JPH0241776B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a data retention method for a semiconductor file, and particularly to a data saving and restoring method for a semiconductor file that enables high-speed access and measures against volatility.

[Background of the invention]

Conventionally, memory media such as magnetic disks, magnetic drums, and magnetic tapes have been used as recording media for external storage devices (hereinafter referred to as files), but these are made of semiconductor memory due to rotation time and positioning time. 5 compared to main memory
The access time is about an order of magnitude long, and the access time during this time is
The problem was how to fill the gap.

Therefore, attempts to use random access type semiconductor memory devices as a file storage medium were gradually realized due to the rapid increase in capacity and price reduction of semiconductor memory devices, as well as the demand for faster access to files. It's coming.

However, semiconductor memory devices have a drawback in that the content data volatizes when the power is turned off, and various data retention methods have been considered as a countermeasure to this problem.

A conventional data retention system for volatile data files stores part of the contents of volatile files in nonvolatile memory upon command from a central processing unit when the power is turned off.

FIG. 1 is an explanatory diagram of a conventional volatile file data retention system. In FIG. 1, 10 is a central processing unit (hereinafter referred to as CPU), 20 and 21 are channel devices (CHL), 30 and 31 are file control units (IOC), 40 is a data volatile file, and 4
1 is a data non-volatile file.

Generally, the contents of data volatile file 40 are:
It is read out in control units by the system program for backup, and once it is read out by the file control device 30,
After being taken into the CPU 10 via the channel device 20, the data is written into a data non-volatile file 41 for data retention via another channel device 21 and a file control device 31.

However, the method shown in FIG. 1 uses a large number of devices and paths when saving data, so it has the disadvantage that as the capacity of the file 40 increases, the system overhead also increases.

There is also an invention that saves data in volatile memory to non-volatile memory in the event of a power outage (Japanese Patent Laid-Open Publication No.
49-24050, JP-A-55-4651),
In either case, only the minimum amount of data required at the time of restarting is saved, and not all data, so a large amount of the latest data is lost. In addition, everything is evacuated according to instructions from the CPU,
Since data cannot be saved based on a volatile file's own judgment, it is not possible to save the latest data when there is no communication with the CPU and retain as much updated data as possible.

[Purpose of the invention]

The purpose of the present invention is to solve such conventional problems, to provide a file using a volatile memory element with a function to save all data on the device alone, and to be able to handle it almost in the same way as a non-volatile file. An object of the present invention is to provide a data retention method for a semiconductor file.

[Summary of the invention]

The semiconductor file data retention system according to the present invention consists of (a) a volatile memory (3 in Figure 2) made up of semiconductor storage elements, and a non-volatile memory (3 in Figure 2) having a capacity equal to or greater than that of the volatile memory. 4) in Figure 2 and a data transfer control means (7 and 8 in Figure 2) that controls data transfer between the nonvolatile memory and the volatile memory, and transfers the data stored in the volatile memory. The data is transferred to the non-volatile memory under the control of the non-volatile memory, and information indicating whether or not the operation was executed correctly is retained (written to the control sector section above 4 in Figure 2), and the data is transferred from the non-volatile memory to the volatile memory. When data is transferred under the control of the transfer control means, the data transfer is performed when the data is correctly stored by referring to the information. (b) It further includes a determining means (9, 11 in FIG. 2) for determining the time point of data transfer between the volatile memory and the non-volatile memory, and based on the determination result of the determining means, the data is stored in the volatile memory. Another feature is that the data is transferred to the nonvolatile memory under the control of the data transfer control means.

[Embodiments of the invention]

FIG. 2 is an internal block diagram of a semiconductor file showing one embodiment of the present invention.

In FIG. 2, 1 is a semiconductor file, 2 is a microprocessor that manages the semiconductor file, and 3 is a microprocessor that manages the semiconductor file.
is a semiconductor memory section where user data is stored;
4 is a backup magnetic disk; 5 is an interface control unit that connects to a higher-level control device; 6 is a data transfer control unit with the higher-level device; and 7 controls the backup of data in the semiconductor memory unit 3 to the magnetic disk 4. An unload control unit, 8 a load control unit that controls restoration of data onto the memory as opposed to saving, 9 a power supply control unit, and 12 a power supply unit that supplies power to the entire file and includes a spare power storage unit. , 11 is a timing circuit. Further, the solid line of the arrow indicates a control signal line, the thick line of the arrow indicates a data line, and the curved line of the arrow indicates a power supply line.

The semiconductor memory section 3 is composed of a plurality of file volumes, and each volume is logically divided by a software interface used from a host device. For example, tracks are divided according to the magnetic disk. The magnetic disk device 4 has a capacity equal to or greater than that of the semiconductor memory section 3, and each track is divided into N fixed length sectors, each sector having an ID section (location identification information section).
It consists of a data section and a gap.

Now, as an example of the present invention, a control sequence when the data evacuation (unload) operation starts when the system power is turned off will be explained with reference to FIG. However, this diagram omits the processing when an abnormal state occurs.

First, when the power to the system is turned off, the power control section 9 detects this and instructs the microprocessor 2 to start an interrupt unload operation (steps 51 and 52). Taking this interrupt as a trigger, the microprocessor 2 first turns on the power to the magnetic disk device 4, waits until it reaches steady rotation, and positions the read/write head of cylinder number 0 and track number 0 by rezero operation (step 53,
54, 55). The microprocessor 2 then activates the read circuit of the semiconductor memory section 3 of the unload control section 7 to prepare for reading from the memory head address, and the magnetic disk device 4 performs positioning to the index ( Steps 56, 57).
After index positioning, ID of first sector
The ID section is first read out and the normality of the ID section is confirmed (steps 58 and 59). After confirming the normality of the sector, the data in the semiconductor memory section 3 is read for one sector (fixed length) of the magnetic disk, and written to the data section of the sector on the disk 4 (step
60). This operation is repeated N sectors in one track as the medium of the magnetic disk 4 rotates, and then
Next, the track is switched on and the same operation is repeated again (steps 62, 63, 64). Furthermore, when the last track in the cylinder of the magnetic disk 4 has been processed, the operation of seeking to the next cylinder is performed instead of the next track switch (step 63,
65). The above-mentioned operation of dividing the data in the memory into fixed sector data lengths of the magnetic disk and sequentially unloading them is repeated until all the data in the semiconductor memory section 3 is read, and once all the data has been read, , stop the memory read circuit in the unload control section 7 (step
61, 66). All of the user data that existed in the semiconductor memory section 3 has now been saved in the magnetic disk device 4. Next, set the unload completion flag to ensure that there is correctly unloaded data on the disk. , is written to the control sector section on the magnetic disk device 4 (step 67). With the above steps, the magnetic disk 4 is no longer needed, and the power is turned off (step 68). The microprocessor 2 notifies the power supply control section 9 of the unload completion signal, and the power supply control section 9 reports the power cutoff to the host device at the same time.
Turn off the power to the entire device 1 (steps 69 and 70).
This completes the unload sequence.
Note that if the cause of this power outage is a power outage, the power supply control section 9 maintains the above operation using the power of the reserve power storage section in the power supply section 12.

What is unique about this sequence is that the data format of the semiconductor memory section 3 is not considered at all, and
This is to save data by dividing memory according to the physical format of a magnetic disk that is an evacuation medium.

FIG. 4 is a diagram illustrating the format of the semiconductor memory section and the track format of the built-in magnetic disk.

As shown in FIG. 4a, the semiconductor memory section 3 is used in a variable length format (soft interface format) consisting of an HA section, a count section, a key section, a data section, etc. from the host device. (As shown in FIG. 4b, the memory section 3 is divided equally into fixed sector lengths of the built-in magnetic disk (disk interface format), and data is sequentially written onto the disk. This unloading operation is performed as follows: The process ends when all sectors of the memory section 3 are written to the disk.

The HA (Home Address) section in Figure 4a stores the track position, and the count section stores the record position (what record it is) and record length (because it is variable length). The key part contains user input based on this key data.
Information for retrieving data is stored. While multiple records (count section and data section) are stored consecutively for one HA section,
The key portion can be provided at any position as required.

FIG. 4b shows data in the semiconductor memory section 3 divided into fixed sector data sections of the magnetic disk, and each divided data is shown in FIG. 4c,
As shown in d, data is written in the data portion of consecutive sectors #0 to #(N-1) after the index for each track. The ID section contains the track number,
Sector numbers etc. are stored.

FIG. 5 is a flowchart of the data restoration operation.

The load sequence is started when the system power is turned on, and is almost the same as the unload sequence except that the flow of data at this time is from the magnetic disk 4 to the semiconductor memory section 3.

However, the difference is that the unload completion flag=1 is used as the load start condition.

First, when the host device notifies the power supply controller 9 that the power has been turned on, the power supply controller 9 issues an interrupt to the microprocessor 2 to start loading.
71, 72). When the magnetic disk device 4 is powered on and reaches steady rotation, the microprocessor 2 reads the unload completion flag from the control sector section on the disk, identifies that the flag content is "1", and reads the unload completion flag from the control sector section on the disk. It is determined that the semiconductor file data has been definitely saved, and loading is started (steps 73, 74, and 75). After locating the first cylinder on the track, the semiconductor memory section write circuit of the load control section 8 is activated to prepare for writing to the memory section 3 (steps 76 and 77). Next, the index of the magnetic disk is positioned, the ID section is read, one sector is read, and it is written into the semiconductor memory section 3 (steps 78 to 81). This is repeated for each sector, and when the last sector in the track is finished, it switches to the next track, and when the last track in the cylinder is finished, it seeks to the next cylinder (steps 83 to 86). . When the loading of all data is completed, the memory write circuit in the load control unit 8 is stopped, the power to the magnetic disk device 4 is cut off, and the power supply control unit 9 is notified of the completion of loading (step 82, 87-89).

When the host device receives the load completion notification from the power supply control unit 9, it learns that the file can be accessed, and accesses the data as necessary.

In the embodiment shown in FIG. 4, format conversion is performed during load and unload operations, but if the data can be saved to the disk in the semiconductor format without performing format conversion, the load and unload operations can be performed. Can be done quickly.

Next, an optical disk writing method that enables the above-mentioned evacuation operation will be described.

FIG. 6 is a diagram showing a spiral writing method for an optical disc.

2. Description of the Related Art When storing a huge amount of data, optical disk devices that serially store data have been put into practical use as inexpensive large-capacity storage devices. This optical disk device enables high-speed writing and access because it writes data serially in a spiral manner.
As shown in FIG. 6, the data track 13 is recorded in a spiral manner on the disk 15 by continuously and gradually moving the head. However, in this device, unlike a normal sector-shaped magnetic disk device that records a plurality of concentric tracks, rewriting immediately leads to data destruction, so protection measures against this are required.

Therefore, as shown in FIG. 7, an ECC section is usually added to each of the ID section and the data section (DATA), and a gap section G for absorbing rotational fluctuations is provided. However, if an ECC section is added, there is no problem with the format of the semiconductor memory section shown in FIG. 4a, so if the format is the same as that of the semiconductor memory section, format conversion is not necessary when saving and restoring. Recording to this disk is easy to control because the head moves in a spiral, starting from the outside and gradually inward.
And high-speed transfer is possible.

Note that it is of course possible to convert the format and rewrite it in sectors.

〔Effect of the invention〕

Thus, in the present invention, a magnetic disk can be used as a built-in nonvolatile memory.

Furthermore, loading/unloading can also be started by a command from a higher-level device. Furthermore, it can also be used in a rewritable optical disk device.

In the embodiment, the case where data is saved when the system power is turned off has been described as an example, but in the present invention, the file device can save data based on its own judgment, so this can be done at various times. For example, if a file device monitors CPU operation for a certain period of time and communication from the CPU is interrupted,
By saving all data, the latest data updated by the CPU can be stored on the disk. Furthermore, when the system's work is completed, it is also possible to save all data to disk by command from the CPU.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a conventional volatile file data retention system, FIG. 2 is an internal block diagram of a semiconductor file showing an embodiment of the present invention, and FIG. 3 is a flowchart of the data saving operation in FIG. , 4th
The figure shows the conversion between the format of the semiconductor memory section and the track format of the magnetic disk, FIG. 5 is a flowchart of the data restoration operation in FIG. 2, and FIG. 6 is a diagram showing the method of writing spiral data on the disk. FIG. 7 is a format diagram of the disk shown in FIG. 1: semiconductor file, 2: microprocessor, 3: semiconductor memory section, 4: magnetic disk device, 5: interface control section, 6: data transfer control section, 7: unload control section, 8: load control section, 9: power supply control section, 10: power supply section, 11: timing circuit.

Claims (1)

[Claims] 1. A volatile memory configured with a semiconductor memory element, a non-volatile memory having a capacity equal to or greater than that of the volatile memory, and data transfer between the non-volatile memory and the volatile memory. a data transfer control means for controlling the data transfer means, and transfers the data stored in the volatile memory to the nonvolatile memory under the control of the data transfer means;
It retains information indicating whether or not the operation was executed correctly, and when data is transferred from the non-volatile memory to the volatile memory under the control of the data transfer control means, the information is referenced to determine whether the operation has been correctly stored. A data retention method for semiconductor files characterized by executing data transfer when the data is present. 2. A volatile memory configured with a semiconductor storage element, a nonvolatile memory having a capacity equal to or greater than the volatile memory, and a data transfer control that controls data transfer between the nonvolatile memory and the volatile memory. and a determining means for determining the time point of data transfer between the memories, and based on the determination result of the determining means, the data stored in the volatile memory is transferred to the non-volatile memory under the control of the data transfer control means. Along with transferring to sexual memory,
When data is transferred from the non-volatile memory to the volatile memory under the control of the data transfer control means, based on the determination result of the determination means, holding information indicating whether or not the operation has been executed correctly; A data retention method for a semiconductor file characterized in that data transfer is performed when the data is correctly stored by referring to information. 3. When saving or restoring data by data transfer, the data transfer control means converts between the upper interface format of the volatile memory and the physical format of the nonvolatile memory, and 3. A semiconductor file data retention system according to claim 1 or 2, characterized in that data is written in sectors. 4. When saving or restoring data by data transfer, the data transfer control means performs writing/reading in the volatile memory while maintaining the host interface format, and writes in the nonvolatile memory in a spiral manner. Characteristic claim 1
A data retention method of a semiconductor file according to item 1 or 2.