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`
`US005634111A
`[11] Patent Number:
`[45] Date of Patent:
`
`5,634,111
`May 27, 1997
`
`United States Patent
`Oeda et al.
`
`[19]
`
`[54] COMPUTER SYSTEM INCLUDING A
`DEVICE WITH A PLURALITY OF
`IDENTIFIERS
`
`[75]
`
`Inventors: Takashi Oeda; Kiyoshi Honda, both of
`Yokohama; Naoto Matsunami,
`Fujisawa; Minoru Yoshida, Odawara,
`all of Japan
`
`[73] Assignee: Hitachi, Ltd., Tokyo, Japan
`
`[30]
`
`[21] Appl. No.: 31,880
`Mar. 16, 1993
`[22] Filed:
`Foreign Application Priority Data
`Mar. 16, 1992
`[JP]
`Japan .................................... 4-058102
`Int. Cl.6
`...................................................... G06F 12/06
`[51]
`[52] U.S. Cl . ....................................... 395/480; 395/497.04
`[58] Field of Search ..................................... 395/325, 650,
`395/405, 480, 497.04; 364/246.3
`
`[56]
`
`References Cited
`
`U.S. PATENT DOCUMENTS
`
`3,988,719
`4,855,905
`4,922,410
`4,924,210
`4,945,512
`4,958,341
`5,097,414
`5,206,937
`5,303,359
`5,321,816
`5,355,453
`5,379,184
`5,410,680
`
`10/1976 Whitby et al ........................ 340/172.5
`8/1989 Estrada et al ..
`5/1990 Morikawa et al ..
`5/1990 Matsui et al ............................ 340/572
`7/1990 Dakarske et al .......................... 365/49
`9/1990 Hemmady et al ..................... 370/60.1
`3/1992 Tone ........................................ 395/425
`4/1993 Goto ........................................ 395/325
`4/1994 Suzuki .................................... 395/100
`6/1994 Rogan et al. . .......................... 395/200
`10/1994 Row et al ............................... 395/200
`1/1995 Barraza et al. . ........................ 361/685
`4/1995 Challa et al. ........................... 395/500
`
`OTHER PUBLICATIONS
`
`PCs & Workstations, Jul. 1, 1991 Computer World, "Ex.ter(cid:173)
`nal SCSI drives Announced" p. 38.
`Computer World Apr. 10, 1989 p. 42, "PCs & Workstations
`New Products".
`
`Computer World Feb. 6, 1989 p. 51, Microcomputing "New
`Products".
`
`"An AFS™-Based Mass Storage System At The Pittsburgh
`Supercomputing Center" Danial Nydick et al, 1991, pp.
`117-122.
`
`"Filtering of Network Addresses in Real Time by Seqential
`Decoding" Wolstenholme, 1988, pp. 55-59.
`
`ANSI X3.131-1986, 1986 pp. 14-17, 25-41.
`
`Microsoft MS-DOS Operating System Version 5.0, User's
`Guide & Reference, 1991 pp. 147-159.
`
`Primary Examiner-Jack B. Harvey
`Assistant Examiner-Paul R. Myers
`Attorney, Agent, or Firm-Antonelli, Terry, Stout & Kraus,
`LLP
`
`[57]
`
`ABSTRACT
`
`A host computer is connected with a magnetic disk storage
`device by an SCSI bus. In the magnetic disk storage device,
`a plurality of partitions are set in a disk drive unit and have
`device identifiers (ID's) respectively allocated thereto as
`SCSI ID's=l. 2 and ,3, which are supported by a disk
`controller. When the host computer has acquired the control
`of the SCSI bus through arbitration and has selected, for
`example, the partition with the device identifier SCSI ID=l,
`the disk controller permits the host computer to access the
`partition in response to the selection. Since the partitions are
`different in attributes, properties etc., they appear as mag(cid:173)
`netic disk storage devices that are separate from one another
`when viewed from the host computer. Thus, the single
`magnetic disk storage device can be managed as a plurality
`of storage devices of different nature.
`
`8 Claims, 6 Drawing Sheets
`
`1A
`
`1B
`
`HOST
`SCSIID=6
`
`SCSIID=1-3
`
`2
`
`a:
`w
`_,J
`...J
`§
`, FOR HOST 1 A
`,
`z >-----1 ----------------- ____ _,,
`8
`, FOR HOST t B
`,,
`115
`---SHARED R-EA[;--
`ci
`NLY
`~ -~ , : ; : -
`
`5
`
`4
`
`41 SCSIID=t
`
`42 SCSIID=2
`
`43 SCSIID=3
`
`Petitioners Microsoft Corporation and HP Inc. - Ex. 1027, p. 1
`
`

`

`U.S. Patent
`
`May 27, 1997
`
`Sheet 1 of 6
`
`5,634,111
`
`FIG.1
`
`1
`
`HOST COMPUTER SCSIID=7
`
`2
`
`SCSIID=1-3
`ffi 41
`_J
`_J 0 ....___...
`a:
`~J(cid:173)
`(f)z _Q
`00
`
`SCSIID=1
`' SCSIID=2
`:~ ',, _______ ,, SCSIID=3
`
`~3_J
`
`FIG.2
`
`CPU
`
`2
`
`101
`
`6
`
`CPU
`
`102
`8
`
`11
`
`12
`
`SCSI CONTROL
`.,.,,71
`LSI
`ID REGISTER #1
`ID REGISTER #2
`c:::.73 l ""72
`11D REGISTER #nl
`
`DISK
`CONTROL
`LSI
`
`PLL/ READ/WRITE
`ENDEC SIGNAL
`PROCESSING
`
`13
`
`BUFFER MEMORY 9
`"---_5_____-/"-----4____./
`
`"----------- ______ ____..,
`
`3
`
`Petitioners Microsoft Corporation and HP Inc. - Ex. 1027, p. 2
`
`

`

`U.S. Patent
`
`May 27, 1997
`
`Sheet 2 of 6
`
`5,634,111
`
`FIG.3
`
`15
`
`171
`,_,
`
`-
`
`.,,;;
`
`.,.
`I_
`f
`
`172
`,-~
`
`..,,
`
`~
`I
`I
`
`173
`,_,
`
`J
`
`~
`
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`0
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`w
`::E
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`w
`u.
`u.
`:::,
`al
`
`I
`I I
`I I
`I I
`I I
`
`C")
`
`I
`0
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`en
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`
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`z
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`0
`
`SCSIID=O
`
`I I •• , ,
`SCSIID=1 SCSIID=2:: SCSIID=3
`--------------' --------------' -------------..!
`~ 17 - -~
`- - - - - 14 - - - - - -
`
`Petitioners Microsoft Corporation and HP Inc. - Ex. 1027, p. 3
`
`

`

`U.S. Patent
`
`May 27, 1997
`
`Sheet 3 of 6
`
`5,634,111
`
`FIG.4
`
`1A
`
`1B
`
`SCSIID=7
`
`SCSII0=6
`
`SCSIID=1-3
`
`2
`
`a:
`w
`...J
`...J
`0 a: ._
`z
`0
`(.)
`
`~
`(/)
`Cl
`
`..
`FOR HOST 1A
`~
`,,
`- - - .... ____________________
`'
`, FOR HOST 18
`,,
`........ ,
`.. ,
`--------. __________
`SHARED READ
`ONLY
`
`41 SCSIID=1
`42 SCSIID=2
`
`43
`
`SCSIID=3
`
`5
`
`' - - - - - - 3 ____ _____.,;
`
`Petitioners Microsoft Corporation and HP Inc. - Ex. 1027, p. 4
`
`

`

`U.S. Patent
`
`May 27, 1997
`
`Sheet 4 of 6
`
`5,634,111
`
`FIG.5
`
`1A
`
`SCSIID=7
`
`18
`
`...-'---
`
`SCSIID=1-4,6
`HOST SCSIID=6
`
`21
`
`5
`
`-1
`-1
`
`ffi
`0 a:
`1-z
`0
`()
`
`~
`(/J
`Cl
`
`',, FOR HOST 1 A . ./
`,,____________________
`, FOR HOST 18
`.......
`--------------------
`SHARED READ
`ONLY
`
`,,,
`_,,"
`
`41 SCSIID=1
`42 SCSIID=2
`
`43
`
`SCSIID=3
`
`22
`
`18
`
`Petitioners Microsoft Corporation and HP Inc. - Ex. 1027, p. 5
`
`

`

`U.S. Patent
`
`May 27, 1997
`
`Sheet 5 of 6
`
`5,634,111
`
`Q
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`
`Petitioners Microsoft Corporation and HP Inc. - Ex. 1027, p. 6
`
`

`

`U.S. Patent
`
`May 27, 1997
`
`Sheet 6 of 6
`
`5,634,111
`
`,-
`
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`
`Petitioners Microsoft Corporation and HP Inc. - Ex. 1027, p. 7
`
`

`

`5,634,111
`
`1
`COMPUTER SYSTEM INCLUDING A
`DEVICE WITH A PLURALITY OF
`IDENTIFIERS
`BACKGROUND OF THE INVENTION
`1. Field of the Invention
`The present invention relates to a computer system and
`external storage therefor. In particular, the computer system
`is such that devices or nodes have peculiar device ID's
`(identifiers) and are connected with one another through an
`interface or network, such as SCSI, IPI (Intelligent Periph(cid:173)
`eral Interface) or Ethernet, for exchanging data, commands,
`messages etc.
`2. Related Art
`As stipulated in, for example, ANSI X3. 131-1986,
`"Small Computer System Interface (SCSI)" issued by ANSI
`(American National Standards Institute), the peripheral
`devices of a prior-art computer system have peculiar device
`ID's, respectively. The LBA (Logical Block Address)
`lengths of the devices, the types of the devices (such as a
`random access device, a sequential access device, a rewrit(cid:173)
`able device, and a read only device), etc. are fixed for the
`respective devices by standards. In addition, although not
`standardized, management for the data reliabilities of the
`individual peripheral devices, management for backing up
`the devices, etc. are carried out for the respective devices at
`the request of the OS ( operating system) of a host computer.
`The prior-art technique is incapable of or has difficulty
`coping with a case, for example, where a magnetic disk
`storage device of large capacity is divided into a plurality of
`partitions with the intention of managing the partitions as
`separate storage areas of different nature (in points of the
`LBA lengths, the backup management, etc.). Accordingly,
`expensive and large-sized magnetic disk storage devices
`need to be installed for respective sorts of data of different
`properties, such as ordinary file data and image data.
`Further, no consideration has been given to sharing the
`peripheral devices between a plurality of hosts. The exclu(cid:173)
`sive control between the hosts in the case of a shared
`magnetic disk storage device cannot be performed on the
`device side, and is inevitably entrusted to the management
`of the host side. For this reason, it is possible that some
`operations of the user of the computer system may bring
`about a situation where data held in the magnetic disk
`storage device are destroyed.
`Further, in case of a network including therein a node 45
`which is physically connected in the same network, but
`which uses a communication protocol differing from that of
`the other nodes, it is difficult for such a single node to use
`two communication protocols properly and so the particular
`node has difficulty communicating with the other nodes.
`Therefore, expensive and large-sized magnetic disk storage
`devices must be installed for the respective different com(cid:173)
`munication protocols.
`SUMMARY OF THE INVENTION
`The first object of the present invention is to solve the
`problems as stated above, and to provide a computer system
`which is permitted to handle data of different properties by
`the use of an identical peripheral device, and also an external
`storage device which serves as the peripheral device.
`The second object of the present invention is to provide a
`computer system which is permitted to share a peripheral
`device among a plurality of computers.
`The third object of the present invention is to provide a
`computer system which is permitted to share a peripheral 65
`device between computers of different communication pro(cid:173)
`tocols.
`
`2
`In order to accomplish the first object, the computer
`system according to the present invention is so constructed
`that peculiar device !D's (identifiers) are respectively allo(cid:173)
`cated to a computer and the peripheral device, and that a
`5 plurality of device ID's are allocated to the peripheral
`device.
`Also, in order to accomplish the first object, the external
`storage device according to the present invention is so
`constructed that a plurality of partitions are set therein, and
`10 that device !D's are allocated to the respective partitions.
`-
`In order to accomplish the second object, the computer
`system according to the present invention is so constructed
`that peculiar device ID's are respectively allocated to the
`plurality of computers and peripheral devices, and that a
`15 plurality of device ID's are allocated to the specified periph(cid:173)
`eral device.
`In order to accomplish the third object, the computer
`system according to the present invention is so constructed
`that device ID's are allocated to the respective computers,
`20 and that device ID's differing for the respective communi(cid:173)
`cation protocols are allocated to the peripheral device.
`In accordance with the first-mentioned construction of the
`present invention, when the computer has selected the
`peripheral device by designating any of the plurality of
`25 device ID's allocated to the peripheral device, this peripheral
`device responds to the computer, and the computer can
`access the peripheral device in regard to the designated
`device ID. Accordingly, the peripheral device seems to the
`computer to be a number of devices, in fact, as many as the
`30 number of allocated device ID's, and the computer can
`handle the data of the different properties by the use of the
`peripheral device.
`With the second-mentioned construction, the device !D's
`are respectively allocated to the partitions of the external
`35 storage device. Therefore, when the computer has selected
`the external storage device by designating one of the device
`ID's, it can access the partition having the designated device
`ID. Accordingly, the partitions form separate devices when
`viewed from the computer, and the data with properties
`40 differing for the respective partitions can be written into and
`read out of these partitions.
`With the third-mentioned construction, when the separate
`computers have selected the specified peripheral device by
`designating the pertinent ones of the plurality of allocated
`device ID's, they can access the peripheral device in regard
`to the designated device ID' s. In this case, when the plurality
`of device ID's allocated to the single peripheral device are
`individually held in correspondence with the separate
`computers, the peripheral device becomes capable of per-
`50 forming the exclusive control between the computers.
`Moreover, when at least two computers are allowed to
`designate a predetermined one of the device ID's, they can
`share the peripheral device by using this predetermined
`device ID.
`55 With the fourth-mentioned construction, the device ID's
`for the respective communication protocols are allocated to
`the peripheral device. Therefore, no matter which commu(cid:173)
`nication protocol the computer having selected the periph(cid:173)
`eral device may have, the computer can access the peripheral
`60 device in regard to the device ID designated by this com(cid:173)
`puter. Accordingly, the plurality of computers having dif(cid:173)
`ferent communication protocols can share such a peripheral
`device.
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`FIG. 1 is a block diagram showing an embodiment of a
`computer system according to the present invention;
`
`Petitioners Microsoft Corporation and HP Inc. - Ex. 1027, p. 8
`
`

`

`5,634,111
`
`3
`FIG. 2 is a block diagram showing a practical example of
`a magnetic disk storage device depicted in FIG. 1;
`FIG. 3 is a block diagram showing another embodiment
`of the computer system according to the present invention;
`FIG. 4 is a block diagram showing still another embodi(cid:173)
`ment of the computer system according to the present
`invention;
`FIG. 5 is a block diagram showing yet another embodi(cid:173)
`ment of the computer system according to the present
`invention;
`FIG. 6 is a block diagram showing a further embodiment
`of the computer system according to the present invention;
`and
`FIG. 7 is a block diagram showing the arrangement of the 15
`principal portions of a SCSI control LSI (large-scale inte(cid:173)
`grated circuit) depicted in FIG. 2.
`
`10
`
`25
`
`4
`arbitration and executes the selection. However, the present
`embodiment differs from the prior art in that the opposite
`device, here, the magnetic disk storage device 3 has a
`plurality of device ID' s. More specifically, as shown in FIG.
`5 1, in the magnetic disk storage device 3, the disk drive unit
`4 is divided into partitions, for example, the three partitions
`41, 42 and 43, for which the different device ID's (here,
`SCSI ID's=l, 2 and 3) are respectively set. Thus, when
`viewed from the host computer 1, the magnetic disk storage
`device 3 seems to be three separate magnetic disk storage
`devices connected to the SCSI bus 2. Since three or more
`devices do not use one bus simultaneously in accordance
`with the SCSI standards, one device can have a plurality of
`device ID's allocated thereto and be made to look like a
`plurality of devices.
`FIG. 2 is a block diagram showing a practical example of
`the magnetic disk storage device 3 depicted in FIG. 1. This
`magnetic disk storage device 3 includes a SCSI control LSI
`(large-scale integrated circuit) 6 which is configured of ID
`20 registers 71, 72, ... and 73. It also includes a disk control
`LSI 8, a buffer memory 9, CPU's 101 and 102, a PLU
`ENDEC (phase-locked loop circuit/encode-decode circuit)
`11, a read/write signal processing circuit 12, and a magnetic
`recording/reproducing head 13.
`In the illustrated example, the disk controller 5 is config-
`ured of the SCSI control LSI 6, the disk control LSI 8, the
`CPU's 101 and 102 which control the respective LSI' s 6 and
`8 by the use of microprograms, and the buffer memory 9
`which is a data transferring buffer. In this regard, an SCSI
`30 control LSI included in a disk controller in the prior art is
`provided with only one register for storing one device ID of
`its own therein. In the selection phase, the SCSI control LSI
`in the prior art performs a control in which a device ID
`requested by the host computer is compared with the device
`35 ID of its own stored in the register. When the device ID' s are
`coincident, the SCSI control LSI responds to the request of
`the host computer and prepares for subsequently accepting
`a command from the host computer, and when not, it does
`not respond.
`In contrast, the SCSI control LSI 6 shown in FIG. 2 is
`provided with the plurality of ID registers 71, 72 and 73 in
`which the device ID's (here, SCSI ID's=l, 2 and 3) set for
`the partitions of the disk drive unit 4 are respectively stored.
`In the selection phase executed by the host computer 1, the
`45 SCSI control LSI 6 compares a device ID requested by the
`host computer 1, with the device ID' s stored in any of the ID
`registers 71-73. When the requested device ID coincides
`with any of the stored device ID's, the SCSI control LSI 6
`acknowledges the coincidence and responds to the request of
`50 the host computer 1. On this occasion, the SCSI control LSI
`6 notifies the device ID requested by the host computer 1, to
`the CPU 101 controlling this LSI 6, and it prepares for
`interpreting a command to be subsequently sent from the
`host computer 1, in accordance with the called device ID.
`55 Likewise, the SCSI control LSI 6 notifies the device ID
`requested by the host computer 1, to the disk control LSI 8
`and the CPU 102 controlling this LSI 8. The notification is
`necessitated for instructing the disk drive 4 to execute an
`appropriate process or for appropriately controlling the
`60 buffer memory 9 after having interpreted the command such
`as the conversion of an LBA (logical block address) into a
`PBA (physical block address).
`Actually, the SCSI control LSI 6 need not be provided
`with the plurality of ID registers. When the number of device
`65 ID's in the whole system is limited to eight as in the SCSI
`standards, the SCSI control LSI 6 may well be provided with
`one ID register of 8 bits, the stages of which are respectively
`
`PREFERRED EMBODIMENTS OF THE
`INVENTION
`
`Now, embodiments of the present invention will be
`described with reference to the drawings.
`FIG. 1 is a block diagram illustrative of one embodiment
`of a computer system according to the present invention.
`The computer system of this embodiment comprises a host
`computer 1, a SCSI bus 2, and a magnetic disk storage
`device 3. The magnetic disk storage device 3 includes a disk
`drive uuit 4 divided into partitions 41, 42 and 43, and a hard
`disk controller 5.
`As illustrated in the figure, in this embodiment the host
`computer 1 and the magnetic disk storage device 3, which
`serves as external storage for the computer 1, are connected
`by the bus 2 conforming to the SCSI which has recently
`become the standard for peripheral equipment interfaces for
`small computer systems. The magnetic disk storage device
`3 is configured of the hard disk controller 5 and the disk
`drive unit 4.
`Here, the prior art will be explained for the sake of
`comparison. In a prior-art computer system having such an 40
`architecture, the host computer 1 and the magnetic disk
`storage 3 have respective device !D's (identifiers) such as
`SCSI ID=l for the former and SCSI ID=2 for the latter. The
`host computer 1 issues comands and exchanges commands,
`messages and data with the magnetic disk storage device 3
`after an "arbitration phase" for acquiring the control of the
`bus 2 to be an initiator and a "selection phase" for selecting
`the magnetic disk storage device 3 which is the opposite
`party of the host computer 1. By way of example, when the
`host computer 1 is to read data out of the magnetic disk
`storage device 3, the arbitration phase is first executed so
`that the host computer 1 may acquire the bus control of the
`SCSI bus 2 and occupy this bus 2. Subsequently, the
`selection phase is executed so that the magnetic disk storage
`device 3 may be designated as the target device. On this
`occasion, the magnetic disk storage device 3 knows that the
`host computer 1 is about to select the storage device 3 itself,
`from the device ID sent by the host computer 1 (actually, a
`transmission line corresponding to the device ID is electri(cid:173)
`cally driven). Then, the magnetic disk storage device 3
`responds to the device ID, thereby informing the host
`computer 1 of the fact that the storage device 3 is ready to
`accept a command. The selection phase is completed by the
`response.
`The present embodiment is similar to the prior art in that
`the peculiar device ID (here, SCSI ID=7) is set for the host
`computer 1, and that the host computer 1 undergoes the
`
`Petitioners Microsoft Corporation and HP Inc. - Ex. 1027, p. 9
`
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`

`5,634,111
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`5
`held in correspondence with the separate device ID's so as
`to store one device ID with one bit.
`The protocol of the SCSI standards consists of the fol(cid:173)
`lowing seven phases:
`1) Arbitration Phase;
`An initiator (a term in the SCSI standards, signifying a
`device on a side on which a command is issued) acqukes the
`control of an SCSI bus. When a plurality of initiators have
`simultaneously intended to acquke the bus control, the
`priority sequence of the initiators is determined on the basis
`of the ID's thereof.
`2) Selection Phase;
`The initiator having acquked the bus mastership desig(cid:173)
`nates the ID of a target (a term in the SCSI standards,
`signifying a device on a side on which a command is
`executed). The designation is done by making "true" that
`data line among eight data lines which corresponds to the ID
`No. of the target. The target recognizes that it has been
`selected. Thenceforth, it undergoes a phase transition until a
`bus free status is restored at the end of the execution of the
`command.
`3) Command Phase;
`The initiator sends the command to the target.
`4) Data Phase;
`In the case of the command, such as read or write, which
`requkes the transfer of data, the target changes its phase
`from the command phase to the data phase, and it awaits the
`data transfer from the initiator for the write command or
`transfers the data to the initiator for the read command.
`5) Status Phase;
`The target reports the result of the command execution to
`the initiator.
`6) Message Phase;
`The target sends a message indicative of the completion
`of the command to the initiator.
`7) Bus Free Phase;
`After sending the message, the target restores the SCSI
`bus to the bus free status which is an unused status.
`FIG. 7 illustrates the arrangement of the principal portions
`of the SCSI control LSI 6 in this embodiment.
`This SCSI control LSI 6 includes comparators 74-76 in
`correspondence with the respective ID registers #1-#n (71, 45
`72 and 73). The comparators 74-76 compare the ID No.
`asserted in the selection phase, with the contents of the
`respective ID registers 71-73. When the ID No. has coin(cid:173)
`cided with any of the contents, the SCSI control LSI 6
`generates an ID coincidence signal at the corresponding 50
`comparator. Then, the LSI 6 informs the CPU 101 of the ID
`No. having coincided, in other words, the device ID
`requested by the host computer 1. The CPU 101 executes the
`subsequent processing of the command, using mode infor(cid:173)
`mation (parameters such as the logical block length of the 55
`device) set for every device ID. As a preferable example, the
`mode information is held in a nonvolatile memory, such as
`disk or ROM, during the turn-OFF of the power source of
`the computer system, whereas it is held in the working
`memory (not shown) of the CPU 101 during the operation of 60
`the computer system. By way of example, the working
`memory is provided in the CPU chip 101, in the disk control
`LSI 8, in the buffer memory 9, or in the SCSI control LSI 6.
`It is now assumed that the device identifier SCSI ID=l has
`been requested by the host computer 1. When a read 65
`command has been subsequently sent from the host com(cid:173)
`puter 1, the disk control LSI 8 and CPU 102 of the disk
`
`6
`controller 5 interprets the device ID (=l) of the device
`having responded in the selection phase, and an LBA
`designated in the command by the host computer 1. Next,
`the disk controller 5 converts the LBA into a PBA which
`5 expresses a physical position in the disk drive 4. Further,
`data are read out of the partition 41 of the disk drive 4 by the
`use of the buffer memory 9 and the EN/DEC PLL 11 as well
`as the read/write signal processing circuit 12. In this
`embodiment, the recording area of a magnetic disk (not
`10 shown) is divided into the partitions 41-43, and the data are
`read out in a subarea corresponding to the partition 41 by the
`magnetic recording/reproducing head 13. A write command
`is executed similarly. A PBA is obtained from the device ID
`of the device having responded in the selection phase, and
`15 an LBA designated in the command by the host computer 1.
`Data are written in the partition corresponding to the PBA.
`Here, in both the read and write operations, the single
`magnetic disk storage device 3 is endowed with different
`attributes ( concerning, for example, an LBA length, the
`20 management of the buffer memory, and a processing method
`on the occurrence of an error) for the respective partitions
`41, 42 and 43 which correspond to the device ID's (SCSI
`ID's=l, 2 and 3) set in this storage device 3. In the prior art,
`such an attribute is set for every device by a mode select
`25 command and cannot be changed for respective partitions.
`Since, as stated above, the different attributes are afforded to
`the respective partitions, the LBA lengths and the buffer
`memory management methods can be set so as to maximize
`effective transfer rates in accordance with the characteristics
`30 of data which are to be stored in the partitions. Besides, the
`buffer memory management methods and the error process(cid:173)
`ing methods can be set in accordance with the requked
`reliabilities of the data.
`In the SCSI standards, the above expedient can be sub-
`35 stituted by allocating different LUN' s (logical unit numbers)
`to the respective partitions 41--43.
`As thus far described, in this embodiment, the single
`magnetic disk storage device 3 seems to be three magnetic
`40 disk storage devices when viewed from the host computer 1.
`Thus, the partition 43 of the device identifier SCSI ID=3, for
`example, can be set as a partition for storing therein data
`created by the user of the computer system, only this
`partition being backed up at a fixed time every day, and the
`partition 41 of the device identifier SCSI ID=L for example,
`can be set as a partition for storing the OS ( operating system)
`of the computer system therein, whereby the logically sepa(cid:173)
`rate partitions are respectively managed with ease.
`Alternatively, the partition 41 and the partition 42 of the
`device identifier SCSI ID=2, for example, can be respec(cid:173)
`tively assigned as a file area for ordinary files and as a file
`area for a real time control, or the partitions 41 and 42, for
`example, can be respectively assigned as a file area for
`ordinary files and as a file area dedicated to motion pictures,
`whereby the block lengths, the architectures of file systems
`(such as directory management systems), data protection
`attributes. etc. are optimized for the respective partitions
`with ease.
`FIG. 3 is a block diagram illustrative of another embodi(cid:173)
`ment of the computer system according to the present
`invention. Numeral 14 indicates a disk array storage device,
`which includes a disk array controller 15, a buffer memory
`16, and a disk array 17 divided into partitions 171, 172 and
`173.
`This embodiment employs the disk array storage device
`14. In FIG. 3, the disk array storage device 14 supports four
`SCSI identifiers (SCSI ID's=0, 1, 2 and 3), which corre-
`
`Petitioners Microsoft Corporation and HP Inc. - Ex. 1027, p. 10
`
`

`

`5,634,111
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`10
`
`7
`spond respectively to the buffer memory 16, partition 171,
`partition 172 and partition 173. As in the foregoing embodi(cid:173)
`ment shown in FIG. 1, a host computer undergoes an
`arbitration and executes a selection. The disk array control(cid:173)
`ler 15 judges which of the four devices consisting of the 5
`buffer memory 16 and the three partitions 171, 172 and 173
`corresponds to a command or data sent via a SCSI bus 2
`from the host computer, on the basis of a device ID
`requested by the host computer. Subsequently, it performs
`processing for the corresponding device.
`Although the four devices with the different device ID's,
`namely, the buffer memory 16 and the partitions 171-173
`are collectively managed by the disk array controller 15,
`they are storage areas which have characteristics differing
`from one another. By way of example, the characteristics are
`as stated below. The buffer memory 16 is a semiconductor 15
`disk, the capacity of which is usually small, but which
`exhibits a very high response rate. Besides, the partition 171
`is "RAID(RedundantArrays of Inexpensive Disks)l" which
`is a disk array of mirror disk configuration. Since data are
`overwritten into the disk array 171, the reliability thereof is 20
`very high. In addition, the partition 172 is "RAID3" which
`is a disk array for high-speed data transfer. The disk array
`172 is suited to quick transfer of long data such as the data
`of a motion picture, or the data of a gigantic array such as
`which would be handled in a scientific or technological 25
`computation. Further, the partition 173 is "RAIDS" which is
`a disk array for heavy transactions. The disk array 173 is
`suitable for an application, such as database or network
`server, in which a data length to be handled is comparatively
`short, but the number ofl/O (input/output) processes per unit 30
`time is large. When viewed from the host computer, all four
`devices 16 and 171-173 seem to be independent of one
`another. As described in the preceding embodiment,
`therefore, the attributes of the individual devices 16 and
`171-173, concerning the block length, the buffer memory 35
`management, the error processing method, the backup
`method, etc. can be optimized and set with ease, and the disk
`array controller 15 can manage these attributes with ease. To
`this end, which of the devices 16 and 171-173 is to be
`accessed may be judged on the basis of the device ID
`designated in the selection phase by the host computer, so as
`to distribute a command process to the judged device. The
`attributes of the respective devices, such as the block
`lengths, may be held within the disk array controller 15 (for
`example, in the internal register of the disk control LSI 8 or
`the register of the CPU 102 as shown in FIG. 2) so as to be
`used in interpreting the command of the host computer.
`FIG. 4 is a block diagram illustrative of still another
`embodiment of the computer system according to the
`present invention. In FIG. 4, symbols IA and lB denote host 50
`computers, and portions corresponding to those of the
`embodiment shown in FIG. 1 are denoted by the same
`numerals.
`The embodiment shown in FIG. 4 is such that a single
`magnetic disk storage device 3 is shared by the plurality of 55
`host computers 1A and lB.
`Referring to FIG. 4, the magnetic disk storage device 3 is
`connected to the two host computers IA and lB through a
`SCSI bus 2. It includes a disk controller 5, and a disk drive
`unit 4 in which three partitions 41, 42 and 43 are set. Here 60
`in this embodiment, the partition 41 (SCSI ID=l) is assigned