JPH05128006A - Virtual computer system - Google Patents

Abstract

PURPOSE:To obtain a virtual computer system capable of rapidly exchanging data in each page. CONSTITUTION:A computer 11 is provided with a real memory 15 for storing data read out from a secondary storage device 14, a map table 18 for allowing real pages stored in the memory 15 to correspond to virtual pages and a map table rewriting means for exchanging entering items relating to two pages to be mutually exchanged in the table 18.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a virtual computer system and, more particularly, to a virtual computer system capable of exchanging blocks each having a predetermined amount of virtual pages at high speed.

[0002]

2. Description of the Related Art In a computer system, required data is often read from a storage medium such as a magnetic disk by a predetermined unit amount and stored in an internal cache memory for use. Consider the case where an access is requested across two tracks stored in cache memory in such a system. cache·
It is assumed that these track data must be consecutive in memory. These track data are stored in the cache memory but are not adjacent to each other in descending or ascending order. For example, after the track data read from the first track, the track data read from the fifth track is arranged, and then the track data read from the second track is arranged. This is the case when accessing the second track data.

In such a case, swapping (exchanging) the fifth track data and the second track data enables continuous access for two tracks.

Conventionally, in such a case, a process of actually swapping data by unit amount has been performed. At this time, in order to exchange 1-word data as a unit amount of data to be processed by the CPU (central processing unit), 6 operations were required as follows.

First, the CPU reads the 1-word data A of the first page among the data of the second track. Next, this 1-word data A is saved in a predetermined memory area. Then, the data B of one word of the first page of the data of the fifth track is read.
Then, the 1-word data B of the fifth track is written in the read-out portion of the data of the second track. Then, the 1-word data A saved in the memory area is read. Finally, this is written in the read portion of the data B of the fifth track.

In this way, when the swap of one word each of the second track data and the fifth track data is completed, the same processing is performed for the next one word,
After that, the same operation is repeated and the data swap for one track is completed.

As described above, in the conventional virtual computer system, when exchanging data, the exchanging of the data is realized while actually moving the data. Therefore, for example, even when swapping the data of one page, assuming that one page is composed of 256 words, the above-mentioned 6-step memory access is performed for each word, resulting in a total of 6 × 256 times. Memory access was required. In case of 1-track swap, set this to 1
There is a problem that the memory access is required to be multiplied by 6 times, and a lot of time is required for the memory processing for swapping.

It is therefore an object of the present invention to provide a virtual computer system capable of quickly exchanging data in page units.

[0009]

According to a first aspect of the present invention, a memory for storing data such as data read from a magnetic disk and a map for associating a real page and a virtual page of this memory with each other are provided. The virtual computer system is provided with a table and a map table rewriting means for exchanging entries relating to both pages to be exchanged in the map table when it is requested to exchange data in page units.

That is, according to the first aspect of the invention, instead of controlling the transfer of actual data, the entry items (entries) relating to both pages of the map table in which the real page and the virtual page are associated are exchanged. To do so. Thus, for example, when one page is written in one word, the exchange can be realized much faster than the case of exchanging the data for one page.

According to a second aspect of the present invention, a memory for storing data such as data read from the magnetic disk,
A map table for associating a real page with a virtual page of this memory, a register, and an entry regarding one of the pages to be exchanged in the map table when it is requested to exchange data in page units. A first processing means for saving an item in a register, a second processing means for writing an entry related to the other page to be exchanged at a location where the above-mentioned entry for one page has been read out, and saving to a register The virtual computer system is provided with a third processing means for writing the written entry in the read location of the entry related to the other page.

That is, according to the second aspect of the invention, the entries such as the address information in the map table are exchanged in page units, and at this time, these entries are temporarily stored in the register so that the data is stored in the memory area. The processing speed is further increased as compared with the case of storing.

[0013]

EXAMPLES The present invention will be described in detail below with reference to examples.

FIG. 1 shows an example of a computer constituting a virtual computer system according to an embodiment of the present invention. The calculator 11 includes a CPU 12. CP
U12 is a secondary storage device 14 including a magnetic disk, a drive device thereof, and the like via a bus 13 such as a data bus.
And a real memory 1 consisting of random access memory, etc.
It is connected to 5. However, illustration of an I / O (input / output) port with the secondary storage device 14 is omitted. Further, when the computer 11 is configured as a part of a workstation, for example, input / output devices such as a keyboard, a display and a mouse are connected to the bus 13 through an interface circuit. Since it is not directly related to, the illustration is omitted.

In this computer 11, a virtual memory 17 is arranged as a virtual memory. Virtual memory 17
Are managed by the map table 18. The allocation unit 1 is provided between the map table 18 and the real memory 15.
9 are arranged. However, the virtual memory 17 does not exist as an actual circuit device, but the actual memory 15
Of course, it is functionally present depending on a predetermined area of the above and a predetermined program stored in the secondary storage device 14. Also, map table and allocation unit 1
9 may exist as an actual circuit device or may exist functionally like the virtual memory 17. In the present embodiment, a predetermined area of the real memory 15 and the secondary storage device 1
Functionally present with 4.

FIG. 2 shows an example of the map table. In the area of a total of 16 pages (1 track) corresponding to the virtual pages V _{1 to} V ₁₆ of the map table 18 in sequence, the real pages R _{1 to} R _{16 of the} real memory 15 are 1 word each as an entry. Remembered Similarly, in the areas for a total of 16 pages corresponding to the other virtual pages V ₁ ′ to V ₁₆ ′ in sequence, the real pages R ₁ ′ to
R ₁₆ ′ is stored as an entry word by word.

In this embodiment, virtual pages V ₁ ...
The data for one track (page 16) represented by V _16, it is assumed that the data swapped for one track represented by the other virtual page V ₁ '~V _16'. In this embodiment, in this case, these entries of the map table 18 are mutually rewritten to realize the real page swap.

FIG. 3 is a diagram for explaining the operation of the virtual computer system when a data swap for one track is requested. First, the CPU 12 reads an entry for one word that describes the real page of the first virtual page V of the corresponding track in the map table 18 (step S101). And
This entry is stored in the general-purpose register of the CPU 14 (step S102).

Next, the CPU 14 reads the entry of the virtual page V'corresponding to the track to be swapped (step S103). Then, this entry is written in the location where the entry of the virtual page V is read (step S104). Next, the contents stored in the general-purpose register are written in the virtual page V, and the swap for one page is completed (step S105).

After this, the CPU 14 checks whether or not there are remaining pages to be swapped (step S106). Then, if there are remaining pages (Y), the respective virtual pages V and V ′ are advanced to the next page (step S107). In the example shown in FIG. 2, the virtual page V ₁ becomes V ₂ and the other virtual page V ₁ ′ becomes V ₂ ′. Then, returning to step S101, swapping for one page is performed.
When the swap for 16 pages is completed in this way (step S106; Y), the swap for one track is completed (END).

It is preferable that the rewriting operation of the map table 18 is continuously executed without interposing other operations.

In the embodiment described above, the data is saved by using the register in the CPU, so that the processing speed is increased as compared with the case of saving the data in the memory. Of course, these entries may be saved in the memory, and even in this case, one page can be processed with one word as compared with the above-mentioned conventional technique, so that one page of data can be processed in 1/256 processing time. You can swap.

In the above-described embodiment, the unit of swapping is one track (16 pages), but it goes without saying that other units may be used.

As described above, according to the present invention, the swap is realized by exchanging the entries of the map table for associating the real page and the virtual page, so that the normal block transfer is performed. Compared with, the processing speed is very high and the system efficiency can be improved. In addition, the amount of code to be fetched is reduced, and the swap execution itself can be realized by hardware or microcode. Therefore, also in this sense, the speed can be increased.

[Detailed Description of Drawings]

FIG. 1 is a block diagram showing an example of a computer that constitutes a virtual computer system according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a usage example of a map table.

FIG. 3 is a flowchart showing a swapping operation.

[Explanation of symbols]

 11 computer 12 CPU 14 secondary storage device 15 real memory 17 virtual memory 18 map table R real page V virtual page

[Procedure amendment]

[Submission date] November 9, 1992

[Procedure Amendment 1]

[Document name to be corrected] Drawing

[Correction target item name] All drawings

[Correction method] Change

[Correction content]

[Figure 1]

[Fig. 2]

[Figure 3]

Claims (2)

[Claims] 1. A memory for storing data, a map table for associating a real page and a virtual page of the memory, and a map table for exchanging the data page by page. A virtual computer system comprising map table rewriting means for exchanging entries relating to both pages to be exchanged. 2. A memory for storing data, a map table for associating a real page and a virtual page of this memory, a register, and a map when it is requested to exchange the data page by page. First processing means for saving the entry related to one page to be exchanged in the table to the register, and the entry related to the other page to be exchanged being read out of the entry related to the one page And a third processing unit for writing the entry saved in the register to the location where the entry related to the other page is read out. Computer system.