WO2002052396A2 - Method and system for reducing fragmentation - Google Patents
Method and system for reducing fragmentation Download PDFInfo
- Publication number
- WO2002052396A2 WO2002052396A2 PCT/IB2001/002458 IB0102458W WO02052396A2 WO 2002052396 A2 WO2002052396 A2 WO 2002052396A2 IB 0102458 W IB0102458 W IB 0102458W WO 02052396 A2 WO02052396 A2 WO 02052396A2
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- file
- deletion
- fragmentation
- files
- storage device
- Prior art date
Links
- 238000013467 fragmentation Methods 0.000 title claims abstract description 58
- 238000006062 fragmentation reaction Methods 0.000 title claims abstract description 58
- 238000000034 method Methods 0.000 title claims abstract description 15
- 238000012217 deletion Methods 0.000 claims abstract description 52
- 230000037430 deletion Effects 0.000 claims abstract description 52
- 230000000694 effects Effects 0.000 claims description 8
- 238000004590 computer program Methods 0.000 claims description 5
- 239000012634 fragment Substances 0.000 description 30
- 238000010586 diagram Methods 0.000 description 6
- 238000013500 data storage Methods 0.000 description 2
- 239000003550 marker Substances 0.000 description 2
- 238000013459 approach Methods 0.000 description 1
- 238000004364 calculation method Methods 0.000 description 1
- 238000007726 management method Methods 0.000 description 1
Classifications
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F16/00—Information retrieval; Database structures therefor; File system structures therefor
- G06F16/10—File systems; File servers
- G06F16/17—Details of further file system functions
- G06F16/1727—Details of free space management performed by the file system
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F3/00—Input arrangements for transferring data to be processed into a form capable of being handled by the computer; Output arrangements for transferring data from processing unit to output unit, e.g. interface arrangements
- G06F3/06—Digital input from, or digital output to, record carriers, e.g. RAID, emulated record carriers or networked record carriers
- G06F3/0601—Interfaces specially adapted for storage systems
- G06F3/0628—Interfaces specially adapted for storage systems making use of a particular technique
- G06F3/0638—Organizing or formatting or addressing of data
- G06F3/064—Management of blocks
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F16/00—Information retrieval; Database structures therefor; File system structures therefor
- G06F16/10—File systems; File servers
- G06F16/16—File or folder operations, e.g. details of user interfaces specifically adapted to file systems
- G06F16/162—Delete operations
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F16/00—Information retrieval; Database structures therefor; File system structures therefor
- G06F16/10—File systems; File servers
- G06F16/17—Details of further file system functions
- G06F16/1724—Details of de-fragmentation performed by the file system
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F3/00—Input arrangements for transferring data to be processed into a form capable of being handled by the computer; Output arrangements for transferring data from processing unit to output unit, e.g. interface arrangements
- G06F3/06—Digital input from, or digital output to, record carriers, e.g. RAID, emulated record carriers or networked record carriers
- G06F3/0601—Interfaces specially adapted for storage systems
- G06F3/0602—Interfaces specially adapted for storage systems specifically adapted to achieve a particular effect
- G06F3/0608—Saving storage space on storage systems
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F3/00—Input arrangements for transferring data to be processed into a form capable of being handled by the computer; Output arrangements for transferring data from processing unit to output unit, e.g. interface arrangements
- G06F3/06—Digital input from, or digital output to, record carriers, e.g. RAID, emulated record carriers or networked record carriers
- G06F3/0601—Interfaces specially adapted for storage systems
- G06F3/0628—Interfaces specially adapted for storage systems making use of a particular technique
- G06F3/0646—Horizontal data movement in storage systems, i.e. moving data in between storage devices or systems
- G06F3/0652—Erasing, e.g. deleting, data cleaning, moving of data to a wastebasket
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F3/00—Input arrangements for transferring data to be processed into a form capable of being handled by the computer; Output arrangements for transferring data from processing unit to output unit, e.g. interface arrangements
- G06F3/06—Digital input from, or digital output to, record carriers, e.g. RAID, emulated record carriers or networked record carriers
- G06F3/0601—Interfaces specially adapted for storage systems
- G06F3/0668—Interfaces specially adapted for storage systems adopting a particular infrastructure
- G06F3/0671—In-line storage system
- G06F3/0673—Single storage device
- G06F3/0674—Disk device
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F3/00—Input arrangements for transferring data to be processed into a form capable of being handled by the computer; Output arrangements for transferring data from processing unit to output unit, e.g. interface arrangements
- G06F3/06—Digital input from, or digital output to, record carriers, e.g. RAID, emulated record carriers or networked record carriers
- G06F3/0601—Interfaces specially adapted for storage systems
- G06F3/0628—Interfaces specially adapted for storage systems making use of a particular technique
- G06F3/0638—Organizing or formatting or addressing of data
- G06F3/0643—Management of files
Definitions
- the present invention relates to methods of and systems arranged for reducing fragmentation.
- the invention also relates to corresponding computer program products.
- a digital storage device is typically a disk on which data is stored.
- the present invention is concerned with such storage devices in which the data storage is potentially temporary, i.e. data is deletable.
- Files are saved to the disk in one or more fragments.
- a fragment contains part or all of a file.
- several fragments may be required.
- the fragments may be scattered around the disk surface. If the disk is near its capacity for data storage, even a relatively small file may have to be split into spaced fragments.
- file fragmentation This spacing of fragments of a file is referred to as file fragmentation.
- free-space fragmentation A highly fragmented disk generally will take longer to read as the read device needs to hunt around the disk to find the relevant fragments. Similarly it can take longer for a file to be saved to a highly fragmented disk as the write device needs to find sufficient fragments for all of the file(s), which clusters may be widely spaced.
- File fragmentation and free-space fragmentation are together referred to as fragmentation.
- a file is to be deleted.
- a user may pre-select files for deletion (similar to a "recycle bin" in a WINDOWS (trade mark) operating system environment) or files may be annotated only to be kept for a certain period of time.
- Such annotation is recorded in the system file manager usually by a marker flag.
- claims 1 and 4 addresses the problem by, when a plurality of files is available for deletion, selectively deleting a file to reduce fragmentation.
- a method of reducing fragmentation of a digital storage device characterised by the method comprising the steps of: determining that a plurality of files is available for deletion; selecting one of the files; and deleting the selected file and not deleting another of the files.
- a system arranged for reducing fragmentation of a digital storage device, characterised by the system comprising means for determining that a plurality of files is available for deletion; means for selecting one of the files; and means for deleting the selected file and not deleting another of the files.
- claims 2 and 7 provide an advantageous way of maximising file defragmentation.
- claims 3 and 8 provide an advantageous way of maximising both file and free-space defragmentation.
- claims 4 and 9 provide an advantageous way of determining which file should be detected to maximise both file and free-space defragmentation.
- claims 5 and 10 provide an advantageous way of taking account of file sizes when determining optimum defragmentation.
- the invention may advantageously be implemented as a digital video recorder, as set out in claim 11.
- the invention may advantageously be implemented as a computer program product, as set out in claim 12. It has been realised that with digital storage devices annotating a plurality of files for deletion, there is an efficient opportunity to reduce fragmentation by selective file deletion.
- Figure 1 is a schematic illustration of a digital video recorder.
- Figure 2 is a functional flow diagram illustrating a file writing operation.
- Figure 3 is a functional flow diagram illustrating a file deleting operation according to an embodiment of the present invention.
- Figure 4 is a functional flow diagram illustrating a file selecting operation according to an embodiment of the present invention.
- FIG. 1 of the drawings that follow there is shown schematically a memory disk 10 of a digital video recorder 20, which digital video recorder has a file manager 30 for controlling files on the disk 10.
- the memory disk 10 has an associated computer program product 40 for operating the digital video recorder according to preferred embodiments of the present invention.
- FIG 2 of the drawings that follow the steps of a file writing operation are shown.
- the flow diagram entries correspond as follows: 100 - SELECT FILE TO WRITE TO DISK
- step 100 a file (not shown) is selected to be written to the disk 10.
- a search of the file manager 30 is undertaken for available free space on the disk 10 (step 102).
- the file to be written is segmented into the required number and size of fragments (step 104) and is then written to the disk 10 (step 106).
- a file manager entry is generated (step 108) in the file manager 30.
- the file may be annotated for deletion at this stage or it may be so annotated later (step 110).
- Annotation is typically by a marker flag on the file manager entry for the file. If it is to be annotated then the corresponding file manager entry is annotated accordingly (step 112).
- a file may be annotated for deletion after a certain period of time, or may be user selected for deletion, for instance by being placed in a recycle bin or the like (in a WINDOWS (trade mark) operating system environment). Given the set or a subset of the files on the disk, a mechanism can mark a number of these for deletion, according to a user profile.
- FIG. 3 shows a deletion operation according to an embodiment of the present invention.
- the flow diagram entries correspond as follows:
- step 200 the file manager 30 is interrogated (step 202) to determine whether multiple files are available for deletion.
- a file is available for deletion if it has been so annotated.
- a file is only available for deletion if in doing so it provides sufficient free-space for the required write operation. This may mean that several of a plurality of files need to be deleted. If only a single file is available for deletion, it is deleted (step 204) and the file manager 30 updated accordingly (step 210). If multiple files are available a file is selected to be deleted to reduce fragmentation (step 206). Options for selecting the file to be deleted in this embodiment of the present invention are set out below.
- the selected file is permanently deleted (step 208) and the file manager 30 is updated accordingly (step 210).
- the specific file to be deleted can be chosen to optimise file defragmentation or free-space defragmentation. There can be several criteria to determine the text file to delete. One is to optimise the file fragmentation level of the files on the disk by deleting the most fragmented file among the available candidates for deletion. A better one is to optimise the fragmentation level and the free-space fragmentation level, since the next file to be written to the disk will benefit from a low free-space fragmentation.
- the optimisation can be improved by taking into account not only the number of fragments, but also the sizes of them.
- File A consists of 2 fragments, file B of 3 fragments, and file C of 3 fragments.
- the free space F consists of 2 fragments. Thus in total there are 10 fragments.
- files A and B are candidates for deletion having been annotated accordingly in the file manager 30, and file C should be left untouched, we need to choose between files A and B for deletion. If we delete the most file fragmented one, which is file B, we get the following result:
- File A consists of 2 fragments, file C of 3 fragments, and the free space F of 4 fragments. This totals 9 fragments. Because of the high fragmentation of the free space, the next file to be stored will probably have a high fragmentation level as well. If instead we optimise on the file fragmentation level of both the files and the free-space, we would delete file A, from which we get the following result:
- File B consists of 3 fragments
- file C of 3 fragments
- free space F consists of 2 fragments, totalling 8 fragments. What is more, since the free-space has a low free-space fragmentation level, the next file to be stored will also have a low fragmentation level.
- the determination of which file to delete whichever selection option is chosen is carried out by interrogating the file manager 30. For every file in a set of deletable files the effect of deletion on file fragmentation and free-space fragmentation is calculated.
- the effect on free-space fragmentation is calculated by calculating the changes the deletion (for each file) would have on the free-space fragments (step 402). New free- space fragments might appear (undesirable), but several free-space fragments can be connected by deletion creating new free-space fragments (desirable). In general, the number of free-space fragments will increase (ie a positive change).
- the file that results in the lowest sum (always zero or negative) of both the fragmentation and free-space fragmentation changes is determined (step 404). Since this mechanism favours large files (being statistically more coalescing), an optional refinement is to normalise on the file size (step 406). This is done by dividing the sum above by the number of clusters in the file. The optimal file is then selected (step 408).
- step 404 can be used to select the file for deletion.
- the effect of deletion on file fragmentation is calculated (step 400).
- File fragmentation over the completed disk would decrease by the number of fragments of the file to be deleted. This is always a negative change.
Abstract
Description
Claims
Priority Applications (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
EP01272156A EP1423783A2 (en) | 2000-12-22 | 2001-12-07 | Method and system for reducing fragmentation |
KR1020027010988A KR20020081696A (en) | 2000-12-22 | 2001-12-07 | Method and system for reducing fragmentation |
JP2002553630A JP2004517399A (en) | 2000-12-22 | 2001-12-07 | Method and system for reducing fragmentation |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
EP00204793.4 | 2000-12-22 | ||
EP00204793 | 2000-12-22 |
Publications (2)
Publication Number | Publication Date |
---|---|
WO2002052396A2 true WO2002052396A2 (en) | 2002-07-04 |
WO2002052396A3 WO2002052396A3 (en) | 2004-03-25 |
Family
ID=8172552
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/IB2001/002458 WO2002052396A2 (en) | 2000-12-22 | 2001-12-07 | Method and system for reducing fragmentation |
Country Status (6)
Country | Link |
---|---|
US (1) | US6757804B2 (en) |
EP (1) | EP1423783A2 (en) |
JP (1) | JP2004517399A (en) |
KR (1) | KR20020081696A (en) |
CN (1) | CN1254735C (en) |
WO (1) | WO2002052396A2 (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN1295592C (en) * | 2002-08-29 | 2007-01-17 | 国际商业机器公司 | Maintaining information in one or more virtual volume aggregates comprising a plurality of virtual volumes |
Families Citing this family (10)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6978283B1 (en) * | 2001-12-21 | 2005-12-20 | Network Appliance, Inc. | File system defragmentation technique via write allocation |
KR100513331B1 (en) * | 2002-06-19 | 2005-09-07 | 엘지전자 주식회사 | Method for temporal deleting and restoring files recorded on rewritable optical disc |
US20050165856A1 (en) * | 2004-01-27 | 2005-07-28 | International Business Machines Corporation | System and method for autonomic performance enhancement of storage media |
US8051115B2 (en) * | 2004-09-08 | 2011-11-01 | Koby Biller | Measuring fragmentation on direct access storage devices and defragmentation thereof |
EP1846828A2 (en) * | 2005-01-31 | 2007-10-24 | Nxp B.V. | Data processing system and method for memory defragmentation |
US20080228693A1 (en) * | 2005-09-26 | 2008-09-18 | Koninklijke Philips Electronics, N.V. | Recycle Bin Function |
US7747578B2 (en) * | 2007-03-09 | 2010-06-29 | Microsoft Corporation | Reducing database fragmentation |
CN103425761B (en) * | 2013-08-05 | 2017-02-08 | 珠海金山网络游戏科技有限公司 | Method, system and device used for defragmentation of packed file |
CN104065906B (en) * | 2014-07-09 | 2017-02-15 | 珠海全志科技股份有限公司 | Video recording method and device of digital video recording equipment |
CN116049021B (en) * | 2022-08-29 | 2023-10-20 | 荣耀终端有限公司 | Storage space management method, electronic device, and computer-readable storage medium |
Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0694831A2 (en) * | 1994-07-29 | 1996-01-31 | Hitachi, Ltd. | Computer system having storage unit provided with data compression function andmethod of management of storage area thereof |
Family Cites Families (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5574907A (en) | 1994-11-30 | 1996-11-12 | Microsoft Corporation | Two-pass defragmentation of compressed hard disk data with a single data rewrite |
US5778392A (en) | 1996-04-01 | 1998-07-07 | Symantec Corporation | Opportunistic tile-pulling, vacancy-filling method and apparatus for file-structure reorganization |
US6092105A (en) * | 1996-07-12 | 2000-07-18 | Intraware, Inc. | System and method for vending retail software and other sets of information to end users |
US5944839A (en) * | 1997-03-19 | 1999-08-31 | Symantec Corporation | System and method for automatically maintaining a computer system |
US5930828A (en) | 1997-03-26 | 1999-07-27 | Executive Software International | Real-time apparatus and method for minimizing disk fragmentation in a computer system |
US6202121B1 (en) * | 1998-04-15 | 2001-03-13 | Microsoft Corporation | System and method for improved program launch time |
-
2001
- 2001-12-07 WO PCT/IB2001/002458 patent/WO2002052396A2/en not_active Application Discontinuation
- 2001-12-07 JP JP2002553630A patent/JP2004517399A/en not_active Withdrawn
- 2001-12-07 CN CNB018054803A patent/CN1254735C/en not_active Expired - Fee Related
- 2001-12-07 EP EP01272156A patent/EP1423783A2/en not_active Withdrawn
- 2001-12-07 KR KR1020027010988A patent/KR20020081696A/en not_active Application Discontinuation
- 2001-12-21 US US10/028,123 patent/US6757804B2/en not_active Expired - Fee Related
Patent Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0694831A2 (en) * | 1994-07-29 | 1996-01-31 | Hitachi, Ltd. | Computer system having storage unit provided with data compression function andmethod of management of storage area thereof |
Non-Patent Citations (1)
Title |
---|
"ALLOCATION PROCEDURES" IBM TECHNICAL DISCLOSURE BULLETIN, IBM CORP. NEW YORK, US, vol. 28, no. 9, 1 February 1986 (1986-02-01), pages 3866-3867, XP000715317 ISSN: 0018-8689 * |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN1295592C (en) * | 2002-08-29 | 2007-01-17 | 国际商业机器公司 | Maintaining information in one or more virtual volume aggregates comprising a plurality of virtual volumes |
Also Published As
Publication number | Publication date |
---|---|
US20020133683A1 (en) | 2002-09-19 |
JP2004517399A (en) | 2004-06-10 |
KR20020081696A (en) | 2002-10-30 |
EP1423783A2 (en) | 2004-06-02 |
WO2002052396A3 (en) | 2004-03-25 |
CN1254735C (en) | 2006-05-03 |
US6757804B2 (en) | 2004-06-29 |
CN1529843A (en) | 2004-09-15 |
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