JPH05308366A - Cache system in lan - Google Patents

Abstract

PURPOSE:To speedily make a response to a client by efficiently using a server- side and a client-side cache memory. CONSTITUTION:The server is provided with a client management table wherein pieces of information on access frequencies of data stored in the server-side cache memory 11, priority order set according to the frequencies, etc., are registered by client terminals connected by a virtual line. The data in the cache memory 11 are controlled according to the priority order and the memory is released from data of a terminal from which the virtual line is disconnected. The interface board 6 of a client terminal, on the other hand, is provided with a CPU, a cache memory, and a command table wherein commands that a user input and data sent from the server corresponding to them are made to correspond to each other. The data are stored in the cache memory and when the user inputs the same command, the stored data are controlled to send back to the user immediately.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cache system in a local area network (LAN),
In particular, the present invention relates to a cache system in a LAN that can respond to clients faster.

[0002]

2. Description of the Related Art Conventionally, when data is communicated between terminals (workstations, servers, etc.) connected to a LAN,
There is known a method of speeding up a request (disk access) from each client by using a disk cache unique to the server. In this method, since all the read / write data to the disk are fetched into the intermediate memory, when the cache memory is of the FIFO type, it tends to become full, and the data which is accessed only once is accumulated and the access frequency High data may be discarded. Regarding the LAN service form, for example,
"Electronic Information and Communication Handbook, The Institute of Electronics, Information and Communication Engineers (1
988), pp. 2670-2673 ".

[0003]

In the above-mentioned conventional technique, when the cache memory is a FIFO type, there is a problem that useless data is accumulated in the cache memory and it is difficult to use the cache memory efficiently. An object of the present invention is to improve such a problem, efficiently use a cache memory to speed up a response to a client, and reduce a load on a CPU of a main body side. To provide.

[0004]

To achieve the above object, a cache system in a LAN of the present invention is a LAN system including a plurality of client terminals (workstations etc.) and a server terminal having a disk cache system. In, in each terminal connected by the virtual line, a client management table for registering information such as the access frequency of data stored in the cache memory on the server side and the priority order set based on the frequency, It is characterized in that it is provided with means (a function of the server side CPU) for managing the data in the cache memory based on the priority and controlling so as to release from the data of the terminal whose virtual circuit is disconnected. In the client terminal, a cache memory, a command table for associating a command input by the user with data transmitted from the server according to the command table, the data is stored in the cache memory, and the same command is input by the user. In this case, a means (CPU function of the client side interface board) for controlling to immediately return the stored data to the user is provided. When the server notifies the data change, the command table is controlled to be released. Further, in the LAN system, the cache memory and the table of the cache system are arranged in the network interface board of each terminal, and the CPU in the interface board realizes the above functions.

[0005]

According to the present invention, the client management table is provided for each client terminal connected by the virtual line, and the cache memory is managed according to the priority order based on the access frequency to the data in the cache memory of the server. In other words, the control is performed such that the data of the client with the lower priority is released and the data of the terminal whose virtual circuit is disconnected is released. As a result, it is possible to operate the cache system efficiently and speed up the response to the request from the client. On the other hand, a cache memory for accumulating received data is provided on the client side, and a command entered by the user and a cache address of the received data corresponding thereto are managed by a command table. That is, when the same command is input, the stored data is controlled to be immediately returned to the user. Thereby, the response to the user's input command can be speeded up. Further, by implementing these cache management functions by the CPU in the interface board, the load on the main body side CPU can be reduced.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing a cache management method using a client management table in one embodiment of the present invention, FIG.
Is a block diagram showing a cache system in one embodiment of the present invention, FIG. 3 is a diagram showing a format of a client management table in one embodiment of the present invention, and FIG. 4 is a configuration of a client side interface board in one embodiment of the present invention. 5 and 5 are diagrams showing the format of the command table in the embodiment of the present invention. In FIG. 2, CPU 1, RAM 2, ROM 3, system bus 4,
The interface board 6 constitutes a client terminal (workstation or the like), and the CPU 7, RAM 8,
ROM 9, system bus 10, cache memory 11,
The disk device 12 and the interface board 13 form a server terminal. These are connected to the LAN, and the server is to be accessed by a plurality of clients (not shown). Also, the server RAM
8 has a disk address management table for managing the data storage position of the disk device 12 and a client management table. This client management table is
As shown in FIG. 3, the cache memory 11 is composed of a priority order for storing data in the disk device 12, the number of times the data is used, an address of a user who has used the data, and an address on the disk address management table. To be done.

With this configuration, the server side manages the cache memory 11 as shown in FIG. That is, when the virtual line is established with the client, the server program in the ROM 9 registers the network address (user address) of the client in the client management table 14. After that, each time the client accesses the hard disk (disk device 12), the area of the number of times of use is incremented, the disk address of the hard disk is stored in the disk address management table 16, and the data is stored in the cache memory 11. To do. Further, the client management table 14 stores a list of disk addresses requested by the client. Next, when there is a disk access (read) request from the client, the server program searches the disk address management table 16 and, if it exists, reads it from the cache memory 11.
Therefore, each time an access request occurs, the usage count area of the client management table 14 increases, and the server program gives priority to the usage count. When the disk address management table 16 is over, the disk address management table 16 storing the lowest one is released based on the priority order of the client management table 14. Also, when the virtual line with the client is disconnected, the disk address management table 16 indicating the user is released.

On the other hand, the interface board 6 of the client, as shown in FIG.
OM25, LAN controller 26, RA for data reception
M27, CPU28, LAN interface (I / F)
It is composed of the part 29 and constitutes a cache system independent of the main body side. With the program (LAN protocol) stored in the ROM 25, the CPU 28 reduces the load on the CPU 1 on the main body side. RAM for data reception
27, as shown in FIG. 5, has a command table 23 showing the correspondence between the input data transmitted from the server and the address of the cache memory 24.

With this configuration, when the virtual line is established with the server, the client program stores the command input by the user of the client in the command table 23 shown in FIG. 5 and sends a request packet to the server. .. Then, when the data for the command is received from the server, the data is stored in the cache memory 24 corresponding to the command table 23 and the data is returned to the user. Next, when the user requests the same command, the request packet is not sent to the network and the data is read from the cache memory 24. In other words, by only updating the sequence number of the virtual circuit in the LAN and not transmitting / receiving data, the response to the user becomes faster and the load on the network is reduced. When the data sent to the client is rewritten (for example, when another client that communicates with the server rewrites the data), the server program sends a packet to the client informing that the data has been rewritten. To do. Upon receiving this packet, the client releases the data from the command table 23. Further, in the present embodiment, the cache system is arranged in the interface board only on the client side, but the cache management function can be realized in the interface board on the server side as well.

[0010]

According to the present invention, the cache table on the server side can be efficiently used by the management table provided for each client, and the data can be returned to the client at a higher speed. Also, by associating the input data of the user with the received data on the client side, it is possible to speed up the response to the user and reduce the load on the network. Further, by implementing the cache system in the interface board, it is possible to reduce the load on the main body side CPU.

[0011]

[Brief description of drawings]

FIG. 1 is a diagram showing a cache management method using a client management table according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a cache system according to an embodiment of the present invention.

FIG. 3 is a diagram showing a format of a client management table in the embodiment of the present invention.

FIG. 4 is a configuration diagram of a client-side interface board according to an embodiment of the present invention.

FIG. 5 is a diagram showing a format of a command table according to an embodiment of the present invention.

[Explanation of symbols]

 1 CPU 2 RAM 3 ROM 4 system bus 6 interface board 7 CPU 8 RAM 9 ROM 10 system bus 11 cache memory 12 disk device 13 interface board 24 cache memory 25 ROM 26 LAN controller 27 data receiving RAM 28 CPU 29 LAN interface section

Claims (3)

[Claims] 1. A LAN system comprising a plurality of terminals and a server terminal having a disk cache system and processing a disk access request from the terminals,
For each terminal connected by the virtual line, a table is provided for registering information including the access frequency of data stored in the cache memory on the server terminal side and the priority order set based on the access frequency. A cache system comprising means for managing the data in the cache memory based on the above, and controlling so as to release the data from the terminal whose virtual circuit has been disconnected. 2. A LAN system comprising a plurality of terminals and a server terminal which has a disk cache system and processes a disk access request from the terminals,
The terminal stores a cache memory, a table in which a command input by a user and data transmitted from a server terminal according to the command are associated with each other, and the transmission data is stored in the cache memory so that the same command is received from the user. A cache system comprising means for controlling the stored data to be immediately returned to the user when input. 3. A LAN system comprising the cache system according to claim 1 or 2, wherein the cache memory, the table, and the control means according to claim 1 are arranged in a network interface board of a server terminal. A LAN system characterized in that the cache memory, the table, and the control means described above are arranged in a network interface board of a terminal.