Process of transferring file, process of gaining access to data and process of writing data

• US 5,715,452 A
• Filed: 12/13/1994
• Issued: 02/03/1998
• Est. Priority Date: 12/27/1993
• Status: Expired due to Fees

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Mori, Toshiaki, Takahashi, Kikuo, Ukai, Toshiyuki, Kagimasa, Toyohiko
• Primary Examiner(s): Black, Thomas G.
• Assistant Examiner(s): RONES, CHARLES
• Application Number:
  US08/357,192
• Time in Patent Office: 1,148 Days
• Field of Search: 395/275, 395/600, 395/425, 395/575, 395/441, 395/601, 395/621, 395/617, 395/491, 340/172.5, 364/200, 364/900
• US Class Current: 1/1
• CPC Class Codes: G06F 3/0613 in relation to throughput
• CPC Class Codes: G06F 3/0655 Vertical data movement, i.e. input-output transfer; data movement between one or more hosts and one or more storage devices
• CPC Class Codes: G06F 3/0674 Disk device
• CPC Class Codes: G11B 20/10 Digital recording or reproducing

Abstract

To transfer a file comprising block data at high speed between sequential access type auxiliary memories, a file transmission program inquires of an operating system about the physical storage positions of the block data, determines a reading order to reduce the read access time on the basis of the results of inquiry, and issues read requests sequentially to the operating system according to the reading order. The file transmission program requests the operating system to transmit the read block data. The block data together with respective logical identification data, for example, logical block numbers, are transmitted to a receiving end which may be another computing system. The operating system at the receiving end is requested to secure the number of physical data blocks required to store the block data. The write order of the block data to the physical data blocks is then determined to reduce the access time and the block data are respectively stored in the secured physical data blocks according to the write order. Sequentially, a pair of the logical identifiers of each block data actually written to the data area and physical identification data of the data blocks are stored in the data area.

Claims

1. A process of transferring requested data from a file, held in a first physical order in a first sequential access type auxiliary memory contained in a first computing system and formed of block data arranged in a logical order, to a second sequential access type auxiliary memory, the process comprising the steps of:

detecting physical positions of a group of the block data that includes the requested data;

determining a read order of the group of block data on the basis of the physical positions to obtain a read time that is less than a read time using the logical order;

reading the group of block data sequentially from the first sequential access type auxiliary memory in the read order;

selecting a group of data blocks of a size to hold the group of block data, from among data blocks in the second sequential access type auxiliary memory;

determining a write order of the group of data blocks on the basis of physical positional relations of the group of data blocks; and

writing the group of block data in the read order to the group of data blocks in the write order.

2. A process of transferring a file as claimed in claim 1, further including:

sequentially transferring in the read order the group of block data together with first logical identification data from the first computing system to a second computing system having the second sequential access type auxiliary memory.

3. A process of transferring a file as claimed in claim 2, wherein said writing step sequentially writes the group of block data together with corresponding ones of the first logical identification data to the group of data blocks.

4. A process of transferring a file as claimed in claim 2, further including the steps of:

prior to said step of writing, allocating temporary second logical identification data to the group of data blocks in the write order;

wherein said step of writing includes issuing a plurality of write requests designating the group of block data in the read order, and writing block data designated by each write request in response to each of the plurality of write requests; and

replacing the second logical identification data with the first logical information data.

5. A process of transferring a file as claimed in claim 2, wherein said writing step is started before the second computing system completes reception of all transferred block data, so that said steps of transferring and writing are conducted in parallel.

6. A process of transferring a file as claimed in claim 4, wherein said writing step is started before the second computing system completes reception of all transferred block data.

7. A process of transferring a file as claimed in claim 2, further comprising the steps of

notifying the second computing system from the first computing system of the total number of block data in the group of data blocks to be transferred before a start of said transferring step;

and

wherein said selecting step is conducted prior to said writing step and prior to completing said transferring step, in response to said notifying step so that the plurality of data blocks in the second auxiliary memory are equal to the total number of data blocks thus notified.

8. A process of transferring a file as claimed in claim 3, further including the steps of:

prior to said step of writing, allocating temporary second logical identification data to the group of data blocks in the write order;

wherein said step of writing includes issuing a plurality of write requests designating the group of block data in the read order, and writing block data designated by each write request in response to each of the plurality of write requests; and

replacing the second logical identification data with the first logical information data.

9. A process of transferring a file as claimed in claim 8, wherein said writing step is started before the second computing system completes reception of all transferred block data, so that said steps of transferring and writing are conducted in parallel.

10. A process of transferring a file as claimed in claim 9, further comprising the steps of

notifying the second computing system from the first computing system of the total number of block data in the group of data blocks to be transferred before a start of said transferring step;

and

wherein said selecting step is conducted prior to said writing step and prior to completing said transferring step, in response to said notifying step so that the plurality of data blocks in the second auxiliary memory are equal to the total number of data blocks thus notified.

21. A process of transferring a file as claimed in claim 9, further including the steps of:

prior to said step of writing, allocating temporary second logical identification data to the group of data blocks in a write order;

wherein said step of writing includes issuing a plurality of write requests designating the group of block data in the read order in sequence, and writing block data designated by each write request to the data blocks in the write order in response to each of the plurality of write requests; and

replacing the second logical identification data with first logical information data.

11. A process of transferring a file formed of a group of block data, comprising:

detecting physical positional relationships of a first group of physical data areas holding the group of block data arranged in a logical order in a first sequential access auxiliary memory by a first file transfer program running in a first computing system;

determining a read order of the group of block data on the basis of the physical positional relationships by the first file transfer program in such a manner as to reduce read time;

sequentially in the read order, issuing from the first file transfer program a plurality of read requests, each designating one block data out of the group of block data and logical identification data so that the group of block data may be read out of the first sequential access auxiliary memory in the read order;

under control of a first operating system being run in the first computing system, sequentially executing the read requests in the read order to control reading the block data from the first auxiliary memory;

transferring the group of block data together with the logical identification data sequentially from the first computing system to a second computing system in the read order;

writing the block data sequentially to a second group of physical data areas in a second sequential access auxiliary memory in the second computing system; and

storing the logical identification data together with the block data to the second sequential access auxiliary memory.

12. A process of transferring a file as claimed in claim 11, further comprising the steps of:

during said transferring step, running a second file transfer program in the second computing system to initiate a second operating system running in the second computing system for selecting the second group of physical data areas of a size to hold the group of block data;

during said transferring step, determining a write order on the basis of physical positional relationships of the second group of physical data areas by the second file transfer program in such a manner as to reduce write time required;

temporarily allocating a group of temporary logical identification data arranged in the write order for identifying block data to be held in the second group of physical data areas;

notifying the second file transfer program of the second group of physical data areas from the second operating system;

sequentially issuing in the read order from the second file transfer program a plurality of write requests for designating the block data and temporary logical identification data; and

executing the write requests under the control of the second operating system.

13. A process of transferring a file as claimed in claim 12, wherein the step of storing the logical identification data includes allocating the logical identification data transferred from the first computing system to each one of the group of physical data areas in place of the temporary logical identification data.

14. A process of transferring a file as claimed in claim 11, wherein the step of detecting includes inquiring of the first operating system about the first group of data areas by the first file transfer program in response to a file transfer request.

15. A process of writing data as a group of block data, which constitute a file and are arranged in a logical order, to a sequential access type auxiliary memory contained in a computing system in a different order from the logical order, comprising the steps of:

from an application program running in the computing system, requesting an operating system running in the computing system to control reading and writing of data from and to the auxiliary memory to select a plurality of physical data areas necessary for storing the group of block data in the auxiliary memory;

selecting the group of physical data areas by the operating system;

notifying the application program of the group of physical data areas from the operating system;

temporarily allocating a group of temporary logical identification data for relatively identifying a group of data blocks to be held in the group of physical data areas;

determining a write order of the group of physical data areas on the basis of physical positional relationships of the group of physical data areas by the application program in such a manner as to reduce time required to write the block data to the group of physical data areas;

sequentially issuing from the application program a plurality of write requests designating the physical data areas in the write order, each including the temporary logical identification data and one block data;

writing the block data designated by the write requests under the control of the operating system to the group of physical data areas to which the temporary logical identification data designated by the write requests has been allocated; and

allocating logical identification data according to the logical order of the group of block data to each of the group of physical data areas by the operating system in place of the temporary logical identification data.

16. A process of parallel accessing block data, which belong to different files held in a sequential access type auxiliary memory in a computing system, from a plurality of application programs running in the computing system, the process comprising the steps of:

issuing from each of the plurality of application programs data access requests in parallel, each including logical identification data of the block data to be accessed in the auxiliary memory;

holding in a queue at least one unexecuted data access request that has been issued from each application program;

detecting physical data blocks in the auxiliary memory logically corresponding to the queued data access requests;

determining an access order to the physical data blocks on the basis of positions of the physical data blocks and of read heads relative to the physical data blocks in such a manner as to reduce access time from a time that would be required to access in order the logical identification data;

executing the queued data access requests according to the access order so as to access the physical data blocks; and

repeating the above detecting, determining and executing steps.

17. A process of gaining access to data as claimed in claim 16, wherein the above holding, detecting, determining and executing steps are carried out by an operating system for reading or writing of data from or to the auxiliary memory.

18. A process of transferring a file as claimed in claim 17, wherein said detecting step includes one of the application programs inquiring of the operating system about the group of data areas.

19. A process of transferring requested data from a file, held in a first physical order in a first sequential access type auxiliary memory contained in a first computing system and formed of block data arranged in a logical order, to a second sequential access type auxiliary memory, the process comprising the steps of:

detecting physical positions of a group of the block data that includes the requested data;

determining a read order of the group of block data on the basis of the physical positions to obtain a read time that is less than a read time using the logical order;

reading the group of block data sequentially from the first sequential access type auxiliary memory in the read order;

selecting a group of data blocks of a size to hold the group of block data, from among data blocks in the second sequential access type auxiliary memory; and

writing the group of block data in the read order to the group of data blocks.

20. A process of transferring a file as claimed in claim 19, further including the steps of:

sequentially transferring in the read order the group of block data together with first logical identification data from the first computing system to a second computing system having the second sequential access type; and

wherein said writing step sequentially writes the group of block data together with corresponding ones of the first logical identification data to the group of data blocks.

22. A process of transferring a file as claimed in claim 20, wherein said writing step is started before the second computing system completes reception of all transferred block data, so that said steps of transferring and writing are conducted in parallel.

23. A process of transferring a file as claimed in claim 20, further comprising the steps of

notifying the second computing system from the first computing system of the total number of block data in the group of data blocks to be transferred before a start of said transferring step;

and

wherein said selecting step is conducted prior to said writing step and prior to completing said transferring step, in response to said notifying step so that the plurality of data blocks in the second sequential access type auxiliary memory are equal to the total number of data blocks thus notified.

24. A process of transferring a file as claimed in claim 23, wherein said writing step is started before the second computing system completes reception of all transferred block data, so that said steps of transferring and writing are conducted in parallel.

25. A process of transferring a file as claimed in claim 19, further comprising the steps of:

transferring the block data from a temporary memory under control of the first operating system to a temporary memory under control of the second operating system;

conducting said steps of detecting, determining and reading with the first operating system, and conducting said steps of selecting and writing with the second operating system in parallel with said transferring step;

notifying the second operating system from the first operating system of the total number of block data in the group of data blocks before a start of said transferring step; and

wherein said selecting step is conducted prior to said writing step and prior to completing said transferring step, in response to said notifying step so that the plurality of data blocks in the second sequential access type auxiliary memory are equal to the total number of data blocks thus notified.

26. A process of writing data as a group of block data which constitute a file to a sequential access type auxiliary memory contained in a computing system, comprising the steps performed by the computing system of:

receiving in the computing system information of an amount of block data in the group of block data to be received;

thereafter selecting a plurality of physical data areas necessary for storing the group of block data in the auxiliary memory on the basis of the amount;

temporarily allocating a group of temporary logical identification data for relatively identifying a group of data blocks to be held in the group of physical data areas;

determining a write order of the group of physical data areas on the basis of physical positional relationships of the group of physical data areas in such a manner as to reduce time required to write the block data to the group of physical data areas;

sequentially issuing from the application program a plurality of write requests designating the physical data areas in the write order, each including the temporary logical identification data and one block data;

receiving some of the block data one of before and after said selecting, allocating, determining and issuing step;

writing the some of the block data designated by the write requests under the control of the operating system to the group of physical data areas to which the temporary logical identification data designated by the write requests has been allocated;

receiving a remainder of the block data one of before and after said selecting, allocating, determining and issuing step;

writing a remainder of the block data designated by the write requests under the control of the operating system to the group of physical data areas to which the temporary logical identification data designated by the write requests has been allocated; and

allocating logical identification data according to the logical order of the group of block data to each of the group of physical data areas by the operating system in place of the temporary logical identification data.