JPH0194455A - System for accessing storage device - Google Patents

Abstract

PURPOSE:To execute a duplication with a few hardwares and to improve a reliability by allowing a memory module, after it is instructed on a standby, to execute writing to an instruction while not to execute an acceptance response to it, and to execute a reading while not to execute the output of read data and acceptance response to a bus. CONSTITUTION:By using standby instruction signal lines 9-11 connected respectively to respective memory modules 5-7 from a high order device 3, for example, the memory module 5 is made into a main memory module, and the memory module 6 is made into a standby memory module. Thereafter, the memory module 6 executes the writing corresponding to a writing instruction from other devices but does not execute the acceptance response. The module 6 is operated so as to execute the reading corresponding to a reading instruction and not to execute the output of the read data and acceptance response to a bus 1. Thus, the duplication can be easily executed, and the reliability can be increased.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to the operation of a storage device used in an information processing device, and particularly to improving the access method of the storage device.

(Prior Art) Conventionally, in this type of storage device, especially in a storage device consisting of a plurality of modules, it has been difficult to use a certain storage area or all storage areas in a duplicated manner.

(Problems to be Solved by the Invention) The above-described conventional storage device consisting of a plurality of memory modules is difficult to use in duplicate, and therefore has the disadvantage that the reliability of the entire storage device cannot be increased. .

An object of the present invention is that a memory module that has been instructed to wait by a host device writes to a write instruction from another device but does not respond to an acceptance response, and reads out a read instruction from another device but does not respond to an acceptance response. The object of the present invention is to provide an access method for a storage device configured to be easily duplexed by eliminating the above-mentioned drawbacks by not outputting read data and not issuing an acceptance response.

(Means for Solving the Problems) A storage device access method according to the present invention includes a storage device,
It is configured to include a host device.

Memory v? , lit consists of multiple memory modules,
It is for storing data.

When a host device instructs a specific memory module to standby, it writes in response to write instructions from other devices but does not respond with an acceptance response, and reads in response to read instructions but does not respond to the bus. This is to operate so that the read data output and the acceptance response are not output.

(Example) Next, the present invention will be explained with reference to the drawings.

FIG. m1 is a block diagram showing an embodiment of the access method of the storage device according to the present invention.

In Figure 1, 1 is a bus, 2 is a storage device, 3 is a host device, 4 is an EPU, and S to 7 are memory modules (
VIO), (Ml), (Mn), and 8 to 11 are signal lines, respectively.

Bus 1 is a common bus, and in Figure @1, host device 3, fEPU 4, and memory modules 5 to 7 are connected to bus 1, but in reality, other devices, For example, an IOP (input/output processor) or the like is often connected.

The storage device 2 consists of a plurality of memory modules 5 to 7,
It doesn't matter how many memory modules you have.

In this type of storage device, each memory module has a mutually different module address, as is well known.

When memory modules 5-5 are accessed by another device, control signals and data necessary for storage operations are commonly sent to all memory modules via bus signal J8.

At this time, which memory module responds to the access depends on the module address, as is well known, and the module address t[
Only the memory module whose address information matches the module address information held by each memory module responds with an acceptance response to the access and executes the read or write operation. Note that during reading, read data is output to bus 1.

In a storage device with such a configuration, if we consider a so-called duplex memory in which the storage contents of any two memory modules are made to match, as shown in FIG. connected 1
stand-by! Indication signal 9-41 is used.

What about memory module 5 and memory module 6 now? It shall be duplicated. Memory module 5 is designated as a main memory module, and memory module 6 is designated as a standby memory module. Naturally, the memory module address is memory module S.

The same value is preset for both.

When another device accesses the memory via bus 1 in this state, the same memory module information is given to the memory modules 5 and 6 and the same address is accessed, and even if the access is a write instruction, For example, the memory module S performs the write operation after responding with an acceptance response. On the other hand, the memory module 6 does not respond with an acceptance response and executes the write operation.

If it is a read instruction, the memory module S issues an acceptance response, executes a read operation, and outputs the read data to the bus 1. On the other hand, when the memory module 6 reads data from the storage element, most read operation parameters such as cycle time are determined by the memory module 5 and MS. However, only the output of read data onto bus 1 and the acceptance response are not executed.

The internal circuit blocks of the memory module mentioned above have some circuits in the well-known circuit configuration. This can be easily achieved by simply adding it.

(Effects of the Invention) As explained above, the present invention has the following advantages: When the IJ module is instructed to stand by by the host device, it writes in response to the write instruction from the (lil! First, in response to a read instruction, reading is performed, but the read data is not output to the bus or an acceptance response is made. By doing so, it is possible to easily realize duplex memory with a small amount of hardware and air, resulting in a highly reliable storage device. This has the effect of making it possible to achieve the following.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of an access method for a storage device according to the present invention. 1...Path 2...Working storage device 3...Upper device 4 Fist - EPU 5~7...Mesori module 8~11...No. signal line

Claims (1)

[Claims] When a storage device that is made up of multiple memory modules and a specific memory module is instructed to stand by, it will write in response to write instructions from other devices, but will not respond with an acceptance response. First, an access method for a storage device characterized in that it comprises a host device that performs reading in response to a read instruction, but does not output read data to a bus and do not issue an acceptance response.