Information storage system for converting data at transfer

• US 5,787,487 A
• Filed: 03/21/1997
• Issued: 07/28/1998
• Est. Priority Date: 11/30/1993
• Status: Expired due to Term

• Current Assignee: Fuji Xerox Company Limited (Xerox Holdings Corp.)
• Original Assignee: Fuji Xerox Company Limited (Xerox Holdings Corp.)
• Inventors: Hashimoto, Sunao, Kawabe, Shigehisa, Horikiri, Kazunori
• Primary Examiner(s): Gossage, Glenn
• Assistant Examiner(s): Ellis, Kevin L.
• Application Number:
  US08/822,146
• Time in Patent Office: 494 Days
• Field of Search: 395/492, 395/497.03, 395/497.04, 395/413, 395/888, 711/165, 711/172, 711/173, 711/203
• US Class Current: 711/165
• CPC Class Codes: G06F 12/023 Free address space management
• CPC Class Codes: G06F 12/08 in hierarchically structured memory systems, e.g. virtual memory systems
• CPC Class Codes: G06F 2212/401 Compressed data

Abstract

An information storage system includes an auxiliary memory unit, a data conversion unit for converting transfer data, a data transfer information memory unit for storing information on data transfer, a data conversion information memory unit for storing information on data conversion, and a storage managing unit, which manages the auxiliary memory unit, for transferring data to the auxiliary memory unit by using the data transfer information stored in the data transfer information memory unit, and at the time of data transfer, instructing the data conversion unit to convert data by using the data conversion information stored in the data conversion information memory unit.

Claims

1. An information storage system which transfers data between a main memory means which stores data in a block unit and an auxiliary memory means which stores data in a block unit for processing, the system comprising:

data conversion information holding means for holding conversion information which associates at least one first data block, corresponding to a data block stored in the auxiliary memory means, with a conversion procedure to convert the at least one first data block, and for holding plural second data blocks, each of which is generated by the conversion procedure and corresponds to a data block of the main memory means;

temporary memory means, which includes a plurality of blocks, each block stores the first data block or one of the second data blocks, for temporarily storing data to be transferred between the auxiliary memory means and the main memory means;

temporary memory managing means for holding a relationship which associates a block of the temporary memory means with the first data block, and associates a block of the temporary memory means with the second data block, and for managing data transfer between the auxiliary memory means and the temporary memory means in accordance with the relationship; and

data converting means for reading out the one first data block from the temporary memory means, for converting the read first data block by using the conversion procedure associated with the read first data block to the plural second data blocks, and for writing each of the converted second blocks into a block of the temporary memory means in accordance with the conversion information held in the data conversion information holding means and the relationship held in the temporary memory managing means.

2. The information storage system according to claim 1, wherein said data conversion means stores a data conversion procedure previously prepared by a user.

3. The information storage system according to claim 1, further comprising:

main memory managing means for holding a page table indicating a relationship among the second data blocks to be stored in the main memory means, a physical address of the main memory means, and a logical address of a virtual memory, for managing an access to the virtual memory, and for managing the main memory means to determine one of the second data blocks to be paged-in or paged-out in accordance with the relationship of the page table; and

a pager for issuing a command to the temporary memory managing means so as to transfer the one second data block to be paged-in, which is determined by the main memory managing means, from the temporary memory means to the main memory means, and for issuing a command to the main memory managing means so as to transfer the one second data block to be paged-out from the main memory means to the temporary memory means.

4. The information storage system according to claim 1, wherein said data conversion means includes a plurality of data conversion procedures, selects one or more data conversion procedures from among those data conversion procedures included therein in accordance with an instruction from said memory managing means, and converts transfer data according to the selected data conversion procedure when data is transferred.

5. The information storage system according to claim 4, wherein the selection of the data conversion procedure is performed on the basis of the result of executing a predetermined procedure.

6. The information storage system according to claim 4, wherein the selection of the data conversion procedure is performed in accordance with a parameter specified by a user.

7. The information storage system according to claim 4, wherein the selection of the data conversion procedure is performed on the basis of system status information or on an attribute of a page.

8. The information storage system according to claim 1, wherein the conversion information held in the data conversion information holding means further associates a reversal conversion procedure which converts the plural second data blocks to the at least one first data block, and wherein the data converting means reads out the plural second data blocks from the temporary memory means, converts the read plural second data blocks by using the reversal conversion procedure associated with the plural second data blocks to the at least one first data block, and writes each of the at least one first data block into a block of the temporary memory means, in accordance with the conversion information held in the data conversion information holding means and the relationship held in the temporary memory managing means.

9. The information storage system according to claim 8, wherein the temporary memory managing means releases a block of the temporary memory means in accordance with a control procedure, the control procedure being stored in a computer readable medium including instructions for:

selecting a block of the temporary memory means;

checking whether the selected block includes one of the plural first data blocks or the second data block, in accordance with the relationship and conversion information;

if the block includes the second data block, retrieving the data conversion information holding means for the second data blocks including the second data block in the selected block;

checking whether a found second data block is present in the temporary memory means in accordance with the relationship held in the temporary memory managing means;

if each found second data block is not present in the temporary memory means, checking whether at least one first data block which is associated with the found second data block by the data conversion information holding means, is present in the temporary memory means;

if the at least one first data block is not present in the temporary memory means, reading a first data block from the auxiliary memory means to collect at least one first data block from the read first data block and first data block stored in the temporary memory means;

activating the data converting means to convert the collected at least one first data block to plural second data blocks;

collecting necessary plural second data blocks for reversal conversion using the converted second data block as newly stored and the already existing second data block;

activating the data converting means to reversely convert the collected necessary plural second data blocks to at least one first data block;

writing the converted at least one first data block into the auxiliary memory means; and

releasing the selected block of the temporary memory means.

10. The information storage system according to claim 8, wherein the temporary memory managing means transfers one-block data from the temporary memory means to the main memory means in accordance with a procedure comprising the steps of:

determining whether the one second data block to be transferred to the main memory means is present in the temporary memory means in accordance with the relationship;

if the one second data block to be transferred to the main memory means is not present in the temporary memory means, finding a conversion procedure necessary to generate a second data block to be transferred to the main memory means and at least one first data block associated with the second data block to be transferred to the main memory means, based on the conversion information held in the data conversion information holding means;

finding whether the at least one first data bock associated with the second data block to be transferred to said main memory means is present in the temporary memory means in accordance with the relationship held in the temporary memory means;

if the at least one first data bock associated with the second data block to be transferred to the main memory means is present in the temporary memory means, converting the at least first data block by corresponding conversion procedure, commanding the data converting means to generate the second data block to be transferred to the main memory means, then transferring the generated second data block to the main storage means;

if the at least one first data bock associated with the second data block to be transferred to the main memory means is not present in the temporary memory means, transferring the first data block from the auxiliary memory means to the temporary memory means; and

converting the at least one first data block associated with the data to be transferred to the main memory means by the conversion procedure, commanding the converting means to generate data to be transferred to the main memory means, then transferring the generated second data block to the main memory means.

11. The information storage system according to claim 9, wherein the control procedure carried out by the temporary memory managing means to release a block of the temporary memory means further comprises the steps of:

if the selected block of the temporary memory means includes the second data block, searching the data conversion information holding means for plural second data blocks including the second data block included in the selected block;

retrieving a block from the temporary memory means which includes the second data block in accordance with the relationship; and

releasing the retrieved block from the temporary memory means.

12. The information storage system according to claim 9, wherein the temporary memory managing means selects the second data block at the time of selecting a block from the temporary memory means.

13. An information storage system which transfers data between a main memory means which stores data in a block unit and an auxiliary memory means which stores data in a block unit for processing, the system comprising

data conversion information holding means for holding conversion information which associates at least one second data block, corresponding to a data block stored in the auxiliary memory means, with a conversion procedure to convert the at least one second data block, and for holding plural first data blocks, each of which is generated by the conversion procedure and corresponds to a data block of the main memory means;

temporary memory means, which includes a plurality of blocks, each block stores one of the plural first data blocks or the second data block, for temporarily storing data to be transferred between the auxiliary memory means and the main memory means;

temporary memory managing means for holding a relationship which associates a block of the temporary memory means with the one first data block, and associates a block of the temporary memory means with the second data block, and for managing data transfer between the auxiliary memory means and the temporary memory means in accordance with the relationship;

data converting means for reading out the one first data block from the temporary memory means, for converting the read at least one second data block by using the conversion procedure associated with the read at least one second data block, to the plural first data blocks and for writing each of the converted first blocks into a block of the temporary memory means in accordance with the conversion information held in the data conversion information holding means and the relationship held in the temporary memory managing means.

14. The information storage system according to claim 13, wherein the conversion information held in the data conversion information holding means further associates a reversal conversion procedure, which converts the plural first data blocks to the at least one second block, with the plural first data blocks and the at least one second data block, and

wherein the data converting means reads out the plural first data blocks from the temporary memory means, converts the read plural first data blocks by using the reversal conversion procedure associated with the plural first data blocks to at least one second data block, and writes each of the converted! at least one second data block into a block of the temporary memory means, in accordance with the conversion information held in the data conversion information holding means and the relationship held in the temporary memory managing means.

15. The information storage system according to claim 14, wherein the temporary memory managing means releases a block in accordance with a procedure comprising the steps of

selecting a block in the temporary memory means;

determining whether the selected block corresponds to the first data block or the second data block based on the relationship and the conversion information;

if the block corresponds to the second data block, retrieving the at least one second data block including the second data block from the conversion information held in the conversion information holding means;

determining whether the at least one second data block is present in the temporary memory means based on the relationship held in the temporary memory managing means;

if the at least one second data block is not present in the temporary memory means, determining whether all of the plural first data blocks associated with the at least one second data block by the data conversion information holding means are present in the temporary memory means;

if all the plural first data blocks are not present in the temporary memory means, writing the first data block in the auxiliary memory means to the temporary memory means;

collecting a plurality of necessary first data blocks from the read first data block and first data block stored in the temporary memory means, converting the plurality of necessary first data blocks by the conversion procedure associated by the conversion information holding means, and commanding said data converting means to write the at least one second data block into the temporary memory means;

preparing at least one necessary second data block using the converted second data block newly stored and second data block already presented;

activating the data converting means to reversely convert the at least one second data block prepared using reversal conversion procedure associated with the at least one second data block into a plurality of first data block and storing the first data blocks in the temporary memory means; and

writing the plurality of first data blocks stored in the temporary memory means into the auxiliary memory means.

16. The information storage system according to claim 14, wherein the temporary memory managing means transfers the second data block from the temporary memory means to the main memory means in accordance with a control procedure comprising the steps of:

checking whether the second data block to be transferred to the main memory means is present in the temporary memory means in accordance with the relationship;

if the second data block is not present in the temporary memory means, searching for the data conversion information holding means for a reversal conversion for generating at least one second data block including the second data block to be transferred and the plural first data blocks associated with the second data block to be transferred;

checking whether all the found plural first data blocks are present in the temporary memory means in accordance with the relationship;

if all the found plural first data blocks are present, activating the data converting means to reversely convert the found plural first data blocks to at least one second data block including the second data block to be transferred, and then transferring the second data block to the main memory means;

if all the found plural first data blocks are not present, transferring the first data block which is not present, from the auxiliary memory means to the temporary memory means; and

activating the data converting means to reversely convert the found plural first data blocks to at least one second data block including the second data block to be transferred, and then transferring the second data block to the main memory means.

17. The information storage system according to claim 15, wherein the control procedure carried out by the temporary memory managing means further comprises the steps of:

if a selected block of the temporary memory means includes the second data block, finding at least one second data block associated with the selected second data block from the conversion information held in the conversion information holding means;

retrieving a block of the temporary memory means in which at least one second data block retrieved using the corresponding relationship is stored; and

releasing a plurality of retrieved blocks.

18. The information storage system according to claim 15, wherein the temporary memory managing means selects the second data block at the time of selecting a block of the temporary memory means.