JPS6246468A - Disk memory device - Google Patents

Abstract

PURPOSE:To speed up sector replacing processing by arranging one stand-by sector on the leading part of each recording track and substituting and assigning a stand-by sector on another track for/to the 2nd defective sector on a recording track having two defective sectors. CONSTITUTION:Each track on a magnetic disk recording medium is divided into 12 equal sectors and each sector is constituted of a GAP 1, an identification part ID, an inspection bit part ECC1, a GAP 2, a DATA, an inspection bit ECC2, and a GAP 3. The ID part is constituted of 3 words consisting of ID1-ID3, the flag of the ID1 indicates the existence of two defective sectors in the track and the ID3 is a field for recording the address of the track having a stand-by sector to be a substitute for the 2nd defective sector. Out of the 12 sectors in one track, the leading sector is used as a stand-by sector and the residual sectors are used as current sectors. Thus, the stand-by sector in the another track having no medium defect is substituted for the 2nd defective sector on the recording track to speed up the processing.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a rotating body storage device, and more particularly to a rotating body storage device that uses a 7-stem alternating sector control method suitable for high-speed processing.

[Background of the invention]

Conventionally, an alternate track processing method has been used as an alternative method for dealing with defects on the medium and has been effective as a means for quickly detecting alternate destination addresses. However, in the alternate track method, when data to be processed for - times spans a plurality of tracks, switching access from the current track to the alternate track occurs, so this problem has not been taken into consideration.

On the other hand, in the embodiment of the replacement sector one-way system described in Japanese Patent Application No. 58-93956, a replacement spare sector is secured in advance in the same track, and a defective sector is relieved with the spare sector. Therefore, it is effective that the time required for alternative processing is fast. However, as the recording density of recent magnetic disks has increased, the probability of medium defects has increased, and it has become rare for multiple defects to exist within a track. In this regard, in the above-mentioned method, a processing delay occurs because alternate tracks are allocated. Also, to make a simple analogy, if you increase the number of spare sectors by two or three, you can achieve the goal of speeding up, but on the other hand,
Media usage efficiency will decrease.

[Purpose of the invention]

An object of the present invention is to provide a disk storage device that can secure spare sectors even if a plurality of bad sectors exist in a track and can perform alternate sector processing without reducing processing speed. There is a particular thing.

[Summary of the invention]

There are no media defects on all tracks.
- In the alternate sector system with one spare sector per track, most of the spare sectors are unused and vacant.

Therefore, we devised a method that effectively uses these empty sectors and maintains the replacement sector processing delay as before. That is, if there are two bad sectors in a -track and a -sector extends beyond the track, there will be no processing delay if the -sector can be replaced with the first sector of the next track. To realize this, K should allocate a spare sector to the leading sector of each track. Also, if the spare sector of the next track is already in use, it is possible to select another track on the same cylinder (in other words, if it is within the range that can be selected using only the electronic circuit without moving the head), the sector will not be missed due to track switching time. The result is the same even if a free spare sector is used.

Considering the media defect rate (1 location/1 megabyte) of a typical disk, the probability that there will be a vacant spare sector within the same cylinder is extremely high, and it has been found that there is no problem at all in practice.

[Embodiments of the invention]

FIG. 1 shows a track format of a magnetic disk storage device as an example.

In the figure, each track of the magnetic disk storage medium is divided into twelve equal length sectors, each sector having a different IID, GAPI, ill, etc. as shown.

Check bit part ECCl, GAP2. Consists of DATA, check bits ECC2 and GAP3.

GAPI, 2 is VF when reading ID part and DATA part
GAP3 has a length corresponding to the time required for the O circuit to synchronize with the reference clock, and GAP3 is used to switch the head from writing to reading state when starting to read the ID section of the next sector after writing is completed. It has a length that corresponds to the required time.

The ID section is further composed of three words, IDI and ID3, as shown in the figure.

The IDI flag is introduced according to the present invention and contains nine pieces of information,
This indicates that there are two bad sectors in the track. Furthermore, ID3 records the address of a track (hereinafter referred to as an alternative track) that has a spare sector that can replace the second bad sector mentioned above. field.

The sector number of ID1 and the track address of ID2 are fields representing the position of the own sector.

In this embodiment, the cylinder number and head number that determine the track position of the magnetic disk are collectively expressed as a track address.

The check bits ECCl and ECC2 are check bit parts for calculating the ID part and the data part, and detecting and correcting errors, respectively.

In this embodiment, for the two sectors in the track, the first sector is set as a spare sector, the sector number of this sector is expressed as all 1, and the remaining 10 sectors are set as working sectors, starting from the first sector. Sector No.

is given from 0 to 11.

FIG. 2 shows typical examples of possible track formats in this embodiment.

(1) in FIG. 2 shows a track where no bad sector exists. The number in the frame represents the sector number, “F
F″ is a hebit-all pattern expressed in a small-hole decimal number.

(2) in FIG. 2 represents a track where the fourth sector is defective. That is, the fourth (shaded part)
The sector number of FF is skipped, and other good sectors constitute -track sectors.

(3) in Figure 2 represents a track with two bad sectors; in this case, the last sector (sector No. 10) of this track is the first sector of the track (4) in Figure 2. has been replaced.

However, (3) is track N and (4) is track N+1
It is clear that the recording operation from track N to N+1 can be performed continuously.

Furthermore, even if (3) and (4) are not consecutive tracks, track switching can be performed within the time set by GAP3, so the continuity of the recording operation is maintained.

FIG. 3 shows an example of 71-ware for implementing the present invention. Reference numeral 10 denotes a channel device for connecting the control device 20 and the CPU, and these are connected by a data line 30 for exchanging data and a control signal line 40 for exchanging control signals. The control device 20 includes a control circuit 50. which includes a microprocessor 60 that controls the entire control device. RAM 70 for storing control information and data;
It consists of a register 80 for storing control information for the disk device 200, a register 90 for reading status information from the disk device f1200, a data bus 100 connecting these, and a control signal line 110 for controlling them.

Next, the operation will be explained. First, control information sent from channel 10 is stored in the control table in RAM 70. The control information includes the address of the sector to be read/written and the number of words to be transferred.
0 first calculates the cylinder number and head number on the disk from this sector address and stores them in the control register 80.

The disk device 200 thereby moves the head to the designated cylinder and further selects the designated head. In this state, when a sector pulse is detected by the disk status information register 90, the control device reads the ID information, and after confirming that the cylinder number, head number, and sector number in the ID section are the desired ones, Performs read/write operations.

FIG. 4 shows an example of alternative processing for defective sectors according to the present invention.

In a fixed length sector type magnetic disk drive, one index pulse is emitted at the beginning of a track, and one sector pulse is emitted at the beginning of each sector.

In normal data read/write processing, after receiving a sector pulse, the ID section of the sector is read, the sector number is confirmed, and after t a data section read or write operation is performed. In the disc of this example.

The processing example is described assuming that the index pulse length is up to the GAP2 area of the ID part, and by checking this index pulse after reading the ID part, it is possible to check whether or not this sector is the beginning of the track. It is.

Now, in the processing flow of FIG. 4, step numbers are attached to the right shoulder of the frame representing each process.

In normal processing, that is, when only one bad sector exists, the process flow is in steps 300 and 305.
,310,315,320,325°330.340,
345, 350, 365, 370°375 route'
is executed, and processing steps 355,360 and 380 through 395,400 are not executed.

When processing a track with two bad sectors, the following processing is performed.

First, after reading the ID section, it is determined in step 330 that the shift flag is 1, and step 335 is executed. In step 335, R the ID1 to ID3 that you just read.
At the same time as registering to AM, the flag itself is also registered. Thereafter, the process progresses and when it passes through step 305 again, it branches to step 380. If the sector No. to be processed now is the final sector.

Furthermore, through steps 385 to 395), step 30
0 selects the track where the alternative sector exists. Thereafter, as the process proceeds, a branch occurs at step 325,
In step 400, the rationality of the sector position is checked (there are two sectors 10 on this track, that is, there is an alternative sector 10 and sector 10 of the own track), and the process starts from step 340. 350
Steps 355 and 360 restore the original target track number and cancel the alternate mode.
When step 370 is executed, the sector number becomes 0, and the process returns to step 300 to select a new track.

〔Effect of the invention〕

According to the present invention, even if a track with a plurality of defective sectors exists, alternative access can be performed without waiting for rotation of the recording medium.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a recording format in an embodiment of the present invention, FIG. 2 is a diagram showing a sector arrangement on a track in an embodiment of the present invention, and FIG. 3 is a block diagram of the control device in FIG. 1. , FIG. 4 is a flowchart of FIG. 3. 10... Channel device, 20... Control device, 30
...Data line.

Claims (1)

[Claims] 1. A case where a recording track consisting of a plurality of sectors is provided on a magnetic recording medium, a part of the sectors on the recording track is provided as a spare sector, and a medium defect exists on the recording track. In a disk storage device that uses the spare sector on the same track as a substitute without using the sector containing the medium defect as a bad sector, one sector of the spare sector is placed at the beginning of each recording track. However, if there are two bad sectors containing medium defects on the same track, a spare sector on another track with no medium defects is allocated as a substitute for the second bad sector on the recording track, As an alternative control means, a flag indicating the existence of the two defective sectors and position information of another track to which the alternative sector is allocated are recorded as part of sector identification information, thereby performing alternative sector control. disk storage device.