JPH04358243A - Semiconductor disk device - Google Patents

Abstract

PURPOSE:To shorten time for saving data and to improve the privacy of data concerning the semiconductor disk device. CONSTITUTION:At a semiconductor disk device 16 equipped with a semiconductor memory 20, memory access control part 19 to write/read data in the semiconductor memory 20, non-volatile medium control part 21 to write the data read by the memory access control part 19 in a non-volatile storage medium 22 and control means 17 to instruct the save of the data, a recording means 18 is provided to execute recording to the memory area, which does not require the save of the data, of the semiconductor memory 20, and when instructing the save of the data by the control means, the save of the data stored in the memory area, to which recording is executed by the recording means 18, of the semiconductor memory 20 can be omitted.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor disk device that uses a semiconductor memory as a storage medium, and more particularly to a semiconductor disk device that reduces the time it takes to save data from a semiconductor memory and improves data confidentiality.

In computer systems, semiconductor disk devices that can compensate for the gap in access speed between magnetic disk devices and main storage devices play an important role. By the way, since semiconductor disk devices use semiconductor memory as a storage medium, data disappears when the power is cut off. Therefore, semiconductor disk devices are equipped with a backup power source, and even if the power supply stops, the power is maintained for a while and the data stored in the semiconductor memory is evacuated to a non-volatile storage medium such as a magnetic disk. When the power is restored, the data is read out to the semiconductor memory again and restored.

[0003] Such data saving and restoring processing is an important technology for semiconductor disk devices.
The processing time is required to be short. Furthermore, since important data is stored in semiconductor disk devices for computer systems, a high level of data confidentiality is required.

0004

2. Description of the Related Art FIG. 4 is a block diagram illustrating an example of the prior art. The semiconductor disk control circuit 1 sequentially executes input/output commands from a host device (not shown).

That is, when data writing is instructed, the memory access control circuit 3 or 4 is controlled via the bus 14 based on the specified address, and the data to be sent by the host device is transferred to the specified semiconductor memory 5 or 6. When instructed to write to the specified address area and read data, the memory access control circuit 3 or 4 is controlled based on the specified address to read data from the specified address area of the semiconductor memory 5 or 6. and transfer it to the higher-level device.

[0006] When the service processor 2 receives a power cutoff signal from a power supply device (not shown), it continues to operate with power supplied from a backup power supply, and memory access control circuits 3 and 4 which also operate with the backup power supply. controlling the disk control circuit 7 via the bus 14;
Execute data backup.

That is, from the memory access control circuit 3,
A plurality of bytes of data are read from the entire area from the first address area to the last address area of the semiconductor memory 5 and sent to the disk control circuit 7 via the bus 14.

The disk control circuit 7 divides a plurality of bytes of data into, for example, two bytes each and sends the data to the adapters 8 to 1.
0 at the same time, and write to the disk devices 11 to 13 at the same time.

Furthermore, data is read out from the memory access control circuit 4 in units of multiple bytes from the entire area from the first address area to the last address area of the semiconductor memory 6.
It is sent to the disk control circuit 7.

Similarly to the above, the disk control circuit 7 divides the plurality of bytes of data into two bytes each and sends the divided data to the adapter 8.
-10 at the same time, and write to the disk devices 11-13 at the same time.

When the service processor 2 is powered on, it controls the disk control circuit 7 to control the disk device 1.
When the data is read from 1 to 13, the memory access control circuit 3 is caused to write the saved data to the entire area of the semiconductor memory 5, and the memory access control circuit 4 is
The data that has been saved is written into the entire area of the semiconductor memory 6.

0012

As described above, conventionally, when data is saved, the entire area of the semiconductor memories 5 and 6 is saved. Therefore, the amount of data to be saved increases, and the saving processing time increases.

[0013] However, this data saving process is maintained using a backup power supply, which is an extremely dangerous situation, and therefore it is necessary to shorten the data saving time. For this reason, conventionally, as shown in disk devices 11 to 13, data is saved to a plurality of disk devices at the same time to improve the apparent data transfer speed and shorten the data save time.

[0014] However, such measures to improve data saving performance by improving hardware increase the amount of hardware and are limited by the performance of the disk device, so there is a problem that it is economically inefficient. There is.

[0015] Also, on the semiconductor memories 5 and 6, there are access attributes such as read-only data or data that can be written/read, and data that can be deleted or not destroyed. Data with different attributes are mixed.

Furthermore, the entire area of the semiconductor memories 5 and 6 is not used without gaps; data is stored with a margin in preparation for an increase in the amount of data, and unused blank spaces are A region exists.

However, conventionally, as described above, once the data has been evacuated to the disk devices 11 to 13, read-only data that does not need to be evacuated again and data that can be deleted are also evacuated. Blank areas for use are also saved.

[0018] Since all of the evacuated data is restored, data and blank areas that may be deleted are also restored. By the way, in general, the host device performs processing to change the areas on the semiconductor memories 5 and 6 in which unnecessary data is recorded to an unused state in which the data is logically erased, a so-called scratch state. , 6, no input/output processing to actually erase data is performed.

This is because the erasing process is also one of the input/output processes, so it becomes a burden on the host device, and extra time is required for erasing. Therefore, there is a problem in that unnecessary data remains in the semiconductor memories 5 and 6 indefinitely and can be read out, making it impossible to maintain data confidentiality.

In view of these problems, the present invention is designed to omit the process of saving read-only data storage areas, data storage areas that may disappear, and unused blank areas of the semiconductor memories 5 and 6. The purpose of this is to shorten the data evacuation processing time, and by writing erasure pattern data to the areas of the disk devices 11 to 13 corresponding to the areas of the semiconductor memories 5 and 6 that require erasure. The purpose is to erase unnecessary data and increase data confidentiality.

[0021]

Means for Solving the Problems FIG. 1 is a block diagram illustrating the principle of the present invention. The semiconductor disk device 16 is
A semiconductor memory 20 that stores data transferred from the host device 15, a memory access control section 19 that accesses this semiconductor memory 20 to write/read data, and the data read by this memory access control section 19.
Nonvolatile medium control unit 21 that writes to nonvolatile storage medium 22
and a control means 17 that instructs the memory access control section 19 and the nonvolatile medium control section 21 to save data, and also instructs the nonvolatile medium control section 21 to write erase pattern data.

A recording means 18 is provided for recording a memory area on the semiconductor memory 20 in which data does not need to be saved, based on a designation from the host device 15. When the control means 17 instructs the saving of data, the saving of the data stored in the memory area of the semiconductor memory 20 recorded by the recording means 18 is omitted, or the data recorded by the recording means 18 is saved. Erasing pattern data is written to the storage area of the nonvolatile storage medium 22 corresponding to the memory area of the semiconductor memory 20 in which the erase pattern data is stored.

[0023]

[Operation] With the above configuration, the data in the memory area recorded by the recording means 18 is not saved from the semiconductor memory 20, so the data is stored in the recording means 18.
By specifying a memory area for read-only data, a memory area for data that can be deleted, and a blank area, you can write/write.
Only data to be read is saved.

[0024] Therefore, since the amount of data to be saved is reduced, the data saving processing time can be shortened. Furthermore, by specifying a memory area for unnecessary data in the recording means 18, when data is saved from the semiconductor memory 20, an erase pattern is written in the area of the nonvolatile storage medium 22 corresponding to the memory area for unnecessary data. Data is written.

When restoring data, writing is performed from the non-volatile storage medium 22 to the entire area of the semiconductor memory 20, so that the memory area of the semiconductor memory 20 where unnecessary data is stored has no erased pattern. Data is restored.

[0026] Therefore, since unnecessary data is erased every time the power is turned off, data confidentiality can be improved.

[0027]

Embodiment FIG. 2 is a block diagram of a circuit showing an embodiment of the present invention, and FIG. 3 is a diagram explaining the operation of FIG. 2.

The same reference numerals as in FIG. 4 indicate the same functions. In order to shorten the data saving time, when the semiconductor disk control circuit 1 is notified from the host device of the address indicating the memory area of the semiconductor memories 5 and 6 that does not require data saving, the semiconductor disk control circuit 1 stores this address in the extent table 23. Store.

That is, as shown at 23 in FIG. 3, the start address and end address are sequentially stored in the order of notification. The start address and end address are 5 and 6 in FIG.
As shown in the figure, the entire area of the semiconductor memory 5 and the semiconductor memory 6
Assuming that the entire area of is regarded as one area, and the diagonally shaded range indicated by ■ to ■ is a memory area that does not require data saving, the respective start and end addresses are memory areas that do not require data saving. -■ ranges are shown respectively.

When the service processor 24 causes the memory access control circuits 3 and 4 and the disk control circuit 7 to perform data saving processing in response to a power cut signal, the service processor 24 refers to this extent table 23 and determines the stored start address and end address. When reading data from the semiconductor memories 5 and 6 according to the address, this specified memory area
Prohibit data reading from ~■.

[0031]Accordingly, in data saving, the data transfer of the memory areas indicated by ① to ② is omitted, so that the data saving time is shortened. When increasing the confidentiality of data, when the semiconductor disk control circuit 1 is notified of the address indicating the memory area of the semiconductor memories 5 and 6 from which data needs to be erased from the host device, the semiconductor disk control circuit 1 receives the start address 23 in FIG. This address is stored in the extent table 23 as shown in the end address.

The start address and the end address are defined by the diagonal lines indicated by ■ to ■, assuming that the entire area of the semiconductor memory 5 and the entire area of the semiconductor memory 6 are one area, as shown in 5 and 6 in FIG. Assuming that the range is a memory area in which data needs to be erased, each of the start address and end address indicates the range of memory areas (1) to (2) in which data is to be erased.

When the service processor 24 causes the memory access control circuits 3 and 4 and the disk control circuit 7 to perform data saving processing in response to a power cut signal, the service processor 24 refers to the extent table 23 and determines the stored start address and end address. Based on the address, the disk control circuit 7 is controlled to control the respective areas of the disk drives 11 to 13 corresponding to the areas of the semiconductor memories 5 and 6 shown in FIG.
Write the erase pattern data.

When the power is turned on to restore data, the service processor 24 controls the disk control circuit 7 to read data from the data save areas of the disk devices 11 to 14, and the memory access control circuit 3 and 4 to write to all areas of the semiconductor memories 5 and 6.

Accordingly, since erasure pattern data is written in the memory areas of the semiconductor memories 5 and 6 shown in (1) to (4) in FIG. 3, unnecessary data is erased without being restored.

[0036]

Effects of the Invention As explained above, the present invention eliminates areas on a semiconductor memory that do not require saving processing, such as read-only data recording areas, data recording areas that may disappear, and unused blank areas. Since the data can be saved, the data saving time can be shortened without relying on hardware improvements.

Furthermore, since no unnecessary data is left on the semiconductor memory, data confidentiality can be improved.

[Brief explanation of drawings]

[Figure 1] Block diagram explaining the principle of the present invention

[Figure 2
] Block diagram of a circuit showing one embodiment of the present invention

[Figure 3
] Diagram explaining the operation of Figure 2

[Figure 4] Block diagram explaining an example of conventional technology

[Explanation of symbols]

1 Semiconductor disk control circuit 2, 24 Service processor 3, 4 Memory access control circuit 5, 6, 20 Semiconductor memory 7 Disk control circuit 8, 9, 10 adapter 11, 12, 13 Disk device 14 Bus 15 Upper device 16 Semiconductor disk device 17 Control means 18 Recording means 19 Memory access control unit 21 Non-volatile medium control section 22 Non-volatile storage medium 23 Extent table

Claims (2)

[Claims] 1. A semiconductor memory (20) that stores data transferred from a host device (15), and a memory access control unit (19) that accesses the semiconductor memory (20) to write/read data. , the data read by the memory access control unit (19) is transferred to a non-volatile storage medium (
a non-volatile medium control unit (21) that writes to the memory access control unit (19) and a non-volatile medium control unit (22);
In a semiconductor disk device (16) equipped with a control means (17) for instructing the semiconductor memory (20) to save data based on a designation from the host device (15),
) is provided with a recording means (18) for recording a memory area in which data does not need to be saved, and when the control means (17) instructs to save data, the memory area recorded by the recording means (18) A semiconductor disk device characterized in that saving of data stored in a memory area of a memory (20) is omitted. 2. A semiconductor memory (20) that stores data transferred from a host device (15), and a memory access control unit (19) that accesses the semiconductor memory (20) to write/read data. , the data read by the memory access control unit (19) is transferred to a non-volatile storage medium (
a non-volatile medium control unit (21) that writes to the memory access control unit (19) and a non-volatile medium control unit (22);
A semiconductor disk device (1) comprising a control means (17) for instructing the non-volatile medium control section (21) to write erasure pattern data.
In 6), a recording means (18) is provided for recording a memory area in which data does not need to be saved on the semiconductor memory (20) based on a designation from the host device (15);
When the control means (17) instructs to save data, the semiconductor memory (20) recorded by the recording means (18)
the non-volatile storage medium (22) corresponding to a memory area of
A semiconductor disk device characterized in that erasure pattern data is written into a storage area of the semiconductor disk device.