Page 1 of 33
`
`Unified Patents Exhibit 1008
`
`

`
`
`U.S. Patent
`
`
`
`
`May 18, 2004
`
`
`
`
`
`
`Sheet 1 of 21
`
`
`
`
`
`US 6,738,877 B1
`
`
`
`ISTORAGEUNH‘
`
`
`
`
`
`
`I:K3J
`
`
`
`
`HOST UNIT
`
`
`
`
`
`
`DRIVE UNIT
`
`
`
`OPTICAL DISK
`
`
`
`Page 2 of 33
`
`Page 2 of 33
`
`

`
`
`U.S. Patent
`
`
`
`
`May 18, 2004
`
`
`
`
`
`
`Sheet2 0f21
`
`
`
`
`
`US 6,738,877 B1
`
`
`
`FlG.2
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`30-2
`
`
`
`HEAD
`AMP
`
`
`
`
`
`
`
`
`34
`
`
`TEMERATURE
`SENSOR
`
`
`
`
`
`32
`
`35
`
`
`
`
`
`I I I I I I I I I I I
`
`_
`-
`
`DRIVER
`
`
`SPINDLE MDTDR
`
`I I
`
`22i
`
`21!
`
`
`
`I
`
` LASER DIDDE
`
`
`
`
`
`
`
`
`
`
`
`CONTROL
`WRITE MUDULATDR
`
`
`
`
`
`
`
`
`
`
`READ DEMUDULATOR
`
`FREQUENCY
`
`SYNTHESIZER
`
`
`26
`
`
`
`
`
`!i I
`
`I II
`
`
`h4C
`
`
`25I
`
`I
`
`1 D
`
`
`
`
`
`
`
`
`
`
`
`
`
` 14 I
`
`
`
`
`
`14-2
`
`
`
`
`
`
`
`
`
`
`
`
`A4 P I}
`
`
`
`
`
`
`40;
`I
`
`44I
`I
`
`
`
`ELECTRDMAGNET
`
`I
`
`II
`
`
`
`FES
`
`DETECTOR
`
`
`
`45
`
`
`
`TES
`
`DETECTOR
`
`
`
`47
`
`
`
`: I I I I I I I I I I I I I I I
`
`54'
`
`‘
`
`LENS POSITION
`
`SENSOR
`
`
`
`
`FOCUS
`
`ACTUATOR
`
`
`LENS
`
`ACTUATOR
`
`
`
`60
`
`
`
`64
`
`
`
`
`
`
`
`DRIVER
`
`FES
`
`DETECTION
`
`
`
`TES
`
`DETECTION
`
`
`
`
`
`
`DRIVER
`
`
`
`
`
`
`
`
`
`||I|°‘||II“Di|I|ea$9||II||V||||I|I|Villk
`
`
`
`
`
`O)0'}U1
`
`DRIVER
`
`
`
`
`
`DRIVER
`
`
`
`42
`
`46
`
`
`
`I'll
`
`
`
`
`
`VIVIVII TZC
`
`
`DETECTION
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`Page 3 of 33
`
`Page 3 of 33
`
`

`
`
`U.S. Patent
`
`
`
`May 18, 2004
`
`
`
`
`
`Sheet 3 of 21
`
`
`
`
`
`
`
`
`US 6,738,877 B1
`
`
`
`
`
`Page 4 of 33
`
`Page 4 of 33
`
`

`
`
`U.S. Patent
`
`
`
`
`May 18, 2004
`
`
`
`
`
`
`Sheet 4 of 21
`
`
`
`US 6,738,877 B1
`
`
`
`
`
`
`FIG.
`
`
`
`4
`
`
`
`
`OPERATOR
`
`
`
`HOST UNIT 5
`
`
`
`DRIVE UNIT 2
`
`
`DISK 3
`
`
`
`INSERT DISK
`
`1-1)
`
`
`
`
`
`PASSWORD SETTING
`
`INPUT
`
`
`READY REPORT
`
`
`
`
`MASTER/USER PASSWORD
`
`
`
`USER NAME LIST
`
`NOTIFICATION
`
`
`
`
`NORMAL END
`
`
`
`
`
`
`
`
`WRITE COMMAND
`
`
`
`
`
`NOT READY
`
`NOTIFICATION
`
`
`USER NAME/PASSWORD
`
`NOTIFICATION
`
`
`
`
`WRITE COMMAND
`
`
`
`
`
`NORMAL END
`
`NOTIFICATION
`
`
`
`WRITE TO DISK
`
`
`
`
`
`
`COMPARE NOTIFIED
`
`PASSWORD 8
`
`
`PASSWORD ON DISK
`
`
`
`
`
`
`EXECUTE WRITE
`
`COMMAND
`
`
`
`
`
`INSERT DISK
`
`
`WRITE COMMAND
`
`
`
`
`WRITE COMMAND
`
`ABNORMAL END
`NOTIFICATION
`
`
`
`
`
`
`USER NAME/PASSWORD
`
`NOTIFICATION
`
`
`
`
`WRITE COMMAND
`
`
`
`
`
`1:3‘:I-51T5211:
`
`I
`
`_L
`
`
`
`
`
`
`
`Page50f33
`
`Page 5 of 33
`
`

`
`
`U.S. Patent
`
`
`
`May 18, 2004
`
`
`
`
`
`Sheet 5 of 21
`
`
`
`
`
`
`
`
`US 6,738,877 B1
`
`
`
`
`
`FIG.
`
`
`
`5
`
`
`
`MASTER PASSWORD
`
`
`
`
`
`wtdis
`
`
`
`
`
`wtdis
`
`wtdis
`
`wtdis
`
`USER PASSWORD
`
`
`
`
`
`USER NAME a
`
`
`USER NAME b
`
`
`USER NAME c
`
`
`USER NAME d
`
`Page 6 of 33
`
`Page 6 of 33
`
`

`
`
`U.S. Patent
`
`
`
`
`May 18, 2004
`
`
`
`
`
`
`Sheet 6 of 21
`
`
`
`
`
`US 6,738,877 B1
`
`
`
`
`
`FIG.
`
`
`
`6
`
`
`
`
`
`OPERATOR
`
`
`
`HOST UNIT 5
`
`
`
`DRIVE UNIT 2
`
`
`
`DISK 3
`
`
`READY REPORT
`
`
`
`
`MASTER/USER PASSWORD.
`
`
`
`USER NAME LIST
`
`NOTIFICATION
`
`
`
`
`NORMAL END
`
`
`
`
`
`
`
`
`READ COMMAND
`
`
`
`
`
`NOT READY
`
`NOTIFICATION
`
`
`
`
`
`
`
`
`EJECT DISK
`
`
`
`
`
`INSERT DISK
`
`
`2-1)
`
`
`
`
`
`PASSWORD SETTING
`
`INPUT
`
`
`
`INSERT DISK
`
`
`READ COMMAND
`
`
`
`
`
`
`
`
`READ COMMAND
`
`ABNORMAL END
`NOTIFICATION
`
`
`
`
`
`
`USER NAME/PASSWORD
`
`NOTIFICATION
`
`
`
`
`USER NAME/PASSWORD
`
`NOTIFICATION
`
`
`
`
`READ COMMAND
`
`
`
`
`READ COMMAND
`
`
`
`
`
`NORMAL END REPORT
`
`
`
`
`COMPARE NOTIFIED
`
`PASSWORD &
`
`
`
`PASSWORD ON DISK
`
`
`
`
`EXECUTE READ
`
`COMMAND
`
`
`
`WRITE T0 DISK '7'9\/I
`
`I
`
`[Q
`
`
`
`
`
`
`
`
`
`r‘——~‘I‘/11#31r“—
`
`Page70f33
`
`Page 7 of 33
`
`

`
`
`U.S. Patent
`
`
`
`May 18, 2004
`
`
`
`
`
`Sheet 7 of 21
`
`
`
`
`
`
`
`
`US 6,738,877 B1
`
`
`
`
`FIG.
`
`
`
`7
`
`
`
`
`MASTER PASSWORD
`
`
`
`USER PASSWORD
`
`
`
`
`
`USER NAME a
`
`USER NAME b
`
`USER NAME c
`
`USER NAME d
`
`
`
`
`
`
`
`
`Page 8 of 33
`
`Page 8 of 33
`
`

`
`
`U.S. Patent
`
`
`
`
`May 18, 2004
`
`
`
`
`
`
`Sheet 8 of 21
`
`
`
`
`
`US 6,738,877 B1
`
`
`
`
`FIG.
`
`
`
`8
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`INSERT D l SK
`
`
`
`
`
`
`LOAD PROCESS
`
`
`
`
`READ PASSWORD
`
`I NFORMAT I ON
`
`
`
`
`
`
`
`3 4
`
`AICJ
`
`
`
`
`s 6
`
`
`
`LOAD PROCESS
`
`COMPLETE
`
`
`
`
`
`
`PASSWORD ?|NFORMATl0 >
`'
`
`
`
`
`
`LOAD PROCESS
`
`INCOMPLETE
`
`
`
`
`
`
`
`Page 9 of 33
`
`Page 9 of 33
`
`

`
`
`U.S. Patent
`
`
`
`May 18, 2004
`
`
`
`
`Sheet 9 of 21
`
`
`
`
`
`
`
`
`US 6,738,877 B1
`
`
`
`
`
`FIG.
`
`
`
`9
`
`
`
`O
`
`S 1 1
`PASSWORD 7| NFORMAT I 0 >
`
`
`
`
`
`MAS
`
`
`
`
`
`
`312
`
`N 0
`
`s 15
`
`
`
`
`
`
`N0 WRITE/READ
`
`PROCESS
`
`
`
`Y E s
`
`USER
`4 NFORMATl0f§l? NOTIFIED
`
`PASSWORD MOTIFIED
`?
`
`WRITE/READ
`PROCESS
`
`
`
`
`
`Page 10 of 33
`
`Page 10 of 33
`
`

`
`
`U.S. Patent
`
`
`
`May 18, 2004
`
`
`
`
`
`Sheet 10 of 21
`
`
`
`
`
`
`
`
`US 6,738,877 B1
`
`
`
`
`FIG. 10
`
`
`
`
`MASTER PASSWORD
`
`
`
`
`USER PASSWORD
`
`
`
`
`
`rddis wtdis
`
`
`
`USER NAME a
`
`
`
`
`
`USER NAME b
`
`
`
`
`
`USER NAME c
`
`
`
`
`
`USER NAME d
`
`
`
`rddis wtdis
`
`
`
`rddis wtdis
`
`rddis wtdis
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`FIG. 11
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`USER NAME 0
`
`
`
`
`
`
`
`
`
`Page 11 of 33
`
`Page 11 of 33
`
`

`
`
`U.S. Patent
`
`
`
`
`
`May 18, 2004
`
`
`
`
`
`
`Sheet 11 of 21
`
`
`
`
`
`US 6,738,877 B1
`
`
`
`
`FIG. 12
`
`
`
`
`
`MASTER PASSWORD
`
`
`
`USER WRITE PASSWORD
`
`
`
`
`
`USER NAME a
`
`USER NAME b
`
`USER NAME c
`
`
`
`
`
`
`
`Page 12 of 33
`
`Page 12 of 33
`
`

`
`
`U.S. Patent
`
`
`
`
`May 18, 2004
`
`
`
`
`
`
`Sheet 12 of 21
`
`
`
`
`
`US 6,738,877 B1
`
`
`
`
`FIG. 13
`
`
`
`5-1
`
`
`HOST UNIT
`
`
`
`
`
`HOST UNIT
`
`
`
`
`HOST UNIT
`
`
`5-2
`
`
`5-3
`
`
`
`
`
`
`
`
`
`
`
` OPTICAL DISK
`
`Page 13 of 33
`
`Page 13 of 33
`
`

`
`
`U.S. Patent
`
`
`
`May 18, 2004
`
`
`
`
`
`Sheet 13 of 21
`
`
`
`
`
`
`
`
`US 6,738,877 B1
`
`
`
`
`FIG. 14
`
`
`
`OPERATOR
`
`
`
`
`
`HOST UNIT 5
`
`
`
`
`
`DRIVE UNIT 2
`
`
`
`
`DISK 3
`
`INSERT DISK
`
`
`
`
`3-1)
`
`
`
`
`PASSWORD SETTING
`
`INPUT
`
`
`
`
`READY REPORT
`
`
`
`
`MASTER/USER PASSWORD.
`
`
`
`USER NAME LIST
`
`NOTIFICATION
`
`
`
`NORMAL END
`
`
`'“3E“T 0'5“ _
`
`
`
`
`READY REPORT
`
`
`WRITE COMMAND
`
`
`
`
`
`
`WRITE T0 DISK
`
`
`
`
`
`
`WRITE COMMAND
`
`
`
`
`
`NOT READY
`
`NOTIFICATION
`
`
`USER NAME/PASSWORD
`
`
`
`
`
`WRITE COMMAND
`
`ABNORMAL END
`NOTIFICATION
`
`
`
`
`
`
`USER NAME/PASSWORD
`
`NOTIFICATION
`
`
`
`
`WRITE COMMAND
`
`
`
`°I°T9 \/
`
`
`
`02
`
`
`
`Ir'——33*_I#31I?
`
`
`
`Page 14 of 33
`
`- NOTIFICATION
`
`
`WRITE COMMAND
`
`
`
`NORMAL END
`
`NOTIFICATION
`
`
`
`
`COMPARE NOTIFIED
`
`PASSWORD &
`
`
`
`PASSWORD ON DISK
`
`
`
`
`EXECUTE WRITE
`
`COMMAND
`
`
`
`Page 14 of 33
`
`

`
`
`U.S. Patent
`
`
`
`May 18, 2004
`
`
`
`
`
`Sheet 14 of 21
`
`
`
`
`
`
`
`
`US 6,738,877 B1
`
`
`
`
`FIG. 15
`
`
`
`
`MASTER PASSWORD
`
`
`
`
`USER PASSWORD
`
`
`
`
`
`wtdis
`
`wtdis
`
`wtdis
`
`wtdis
`
`
`
`PATH INFORMATION
`
`
`
`USER NAME a
`
`
`USER NAME b
`
`
`USER NAME c
`
`
`USER NAME d
`
`
`Page 15 of 33
`
`Page 15 of 33
`
`

`
`
`U.S. Patent
`
`
`
`May 18, 2004
`
`
`
`
`
`Sheet 15 of 21
`
`
`
`
`
`
`
`
`US 6,738,877 B1
`
`
`
`
`FIG. 16
`
`
`
`OPERATOR
`
`
`
`
`
`HOST UNIT 5
`
`
`
`
`
`DRIVE UNIT 2
`
`
`
`
`DISK 3
`
`
`
`
`
`
`
`
`
` WRITE TO DISK
`
`
`
`EJECT DISK
`
`
`
`
`
`
`READY REPORT
`
`
`
`
`MASTER/USER PASSWORD.
`
`
`
`USER NAME LIST
`
`NOTIFICATION
`
`
`NORMAL END
`
`
`
`
`READY REPORT
`
`
`
`
`READ COMMAND
`
`
`
`
`
`
`
`NOT READY
`NOTIFICATION
`
`
`
`
`INSERT DISK
`
`
`
`
`
`PASSWORD SETTING
`
`INPUT
`
`
`
`
`
`
`
`INSERT DISK
`
`
`READ COMMAND
`
`
`
`
`
`
`
`
`READ COMMAND
`
`ABNORMAL END
`NOTIFICATION
`
`
`
`
`I
`
`L
`
`
`
`551r—“3——1
`r‘*—5‘—‘IF‘
`
`
`
`
`
`
`
`
`
` N
`
`
`
`
`
`
`
`
`
`USER NAME/PASSWORD
`
`NOTIFICATION
`
`
`READ COMMAND
`
`
`
`
`USER NAME/PASSWORD
`
`NOTIFICATION
`
`
`
`
`READ COMMAND
`
`
`
`
`COMPARE NOTIFIED
`
`PASSWORD &
`
`
`PASSWORD ON DISK
`
`
`
`
`
`ORMAL END REPORT
`
`
`
`
`EXECUTE READ
`
`COMMAND
`
`
`
`Page 16 of 33
`
`Page 16 of 33
`
`

`
`
`U.S. Patent
`
`
`
`May 18, 2004
`
`
`
`
`
`Sheet 16 of 21
`
`
`
`
`
`
`
`
`US 6,738,877 B1
`
`
`
`
`FIG. 17
`
`
`
`MASTER PASSWORD
`
`
`
`
`
`
`USER PASSWORD
`
`
`
`
`
`USER NAME a
`
`
`USER NAME b
`
`
`USER NAME c
`
`
`
`PATH INFORMATION
`
`rwb
`
`rwh
`
`mfis
`
`
`
`USER NAME d
`
`rwm
`
`
`
`Page 17 of 33
`
`Page 17 of 33
`
`

`
`
`U.S. Patent
`
`
`
`
`May 18, 2004
`
`
`
`
`
`
`
`Sheet 17 of 21
`
`
`
`US 6,738,877 B1
`
`
`
`
`FIG. 18
`
`
`
`
`
`S1
`
`
`
`32
`
`83a
`
`
`
`
`
`
`
`START
`
`
`
`
`
`
`
`
`INSERT DISK
`
`
`
`
`
`
`LOAD PROCESS
`
`
`
`
`READ PASSWORD
`
`I NFORMAT I ON
`
`
`
`
`
`
`
`
`
`
`s e
`
`
`LOAD PROCESS
`
`COMPLETE
`
`
`
`
`
`n1c>
`
`
`
`
`
`3 4
`
`
`
`PASSWORD ?lNFORMATl0 >
`'
`
`
`
`
`
`
`LOAD PROCESS
`
`INCOMPLETE
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`Page 18 of 33
`
`Page 18 of 33
`
`

`
`
`U.S. Patent
`
`
`
`
`May 18, 2004
`
`
`
`
`
`
`Sheet 18 of 21
`
`
`
`
`
`US 6,738,877 B1
`
`
`
`
`FIG. 19
`
`
`
`
`
`
`
`S 1 1
`PASSWORD J NFORMAT I O >
`
`
`
`YES
`
`usen
`4 NFORMATION? NOTIFIED
`
`s 12
`
`N o
`
`
`
`MAS
`
`O
`
`
`
`
`
`
`
`<' ASSWORD INFORMATION
`MATCH 7
`
`WR I TE/ READ
`PROCESS
`
`
`
`
`
`
`
`
`
`
`
`
`NO WR I TE/ READ
`
`PROCESS
`
`815
`
`
`
`
`
`
`Page 19 of 33
`
`msswonn 7N0T|FlED
`
`Page 19 of 33
`
`

`
`
`U.S. Patent
`
`
`
`
`
`May 18, 2004
`
`
`
`
`
`
`Sheet 19 of 21
`
`
`
`
`
`US 6,738,877 B1
`
`
`
`
`
`FIG. 20
`
`
`MASTER PASSWORD
`
`
`
`
`USER PASSWORD
`
`
`
`
`
`
`
`USER NAMEa
`
`
`
`USER NAMEb
`
`
`
`
`
`USER NAME c
`
`
`
`
`
`USER NAME d
`
`
`
`rddis wtdis
`
`
`PATH INFORMATION
`
`
`
`Page 20 of 33
`
`
`
`
`
`rddis
`
`wtdis
`
`rddis wtdis
`
`rddis wtdis
`
`Page 20 of 33
`
`

`
`
`U.S. Patent
`
`
`
`May 18, 2004
`
`
`
`
`
`Sheet 20 of 21
`
`
`
`
`
`
`
`
`US 6,738,877 B1
`
`
`
`
`
`FIG. 21
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`Page 21 of 33
`
`Page 21 of 33
`
`

`
`
`U.S. Patent
`
`
`
`May 18, 2004
`
`
`
`
`
`Sheet 21 of 21
`
`
`
`
`
`
`
`
`US 6,738,877 B1
`
`
`
`
`
`FIG. 22
`
`
`
`MASTER PASSWORD
`
`
`
`USER WRITE PASSWORD
`
`
`
`
`
`
`
`
`
`PATH INFORMATION
`
`USER NAME a
`
`USER NAME b
`
`USER NAME c
`
`
`
`
`
`Page 22 of 33
`
`Page 22 of 33
`
`

`
`
`ACCESS CONTROL METHOD, STORAGE
`
`
`
`APPARATUS AND STORAGE MEDIUM
`
`
`
`
`
`1
`
`
`
`
`
`US 6,738,877 B1
`
`
`
`
`
`
`
`2
`word and a master password which limit access to the
`
`
`
`
`
`
`
`
`
`
`portable storage medium, wherein a modification of the user
`
`
`
`
`
`
`
`
`
`password is permitted by specifying the master password,
`
`
`
`
`
`
`
`
`and said user password is provided in common with respect
`
`
`
`
`
`
`
`
`
`
`to a plurality of users and permits access to a data region on
`
`
`
`
`
`
`
`
`
`
`
`
`the portable storage medium by specifying the user
`
`
`
`
`
`
`
`
`password, and prohibits at least one of write and read with
`
`
`
`
`
`
`
`
`
`
`
`respect to each of the plurality of users. According to the
`
`
`
`
`
`
`
`
`
`
`
`access control method of the present invention, it is possible
`
`
`
`
`
`
`
`
`
`
`to positively prevent unauthorized access to data and pro-
`
`
`
`
`
`
`
`
`grams stored in a portable storage medium such as optical
`
`
`
`
`
`
`
`
`
`
`disks, and to enable a relatively simple management of a
`
`
`
`
`
`
`
`
`
`
`password, by providing a simple mechanism with respect to
`
`
`
`
`
`
`
`
`the security of the data and the programs stored in the
`
`
`
`
`
`
`
`
`
`
`portable storage medium.
`
`
`
`In the access control method the storage apparatus may be
`
`
`
`
`
`
`
`
`
`
`coupled to a plurality of host units via a plurality of paths,
`
`
`
`
`
`
`
`
`
`
`
`
`path information related to the paths may be added to the
`
`
`
`
`
`
`
`
`
`
`
`user password, and access to the data region on the portable
`
`
`
`
`
`
`
`
`
`
`
`storage medium may be permitted by specifying the user
`
`
`
`
`
`
`
`
`
`password and the path information.
`
`
`
`
`
`In the access control method, prohibiting at least one of
`
`
`
`
`
`
`
`
`
`
`the write and read may be set independently with respect to
`
`
`
`
`
`
`
`
`
`
`
`each of the plurality of users.
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`Another object of the present invention is to provide an
`
`
`
`
`
`
`
`
`
`
`access control method for a storage apparatus which reads
`
`
`
`
`
`
`
`
`
`information from a portable storage medium in response to
`
`
`
`
`
`
`
`
`
`a request from at least one host unit, comprising the steps of
`
`
`
`
`
`
`
`
`
`
`
`
`reading from the portable storage medium a master pass-
`
`
`
`
`
`word and a user password which limit access to the portable
`
`
`
`
`
`
`
`
`
`
`
`
`
`storage medium, wherein a modification of the user pass-
`
`
`
`
`
`
`word is permitted by specifying the master password, and
`
`
`
`
`
`
`
`
`
`
`
`said user password is provided in common with respect to a
`
`
`
`
`
`
`
`
`
`
`plurality of users and permits access to a data region on the
`
`
`
`
`
`
`
`
`
`
`
`
`portable storage medium by specifying the user password,
`
`
`
`
`
`
`
`
`and prohibits at least one of write and read with respect to
`
`
`
`
`
`
`
`
`
`
`
`
`each of the plurality of users. According to the access control
`
`
`
`
`
`
`
`
`
`
`
`method of the present invention, it is possible to positively
`
`
`
`
`
`
`
`
`
`
`prevent unauthorized access to data and programs stored in
`
`
`
`
`
`
`
`
`
`a portable storage medium such as optical disks, and to
`
`
`
`
`
`
`
`
`
`
`enable a relatively simple management of a password, by
`
`
`
`
`
`
`
`
`
`providing a simple mechanism with respect to the security of
`
`
`
`
`
`
`
`
`
`the data and the programs stored in the portable storage
`medium.
`
`
`
`
`
`
`
`
`
`
`
`In the access control method, the storage apparatus may
`
`
`
`
`
`
`
`
`
`be coupled to a plurality of host units via a plurality of paths,
`
`
`
`
`
`
`
`
`
`
`path information related to the paths may be added to the
`
`
`
`
`
`
`
`
`
`
`
`
`user password, and access to the data region on the portable
`
`
`
`
`
`
`
`
`
`
`
`storage medium may be permitted by specifying the user
`
`
`
`
`
`
`
`
`
`password and the path information.
`
`
`
`
`
`In the access control method, prohibiting at least one of
`
`
`
`
`
`
`
`
`
`
`the write and read may be set independently with respect to
`
`
`
`
`
`
`
`
`
`
`
`each of the plurality of users.
`
`
`
`
`
`
`Another object of the present invention is to provide a
`
`
`
`
`
`
`
`
`
`
`storage apparatus which writes information on a portable
`
`
`
`
`
`
`
`
`storage medium in response to a request from at least one
`
`
`
`
`
`
`
`
`
`
`
`host unit, comprising a writing unit for writing on the
`
`
`
`
`
`
`
`
`
`
`detachable storage medium a user password and a master
`
`
`
`
`
`
`
`
`
`password which limit access to the portable storage medium;
`
`
`
`
`
`
`
`
`
`and an access control part which permits a modification of
`
`
`
`
`
`
`
`
`
`
`the user password by specifying the master password, per-
`
`
`
`
`
`
`
`
`mits access to a data region on the portable storage medium
`
`
`
`
`
`
`
`
`
`
`by specifying the user password which is provided in
`
`
`
`
`
`
`
`
`
`common with respect to a plurality of users, and prohibits at
`
`
`
`
`
`
`
`
`
`
`least one of write and read with respect to each of the
`
`
`
`
`
`
`
`
`
`
`
`
`plurality of users. According to the storage apparatus of the
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`10
`
`
`15
`
`
`
`
`
`
`
`20
`
`25
`
`30
`
`35
`
`
`40
`
`
`45
`
`
`
`50
`
`
`
`55
`
`60
`
`
`
`
`
`65
`
`
`
`
`
`
`
`BACKGROUND OF THE INVENTION
`
`
`
`
`1. Field of the Invention
`
`
`
`
`
`
`
`
`
`
`
`
`The present invention generally relates to access control
`
`
`
`
`
`
`
`methods, storage apparatuses and storage mediums, and
`
`
`
`
`
`
`
`more particularly to an access control method, a storage
`
`
`
`
`
`
`
`
`apparatus and a storage medium for providing security with
`
`
`
`
`
`
`
`
`
`respect to data stored in the storage medium.
`
`
`
`
`
`
`
`
`2. Description of the Related Art
`
`
`
`
`
`
`Conventionally, portable storage mediums typified by
`
`
`
`
`
`
`optical disks are designed to achieve high compatibility
`
`
`
`
`
`
`
`
`among storage apparatuses such as optical disk units. Hence,
`
`
`
`
`
`
`
`
`
`no special mechanism is provided with respect to the secu-
`
`
`
`
`
`
`
`
`
`
`rity of data and programs stored in the optical disk. For this
`
`
`
`
`
`
`
`
`
`
`
`
`reason, if an optical disk of an authorized user falls in the
`
`
`
`
`
`
`
`
`
`
`
`
`hands of an unauthorized user, the unauthorized user can
`
`
`
`
`
`
`
`
`
`make access to the data and the programs stored in this
`
`
`
`
`
`
`
`
`
`
`
`optical disk. As a result, the unauthorized user may without
`
`
`
`
`
`
`
`
`
`
`authorization read the data and the programs from the
`
`
`
`
`
`
`
`
`
`optical disk or, even rewrite the data and the programs stored
`
`
`
`
`
`
`
`
`
`
`
`in the optical disk.
`
`
`
`
`Accordingly, the conventional optical disk is not provided
`
`with a special mechanism with respect to the security of the
`
`
`
`
`
`
`
`
`data and the programs stored in the optical disk, and there
`
`
`
`
`
`
`
`
`
`
`
`were problems in that an unauthorized user may without
`
`
`
`
`
`
`
`
`
`
`
`authorization read the data and the programs from the
`
`
`
`
`
`
`
`
`
`optical disk or, even rewrite the data and the programs stored
`
`
`
`
`
`
`
`
`
`in the optical disk.
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`On the other hand, in the case of portable magnetic disks
`
`
`
`
`
`
`
`
`
`
`
`such as floppy disks, it is known to provide a protection
`
`
`
`
`
`
`
`
`
`
`
`function by storing a password with respect to a document
`
`
`
`
`
`
`
`
`
`
`which is stored in the floppy disk, so that an access to the
`
`
`
`
`
`
`
`
`
`
`
`
`
`document cannot be made unless the password is input.
`
`
`
`
`
`
`
`
`
`However, this protection function had the following prob-
`
`
`
`
`
`
`
`
`lems in a case where the floppy disk is used by a plurality
`
`
`
`
`
`
`
`
`
`
`
`
`
`of users who use a common computer system, for example.
`
`
`
`
`
`
`
`
`
`
`In other words, all of the plurality of users must be informed
`
`
`
`
`
`
`
`
`
`
`
`
`of the password necessary to make access to the floppy disk,
`
`
`
`
`
`
`
`
`
`
`
`and there were problems in that it is difficult to manage the
`
`
`
`
`
`
`
`
`
`
`
`
`password, and that
`the management of the password
`
`
`
`
`
`
`
`
`becomes extremely troublesome and complex when the
`
`
`
`
`
`
`
`number or the number of kinds of floppy disks becomes
`
`
`
`
`
`
`
`
`
`large.
`
`
`
`SUMMARY OF THE INVENTION
`
`
`
`
`Accordingly, it is an object of the present invention to
`
`
`
`
`
`
`
`
`
`
`provide a novel and useful access control method, storage
`
`
`
`
`
`
`
`
`
`apparatus and storage medium,
`in which the problems
`described above are eliminated.
`
`
`
`
`
`
`
`
`
`
`
`
`Another and more specific object of the present invention
`
`
`
`
`
`
`
`
`
`to provide an access control method, a storage apparatus and
`
`
`
`
`
`
`
`
`
`a storage medium which can positively prevent unauthorized
`
`
`
`
`
`
`
`
`access to data and programs stored in a portable storage
`
`
`
`
`
`
`
`
`
`
`medium such as optical disks, and to enable a relatively
`
`
`
`
`
`
`
`
`
`
`simple management of a password, by providing a simple
`
`
`
`
`
`
`
`
`
`mechanism with respect to the security of the data and the
`
`
`
`
`
`
`
`
`
`
`
`programs stored in the portable storage medium.
`
`
`
`
`
`
`
`Still another object of the present invention is to provide
`
`
`
`
`
`
`
`
`
`
`an access control method for a storage apparatus which
`
`
`
`
`
`
`
`
`
`writes information on a portable storage medium in response
`
`
`
`
`
`
`
`
`to a request from at least one host unit, comprising the steps
`
`
`
`
`
`
`
`
`
`
`
`
`of writing on the detachable storage medium a user pass-
`
`
`
`
`
`
`
`
`
`
`
`Page 23 of 33
`
`Page 23 of 33
`
`

`
`
`
`US 6,738,877 B1
`
`
`
`
`
`
`
`
`
`
`
`3
`present invention, it is possible to positively prevent unau-
`
`
`
`
`
`
`
`
`thorized access to data and programs stored in a portable
`
`
`
`
`
`
`
`
`
`storage medium such as optical disks, and to enable a
`
`
`
`
`
`
`
`
`
`relatively simple management of a password, by providing
`
`
`
`
`
`
`
`a simple mechanism with respect to the security of the data
`
`
`
`
`
`
`
`
`
`
`and the programs stored in the portable storage medium.
`
`
`
`
`
`
`
`
`
`In the storage apparatus, the storage apparatus may be
`
`
`
`
`
`
`
`
`
`coupled to a plurality of host units via a plurality of paths,
`
`
`
`
`
`
`
`
`
`
`
`
`path information related to the paths may be added to the
`
`
`
`
`
`
`
`
`
`
`
`user password, and access to the data region on the portable
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`storage medium may be permitted by specifying the user
`
`
`
`
`
`password and the path information.
`In the storage apparatus, prohibiting at least one of the
`
`
`
`
`
`
`
`
`
`write and read may be set independently with respect to each
`
`
`
`
`
`
`
`
`
`
`
`of the plurality of users.
`
`
`
`
`Still another object of the present invention is to provide
`
`
`
`
`
`
`
`
`
`
`a storage apparatus which reads information from a portable
`
`
`
`
`
`
`
`
`
`storage medium in response to a request from at least one
`
`
`
`
`
`
`
`
`
`
`
`host unit, comprising a reading unit for reading from the
`
`
`
`
`
`
`
`
`
`
`portable storage medium a master password and a user
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`password which limit access to the portable storage medium;
`
`
`
`
`
`
`
`
`
`
`and an access control part which permits a modification of
`
`
`
`
`
`
`
`
`the user password by specifying the master password, per-
`
`
`
`
`
`
`
`
`
`
`
`mits access to a data region on the portable storage medium
`
`
`
`
`
`
`
`
`
`by specifying the user password which is provided in
`
`
`
`
`
`
`
`
`
`
`common with respect to a plurality of users, and prohibits at
`
`
`
`
`
`
`
`
`
`
`
`
`least one of write and read with respect to each of the
`
`
`
`
`
`
`
`
`
`
`plurality of users. According to the storage apparatus of the
`
`
`
`
`
`
`
`
`present invention, it is possible to positively prevent unau-
`
`
`
`
`
`
`
`
`
`thorized access to data and programs stored in a portable
`
`
`
`
`
`
`
`
`
`storage medium such as optical disks, and to enable a
`
`
`
`
`
`
`
`relatively simple management of a password, by providing
`
`
`
`
`
`
`
`
`
`
`a simple mechanism with respect to the security of the data
`
`
`
`
`
`
`
`
`
`and the programs stored in the portable storage medium.
`In the storage apparatus, the storage apparatus may be
`
`
`
`
`
`
`
`
`
`coupled to a plurality of host units via a plurality of paths,
`
`
`
`
`
`
`
`
`
`
`
`
`path information related to the paths may be added to the
`
`
`
`
`
`
`
`
`
`
`
`user password, and access to the data region on the portable
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`storage medium may be permitted by specifying the user
`
`
`
`
`
`password and the path information.
`In the storage apparatus, prohibiting at least one of the
`
`
`
`
`
`
`
`
`
`write and read may be set independently with respect to each
`
`
`
`
`
`
`
`
`
`
`of the plurality of users.
`
`
`
`
`
`A further object of the present invention is to provide a
`
`
`
`
`
`
`
`
`
`
`
`storage medium comprising a data region storing data; and
`
`
`
`
`
`
`
`
`
`a region other than said data region, storing a master
`
`
`
`
`
`
`
`
`
`
`password and a user password which limit access to the
`
`
`
`
`
`
`
`
`
`
`storage medium, wherein the master password is provided to
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`permit a modification of the user password by specifying the
`
`
`
`
`
`
`
`
`
`master password, and the user password is provided in
`
`
`
`
`
`
`
`
`
`
`common with respect to a plurality of users and permits
`
`
`
`
`
`
`
`
`
`
`access to a data region on the storage medium by specifying
`
`
`
`
`
`
`
`
`
`
`
`the user password, and prohibits at least one of write and
`
`
`
`
`
`
`
`
`
`
`
`read with respect to each of the plurality of users. According
`
`
`
`
`
`
`
`
`
`
`
`to the storage medium of the present invention, it is possible
`
`
`
`
`
`
`
`
`to positively prevent unauthorized access to data and pro-
`
`
`
`
`
`
`
`
`
`grams stored in a portable storage medium such as optical
`
`
`
`
`
`
`
`
`
`disks, and to enable a relatively simple management of a
`
`
`
`
`
`
`
`
`password, by providing a simple mechanism with respect to
`
`
`
`
`
`
`
`
`
`
`the security of the data and the programs stored in the
`
`
`
`portable storage medium.
`In the storage medium, path information related to a path
`
`
`
`
`
`
`
`
`
`
`may be added to the user password, and the user password
`
`
`
`
`
`
`
`
`
`
`
`and the path information may be provided to permit access
`
`
`
`
`
`
`
`
`
`
`to said data region by specifying the user password and the
`
`
`
`
`
`
`
`
`
`
`
`
`
`path information.
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`10
`
`
`
`15
`
`
`20
`
`25
`
`30
`
`
`
`35
`
`
`
`40
`
`45
`
`
`
`50
`
`
`
`55
`
`
`
`60
`
`
`
`65
`
`
`
`Page 24 of 33
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`4
`In the storage medium, prohibiting at least one of the
`
`
`
`
`
`
`
`
`
`write and read may be set independently with respect to each
`
`
`
`
`
`
`
`
`
`
`of the plurality of users.
`
`
`
`
`
`Other objects and further features of the present invention
`
`
`
`
`
`
`
`
`
`will be apparent from the following detailed description
`
`
`
`
`
`
`
`
`when read in conjunction with the accompanying drawings.
`
`
`
`
`
`
`
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`
`
`
`
`FIG. 1 is a system block diagram showing a first embodi-
`
`
`
`
`
`
`
`
`
`ment of a storage apparatus according to the present inven-
`
`
`
`
`
`
`
`
`
`tion;
`
`FIG. 2 is a system block diagram showing an embodiment
`
`
`
`
`
`
`
`
`of the construction of a drive unit;
`
`
`
`
`
`
`
`FIG. 3 is a cross sectional view showing the general
`
`
`
`
`
`
`
`
`
`construction of an enclosure;
`
`
`
`
`FIG. 4 is a time chart for explaining the operation of the
`
`
`
`
`
`
`
`
`
`
`
`first embodiment when carrying out a write operation;
`
`
`
`
`
`
`
`
`FIG. 5 is a diagram for explaining a format of a master
`
`
`
`
`
`
`
`
`
`
`
`
`password, a user password and a user name list;
`
`
`
`
`
`
`
`
`
`FIG. 6 is a time chart for explaining the operation of the
`
`
`
`
`
`
`
`
`
`
`
`first embodiment when carrying out a read operation;
`
`
`
`
`
`
`
`
`FIG. 7 is a diagram for explaining a format of the master
`
`
`
`
`
`
`
`
`
`
`
`
`password, the user password and the user name list;
`
`
`
`
`
`
`
`
`
`FIG. 8 is a flow chart for explaining the operation when
`
`
`
`
`
`
`
`
`
`
`inserting an optical disk into the storage apparatus;
`
`
`
`
`
`
`
`
`FIG. 9 is a flow chart for explaining the operation when
`
`
`
`
`
`
`
`
`
`
`executing a write/read command;
`
`
`
`
`FIG. 10 is a diagram for explaining a first modification of
`
`
`
`
`
`
`
`
`
`
`the format of the master password, the user password and the
`
`
`
`
`
`
`
`
`
`
`
`user name list;
`
`
`
`FIG. 11 is a diagram for explaining a second modification
`
`
`
`
`
`
`
`
`
`of the format of the master password, the user password and
`
`
`
`
`
`
`
`
`
`
`
`the user name list;
`
`
`
`
`FIG. 12 is a diagram for explaining a third modification
`
`
`
`
`
`
`
`
`
`
`of the format of the master password, the user password and
`
`
`
`
`
`
`
`
`
`
`
`the user name list;
`
`
`
`
`FIG. 13 is a system block diagram showing a second
`
`
`
`
`
`
`
`
`
`
`embodiment of the storage apparatus according to the
`
`
`
`
`
`
`
`
`present invention;
`
`
`FIG. 14 is a time chart for explaining the operation of the
`
`
`
`
`
`
`
`
`
`
`second embodiment when carrying out a write operation;
`
`
`
`
`
`
`
`
`FIG. 15 is a diagram for explaining a format of a master
`
`
`
`
`
`
`
`
`
`
`
`
`password, a user password and a user name list;
`
`
`
`
`
`
`
`
`
`FIG. 16 is a time chart for explaining the operation of the
`
`
`
`
`
`
`
`
`
`
`second embodiment when carrying out a read operation;
`
`
`
`
`
`
`
`
`FIG. 17 is a diagram for explaining a format of the master
`
`
`
`
`
`
`
`
`
`
`
`password, the user password and the user name list;
`
`
`
`
`
`
`
`
`
`FIG. 18 is a flow chart for explaining the operation when
`
`
`
`
`
`
`
`
`
`
`inserting an optical disk into the storage apparatus;
`
`
`
`
`
`
`
`
`FIG. 19 is a flow chart for explaining the operation when
`
`
`
`
`
`
`
`
`
`
`executing a write/read command;
`
`
`
`
`FIG. 20 is a diagram for explaining a first modification of
`
`
`
`
`
`
`
`
`
`
`the format of the master password, the user password and the
`
`
`
`
`
`
`
`
`
`
`
`user name list;
`
`
`
`FIG. 21 is a diagram for explaining a second modification
`
`
`
`
`
`
`
`
`
`of the format of the master password, the user password and
`
`
`
`
`
`
`
`
`
`
`
`the user name list; and
`
`
`
`
`
`FIG. 22 is a diagram for explaining a third modification
`
`
`
`
`
`
`
`
`
`
`of the format of the master password, the user password and
`
`
`
`
`
`
`
`
`
`
`
`the user name list.
`
`
`
`
`DESCRIPTION OF THE PREFERRED
`
`
`
`EMBODIMENTS
`
`FIG. 1 is a system block diagram showing a first embodi-
`
`
`
`
`
`
`
`
`
`ment of a storage apparatus according to the present inven-
`
`
`
`
`
`
`
`
`
`
`
`
`Page 24 of 33
`
`

`
`
`
`US 6,738,877 B1
`
`
`
`
`
`
`
`5
`tion. This first embodiment of the storage apparatus employs
`
`
`
`
`
`
`
`
`
`a first embodiment of an access control method according to
`
`
`
`
`
`
`
`
`
`
`the present invention, and creates a first embodiment of a
`
`
`
`
`
`
`
`
`
`
`storage medium according to the present invention. In this
`
`
`
`
`
`
`
`
`
`embodiment, the present invention is applied to an optical
`
`
`
`
`
`
`
`
`
`disk unit which writes information on and/or reads infor-
`
`
`
`
`
`
`
`
`mation from an optical disk, that is, read/write information
`
`
`
`
`
`
`
`
`with respect to the optical disk.
`
`
`
`
`
`
`Astorage apparatus 1 is made up of a drive unit 2, and an
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`optical disk 3 is inserted with respect to the drive unit 2 as
`
`
`
`
`
`
`
`
`
`
`
`
`
`a portable storage medium. This storage apparatus 1 is
`
`
`
`
`
`
`
`
`
`provided as an auxiliary storage apparatus of a host unit 5,
`
`
`
`
`
`
`
`
`
`
`
`and the drive unit 2 writes data in the optical disk 3 and reads
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`data from the optical disk 3, in response to an instruction
`
`
`
`
`
`
`
`
`
`
`
`
`from the host unit 5. The host unit 5 is made up of a known
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`personal computer which is made up of a keyboard, a
`
`
`
`
`
`
`
`
`
`display part, a main body part and the like.
`
`
`
`
`
`
`
`
`
`FIG. 2 is a system block diagram showing an embodiment
`
`
`
`
`
`
`
`
`
`
`of the construction of the drive unit 2. As shown in FIG. 2,
`
`
`
`
`
`
`
`
`
`
`
`
`
`the drive unit 2 generally includes a control unit 10 and an
`
`
`
`
`
`
`
`
`
`
`
`
`enclosure 11. The control unit 10 includes a microprocessor
`
`
`
`
`
`
`
`
`
`
`unit (MPU) 12 which generally controls the operation of the
`
`
`
`
`
`
`
`
`
`optical disk unit, an interface 17 which exchanges com-
`
`
`
`
`
`
`
`
`mands and data between the host unit 5, an optical disk
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`controller (ODC) 14 which carries out processes required to
`read/write data with respect to the optical disk 3, a digital
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`signal processor (DSP) 16, and a buffer memory 18. The
`
`buffer memory 18 is used in common by the MPU 12, the
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`ODC 14 and the interface 17, and includes dynamic random
`
`
`
`
`
`
`
`
`access memory (DRAM), for example. A crystal oscillator
`
`
`
`
`
`
`
`101 is coupled to the MPU 12.
`The ODC 14 includes a formatter 14-1 and error correc-
`
`
`
`
`
`
`
`
`
`tion code (ECC) processor 14-2. At the time of a write
`
`
`
`
`
`
`
`
`
`
`
`access, the formatter 14-1 divides NRZ write data into sector
`
`
`
`
`
`
`
`
`
`
`units of the optical disk 3 and generates a recording format,
`
`
`
`
`
`
`
`
`
`
`
`and the ECC processor 14-2 generates and adds an ECC with
`
`
`
`
`
`
`
`
`
`
`
`respect to sector write data units and also generates and adds
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`if necessary a cyclic redundancy check (CRC) code. Further,
`
`the ECC processor 14-2 converts the sector data with the
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`encoded ECC into a 1-7 run length limited (RLL) code, for
`example.
`
`At the time of a read access, a reverse conversion of the
`
`
`
`
`
`
`
`
`
`
`
`
`1-7 RLL is carried out with respect to the sector data, and
`
`
`
`
`
`
`
`
`
`
`
`
`after carrying out the CRC, the error detection and error
`
`
`
`
`
`
`
`
`
`
`correction using the ECC are carried out in the ECC pro-
`
`
`
`
`
`
`
`
`
`
`cessor 14-2. Further,
`the NRZ data in sector units are
`
`
`
`
`
`
`
`
`
`
`connected in the formatter 14-2 so as to transfer a NRZ read
`
`
`
`
`
`
`
`
`
`
`
`
`data stream to the host unit 5.
`
`
`
`
`
`
`
`Awrite large scale integrated (LSI) circuit 20 is provided
`
`
`
`
`
`
`
`
`
`
`with respect to the ODC 14. This write LSI 20 includes a
`
`
`
`
`
`
`
`
`
`
`
`
`write modulator 21 and a laser diode control circuit 22. A
`
`
`
`
`
`
`
`
`
`
`
`control output of the laser diode control circuit 22 is supplied
`
`
`
`
`
`
`
`
`
`
`
`to a laser diode unit 30 which is provided in an optical unit
`
`
`
`
`
`
`
`
`
`
`
`
`
`of the enclosure 11. The laser diode unit 30 integrally
`
`
`
`
`
`
`
`
`
`
`includes a laser diode 30-1 and a monitoring detector 30-2.
`
`
`
`
`
`
`
`
`
`
`The write modulator 21 converts the write data into the data
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`format of the pit position modulation (PPM) recording (or
`
`
`
`
`
`
`
`
`mark recording) or, a pulse width modulation (PWM)
`
`
`
`
`recording (or edge recording).
`When recording and reproducing data with respect to the
`
`
`
`
`
`
`
`
`
`optical disk 3 using the laser diode unit 30, this embodiment
`
`
`
`
`
`
`
`
`
`
`
`can use any one of writable magneto-optical (MO) cartridge
`
`
`
`
`
`
`
`
`
`mediums having the storage capacities of 128 MB, 230 MB,
`
`
`
`
`
`
`
`
`
`
`540 MB and 640 MB. In the MO cartridge mediums having
`
`
`
`
`
`
`
`
`
`
`
`the storage capacities of 128 MB and 230 MB, the PPM
`
`
`
`
`
`
`
`
`
`
`
`recording is employed to record the data in correspondenc