is formatted (302).
, 301 is repeated to complete the formatting of the ID and magnetic disk medium.

However, in the present invention, as shown in FIG. 4(b), first, formatting of one track of the ID magnetic disk medium is performed on the HDC 2 (401). This process is the same as the conventional process 301. After this formatting, sector search data is set in the first byte of the data area of each sector in the data buffer area (402). That is, the same number as the sector number of the ID part is set in the first byte of the data part of each sector. Next, the HDC 2 writes the sector search data to one track of the magnetic disk medium of the HD 3 (403). The above process is repeated until the final cylinder (track) (404), thereby completing the formatting of the ID and magnetic disk medium. An example of one sector after this formatting is shown in FIG. Here, the data length of one sector is 256 bytes, so within one sector there is a sector search area of 1 byte and a sector search area of 256 bytes.
This means that it is formatted into a 5-byte data area.

FIG. 1 is a flowchart of a data check processing operation showing an embodiment of the present invention. This shows the process when data is checked using a magnetic disk medium formatted as described above. The data check will be explained below according to the flow shown in FIG.

First, in a system like the one shown in Figure 2, the CPU
issues a read command to HDC2 and specifies a sector address (101), and upon receiving this command, HDC2
searches the ID section of the sector corresponding to the specified sector address, and then reads the data in the sector search area of the first byte of the data section as shown in FIG. 5 (102). The HDC 2 transfers this read data to the CPUI. CPUt checks whether the read and transferred data (sector number of the search area) matches the target sector number (103). If they match, it is determined that the reading is normal, the check process ends, and the process moves to the next process. If they do not match, retry is repeated, for example, about eight times (104).

Also, if the match does not match even after retrying 8 times, the CPU
As an error process, I displays a message to that effect on, for example, a display device (not shown). Although the number of retries is set to eight here, it is not limited to this number.

As described above, in this embodiment, a sector search area is provided in the data section of one sector, and the same number as the sector number of the ID section is stored in the sector search area.
The CPU 1 can now determine whether reading of the target sector is normal.

In this embodiment, a disk data check in a system using a floppy disk device has been described, but it is obvious that the present invention can be similarly applied to a system using a floppy disk device.

Effects As explained above, according to the present invention, target data can be reliably read in a magnetic disk device.
This makes it possible to improve the reliability of read data.

[Brief explanation of the drawing]

FIG. 1 is a flowchart of a data check operation showing an embodiment of the present invention, FIG. 2 is a configuration diagram of a system to which the present invention is applied, FIG. 3 is a diagram showing a sector format of a magnetic disk medium, and FIG. 4 is a comparison diagram of the disk formatting flow according to the embodiment of the present invention and the conventional flow,
FIG. 5 is a diagram showing an example of the structure of one sector subjected to ID formatting according to the embodiment of the present invention. 1: CPU, 2: HDC, 3: HD. Figure 1 Figure 2 Figure 4 Figure Ca)

Claims (1)

[Claims] (1) A magnetic disk that is formatted into an ID field that records ID information such as the start of a sector and an address, and a data field that records data, and the writing of data to or reading data from the magnetic disk, and the data In a magnetic disk device having a control means for transferring data, a search area is formatted in the data field in addition to the ID information in the ID field for the host device to determine whether or not the read data is in the target sector. , sets the same number as the sector number of the ID information in the search area, receives data given from the host device, causes the control means to read data in the search area, and transfers the read data to the host device. When this happens, the host device compares and checks the data in the search area and the data provided by the host device.