Electrical computers and digital processing systems: memory – Storage accessing and control – Control technique
Reexamination Certificate
1999-12-07
2001-11-27
Nguyen, Than (Department: 2187)
Electrical computers and digital processing systems: memory
Storage accessing and control
Control technique
C711S001000, C711S002000, C711S005000, C711S200000, C711S201000, C711S202000, C711S203000, C711S204000, C711S205000
Reexamination Certificate
active
06324630
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates generally to an information processing apparatus comprising a main storage and an extended storage, and more particularly to an information processing apparatus which is suitable for drastically improving a data move capability between a main storage and an extended storage.
A general purpose information processing apparatus is typically composed of a central processing unit (hereinafter abbreviated as “CPU”), a main storage (hereinafter abbreviated as “MS”), an input/output processing unit (hereinafter abbreviated as “IOP”), input/output devices connected to the IOP, and so on.
An input/output data processing procedure in the information processing apparatus composed of the units mentioned above is generally executed in the following manner. First, the IOP transfers input data from input/output devices connected to the IOP to the MS for temporarily storing the input data in the MS, and the data stored in the MS is processed by the CPU and again stored in the MS after the processing is completed. The processed data stored in the MS is then outputted to input/output devices through the IOP as output data.
The sequence of operations in the foregoing input/output data processing procedure is generally executed under the control of an operating system (hereinafter abbreviated as “OS”) resident on the information processing apparatus. In addition, an approach for providing the OS with a virtual storage function is generally employed for apparently eliminating a limit to the capacity of the MS.
When the virtual storage function is included in an OS, a virtual storage device uses a storage capacity significantly larger than a real storage capacity of a MS. Thus, a portion of input/output devices connected to an IOP is generally used as an external storage device serving as a storage medium for the virtual storage device, such that data overflowing the actual storage capacity of the MS is temporarily stored in the external storage device. In this event, a data move operation, i.e., so-called page-in/page-out operations are executed by the MS and the external storage device under the control of the OS. Since the page-in/page-out operations are extremely frequently executed, the data move capability between the MS and the external storage device is a critical factor for determining the information processing performance of the information processing apparatus.
In recent years, it is a general tendency to employ an additional storage device called an “extended storage” (hereinafter abbreviated as “ES”) which plays a different role from the MS and the external storage device for improving the data move capability in the page-in/page-out operations. The ES is a storage device dedicated to store, under the control of the OS, a portion or all of page data sets (data blocks) conventionally adapted to temporarily store data overflowing a real storage capacity of a MS using an external storage device connected to the IOP. The data move capability between the MS and the ES associated with page-in/page-out operations is quite higher as compared with the data move capability between the MS and an external storage device, since the former can move data without the intervention of an input/output interface. An increased data move capability between the MS and the ES associated with the page-in/page-out operations results in remarkable improvements in the information processing performance of the information processing apparatus.
U.S. Pat. Nos. 3,723,976; 4,761,737; 4,075,694; 4,685,057; and 5,371,867 disclose general services and functions of ES's in information processing apparatuses.
It should be noted that a page-in operation involving actual data transfer from an ES to a MS and a page-out operation involving actual data transfer from a MS to an ES are extremely frequently executed during the progress of data processing, so that the data transfer capability between the ES and the MS largely affects the data processing performance of the information processing apparatus.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide an information processing apparatus comprising a MS and an ES as mentioned above which is intended to drastically improve an apparent data move capability between the MS and the ES to achieve remarkable improvements in the performance of a data processing procedure employing a virtual storage function of the information processing apparatus, in view of the technical background in which the performance of the data processing procedure employing the virtual storage function is determined depending on the data move capability between the MS and ES associated with page-in and page-out operations, and the data move capability between the MS and the ES is a critical factor for determining an upper limit to the information processing performance of the information processing apparatus.
According to the present invention, in an information processing apparatus having a storage unit including a plurality of storage modules, being assignable to a main storage or to an extended storage, a first address array connected to the respective storage modules and having address entries for a plurality of modules assigned to the main storage within the plurality of storage modules, a second address array connected to the respective storage modules and having address entries for a plurality of modules assigned to the extended storage within the plurality of storage modules, and a system controller connected to the first and second address arrays, respectively, a method of processing a data move instruction for moving data between the main storage and the extended storage, comprising the steps of:
inputting address entries for a plurality of modules assigned to the main storage within the plurality of storage modules to the first address array;
inputting address entries for a plurality of modules assigned to the extended storage within the plurality of storage modules to the second address array;
in response to a data move instruction for moving data between the main storage and the extended storage, moving an address entry indicative of the storage module specified by the move instruction between the first and second address arrays; and
changing a flag in the address entry from one of values specifying the main storage and the extended storage to the other.
First and second latches connected to the first and second address arrays, respectively, for latching outputs thereof are both connected to each of the plurality of storage modules.
The system controller, responsive to a data move instruction, before moving an address entry indicative of the storage module between the first and second address arrays, can set a flag in another address entry to a value other than values specifying the main storage and the extended storage and issue an instruction to the storage module specified by the other address entry to move data in the storage module.
A system according to the present invention comprises:
a storage device including a plurality of storage modules, each of which is assigned to and used as each area (data block) of a main storage (MS) or an extended storage (ES) during operation of the system;
a MS address array having a plurality of storage entries corresponding to respective areas in the MS, each for storing an identifier indicative of a storage module assigned to an associated area in the MS; and
an ES address array having a plurality of storage entries corresponding to respective areas in the ES, each for storing an identifier indicative of a storage module assigned to an associated area in the ES.
When an access request for accessing the MS or the ES is issued from an IOP or an IP, a storage module identifier is retrieved from a storage entry corresponding to an access requested area in the MS address array or the ES address array to select a storage module indicated by the identifier for executing the access operation. In other words, the IOP and the IP do not at all take into account the storage device,
Antonelli Terry Stout & Kraus LLP
Hitachi , Ltd.
Nguyen Than
LandOfFree
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