JPH03126145A - Memory protecting system for storage device - Google Patents

Abstract

PURPOSE:To surely protect a memory by storing memory protect information for read/write inhibition in a reserved area and reading out memory protect information to compare it with contents of an access instruction at the time of issue of an access request. CONSTITUTION:A reserved area 2 where memory protect information indicating the position of a certain memory area is held is provided in a storage part 1, and a comparing means 4 which compares the memory area designated by a read or write request with the certain memory area designated by memory protect information read out of the reserved area 2 and a suppressing part 5 which suppresses read or write of a read/write instructing part 3 based on the comparison result of the comparing means 4 are provided. If they have an overlapping area, the suppressing part 5 suppresses read/write of the read/ write indicating part for contents of the overlapping part. Thus, the memory of the storage device 1 is surely protected with a high reliability.

Description

[Detailed description of the invention] (Table of contents) Overview Industrial field of application Prior art (Fig. 5) Means for solving the problem to be solved by the invention (Fig. 1) Effect
(Figure 1) Example (
Figure 2.3.4) Effects of the invention [Summary] The invention includes a non-volatile storage section and a write/read instruction section that instructs writing or reading from the storage section in response to a request specifying a memory area of the storage section. The purpose of the present invention is to provide a memory protection method for a storage device that can securely and reliably protect the memory of the storage device, regarding a memory protection method for a storage device that prohibits writing or reading from a certain memory area. A reserve area that holds memory protection information indicating the location of the certain memory area is provided in the storage unit, and the memory area designated by a write or read request and the certain area indicated by the memory protection information read from the reserved area are provided. This configuration includes a comparison unit that compares the memory area with a memory area, and a suppression unit that suppresses writing or reading of the write/read instruction unit based on the comparison result by the comparison unit.

(Industrial Application Field) The present invention is applicable to SCSI (Small Compute)
It pertains to the memory protection method of storage devices connected to small computers such as personal computers through SystemInterface), etc., and is particularly applicable to non-volatile storage units and the memory areas of the storage units that are protected by write or read requests that specify the memory area of the storage units. The present invention relates to a memory protection method that includes a write/read instruction section that instructs writing or reading from a storage section, and prohibits writing or reading from a certain memory area.

2. Description of the Related Art In small computers such as personal computers, processing power and processing speed have significantly improved due to advances in technology. Along with this, the size of programs and the amount of data to be handled have become larger, and storage devices for storing them are also desired to be faster and larger in capacity.

Hard disks, large-capacity floppy disks, optical disks, and the like are used as storage devices that meet these demands.

Recently, instead of hard disks, FA (Facto
In the field of automation, etc., RAM disks, which are IC memories using SRAM and backed up by batteries, have begun to be used, making them look like hard disks.

The interface that connects these storage devices and computers is S A S I (Shugart As5
o -ciates System Interface
e) and its upper specification, 5CSI, etc. are used. In particular, 5CSI has high performance and expandability, allowing a large number of devices to be connected simultaneously and high-speed data transfer, making it an internationally highly versatile interface.

In this way, the performance of computers and storage devices has improved,
As the size of programs and the amount of data to be handled increases, the damage caused by destruction of programs and data files in the storage device also increases.

Furthermore, multiple users often use a common storage device, and in this case, there is a risk that other users may destroy files or take out data.

Therefore, it is necessary to protect only the necessary portions of files to protect system programs and data.

[Conventional technology]

Conventionally, there has been a system shown in FIG. 5 as a memory protection system for a storage device using a 5CSI interface for protecting data recorded in a certain memory area.

This method uses a storage unit 5 provided in a hard disk device, etc.
1, a write/read instruction unit 53 that instructs writing or reading to the storage unit 51 by a write or read request (file access command) specifying a memory area of the storage unit 51; It has a suppression unit 55 that suppresses writing or reading to a certain memory area based on the content and memory area indicated by the Set Limlts command added to the request.

Here, the "certain memory area" is what is called a protected area, and refers to an area where writing, reading, or both writing and reading to the memory area is prohibited, and the memory contents recorded in the area. An area where reading or writing to the area is prohibited.

The "rSet Limlts command" is an instruction for memory protection used in the 5CSI interface, and is used to protect a certain memory area (1 link command, which is a series of write or read commands following the Set Limlts command). protected area),
A command to prohibit writing or reading.

That is, conventionally, the Set Limits command is issued by specifying the content and range to be protected when writing or reading for each link command, which is the range to which the command is applied.

(Problem to be Solved by the Invention) By the way, in the conventional method, until the end of one link command (for example, a write or read command) string following the Set Lim1ts command, which is a protect command on the 5CSI, When the link command sequence ends, the protection required by the Set Limits command will be canceled.

Therefore, to protect memory, Set Lim must be set each time a write or read access request is made.
It is necessary to issue the 1ts command.

Therefore, there is a risk of forgetting to issue the Set Lim1ts command and issuing a write command alone, and failing to protect the file. - It is often difficult to restore data once it has been destroyed, and it is difficult to protect the memory. The problem was that there was a risk that the reliability of the system would be lacking.

Furthermore, the memory protection range specified by the Set Limlts command is specified only for the range to be written or read by the one link command sequence within the applicable range specified in advance by the command. Therefore, if there are multiple protected areas, the corresponding Set
Only the protected area within the range specified by the Lim1ts command is valid; it is not possible to specify all protected areas. However, since the memory in the area is not protected, there is a problem that the memory may not be completely protected.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a memory protection method for a storage device that can securely and reliably protect the memory of the storage device.

[Means to solve the problem]

In order to solve the above-mentioned technical problems, the present invention, as shown in FIG. Alternatively, in a memory protection system for a storage device that has a write/read instruction unit 3 that instructs reading, and prohibits writing or reading from a certain memory area, a reserved area that holds memory protection information indicating the position of the certain memory area. 2 provided in the storage unit 1, and comparing means 4 for comparing a memory area specified by a write or read request with a fixed memory area indicated by the memory protection information read from the reserve area 2; The control unit 5 includes a suppression unit 5 that suppresses writing or reading to the write/read instruction unit 3 based on the comparison result obtained by the comparison result obtained by the method 4.

(effect) The operation of the present invention will be explained.

When an operator requests the storage unit 1 to write or read data specifying a memory area of the storage unit 1, the write/read instruction unit 3 and the comparison means 4 are notified of this request.

The write/read instruction unit 3 issues an instruction to read the memory protection information held in the reserved area 2, and the comparison unit 4 compares the memory protection information with the instruction.

Here, "memory protection information" is at least the content of protection,
For example, it indicates read protection, write protection, protection including both, and the location of the memory area to be protected.

A comparison result indicating the presence or absence of an overlapping portion regarding the protection content and memory location indicated by the memory protection information and the request content and memory area location is sent to the suppression unit 5;
If there is an overlapping part, the write/read instruction section 3
The contents indicated by the overlapping portions are suppressed, and the portions where there is no overlapping portion are not suppressed.

Therefore, the write/read instruction unit 3 instructs the unsuppressed portion to write or read as requested.

In addition, in the present invention, since the reserve area 2 is provided in the non-volatile storage unit 1, even if the power to the storage unit 1 is turned off, the memory protection information is stored in the reserve area 2. It is retained and is not erased, and there is no need to specify the fixed memory area each time it is written or read, and there is no need for a link command sequence as in the conventional case.

(Example) Next, a memory protection system for a 5CSI storage device according to this example will be described.

As an example of the storage device according to this embodiment, 5CSI RAM
The disk device is shown in FIG.

This device mainly consists of a personal computer 100 and a RAM disk device 102 which is a CPU-mounted control card as a storage device, and the storage device 102 is controlled so that it behaves like a hard disk device from the outside. RD C (RAMDisk Controller)
5CSI interface board 10 as r);
S RAM (Static Random Access
Memory) board 20, 30. -... and a memory interface 103.

Furthermore, as shown in the figure, the present device includes the personal computer 10.
Power supply 10 for 0 and 5 CSI interface board 10
1, and the S RAM boards 20, 30 . . . , each battery power source 25° 35, . . .

As shown in FIG. 2, the 5CSI interface board 10 has a 5PC (SC3I Protocol) that controls the hardware connection with the 5C3I interface
controller) 12, and a firmware section 11 corresponding to the above-mentioned write/read instruction section 3, comparing means 4, and suppressing section 5, and the above-mentioned SR
AM board 20, 30. . . , a parity check circuit 13 that performs a parity check when writing or reading from the SRAM board 20, 30 . DMAC (Direct Memory) transfers data read or written at high speed.
Access Controller) 14 control;
It has a status display section 15 that externally displays various operating statuses of the RAM disk device.

Further, the firmware section 11 has CPol lb, R
It has an OMI 1c and a RAM 11a, and the RAM
The various controls described above are performed by firmware stored in the ROMI lc and the ROMI lc.

Each SRAM board 20, 30. . . . as shown in FIG.
, 31. . . . and a control circuit 23 that performs various controls such as writing and reading regarding the SRAMs 21, 31, .
, 33. ...and the S RAM21.31. ...
A battery voltage monitoring section 24, 34. monitors the voltage of the backup battery. ... and each SRAM2
1,31. . . . are the batteries 25, 35 . It is backed up by...

Note that the SRAM board can be added within the capabilities of the 5C3I boat.

Furthermore, each SRAM 21, 31 . The reserved area in which the protection information is held is SRAM boat 2.
If only one 0 is mounted, reserve area 22
' If two SRAM boards 20 and 30 are mounted, it is not provided in the reserve area 32. In short, it is provided only in the final mounted SRAM board. This area is protected against normal file access and is a dedicated area for the protect information management table in which memory protect information is written.

FIGS. 3a and 3b show the user-used area and reserved area of this RAM disk device, and the memory protection information held in the reserved area.

The reserved area is an area where memory protection information is held, and as shown in FIG. The memory protect information is saved unless a Set Limits command containing update information such as modification or deletion is issued, and will not disappear even if the power to the RAM disk device is turned off. For example, as shown in FIG. 3a, the reserved area is provided at the lowest address of the memory, but this is not particularly limited to the lowest address.

The memory protect information stored in this reserved area is as shown in FIG. 3, for example.

Information indicating whether or not a protected area where writing or reading is prohibited is set in the user area is recorded in the top area of the reserved area, and if a protected area is set, The number is then recorded. Then, the start block address and end block address of each protect area are recorded. By using such memory protect information, it is possible to manage multiple protected areas within the same file. Here, the start block address of the protect area is 5C
It is determined from the protect start block address and protect block length specified when the Set Limlts command on 3I is issued.

The processing procedure when accessing files in this RAM disk device will be explained.

As shown in the processing flowchart of the CPU 11b of the firmware section 11 in FIG.
00 to 5C via the 5CSI interface 16
When you enter the SI command, it is Set Lim1ts
Checks whether it is a command or not. Set Lim1ts
If it is not a command, a check is made in step S2 to see if it is a write or read command. If it is a command other than a write or read command, the corresponding 5CSI protocol processing is performed, and if it is a write/read command, the process advances to step S3. In step S3, it is determined whether memory protect information is already held in the reserved area.

If memory protect information is already held in the reserved area, the firmware section 1
The write/read instruction unit 3 of No. 1 is the reserved area 22
, 32. . . . will issue an instruction to read the memory protect information.

The read memory protect information is used by the comparing means 4 of the firmware section 11 to compare the content of the request for the write/read command with the content of the memory protect information.

This comparison result is determined by the suppression unit 5 of the firmware unit 11, and if the comparison result indicates that there is an overlapping portion in the content, the suppression unit 5 causes the firmware unit 11 to write and read the overlapping portion. Instruction part 3
If there is no overlapping portion, the suppression unit 5 does not suppress writing or reading to the write/read instruction unit 3, and in step S7 Or read processing will be performed.

Further, even if the memory protect information is not yet stored in the reserved area in step S3, the process proceeds to step S7, and the SRAM of the SRAM boards 20, 30, . . .
M21,31. A write or read process will be performed on...

On the other hand, if it is the Set Limlts command in step S1, the process advances to step S8, and the reserved areas 22, 32 . It is determined whether memory protect information is stored in ..., and if memory protect information is already stored, the process advances to step S9, and the area specified by the Set Lim1ts command and the area that has already been stored are It is determined whether the protected areas match.

If they match, unprotect the same area,
Since it is possible that the protection contents may change from read prohibition to write prohibition or vice versa, proceed to step SIO next.
The reserved area 22°32. Set the contents of the memory protect information stored in ... to a new Set Lim.
The update is performed by replacing the contents with the contents of the 1ts command.

On the other hand, if the contents of the area specified by the Set Lim1ts command do not match the contents of the memory protect area in the reserve area in step S9, it is determined that a new protect area is to be set, and the reserve area is set in step Sll. The contents of the memory protection information in the file will be added.

Further, in step S8, the reserve area 22°32, . . .
If the memory protect information is not stored in the reserved area, it is assumed that the first protected area is set, and the memory protect information in the reserved area is newly registered and stored in step Sll.

In this way, according to the RAM disk device of this embodiment, 5
Not only can you use the Set Lim1ts command, which is a csr command, but you can also avoid the drawbacks of the Set Lim1ts command, such as the inability to save commands and the restriction that one file can only be protected. Become.

Although we have described a RAM disk device that uses SRAM as a memory element as an example of a 5CSI storage device, it is also possible to use a hard disk, optical disk, etc. as long as it uses 5C3I and uses a non-volatile memory element. Protect information can be managed.

Further, in this embodiment, a part of the memory element of the storage device is used as the reserve area 1, but it is also possible to separately provide a non-volatile memory element exclusively for the reserve area.

In this way, the file protection information of the Set Lim1ts command is saved, and the SetLim1ts command is saved unless changed or deleted.
File protection is ensured without issuing an imits command, and furthermore, it is possible to set a plurality of protected areas in the same file.

As described above, according to the memory protection method of the 5CSI storage device according to this embodiment, the 5CSI command Set
While using Limlts, it becomes possible to save memory protect information, and furthermore, it becomes possible to set a plurality of protected areas in the same file. Therefore, the memory protect information is protected without having to issue the Set Lim1ts command every time a file access command is issued, and the Set
There is no risk of file destruction due to forgetting to add the Limlts command, and the protected area can be set in detail, allowing efficient use of memory. In addition, since this memory protection information is retained on the battery-backed SRAM, it is permanently retained (stored in hardware) even if the device power is turned off until battery power is no longer supplied.
More reliable protection can be applied compared to software protection.

This makes it possible to avoid the risk of file destruction, etc., even when multiple users share the same use.

〔Effect of the invention〕

As explained above, according to one aspect of the present invention, a reserved area is provided in a non-volatile storage section, memory protection information for which writing and reading are prohibited is stored, and when an access request is made, the reserved area read instruction section reading the memory protect information stored in the reserved area and comparing it with the contents of the access instruction by the comparing means;
Writing or reading of the overlapping portion is suppressed by the suppressing means.

Therefore, for example, in the 5C3I interface, Se
There is no need to issue the tLimlts command each time as in the past, and memory protection information is automatically read from the reserved area every time there is a write or read request, and processing such as comparison is automatically performed. This makes it possible to provide a reliable memory protection method for a storage device that ensures memory protection.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of the principle of the present invention, Fig. 2 is a block diagram of the equipment configuration according to the embodiment, and Fig. 3 is a RAM according to the embodiment.
A diagram showing a memory map of a file area and a reserve area of a disk device, FIG. 4 is a processing flow chart according to the embodiment, and FIG. 5 is a block diagram according to a conventional example. 1 (21, 31,...)...Non-volatile storage section (S
RAM) 2 (22, 32,...)... Reserve area 3 (1
1)...Writing/reading instruction unit (firmware unit) 4(11)...Comparing means (firmware unit) 5(1
1)... Suppression section (firmware section)
; 1 hanging 111 17 Figure 2 Fish of the invention 5f7-o-/Hanging 1g111! l RAM disk device

Claims (1)

[Scope of Claims] A non-volatile storage unit (1), and a write/read device that instructs writing or reading to the storage unit (1) in response to a write or read request that specifies a memory area of the storage unit (1). In a memory protection method for a storage device that includes an instruction section (3) and prohibits writing or reading from a certain memory area, a reserved area (2) holding memory protection information indicating a position of the certain memory area is set as the storage area. a comparison means (4) for comparing the memory area designated by the write or read request and the fixed memory area indicated by the memory protection information read from the reserve area (2);
A memory protection method for a storage device, comprising: a suppression unit (5) that suppresses writing or reading to the write/read instruction unit (3) based on the comparison result by the comparison unit (4).