JPS626355A - computer - Google Patents

Abstract

PURPOSE:To shorten the access time of a magnetic disk device connected to a computer system via a network by using a cache memory which stores the data transferred between a system and a network. CONSTITUTION:A computer system 1 is connected to the network 6 and contains the cache memory 402 which stores data transferred with the network 6. The memory 402 as well stores the data transferred between a central processing unit 2 and magnetic disk deices 71 and 72 set on the network 6. When the unit 2 tries to read the data on the devices 71 and 72, these data are read out of the memory 402 as long as they are stored in the memory 402.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a computer that communicates with other devices via a network.

2. Description of the Related Art A conventional computer has a configuration as shown in FIG.

In the figure, 2 is a central processing unit. 3 is a main storage device. 6 is a network. A communication control device 41 controls data transfer between the central processing unit 2 and the network 6 or between the main storage device 3 and the network 6. A computer system 1 is composed of a central processing unit 2, a main storage device 3, and a communication control device 41. Reference numeral 71 denotes a magnetic disk device, which enables the computer system 1 to access files in the magnetic disk device 71 by connecting to the network 6 via the communication control device 42 .

The operation of the combiator system configured as described above will be described below.

That is, when the computer system 1 reads a file stored in the magnetic disk device 71, the data sent through the network 6 is sent to the central processing unit 2 or the main memory via the communication control device 4 within the computer system 1. Transferred to device 3. Conversely, when writing data from the computer system 1 to the magnetic disk device 71, the data is sent from the central processing unit 2 or main storage device 3 to the network 6 through the communication control device 4 within the computer system 1.

Problems to be Solved by the Invention Magnetic disk drives generally require an average seek time of several tens of milliseconds and an average rotational waiting time of several tens of milliseconds. As a result, the data transfer time between the magnetic disk drive 71 and the central processing unit 2 often occupies a considerable portion of the entire processing time of the computer system 1.

In view of the above problems, the present invention provides a computer that shortens the access time of a magnetic disk device connected via a network.

Means for Solving the Problems In order to solve the above problems, the computer of the present invention has the following steps:
It is equipped with a cache memory in which data transferred to and from the network is stored.

According to the above-described configuration, the present invention also stores data transferred between the central processing unit and the magnetic disk device on the network in the cache memory, and when the central processing unit attempts to read the data on the magnetic disk device. , if the data is stored in the cache memory, the data is read from the cache memory. As a result, it is possible to reduce the number of accesses to a magnetic disk device that requires a long access time, and to shorten data access time.

Embodiment FIG. 1 is a block diagram showing one embodiment of the computer system of the present invention. In FIG. 1, 1 is a computer system. 2 is the central processing unit, 3 is the main memory, 8
is an internal bus. Reference numeral 41 denotes a communication control device connected to the internal bus 8 and the network 6. The communication control bag device 41 controls the central processing unit and a specified magnetic disk device 71 on the network 6 based on a command from the central processing unit 2. (or 72).

The communication control device 41 includes a magnetic disk device 71 (or 72
) to the central processing unit 2, and a directory section 4 as mapping information for the data stored in the cache memory 5.
01. As shown in FIG. 2, the directory information includes the magnetic disk number and magnetic disk address of the corresponding data (on the cache memory 402).
It consists of a cache memory address and control information.

The operation of the computer configured as described above will be explained. Now, it is assumed that the central processing unit 2 issues a read request to the communication control unit 41 to read data from the magnetic disk unit W71. When the communication control device 41 accepts the read request, it searches the directory section 401 using the designated magnetic disk number and magnetic disk address (step Sl).

Next, the communication control device 41 determines whether or not the corresponding data exists in the cache memory 402 through the above search, that is, if there is a hit (cache hit) in the cache memory 402.
A check (directory check) is performed to see whether or not the above has been done (step S2).

If the determination is NO (that is, a cache miss), the communication control device 41 requests the designated magnetic disk device to transfer the corresponding data (step S3).

Then, the communication control device 41 transfers the read data to the central processing unit 2, registers directory information in the directory section 401, and stores the corresponding data in the cache memory 402.

On the other hand, if the determination in step S2 is YES (that is, cache hit), the communication control device 41 does not issue a data read request to the magnetic disk device (71 or 72), The cache memory 402 is accessed using the cache memory address (cache memory address) (step S4).
. The communication control device 41 then uses a cache memory 402.
The data read from is transferred to the central processing unit 2.

As described above, according to this embodiment, in the case of a cache hit, data transfer is performed from the cache memory 402 instead of data transfer from the magnetic disk device (71 or 72), so that the data transfer time is significantly shortened.

In the above embodiment, the data transfer destination is the central processing unit 2, but the main storage device 3 may also be used.

Effects of the Invention As described above, according to the present invention, data access time from a magnetic disk device connected via a network can be shortened with a simple configuration, and it is extremely useful in practice.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a diagram showing the format of directory information applied in the above embodiment, FIG. 3 is a flowchart for explaining the operation of the above embodiment, and FIG. FIG. 4 is a block diagram of a conventional computer system. l... Computer system, 2...
Central processing unit, 3...Main storage device, 41.42
．． 43... Communication control device, 401...
Directory section, 402, old cache memory, 6
...Network, 71.72...Magnetic disk device, 8...Internal bus. Name of agent: Patent attorney Toshio Nakao Haka 1 person 1...
Go〉hi 111-2 System 2...Chuuya processing tea I 3...The above 71 meaning, (Set 4d2... Kiya... Nosh memory 6... Ne soto work 7I72... Stone ore air de 'Inner 2nd lid 8...Inner pass Fig. 2 13 Fig. 4

Claims (2)

[Claims] (1) A computer connected to a network and comprising a central processing unit, a main memory, and a cache memory in which data transferred between the central processing unit and the network is stored. (2) The computer according to claim 1, wherein data transfer is performed between the main storage device and the network.