United States Patent [19]
`Murata
`
`lllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllll
`5,506,692
`Apr. 9, 1996
`
`US005506692A
`[11] Patent Number:
`[45] Date of Patent:
`
`[54] IMAGE HANDLING APPARATUS HAVING
`FILE SYSTEM EMULATION MEANS
`
`[75] Inventor: Kazuyuki Murata, Tsuzuki, Japan
`
`[73] Assignee: Matsushita Electric Industrial Co.,
`Ltd., Kadoma, Japan
`
`[21] Appl. No.: 259,530
`[22] Filed:
`Jun. 14, 1994
`
`Related U.S. Application Data
`
`[62] Division of Ser. No. 36,028, Mar. 23, 1993.
`[30]
`Foreign Application Priority Data
`
`Apr. 9, 1992
`Aug. 7, 1992
`
`[JP]
`[JP]
`
`Japan .................................. .. 4-088541
`Japan .................................. .. 4-211102
`
`[51] Int. Cl.6 ............................. .. H04N 1/00; H04N l/21;
`G06F 3/00; GO6F 9/455; G06F 13/00
`[52] U.S. Cl. ........................ .. 358/442; 358/444; 395/112;
`395/115; 395/500; 395/828; 395/830; 395/882;
`395/883; 395/892
`[58] Field of Search ................................... .. 358/442, 468,
`358/444, 296; 395/500, 275, 112, 114,
`115, 828, 830, 882, 883, 892
`
`[56]
`
`References Cited
`
`U.S. PATENT DOCUMENTS
`
`5,088,033
`
`2/1992 Binkley et al. ....................... .. 395/500
`
`OTHER PUBLICATIONS
`Operating Systems: Design and Implementation, Andrew S.
`Tanenbaum, 1987, pp. 299—308.
`Primary Examiner-Scott A. Rogers
`Attomey, Agent, or Firm—Ratner & Prestia
`[57]
`ABSTRACT
`
`An image forming apparatus which is used with an external
`host computer. The image forming apparatus includes an
`interface for connecting the image forming apparatus to the
`external host computer. The image forming apparatus fur
`ther includes a ?le system emulator which emulates a ?le
`system contained in the disk storage apparatus of the exter
`nal host computer. The ?le system emulator makes the
`image forming apparatus look like the disk storage apparatus
`to the external host computer connected to the image form
`ing apparatus to transfer images from the external host
`computer to the image forming apparatus via the interface
`device.
`
`10 Claims, 7 Drawing Sheets
`
`Apple 1008
`U.S. Pat. 6,470,399
`
`

`
`US. Patent
`
`Apr. 9, 1996
`
`Sheet 1 of 7
`
`5,506,692
`
`Fig.
`
`L
`
`475700 I
`6 “S
`5
`
`Q
`
`3|
`
`5:lO
`
`8
`T
`9
`
`

`
`U.S. Patent
`
`Apr. 9, 1996
`
`Sheet 2 of 7
`
`5,506,692
`
`3
`
`IMAGE
`
`J SCSI BUS
`
`63
`
`NONVOL
`
`
`
`SCSI50EMEMORYCTRL54
`
`
`
`3’ n_ PITP
`
`ENCD
`
`(,3
`
`D)
`LI
`
`(D
`O’)
`
`g
`
`3
`
`31
`
`A/D
`
`AMP
`
`CCD
`
`NC
`
`’)
`
`MEM
`
`SELECTOR
`
`O(D
`
`3
`
`COMP
`
`

`
`US. Patent
`
`Apr. 9, 1996
`
`Sheet 3 of 7
`
`5,506,692
`
`Fig.4
`
`#SCANNER PARAMETER FILE EXAMPLE
`# AREA PARAMETERUnCh)
`# X,Y,XL,YL
`1.2
`2.4 ‘
`5.5
`6.3
`#ZOOMING PARAMETER(%) XZ,YZ
`100
`150
`
`#IMAGE PROCESSING PARAMETER
`#
`SIMPLE BI-LEVEL IMAGE
`#
`BI-LEVEL COMPRESSION IMAGE(MH)
`#
`BI-LEVEL COMPRESSION IMAGE(MR)
`#
`BI-LEVEL COMPRESSION IMAGE(MMR)
`#
`ERROR DIFFUSION BI-LEVEL IMAGE
`#
`88ITS GRAY SCALE IMAGE
`88ITS.GRAY SCALE COMPRESSION IMAGE ->6
`#
`1
`
`#GAMMA TRANSFER PARAMETER
`#
`LINEAR
`->O
`#
`DENSITY
`-->1
`#
`DATE SETTABLE —>2
`2
`
`#GAMMA TRANSFER DATA TABLE
`#DATA MUST BE 0 <=.2ss> =
`00 1017 'IC2O 24 27 2A 20 3O 32 35 37 3A 3C 3E
`40 42 44 46 47 49 48 4D 4E 50 51 53 54 56 57 59
`5A 5C SD 5E 60 61 62 64 65 66 67 69 6A 6B 6C 6D
`6F 70 71 72 73 74 75 76 77 79 7A 7B 7C 7D 7E 7F
`80 81 82 83 84 85 86 87 87 88 89 8A 8B 8C 8D 8E
`8F 90 91 91 92 93 94 95 96 97 97 98 99 9A 9B 9C
`9C 90 9E 9F A0 A0 A1 A2 A3 A4 A4 A5 A6 A7 A7 A8
`A9 AAAAABACADADAEAF B0 B0 B1 B2 B3 B3 B4
`B5 B5 B6 B7 B7 B8 89 BA BA BB BC BC BD BE BE BF
`CO C0 C1 C2 C2 C3 C4 C4 C5 C6 C6 C7 C7 C8 C9 C9
`CA C8 C8 CC CC CD CE CE CF D0 D0 D1 D1 D2 D3 D3
`D4 D4 D5 D6 D6 D7 D7 D8 D9 D9 DA DA DB DC DC DD
`DD DE DE DF E0 E0 E1 E1 E2 E2 E3 E4 E4 E5 E5 E6
`E6 E7 E7 E8 E9 E9 EA EA EB EB EC EC ED ED EE EE
`EF F0 F0 F1 F1 F2 F2 F3 F3 F4 F4 F5 F5 F6 F6 F7
`F7 F8 F8 F9 F9 FA FA F8 F8 PC PC FD FD FE FE FF
`
`

`
`US. Patent
`
`Apr. 9, 1996
`
`Sheet 4 0f 7
`
`5,506,692
`
`Fig.5
`
`FILE
`SYS. PREPARED
`?
`
`umkfsn
`COMMAND
`
`MOUNT
`FILE SYS.
`
`WRITE TO
`PARA FILE
`
`UNMOUNT
`FILE SYS.
`
`MOUNT
`AGAIN
`
`<._.____
`
`READ
`IMAGE DATA
`
`YES
`
`PARA.
`SHOULD BE
`CHANGED
`?
`
`

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`US. ‘Patent
`
`Apr. 9, 1996
`
`Sheet 5 0f 7
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`5,506,692
`
`Fig} 6
`
`boot block(8l<B)
`
`super bLock(8KB)
`
`super block copY(8K8)
`
`cytinder group 1
`
`cylinder group 2
`
`cylinder group 3
`
`cyUnder group n
`
`cytinder group block
`
`i-node table
`
`data blocks
`
`

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`US. Patent
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`Apr. 9, 1996
`
`Sheet 6 0f 7
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`5,506,692
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`Fig.8 '
`
`152
`
`SCSI BUS
`
`CPU BUS
`
`131
`3
`SCSI
`IMAGE
`CTRL \
`MEMORY
`151m 153% 154
`122
`150” CPU
`PRINTER
`CLRL
`
`163’\/ MEMORY <}_—- “SS/‘i N
`
`NONVOL.
`
`I
`
`156
`
`LASER
`DRIVER
`
`Fig.9
`
`#PRINTER PARAMETER FILE EXAMPLE
`
`# PAPER 0->A41-> B4
`0
`
`# PRINTING DIRECTION 0->PORTRAIT 1->LANDSCAPE
`0
`# PRINT VOLUME
`1
`
`

`
`U.S. Patent
`
`Apr. 9, 1996
`
`Sheet 7 0f 7
`
`5,506,692
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`Fig. 10
`
`"mkfs”
`COMMAND
`
`MOUNT
`FILE SYS.
`
`I———>
`
`WRITE TO
`PAFIA FILE
`
`UNMOUNT
`FILE SYS.
`
`MOUNT
`AGAIN
`
`WRITE
`IMAGE DATA
`
`YES
`
`PARA.
`SHOULD BE
`CHANGED
`?
`
`

`
`1
`IMAGE HANDLING APPARATUS HAVING
`FILE SYSTEM EMULATION MEANS
`
`This application is a division of application Ser. No.
`08/036,028, ?led Mar. 23, 1993, (status: pending)
`
`BACKGROUND OF THE INVENTION
`
`1. Field of the Invention
`The present invention relates generally to an image han
`dling apparatus, and more particularly to an image scanner
`and to an image forming apparatus both for transferring data
`to and from an external host apparatus via an interface.
`2. Description of the Prior Art
`A computer is generally operatively connected to several
`peripheral devices such as, for example, a magnetic disc, a
`magnetic tape, a printer or the like. Recently, a small
`computer system interface (SCSI) is standardized as an
`interface means for carrying out high-speed data transfer.
`Through the standardization, the SCSI is in wide practical
`use today as an interface for various computers.
`By virtue of marked improvement in performance of
`small computers, e.g. workstations, the development from
`character codes to bit-map data, which has hitherto been
`carried out in a printer, tends to be carried out in the
`computer using outline font data which the computer has.
`Whereas the technique of developing, for example, fonts to
`the bit-map data in the computer has advantages in adding
`other fonts, the use of the SCSI is inevitably required for
`high-speed data transfer because the quantity of data to be
`transferred from the computer to the printer is increased.
`In applications where an image scanner or an image
`fomiing apparatus is connected to an SCSI of a computer
`employed as a host computer, and parameter setting for such
`apparatus or image data transfer is carried out by the
`computer, the computer is required to have a software
`“device driver” for the apparatus connected thereto.
`Because image scanners or image forming apparatus are
`not standardized in kind of parameters which can be set or
`in functions, the device driver therefor is not generally
`contained in an operating system (OS) of the computer.
`Accordingly, it is necessary to prepare the device driver for
`the image scanner or the image forming apparatus connected
`to the host computer.
`Under the present conditions discussed above, however,
`in order to enable a certain image scanner or image forming
`apparatus to be connected to any one of various types of host
`computers, it is necessary to prepare a device driver for each
`type of host computer. As a result, the problem arises that the
`preparation of the device driver requires much labor and
`increases costs.
`
`SUMMARY OF THE INVENTION
`
`The present invention has been developed to overcome
`the above-described disadvantages.
`It is accordingly an object of the present invention to
`provide an improved image handling apparatus, for example
`an image scanner or an image forming apparatus, which
`requires no preparation of any new device driver.
`In accomplishing the above and other objects, an image
`scanner according to the present invention comprises means
`for reading an image, an interface means for connecting the
`image scanner to an external host apparatus, and a ?le
`system emulation means for emulating a ?le system con
`tained in the external host computer.
`
`5,506,692
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`2
`When the present invention is applied to an image fonn
`ing apparatus, the read means is replaced with an image
`forming means for forming an image on a recording
`medium.
`Because an operating system of a computer constructs a
`?le system in a hard disc, there invariably exists a device
`driver for the hard disc.
`As discussed hereinabove, because the image scanner or
`image fonning apparatus according to the present invention
`is provided with the ?le system emulation means, the control
`of the apparatus or the transfer of image data can be carried
`out using the device driver for existing hard discs. Further~
`more, because the operating system is provided with various
`commands or system calls which are utilized to access to the
`?le system, development of application software for use in
`a host computer operatively connected to the image scanner
`or image forming apparatus is facilitated.
`In applications where the image scanner or image forming
`apparatus according to the present invention is connected to
`an external host computer, it is not necessary to prepare the
`device driver for each type of computer if the ?le system of
`the computer is the same. In short, the apparatus can be
`connected to any one of various types of computers having
`the same ?le system, e.g. any one of all computers having
`software called the “UNIX” as an operating system.
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`The above and other objects and features of the present
`invention will become more apparent from the following
`description of preferred embodiments thereof with reference
`to the accompanying drawings, throughout which like parts
`are designated by like reference numerals, and wherein:
`FIG. 1 is a perspective view of an image scanner accord
`ing to the present invention which is connected to an
`external host computer;
`FIG. 2 is a schematic sectional view of the image scanner
`of FIG. 1;
`FIG. 3 is a block diagram of the image scanner of FIG. 1;
`FIG. 4 is a programmed ?le that is read by the computer
`when parameters are set in;
`FIG. 5 is a ?owchart indicating the procedure at the time
`the image scanner is controlled by a workstation;
`FIG. 6 is a schematic view indicating the layout of a ?le
`system contained in the workstation;
`FIG. 7 is a perspective view of an image forming appa
`ratus according to the present invention which is connected
`to an external host computer;
`FIG. 8 is a block diagram of the image forming apparatus
`of FIG. 7;
`FIG. 9 is a programmed ?le that is read by the computer
`when parameters are set in; and
`FIG. 10 is a ?owchart indicating the procedure at the time
`the image forming apparatus is controlled by a workstation.
`
`10
`
`20
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`25
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`35
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`40
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`45
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`50
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`55
`
`DETAILED DESCRIPTION OF THE
`PREFERRED EMBODIMENTS
`
`Referring now to the drawings, there is shown in FIG. 1
`an image scanner 20 embodying the present invention. The
`image scanner 20 is connected to an external host computer
`via an SCSI bus 22. In FIG. 1, the external host computer is
`a workstation 21 having the “UNIX” as an operating system.
`A hard disc in which a ?le system for the workstation 21 has
`been formulated is accommodated in the workstation 21 and
`
`65
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`5,506,692
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`3
`is connected to the SCSI bus 22 inside the workstation 21.
`FIG. 2 schematically depicts the internal construction of
`the image scanner 20 according to the present invention. The
`image scanner 20 comprises a document platform 1 made of
`glass on which a document 2 is to be placed with the image
`surface thereof directed downwards, a document cover 3 to
`be overlaid on the document 2 to hold the document 2, and
`a scanning unit 6 comprising a ?uorescent lamp 4 and a
`re?ection mirror 5. The scanning unit 6 is driven by a motor
`(not shown) and is moved in a direction shown by an arrow
`S at a constant speed to carry out sub-scanning with respect
`to the document 2. The image scanner 20 further comprises
`a half-speed unit 7, a lens 10, and a line-type CCD image
`sensor 31. The half-speed unit 7 comprises two mirrors 8 and
`9. During scanning, when the scanning unit 6 is moved in the
`direction of the arrow S, the half-speed unit 7 is moved in
`a direction shown by an arrow T at a speed half of the
`scanning unit 6. Re?ected light from the document 2 is
`further re?ected by the mirrors 5, 8, and 9, and is focused on
`the CCD image sensor 31 by the lens 10 for image forma
`tion. The CCD image sensor 31 carries out main-scanning in
`the line direction with respect to the re?ected light from the
`document 2 to convert it to an electric signal.
`As shown in FIG. 3, the CCD 31 reads the re?ected light
`from the document 2 at a resolution of 400 dpi, converts it
`to the electric signal, and outputs an analogue image signal
`32. The analogue image signal 32 is then ampli?ed by an
`ampli?er 33 and is converted to a digital image signal 35 by
`an 8-bit A/D converter 34. A gamma transfer circuit 36
`carries out digital-to-digital conversion for conversion of the
`gradation characteristic, thereby converting the digital
`image signal 35 to an image signal 37. The gamma transfer
`circuit 36 is comprised of a look-up table formulated by the
`use of a RAM. The RAM is connected to a CPU bus 51 of
`a CPU 50, and data stored therein can be set by the CPU 50.
`Accordingly, the conversion characteristic of the gamma
`transfer circuit 36 can be changed by the CPU 50.
`A zooming circuit 38 carries out a zooming operation in
`the direction of main-scanning by interpolating or thinning
`out the image signal 37, and outputs an image signal 39. The
`CPU 50 sets the zooming rate of the zooming circuit 38 via
`the CPU bus 51. The zooming operation in the sub-scanning
`direction is carried out by changing the speed of movement
`of the scanning unit 6 shown in FIG. 2. A trimming circuit
`40 carries out a trimming operation wherein only part of the
`image signal 39 that is indicative of a predetemrined rect
`angular region on the document 2 is made effective, and
`outputs an image signal 41. The trimming circuit 40 is
`connected to the CPU bus 51 of the CPU 50, and the
`trimming region can be set by the CPU 50.
`A binary circuit 42 compares the image signal 41 with a
`predetermined threshold value and outputs a binary image
`signal 43. The threshold value can be set by the CPU 50. A
`compression circuit 44 encodes and compresses the binary
`55
`image signal 43 and outputs a compressed binary image
`signal 45. The compression circuit 44 carries out the encod
`ing using any one of three binary image encoding methods:
`MH; MR; and MMR. The selection of an appropriate
`compression method is carried out by the CPU 50. A
`60
`pseudo-half-tone processor 46 processes the image signal 41
`using the error diffusion method and outputs an image signal
`47. An encoder 48 encodes and compresses the image signal
`41 and outputs an encoded image signal 49.
`A selector 60 selects an appropriate signal from among
`the compressed binary image signal 45, the binary image
`signal 43, the image signal 47, the image signal 41, and the
`
`50
`
`45
`
`65
`
`20
`
`30
`
`35
`
`4
`encoded image signal 49. After the selection, the selector 60
`outputs an image signal 61. The appropriate signal selection
`is carried out by the CPU 50 via the CPU bus 51. An image
`memory 62 stores the image signal 61 selected by the
`selector 60. Because the image memory 62 is connected to
`the CPU bus 51, the image memory 62 is freely accessible
`from the CPU 50 and an SCSI controller 64. A data counter
`65 counts the quantity of image data to be read and that of
`image date actually stored in the image memory 62. Indi
`vidual values counted can be read from the CPU 50 via the
`CPU bus 51.
`Data stored in a nonvolatile memory 63 can be read or
`rewritten by the CPU 50 via the CPU bus 51. The SCSI
`controller 64 is a controller, controlled by the CPU 50, for
`carrying out data transfer to and from the external host
`computer via the SCSI.
`The operation of the workstation 21 and the image
`scanner 20 at the time the image scanner 20 is controlled by
`the workstation 21 is discussed hereinafter.
`The image scanner 20 emulates the ?le system of the
`“UNIX" as if it were a hard disc. Accordingly, the image
`scanner 20 looks like the hard disc from the workstation 21
`and can be handled as the hard disc.
`The image scanner 20 according to the present invention
`is controlled by the workstation 21 as follows.
`When the image scanner 20 connected to the workstation
`21 is operated by the workstation 21 for the ?rst time, the
`workstation 21 prepares a ?le system in the image scanner
`20, as is the case with the hard disc. In practice, an “mkfs”
`or “newfs” command of the “UNIX” is executed. At this
`moment, the operating system provides a device ?le and a
`device driver required for operating the hard disc as those
`required for preparing the ?le system. The preparation of the
`?le system enables basic information of the ?le system to be
`written to a predetermined region, i.e. a super block of the
`hard disc (image scanner).
`In the image scanner 20, the information written to the
`super block is stored in the nonvolatile memory 63. There
`after, when a request to read the data stored in the super
`block is sent from the workstation 21, the image scanner 20
`outputs the data stored in the nonvolatile memory 63.
`Because the information of the super block is stored in the
`nonvolatile memory 63, even if a power supply to the image
`scanner 20 is cut oif, further preparation of the ?le system
`is no longer required.
`As discussed above, if the preparation of the ?le system
`is carried out with respect to the image scanner 20, the
`workstation 21 can “mount” the image scanner 20 which
`emulates the ?le system, as is the case with the ?le system
`of the hard disc. The “mounting” operation is to establish
`linkage between the ?le system and device ?les in the hard
`disc. After the “mounting” operation, the workstation 21 can
`access to ?les contained in the ?le system prepared in the
`hard disc. The “mounting” operation is executed using a
`“mount” command of the “UND(”.
`Upon completion of the “mounting” operation, when the
`?le system emulated by the image scanner 20 is viewed from
`the workstation 21, one ?le seems to exist therein. This ?le
`is a parameter ?le required to set parameters for the image
`scanner 20. In order for the image scanner 20 to pretend to
`contain the parameter ?le therein, as viewed from the
`workstation 21, i-node data having information required for
`the workstation 21 to access to the parameter ?le are created
`in the image scanner 20 and are transferred to the worksta
`tion 21 according to a request from the workstation 21.
`The name of the parameter ?le is “scan. para”. The
`attribute of the parameter ?le is “write only”. The parameter
`
`

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`5,506,692
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`25
`
`5
`?le is a ?le required to set the operation mode of the image
`scanner 20 such as, for example, the zooming ratio, the read
`area, the gamma transfer characteristic, the binary process or
`the like, and is represented using a predetermined format.
`FIG. 4 depicts one example of the parameter ?le. Lines
`starting from “#” are comment lines. The parameters are
`represented in the following order using numerals.
`(1) Read area: upper left coordinates (X, Y); length in the
`direction of X (XL); and length in the direction of Y
`(YL), (unit: inch)
`(2) Zoom. ratio: zooming ratio in the direction of X (XZ);
`and zooming ratio in the direction of Y (YZ), (unit: %)
`(3) Image process. method: binary process or the presence
`or absence of the compression process
`(4) Gamma trans. mode: no transfer when 1; transfer from
`re?ectance to density when 2; and designation of
`gamma transfer table when 3
`(5) 'y trans. table: to be represented by hexadecimal
`numbers
`The workstation 21 sets the operation mode of the image
`scanner 20 by writing the parameter ?le to the image scanner
`20. The writing of the parameter ?le for the setting of the
`operation mode of the image scanner 20 can greatly facili—
`tate the setting of the parameters of the image scanner 20.
`Because the “UNIX” operating system executes buffering
`such that data to be read from or written to the ?le system
`are temporarily stored in a buffer of a main memory of the
`workstation, it is necessary to “unmount” the ?le system in
`order to actually write the data to the hard disc. A “umount”
`command of the “UNIX" is used for this purpose.
`The image scanner 20 reads a document in accordance
`with the parameters at the time the parameter ?le has been
`written. At this moment, the read image data are stored in the
`image memory 62 inside the image scanner 20. When the
`quantity of the image data is greater than the capacity of the
`image memory 62, the image data as many as the image
`memory 62 can accommodate are temporarily stored in the
`image memory 62.
`Subsequently, in order for the workstation 21 to read the
`image data from the image scanner 20, the ?le system to be
`emulated by the image scanner 20 is “mounted” again. As
`viewed from the workstation 21, there seem to exist two ?les
`in the ?le system emulated by the image scanner 20. One of
`them is the aforementioned parameter ?le “scan para”
`whereas the other is an image data ?le, the name of which
`is “image. data”. The attribute of the image data ?le is “read
`only”.
`In order for the image scanner 20 to pretend to contain the
`image data ?le therein, as viewed from the workstation 21,
`the CPU 50 of the image scanner 20 creates i-node data
`having information required for the workstation 21 to access
`to the image data ?le and transfers them to the workstation
`21 in response to a request from the workstation 21. The size
`of the image data ?le as viewed from the workstation 21
`depends upon the operation mode which has been set in the
`image scanner 20 by writing to the parameter ?le. The
`workstation 21 reads the contents of this data ?le so that the
`image data read by the image scanner 20 may be transferred
`to the workstation 21.
`FIG. 5 depicts a ?owchart indicating the above-described
`control procedure at the time the image scanner 20 accord
`ing to the present invention is controlled by the workstation
`21.
`The operation of the image scanner 20 is discussed
`hereinafter in association with the procedure of the work
`station 21.
`
`45
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`50
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`55
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`60
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`65
`
`6
`FIG. 6 schematically depicts an ordinary layout of the ?le
`system of the workstation containing therein the “UNIX” as
`the OS. First 8 KB of the ?le system is allocated to a boot
`block including boot programs required for booting the
`workstation 21. The next 8 KB is an area called the super
`block which is generally used to store the then conditions of
`the ?le system such as, for example, the number of ?les, the
`size of the ?le system and the like. The super block is
`followed by a plurality of cylinder groups. Each cylinder
`group is made up of a copy of the super block, a cylinder
`group block, an i-node table, and data blocks. Data such as
`the number of i-nodes, that of the data blocks, an i-node map
`used, or a map of empty blocks are stored in the cylinder
`data blocks. The i-node is information indicating the
`attribute of a ?le or the location of a data block in which the
`?le exists. Because a directory is also handled as a ?le,
`i-nodes are required by the number of ?les and directories.
`A predetermined extent is allocated to the area of the i~node
`table including a plurality of i-nodes at the time the ?le
`system is ?rst prepared.
`The image scanner 20 which emulates the ?le system
`having the “UNIX” and shown in FIG. 6 operates as follows.
`The operation at the time the workstation 21 prepares the
`?le system is initially discussed. The ?le system used herein
`is a ?le system to be emulated by the image scanner 20. The
`workstation 21 writes to the boot block and to the super
`block positioned at the ?rst 8 KB and at the next 8 KB of the
`?le system, respectively. The CPU 50 of the image scanner
`20 stores these 16 KB data in the nonvolatile memory 63.
`When a data read request for reading the data of these blocks
`is sent from the workstation 21, the CPU 50 reads the data
`from the nonvolatile memory 63 and transfers them to the
`workstation 21. Likewise, when a data write request for
`writing data into these blocks is sent from the workstation
`21, the CPU 50 writes the data to the nonvolatile memory
`63.
`Thereafter, the workstation 21 writes a copy data of the
`super block to the ?rst 8 KB of each cylinder block of the
`?le system. At this moment, the CPU 50 can know from the
`data of the super block, the location of each cylinder in the
`?le system. Accordingly, when the CPU 50 has received the
`copy data of the super block of the ?le system from the
`workstation 21, the CPU 50 discards such data. On the other
`hand, when a read request is received, the data of the super
`block are outputted from the nonvolatile memory 63. Alter
`natively, the data of each copy of the super block may be
`stored in the nonvolatile memory 63. In this case, when a
`read request is received, the copy data of the super block are
`outputted from the nonvolatile memory 63.
`Thereafter, the workstation 21 writes to the cylinder group
`block of each cylinder group. The CPU 50 can know the
`location and size of the cylinder group block in the ?le
`system from the data of the super block. The CPU 50 stores
`the data of the cylinder group block in the nonvolatile
`memory 63. When a read request of such data is sent from
`the workstation 21, the CPU 50 reads the data from the
`nonvolatile memory 63 and transfers them to the worksta
`tion 21. Likewise, when a data write request is sent from the
`workstation 21, the CPU 50 writes data to the nonvolatile
`memory 63.
`Subsequently, the workstation 21 carries out initialization
`with respect to the i-node table of each cylinder group. The
`CPU 50 can know the location and size of the i-node table
`in the ?le system from the data of the cylinder group block.
`The CPU 50 discards data to be written to the i-node table.
`When the workstation 21 “mounts” the ?le system emu
`lated by the image scanner 20, the workstation 21 reads the
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`super block, the cylinder group block, and the i-node table
`from the ?le system. When the CPU 50 has received a read
`request for reading the super block and the cylinder group
`block, the CPU 50 reads the corresponding data from the
`nonvolatile memory 63 and transfers them to the worksta
`tion 21. The CPU 50 creates a root directory and i-node data
`of the parameter ?le “scan. para” and transfers them to the
`workstation 21.
`The CPU 50 knows the location of the data region of the
`parameter ?le in the ?le system from the created i-node data
`of the parameter ?le. Accordingly, the CPU 50 can know the
`writing of the parameter data from the workstation 21 to the
`parameter ?le “scan. para”. The CPU 50 makes an analysis
`of the data written to the parameter ?le, obtains the param
`eters, and reads the document in accordance with the set
`operation mode.
`The read image data are stored, from the beginning of the
`image, in the image memory 62 in accordance with a read
`region set in the parameter ?le. When the capacity of the
`image memory 62 is less than the quantity of the image data,
`a limited quantity of image data corresponding to the
`capacity of the image memory 62 is stored. The CPU 50 can
`know from the value of the data counter 65, the quantity of
`the whole image data to be read, that of the image data stored
`in the image memory 62, and the region of the image stored
`in the image memory 62.
`After the image reading, when a read request of the i-node
`table of the ?le system is sent from the workstation 21, the
`CPU 50 creates the root directory, the i-node of the param
`eter ?le “scan. para”, and that of the image data ?le “image.
`data”, and transfers them to the workstation 21. The size of
`the image data ?le is equal to that of the whole image data
`detected by the data counter 65.
`When a read request for reading data located at a certain
`position in the image data ?le is sent from the workstation
`21, and if the requested data exist in the image memory 62,
`the CPU 50 transfers such data to the workstation 21 via the
`SCSI controller 64. If the image memory 62 contains no
`requested data, the CPU 50 reads a region of the document
`corresponding to the requested data and stores it in the image
`memory 62. Thereafter, the CPU 50 takes out the data from
`the image memory 62 and transfers them to the workstation
`21. As described above, because the image scanner 20 has an
`image memory, it can take full advantage of high-speed data
`transfer through the SCSI. Furthermore, because the image
`memory is not necessarily required to have a capacity
`su?icient to store the entire region to be read, the memory
`need not have a capacity unduly greater than that necessary.
`It is to be noted here that a magnetic storage may be used
`in place of the nonvolatile memory 63.
`FIG. 7 depicts an image fornring apparatus 120 according
`to the present invention, which is connected to an external
`host computer via an SCSI bus 122. The external host
`computer shown in FIG. 7 is a workstation 121 having the
`“UNIX” as an operating system. A hard disc in which a ?le
`system for the workstation 121 has been formulated is
`accommodated in the workstation 121 and is connected to
`the SCSI bus 122 inside the workstation 121.
`FIG. 8 is a block diagram of the image forming apparatus
`120 according to the present invention.
`Data stored in a nonvolatile memory 163 can be read or
`rewritten by a CPU 150 via a CPU bus 151. An SCSI
`controller 164 carries out data transfer to and from the
`external host computer via the SCSI and is controlled by the
`CPU 150.
`An image memory 152 stores bit-map image data trans
`ferred via the SCSI bus 122 by at least one page. At the time
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`the image data have been stored by one page in the image
`memory 152, a printer engine (not shown) commences an
`image forming operation, and image data 153 are outputted
`from the image memory 152 to a printer engine controller
`154 in synchronism with the operation of an image forming
`unit. The printer engine controller 154 outputs a laser
`modulation signal 155 to a laser driver 156 based on the
`image signal 153. Because the image forming unit com
`prises a conventionally known laser printer employing a
`semiconductor laser, explanation thereof is omitted.
`The operation of the workstation 121 and the image
`forming apparatus 120 at the time the image forming appa
`ratus 120 is controlled by the workstation 121 is discussed
`hereinafter.
`The image forming apparatus 120 emulates a ?le system
`of the “UNIX” as if it were a hard disc. Accordingly, the
`image forming apparatus 120 looks like the hard disc from
`the workstation 121 and can be handled as the hard disc.
`The image forming apparatus 120 according to the present
`invention is controlled by the workstation 121 as follows.
`When the image forming apparatus 120 connected to the
`workstation 121 is operated by the workstation 121 for the
`?rst time, the workstation 121 prepares a ?le system in the
`image forming apparatus 120, as is the case with the hard
`disc. In practice, an “mkfs” or “newfs” command of the
`“UNIX” is executed. At this moment, the operating system
`provides a device ?le and a device driver required for
`operating the hard disc as those required for preparing the
`?le system. The preparation of the ?le system enables basic
`information of the ?le system to be written to a predeter
`mined region, i.e. a super block of the hard disc.
`I
`In the image forming apparatus 120, the information
`written to the super block is stored in the nonvolatile
`memory 163. Thereafter, when a request to read the data
`stored in the super block is sent from the workstation 121,
`the image forming apparatus 120 outputs the data stored in
`the nonvolatile memory 163 to the SCSI bus 122. Because
`the information of the super block is stored in the. nonvola
`tile memory 163, even if a power supply to the image
`forming apparatus 120 is cut off, further preparation of the
`?le system is no longer required.
`As discussed above, if the preparation of the ?le system
`is carried out with respect to the image forming apparatus
`120, the workstation 121 can “mount” the