EP1110219A1 - Procede ameliore permettant l'operation de formatage de secteur variable dans un systeme informatique - Google Patents

Procede ameliore permettant l'operation de formatage de secteur variable dans un systeme informatique

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Publication number
EP1110219A1
EP1110219A1 EP99938938A EP99938938A EP1110219A1 EP 1110219 A1 EP1110219 A1 EP 1110219A1 EP 99938938 A EP99938938 A EP 99938938A EP 99938938 A EP99938938 A EP 99938938A EP 1110219 A1 EP1110219 A1 EP 1110219A1
Authority
EP
European Patent Office
Prior art keywords
sectors
logical
sector
physical
computer system
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP99938938A
Other languages
German (de)
English (en)
Inventor
Craig F. Russ
Jeffery A. Stell
Michael J. Saunders
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Unisys Corp
Original Assignee
Unisys Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Unisys Corp filed Critical Unisys Corp
Publication of EP1110219A1 publication Critical patent/EP1110219A1/fr
Withdrawn legal-status Critical Current

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Classifications

    • 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
    • G06F3/061—Improving I/O performance
    • G06F3/0613—Improving I/O performance in relation to throughput
    • 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
    • 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
    • G06F3/0655—Vertical data movement, i.e. input-output transfer; data movement between one or more hosts and one or more storage devices
    • G06F3/0661—Format or protocol conversion arrangements
    • 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
    • G06F3/0683—Plurality of storage devices
    • G06F3/0689—Disk arrays, e.g. RAID, JBOD
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B20/00—Signal processing not specific to the method of recording or reproducing; Circuits therefor
    • G11B20/10—Digital recording or reproducing
    • G11B20/12—Formatting, e.g. arrangement of data block or words on the record carriers
    • G11B20/1217—Formatting, e.g. arrangement of data block or words on the record carriers on discs
    • G11B20/1252—Formatting, e.g. arrangement of data block or words on the record carriers on discs for discontinuous data, e.g. digital information signals, computer programme data
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B20/00—Signal processing not specific to the method of recording or reproducing; Circuits therefor
    • G11B20/10—Digital recording or reproducing
    • G11B20/18—Error detection or correction; Testing, e.g. of drop-outs
    • G11B20/1833—Error detection or correction; Testing, e.g. of drop-outs by adding special lists or symbols to the coded information

Definitions

  • the present invention generally relates to computer data storage, and more particularly, to an improved method for enabling a computer system having a predetermined logical sector format to read from and write to a sector-formatted storage medium that has a physical sector format that differs from the logical sector format of the computer system.
  • Unisys 2200 and Clearpath HMP IX computer systems which run the Unisys 2200 operating system, were originally architected around a physical sector size of 504 bytes, and hence, data is arranged internally in logical sectors of 504 bytes.
  • Disks based on the larger 512 byte physical sector format can hold more data on the same disk, resulting in a lower cost per megabyte. Also, since each disk on a bus will contain more data, there is more storage capacity served by a given host I/O bus. Additionally, because more data can be stored on each disk, fewer disks may be required, resulting in a smaller data footprint, and lower power & cooling requirements.
  • Unisys Because of the advantages of using industry standard disk technology, and also because it is becoming increasingly difficult to find disk vendors willing to support non-standard disk sector sizes, Unisys has developed methods to enable both its A Series/Clearpath HMP NX (180 byte sectors) and 2200/Clearpath HMP IX (504 byte sectors) computer systems to operate with storage media having a 512 bytes physical sector format, in addition to their existing proprietary formats.
  • the 504 byte logical sectors internal to the computer system are close in size to the 512 byte physical sectors of an industry standard disk, the 504 byte logical sectors are made to correspond one-to-one with respective 512 byte physical sectors on an attached storage device.
  • the I/O channel simply adds eight (8) extra ("pad") bytes to the logical sector as the data is transferred from the host to the storage device.
  • the I/O channel strips the last eight (8) pad bytes from the incoming data before passing the first 504 bytes into a corresponding logical sector buffer.
  • Figure 1 illustrates the manner in which 180 byte logical sectors of the Unisys A Series and Clearpath HMP NX are mapped to the 512 byte physical sectors of a storage medium in accordance with the method described in application serial no. 08/758,836.
  • logical sector 0 in physical sector 0
  • logical sectors are stored one after the other within the physical sectors on the disk, completely filling each successive physical sector.
  • some logical sectors e.g., logical sector 2 will span two physical sectors (e.g., physical sectors 0 and 1).
  • FIG. 2 illustrates the read-modify- write process as implemented on an MCP server 10 (i.e., a Unisys A Series or Clearpath HMP NX computer system executing the MCP operating system).
  • MCP server 10 i.e., a Unisys A Series or Clearpath HMP NX computer system executing the MCP operating system.
  • MCP server 10 i.e., a Unisys A Series or Clearpath HMP NX computer system executing the MCP operating system.
  • the MCP server 10 will make a write request addressed to logical sector 1, with a specified length of four logical sectors.
  • the logical sector request is mapped to the corresponding physical sectors of the disk - in this example, physical sectors 0 and 1.
  • the write request will begin in the middle of physical sector 0 of the disk 14.
  • step 20 physical sectors 0 and 1 are automatically pre-read into physical sector buffers 16 and 18, respectively, as shown at step 20.
  • a "merge" cycle is then begun in which the data that formerly resided at logical sector 0 is re- written to physical sector 0 from its buffer 16 (step 22).
  • the data in the application program buffer 12 is aligned beginning at logical sector 1, through logical sector 4, overwriting what previously resided there on the disk (step 24).
  • step 26 the trailing data (i.e., part of logical sector 5) that formerly resided at the end of physical sector 1 is merged to complete the contents of physical sector 1.
  • a successful completion status is then presented to the MCP server 10.
  • the MCP server 10 is able to interoperate with the 512 byte/sector disk 14 in a manner that is transparent to the operating system and to any applications that need to read and write data to the disk 14.
  • the present invention is directed to an improved method for enabling a computer system having a predetermined logical sector format to read from and write to a sector-formatted storage medium that has a different, larger physical sector format than the logical sector format of the computer system. More specifically, the present invention provides an improved method for enabling a computer system in which data is arranged internally in logical sectors to read and write data to a sector-formatted storage medium arranged in physical sectors, wherein the size of a logical sector is less than the size of a physical sector such that a plurality P of logical sectors of the computer system will fit consecutively within a number N of physical sectors of the sector-formatted memory, P being greater than N.
  • consecutive physical sectors of the sector-formatted storage medium are filled with consecutive logical sectors of data of the computer system, such that each consecutive N physical sectors holds P consecutive logical sectors stored sequentially within the N physical sectors, with a remaining portion at the end of each consecutive N physical sectors being unfilled and the beginning of every Pth logical sector being aligned with the beginning of every respective Nth physical sector.
  • this manner of laying out logical sectors within the physical sectors of the storage medium eliminates the need to perform a read-modify-write process on certain write operations, thus improving the write performance of the computer system.
  • additional performance enhancements can be achieved, in combination with this method, by (i) aligning file rows within the computer system on logical sector boundaries defined by every Pth logical sector, (ii) aligning directory structures within the computer system on logical sector boundaries that are multiples of P logical sectors, and accessing the directory structures in multiples of P logical sectors beginning on those boundaries, (iii) setting a file size attribute, which controls the amount of data physically written to the storage medium at a time, to be a multiple of P logical sectors, and/or (iv) altering certain application programs so that they issue write requests in multiples of P logical sectors.
  • the remaining portion at the end of each N physical sectors is unfilled by, for example, padding it with all zeroes, all ones, or some predetermined pattern
  • the remaining portion can be used to hold an error checking code, an error correcting code, an indication of a status of the N physical sectors of which it is a part, or other information concerning the N physical sectors of which it is a part.
  • Figure 1 shows a prior art method in which logical sectors of data are stored in physical sectors of a storage medium
  • Figure 2 illustrates a read-modify-write process that must be performed during write operations in accordance with the prior art method shown in Figure 1 ;
  • FIG. 3 is a block diagram of an exemplary computer system in which the present invention may be implemented
  • Figure 4 illustrates a preferred embodiment of the method of the present invention, as implemented in a computer system in which data is arranged in logical sectors of 180 bytes and which is attached to a storage medium having physical sectors of 512 bytes;
  • Figure 5 illustrates a write operation in accordance with the embodiment illustrated in Figure 4.
  • Figure 6 illustrates a read operation in accordance with the embodiment illustrated in Figure 4;
  • Figure 7 illustrates further aspects of the method of the present invention;
  • Figure 8 illustrates still further aspects of the method of the present invention.
  • FIG. 9 illustrates an alternate embodiment of the method of the present invention.
  • the present invention is directed to an improved method for enabling a computer system having a predetermined logical sector format to read from and write to a sector- formatted storage medium that has a different, larger physical sector format than the logical sector format of the computer system.
  • the present invention may be embodied in the form of hardware, software, or a combination of both hardware and software.
  • the invention may take the form of program code (i.e., instructions) embodied in tangible media, such as floppy diskettes, CD-ROMs, hard drives, or any other machine-readable storage medium, wherein, when the program code is loaded into and executed by a machine, such as a computer, the machine becomes an apparatus for practicing the invention.
  • the methods and apparatus of the present invention may also be embodied in the form of program code that is transmitted over some transmission medium, such as over electrical wiring or cabling, through fiber optics, or via any other form of transmission, wherein, when the program code is received and loaded into and executed by a machine, such as a computer, the machine becomes an apparatus for practicing the invention.
  • program code When implemented on a general-purpose processor, the program code combines with the processor to provide a unique apparatus that operates analogously to specific logic circuits.
  • Figure 3 shows an exemplary computer system in which the present invention may be implemented.
  • the computer system 30 has an operating system 32 on which one or more application programs 34 may be running.
  • the computer system 30 also has an I/O processing subsystem 36, which may comprise hardware and/or software, for performing I/O processing.
  • a storage medium 40 such as a magnetic disk medium, is attached to the I/O processing subsystem 36 via an interface 38, such as SCSI, Fibre Channel, or the like.
  • Application programs 34 and/or the operating system 32 make use of logical sector buffers 42 to prepare data for transfer to the storage medium via the I/O processing subsystem 36 and interface 38.
  • logical sector means a unit of data of which the computer system is capable of transferring to a sector-formatted storage medium, or other sector-formatted input/output medium, in which data is arranged in physical sectors on the medium.
  • the size of a logical sector is the same as the size of a corresponding physical sector on the medium.
  • a logical sector has a size of 180 bytes, and storage media specifically designed for such computer systems have corresponding physical sectors of the same size.
  • the present invention provides an improved method of achieving this capability.
  • the present invention can be implemented as part of the operating system 32 and/or I/O processing subsystem 36.
  • the present invention provides an improved method for enabling a computer system in which data is arranged internally in logical sectors to read and write data to a sector-formatted storage medium arranged in physical sectors, wherein the size of a logical sector is less than the size of a physical sector such that a plurality P of logical sectors of the computer system will fit consecutively within a number N of physical sectors of the sector- formatted memory, P being greater than N.
  • consecutive physical sectors of the sector- formatted storage medium are filled with consecutive logical sectors of data of the computer system, such that each consecutive N physical sectors holds P consecutive logical sectors stored sequentially within the N physical sectors, with a remaining portion at the end of each consecutive N physical sectors being unfilled and the beginning of every Pth logical sector being aligned with the beginning of every respective Nth physical sector.
  • this manner of laying out logical sectors within the physical sectors of the storage medium eliminates the need to perform a read-modify-write process on certain write operations, thus improving the write performance of the computer system.
  • additional performance enhancements can be achieved, in combination with this method, by (i) aligning file rows within the computer system on logical sector boundaries defined by every Pth logical sector, (ii) aligning directory structures within the computer system on logical sector boundaries that are multiples of P logical sectors and accessing the directory structures in multiples of P logical sectors beginning on those boundaries, (iii) setting a file size attribute, which controls the amount of data physically written to the storage medium at a time, to be a multiple of P logical sectors, and/or (iv) altering certain application programs so that they issue write requests in multiples of P logical sectors.
  • Figure 4 illustrates a preferred embodiment of the method of the present invention, as implemented in a computer system in which data is arranged in logical sectors of 180 bytes and which is attached to a storage medium having physical sectors of 512 bytes.
  • a computer system might, for example, be a Unisys A Series or Clearpath HMP NX computer system running the Unisys MCP operating system (i.e., an MCP server).
  • consecutive physical sectors of the sector-formatted storage medium are filled with consecutive logical sectors of data of the computer system, such that each consecutive physical sector holds two (2) consecutive logical sectors stored sequentially within the physical sector, with a remaining 152 byte portion at the end of each physical sector being unfilled - the I/O processing subsystem preferably "pads" out these bytes during a write operation.
  • the beginning of every even-numbered logical sector i.e., every 2 nd logical sector
  • P equals 2 nd logical sector
  • Figure 5 illustrates a write operation in accordance with the embodiment illustrated in Figure 4, as implemented in an MCP server 50.
  • MCP server 50 will make a write request addressed to logical sector 0, with a specified length of four logical sectors.
  • the logical sector request is mapped to the corresponding physical sectors of the disk - in this example, physical sectors 0 and 1.
  • the write request will begin at the beginning of physical sector 0, as shown. Because of this, there is no need to preserve any leading data prior to writing the user data.
  • the present method provides a significant improvement in performance over the prior art method.
  • the beginning and end of a write request is aligned with the useable data within the physical sectors, no read-modify-write process has to be performed.
  • the data can simply be written to disk.
  • the write operation is performed as follows. First, at step 56, the user data in logical sectors 0 and 1 is aligned with the beginning of physical sector 0, and then written to that sector, overwriting what previously resided there on the disk.
  • the I/O processing subsystem (not shown) then automatically pads the end of physical sector 0 as the data is being transferred to the disk (step 58), as illustrated by the striped area following logical sector 1. In this embodiment, the pad is 152 bytes in length.
  • the user write data for logical sectors 2 and 3 is aligned at the start of the next physical sector, physical sector 1, overwriting what previously resided there on the disk (step 60).
  • the I/O processing subsystem again automatically pads the end of physical sector 1 (step 62). A successful completion status is then presented to the MCP server. This method is completely transparent to the operating system and any application programs running on it.
  • Figure 6 illustrates a read operation in accordance with the present embodiment.
  • the MCP server 50 makes a read request addressed to logical sector 0 that is four sectors in length.
  • the I/O subsystem will recognize the request as being directed to the 512 byte sector disk 54, and will map the logical sector request into the physical sectors of the disk 54 - in this case, physical sectors 0 and 1.
  • a disk read operation will then be performed, beginning at physical sector 0, for 2 physical sectors.
  • logical sector 0 will be aligned into the beginning of the applications buffer 52, followed by logical sector 1. When the "pad" area at the end of physical sector 0 is read, this data is discarded, or stripped out (step 66).
  • Logical sectors 2 and 3 are then read out of physical sector 1 and assembled into the application's buffer 52 behind logical sectors 0 and 1 (step 68). Again, the pad area at the end of physical sector 1 is discarded (step 70). A successful completion status is then presented to the MCP server 50, completing the read operation. As with the write operation, the handling of the pad areas and the assembly of the logical sectors into the application's buffer 52 are transparent to the application program and operating system.
  • file rows within the computer system are aligned on logical sector boundaries defined by every Pth logical sector. Additionally, file row size is preferably set to a multiple of P logical sectors. A file row is the quantity by which disk space is assigned to files.
  • a file row size can be defined by the user in several ways, e.g., blocks per row or records per row, but is converted by the operating system into logical sectors per row.
  • file rows would be aligned on even numbered logical sector boundaries (i.e., every 2 nd logical sector), and would have a size that is a multiple of 2 logical sectors.
  • a file size attribute in the operating system environment which controls the amount of data physically written to the storage medium at a time, can be set to a multiple of P logical sectors (e.g., 2 logical sectors in the present embodiment).
  • P logical sectors e.g. 2 logical sectors in the present embodiment.
  • BLOCKSIZE a user specified logical file attribute
  • a disk file in the MCP environment consists of records, and groups of records form blocks. BLOCKSIZE controls the size of these blocks.
  • a write operation is only initiated when enough logical records have been written by the application program to fill up a block. For example, suppose a disk file contained 180 byte records, with 10 records per block. The first nine sequential writes to the file would only result in the data being put into system I/O buffers in main memory; a request to write the 10 th record would cause the operating system to physically write the entire block to disk.
  • size attribute e.g., BLOCKSIZE
  • file rows have been allocated by the operating system on even numbered logical sector boundaries, i.e., every Pth logical sector. Two rows of a file are shown, "ROW 1" and "ROW 2".
  • the block size optimization technique is also illustrated.
  • the block size attribute which controls the amount of data physically written to disk at a time (i.e., one block), has been set equal to two (2) logical sectors - a multiple of P.
  • any other multiple of P logical sectors could equally have been used.
  • the block size attribute is set to a multiple of P logical sectors, as shown here, all blocks begin and end on Pth logical sector boundaries.
  • all of the blocks are 2 logical sectors in size, numbered "BLOCK 1" through “BLOCK 6", and they each begin on respective even numbered logical sector boundaries (i.e., every 2 nd logical sector).
  • items of data within the directory are created by the operating system in even numbers of logical sectors, i.e., multiples of P logical sectors, resulting in all items beginning and ending on even numbered logical sector boundaries.
  • An "item” within a directory row can be a disk file header (describing the location and attributes of a user or system file) or a system maintained data structure. They are generically referred to as "data” in the Figure.
  • "DATA 1" represents a disk directory data item which is 4 logical sectors in size
  • DATA 2 represents a second item that is 2 logical sectors in size.
  • "DATA 1 " and "DATA 2" are contained within "ROW 1 " of the directory.
  • DATA 3 a third item that is 6 logical sectors in size, is contained within "ROW 2" of the directory. Additional performance improvements can be achieved by altering certain application programs so that they issue write requests in multiples of P logical sectors. For example, application programs written for the MCP operating system can make use of a DIRECT I O feature of the MCP operating system. DIRECT I/O gives the application program explicit control over buffer allocation and over buffer mapping on I/O operations to a file's logical sector oriented address space. These applications can be made to perform better in accordance with the present invention by configuring them to issue DIRECT I/O write requests that are multiple of P logical sectors and begin at file relative logical sector addresses that are multiples of P.
  • Figure 9 illustrates an alternate embodiment of the method of the present invention, again as implemented in a computer system in which data is arranged in logical sectors of 180 bytes and which is attached to a storage medium having physical sectors of 512 bytes.
  • consecutive physical sectors of the sector-formatted storage medium are filled with consecutive logical sectors of data of the computer system, such that every two (2) consecutive physical sectors holds five (5) consecutive logical sectors stored sequentially within the two physical sectors, with a remaining 124 byte portion at the end of every pair of physical sectors being unfilled - the I/O processing subsystem preferably "pads" out these bytes during a write operation.
  • the beginning of every 5th logical sector is aligned with the beginning of every respective 2 nd physical sector.
  • P equals 5
  • N 2 nd physical sector 2.
  • performance in the embodiment illustrated in Figure 9 can be enhanced by (i) aligning file rows within the computer system on logical sector boundaries defined by every 5th logical sector, (ii) aligning directory structures within the computer system on logical sector boundaries that are multiples of five (5) logical sectors and accessing the directory structures in multiples of five logical sectors beginning on those boundaries, (iii) setting a file size attribute, which controls the amount of data physically written to the storage medium at a time, to be a multiple of five (5) logical sectors, and/or (iv) altering certain application programs so that they issue write requests in multiples of five (5) logical sectors.
  • the unfilled remaining portion at the end of every N physical sectors is simply padded out during data transfer to the physical sectors, with, for example, all zeroes, all ones, or some predetermined pattern
  • the remaining portion can alternatively be used to include meaningful information.
  • the remaining portion could be used to provide some form of status indication about the N physical sectors to which it belongs, such as, for example, "unused" or "in use.”
  • the remaining portion could be used to hold an error check on the P logical sectors within the N physical sectors, such as a 32 bit checksum, a 64 bit checksum, a cyclic redundancy check (CRC), or an error correcting code (ECC).
  • an error check on the P logical sectors within the N physical sectors such as a 32 bit checksum, a 64 bit checksum, a cyclic redundancy check (CRC), or an error correcting code (ECC).
  • CRC cyclic redundancy check
  • ECC error correcting code
  • this would allow detection (on subsequent read) of the case where N is greater than 1 and a write of N physical sectors is interrupted (by power failure or hardware failure) after one or more physical sectors were written but before all N physical sectors were written.
  • the remaining portion could also include information such as a sector number on a particular physical pack. This would allow the computer system to check for data that has been written to the wrong place due to outboard hardware errors.
  • this mechanism takes the form of a system console command that allows a system operator to designate a 512 byte sector disk to be accessed using the method of the present invention.
  • the code that implements support for this command is part of the MCP operating system, although in other embodiments, it could comprise a separate utility.
  • INITIALIZE When the system console command, called INITIALIZE, is executed, data is placed within various specific locations in logical sectors 0 through 27 (the first 28 logical sectors) of the 512 byte sector disk. This corresponds to physical sectors 0 through 13. There are two locations that uniquely identify a disk as being accessible via the method of the present invention.
  • a "NOL2" field contains a specific 4 byte pattern that causes the MCP to inform the I/O processor and channel to manage the physical sectors by packing 2 logical sectors within a physical sector.
  • a "NOLI" field contains a specific 4 byte pattern that causes the MCP to allocate the directory and file rows of that disk so that write access is optimized in the manner described above.
  • the present invention is directed to an improved method for enabling a computer system in which data is arranged internally in logical sectors to read and write data to a sector-formatted storage medium arranged in physical sectors, wherein the size of a logical sector is less than the size of a physical sector such that a plurality P of logical sectors of the computer system will fit consecutively within a number ⁇ of physical sectors of the sector-formatted memory, P being greater than ⁇ .

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  • Engineering & Computer Science (AREA)
  • Theoretical Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Human Computer Interaction (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Signal Processing (AREA)
  • Signal Processing For Digital Recording And Reproducing (AREA)
  • Information Retrieval, Db Structures And Fs Structures Therefor (AREA)

Abstract

L'invention concerne un procédé permettant à un système informatique dans lequel les données sont disposées de manière interne dans des secteurs logiques, de lire et écrire des données, dans un support de mémorisation formaté par secteur, disposé dans des secteurs physiques, la taille d'un secteur logique étant inférieure à celle d'un secteur physique. Ledit procédé consiste à remplir des secteurs physiques consécutifs du support de mémorisation formaté par secteur, de secteurs logiques consécutifs de données du système informatique, de sorte que chaque N secteur physique conserve P secteurs logiques consécutifs mémorisés séquentiellement dans les N secteurs physiques, une partie restante à l'extrémité de chaque N secteur physique n'étant pas remplie et le début de chaque Pième secteur logique étant aligné avec le début de chaque Nième secteur physique, P étant supérieur à N.
EP99938938A 1998-08-31 1999-08-02 Procede ameliore permettant l'operation de formatage de secteur variable dans un systeme informatique Withdrawn EP1110219A1 (fr)

Applications Claiming Priority (3)

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US144300 1988-01-14
US14430098A 1998-08-31 1998-08-31
PCT/US1999/017464 WO2000013180A1 (fr) 1998-08-31 1999-08-02 Procede ameliore permettant l'operation de formatage de secteur variable dans un systeme informatique

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EP1110219A1 true EP1110219A1 (fr) 2001-06-27

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