JPS6151345B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a flexible disk memory control device.

A flexible disk memory is a magnetic disk memory in which a flexible disk such as Mylar film is coated with a magnetic material. Figures 1a and 1b show the relationship between this disk and the magnetic head.
In the figure, a flexible disk 1 rotates around a rotating shaft 2, and can be read and written via a magnetic head 3 driven by a head moving mechanism 5. A head load pad 4 is provided on the opposite side of the magnetic head 3. Further, the head moving mechanism 5 is controlled by a control device 50. In the figure,
Figure a shows the non-operating state, in which the magnetic head 3 and head load pad 4 are separated from the disk 1. Figure b shows the operating state, in which the magnetic head 3 and head load pad 4 are both holding the disk 1, that is, are in contact with each other.

Due to the wear of the disk surface due to this contact, the disk has a finite lifespan, and this lifespan is usually expressed as the number of times the head can read and write with the head in contact with one track, and is about one million passes. However, in actual use, it is difficult to predict when a track will reach the end of its life because it does not keep track of how many times a track is accessed.

FIG. 2 shows the relationship with the tracks on the disk surface. In the figure, tracks 0, 1, 2...n are defined from the outside to the inside. If an error occurs on a particular track on a disk with this configuration, is the cause of the error due to wear on the disk surface due to a large number of accesses, or is it a hardware or system error? It is important to understand whether FIG. 2 shows an example where the track 2 is worn out.

In order to eliminate these problems, it would be possible to count the number of accesses to each track, but in reality, it is virtually impossible to store the number of accesses for each track in the main memory of a computer system. It is. The reason is that flexible disks are replaceable like magnetic tapes, and
This is because when all the data is written to the recording capacity of one disk, it is written to another disk, so the number of tracks appears to be infinite.

SUMMARY OF THE INVENTION An object of the present invention is to provide a flexible disk memory control device that records the actual number of times a flexible disk memory is used so that the disk can be used within its service life.

The gist of the present invention is to sequentially record the number of uses of a flexible disk memory in the disk memory itself, read out the number of uses as needed, and compare it with the set number of uses to detect the service life. This is what I did.

FIG. 3 is a diagram showing an embodiment of the present invention. In the figure, a magnetic head 3 and a head load pad 4 are shown.
The positional relationship with disk 1 is omitted. An index detector 6 for detecting the starting point position of each track is attached to the disk 1. This allows one revolution of the track to be detected.

Position control of the magnetic head 3 and head pad pad 4 is performed by a position control circuit 11. This position command to the position control circuit 11 is issued by the track address register 7.

The write/read control circuit 12 is for passing write or read commands to the magnetic head 3 and the data at that time. The track address register 7 and the write/read control circuit 12 are controlled by a control circuit 14 and also perform predetermined data exchange. This control circuit 14 is controlled under the management of an external circuit, particularly a central processing unit 15 on the computer side. Between the central processing unit 15 and the control circuit 14, addresses 15a for disk track selection, data 15b, and write and read commands 15 are provided.
c is communicating. Between the control circuit 14 and the track address register 7, the track address 14 is
data 14b and a write or read command 14c are communicated between the control circuit 14 and the write/read control circuit 12 during writing or reading. The flow of each signal is as shown by the arrows.

The track pass counter 8 counts the number of passes for each track. The way to use this counter 8 is to preset the number of passes up to that point when a particular track is in use, and then use this preset value as the index detection circuit 6.
The number of passes is detected by sequentially counting up the index signals obtained. This preset value is normally stored on a specific track on disk 1, and the pass count may be read from this track and set as a preset, but in reality, the pass count is stored each time each track is accessed. Reading the number of times affects the actual access time, so before using the disk, it is read from the disk, stored in another memory, and read by accessing that memory. . In the illustrated embodiment, a pass count memory 9 serves as the memory.

The pass number memory 9 uses the track address specified by the address register 7 as an address to write the contents of the counter 8, write the preset value to the counter 8, and write the pass number through the read/write control circuit 12. It is configured to store data for writing onto the disk a number of times. This pass count memory 9 has addresses for the total number of tracks, and stores the pass count of the corresponding track for each address.

The disk control circuit 13 controls whether or not to count the number of passes. That is, there are two types of data communication between disks. 1st
The second is the case of writing and reading data according to the normal purpose of use, and the second is the writing of the pass count value on the disk, which is an important matter for this embodiment, and This is an example of reading. Here, in the first type of case, control is performed according to instructions from the central processing unit 15 or results of data communication, and the control circuit 13 has no direct involvement. The role of the control circuit 13 is to provide guidance in the latter case. For this purpose, the control circuit 13 provides various controls for accessing the track that stores the number of passes. Specifically, it supplies the address of the track for storing the number of passes and instructs to count the number of passes. signal 13
Signal a is a pass count instruction signal, signal 13b is a write or read command signal for storing or reading the pass count, and supplies the address on the track at that time to the track address register 7. The former command for counting the number of passes is inverted via the inverter 16 and becomes the gate signal 16a of the AND gate 10.

The determination circuit 17 is a circuit that accepts the output of the pass count memory 9, compares it with a pre-given allowable number of uses, and determines the durability state of the disk.

Let's explain the overall operation based on the above configuration.
The operation timing diagram at this time is shown in FIG.
First, before reading and writing data to the disk, the number of passes for each track up to that point is
It is assumed that the data is stored on a predetermined specific track. Therefore, it must be read from that particular track and stored in the pass count memory 9 prior to actual data communication. This operation is performed according to instructions from the disk control circuit 13. That is, the control circuit 13 receives the read command signal 13
b is sent to the read/write control circuit 12. at the same time,
A specific track address storing the number of passes is sent to the track address register 7, and the head 3,
Control the position of pad 4. Next, the data on that track is read out to the read/write control circuit 12 and set in the counter 8. On the other hand, the track address in the track address register 7 is sent to the pass number memory 9, and the contents of the counter 8 are sequentially written in accordance with the address. The role of the counter 8 at this time is the same as that of the data register. Of course, a data register may be added. The address of the specific track at this time is just a track address, and does not indicate detailed addresses within that track address. Therefore, it is not possible to sequentially write to addresses in the memory 9 unless detailed addresses are specified. Although this can be done by providing an address conversion means between the register 7 and the memory 9, in this embodiment, it is assumed that the address conversion means is provided by the disk control circuit 13. At this time, the detailed address is given to the memory 9 via the track address register 7. Note that this memory 9 also requires a read/write control circuit, but this role is assigned to the disk control circuit 13. The output 13c of this control circuit 13 serves as a write command signal.

Thus, the number of passes for each track on a particular track will be stored in memory 9 prior to actual operation of the disk. Next, move on to the actual memorization operation. Let us now assume that track #3 is read and written, and then track #n is read and written. First, when reading or writing track #3, the track address is stored in track address register 7.
is provided from the central processing unit 15. Then, according to the contents of the track address register 7,
The pass count value of that track is read out from the memory 9 (the read command is issued by the signal 13c) and preset in the counter 8. Additionally, a read/write command signal 14c is provided. Thus, track #3 on the disk is selected and read/written. FIG. 4a shows the index signal 6a, FIG. 4b shows the contents of the register 7,
FIG. 4c shows the output signal 16a of the inverter 16.
It is shown. This output signal 16a may be synchronized with the head load pad instruction signal (specifically, the head load pad instruction signal is synchronized with the gate 16a).
). The index signal 6a is output every revolution of the track. This signal 6a passes through the gate 10 and becomes the count input of the counter 8. Therefore, the counter 8 counts up each time the index signal reaches the preset value and accumulates the number of passes. In the figure, track #3 is assumed to rotate five times. Then, upon completion of the selection #3, the contents of the counter 8 at that time are stored in the memory 9. Next, track #n is selected and the pass count value is stored in the memory 9 through the same operation process. Figure 4d
4 shows the contents of the counter 8, and FIG. 4e shows the contents of the memory 9. Thus, at the end of the series of operations, the contents of the memory 9 are stored on the disk as the number of passes for each track at the time of completion by accessing the previously read tracks again. FIG. 4f shows this situation.

The time point at which the determination circuit 17 makes the determination does not necessarily need to be specified. This determination point may be before the start of counting the number of passes, or may be at the time of rewriting to the track. In this judgment circuit 17,
By comparing the allowable number of uses given in advance and the actual number of passes, it is determined whether the product can withstand use. As for the utilization of the determination result, if at least one track has reached its usable durability, the disk itself may be made unusable, or only that track may be prohibited from being accessed. This can be achieved by software.

According to the above embodiment, (1) since it is possible to know the number of times the track has been used for each disk, it is possible to predict the life of the disk, thereby improving reliability.

(2) Only the same track is accessed by the software, and it is possible to prevent waste such as the entire disk becoming unusable due to wear on only some tracks.

Note that among the tracks, which track is used for storing the number of passes is essentially arbitrary;
In general, flexible disk memories do not use the innermost track (spare track) as a data track for reasons of data safety. Therefore, in practice, this innermost track may be used as the pass count storage area. In the above embodiment, the number of passes is stored in the disk itself, but under certain usage restrictions, a dedicated memory other than the main memory may be prepared and stored in this. Note that when storing the number of passes associated with data exchange between disks, the number of passes may be stored for each disk.

According to the present invention described above, it has become possible to correctly recognize the past usage status of a flexible disk memory.

[Brief explanation of the drawing]

1a and 1b are diagrams showing the relationship between a disk and a head, which are objects of the present invention; FIG. 2 is a diagram showing the track state of the disk; FIG. 3 is a diagram showing an embodiment of the present invention; b, c, d, e, f are time charts. 1...Flexible disk memory, 3...Magnetic head, 4...Head load pad, 9...Pass number memory.

Claims (1)

[Claims] 1. A counter that counts the number of passes the magnetic head makes while in contact with each track of a flexible disk memory, a memory that stores the counted value of the counter for each track, and a memory that stores the count value of the counter for each track. A control device for a flexible disk memory, comprising determining means for determining the usage status of each track of the disk memory at any time according to the contents. 2. A counter that counts the number of times the magnetic head rotates while in contact with each track of the flexible disk memory, a memory that temporarily stores the counted value of the counter for each track, and a memory that stores the contents of the memory in the disk memory. The means for storing in a specific track above and the count value for each track stored on the disk memory are read out at any time and compared with a preset pass count value to determine the usage status of each track. A flexible disk memory control device comprising a determination means. 3. A flexible disk memory control device according to claim 2, wherein the track used to write count values on the disk is a spare track other than the data track.