WORLD INTELLECTUAL PROPERTY ORGANIZATION
`International Bureau
`
`INTERNATIONAL APPLICATION PUBLISHED UNDER THE PATENT COOPERATION TREATY (PCT)
`
`(51) International Patent Classification:
`
`(11) International Publication Number:
`
`WO 92/21224
`
`”°‘ °'““““‘'
`
`(43) International Publication Date:
`
`10 December 1992 (10.12.92)
`
`(21) International Application Number:
`
`PCT/US92/04534
`
`(22) International Filing Date:
`
`23 May 1992 (2ti.05_92)
`
`(30) Priority data:
`706,760
`
`29 May 1991 (2905.91)
`
`US
`
`(71) Appliutnt: MAXOPTIX CORPORATION [US/US]; 2520
`Junction Avenue, San Jose, CA 95134 (US).
`
`(72) Inventor: JORGENSEN, Richard, A.
`nue, San Jose, CA 95128 (US).
`
`; 2068 Bel Air Ave-
`
`(74) Agents: McFARLAND, James, D. et al.; Blakely, Soko-
`loff, Taylor & Zafman, 12400 Wilshire Boulevard, Ttb
`Floor, Los Angeles, CA 90025 (US).
`
`(81) Designated States: AT, AT (European patent), AU, BB, BE
`(European patent), BF (OAPI patent), BG, BJ (OAPI
`patent), BR, CA, CF (OAPI patent), CG (OAPI patent),
`CH, CH (European patent), CI (OAPI patent), CM
`(OAPI patent), DE, DE (European patent), DK, DK
`(European patent), ES, ES (European patent), FI, FR
`(European patent), GA (OAPI patent), GB, GB (Euro-
`pean patent), GN (OAPI patent), GR (European pa-
`tent), HU, IT (European patent), JP, KP, KR, LK, LU,
`LU (European patent), MC (European patent), MG, ML
`(OAPI patent), MR (OAPI patent), MW, NL, NL (Euro-
`pean patent), NO, RO, RU, SD, SE, SE (European pa-
`tent), SN (OAPI patent), TD (OAPI patent), TG (OAPI
`patent).
`
`Published
`Without intematfanal search report and to be republished
`upon receipt of that report.
`
`(54)Title: OPTICAL DISK DRIVE ASSEMBLY HAVING SELECTABLE COMPRESSION AND EMULATION
`
`(57) Abstract
`
`A system is disclosed for storing data on, and re-
`ceiving data front, an optical disk. The data may be pro-
`vided by a host computer. A compression/decompression
`circuit is included, and the data may be compressed or un—
`compressed in this circuit, at the option of a user, who can
`select from compression modes including a bypass mode
`and a target ratio mode. A converter circuit is included for
`translating from the host computer‘s commands to the opt-
`ical disk drives commands. The user may select a specific
`emulation for compatibility with other disk systems, and
`the user may select specific setup parameters for compatib-
`ility with a variety of host computers. Process control circu-
`itry operates the compression and decompression circuit in
`
`one of a number of modes and emulations. The system
`may be enclosed in a full form factor size package. A dis-
`play and manual controls, accessible to a user, are pro-
`vided for user interface with the system. Many user options
`are provided to enhance compatibility with a wide variety
`of disk systems. The present invention provides a large sto-
`rage capability for storing large amounts of information in
`less physical space. The system of the present invention is
`suitable for ”plug and play" installation by computer man-
`ufacturers. As an additional advantage, the user can easily
`monitor data compression with the display that shows the
`compression ratio, continuously updated.
`
`Data and
`"‘5“"-'="°"3
`
`Pmcess comm cflcun
`
`compression,
`Mama,
`gemmpreggion I
`
`Circuit
`
`-
`
`'
`
`Opucal Disk Drive 5ub_AssemW
`
`
`
`Apple 1011
`
`Apple 1011
`U.S. Pat. 9,189,437
`
`

`
`FOR THE PURPOSES OF INf"0KMATION ONLY
`
`Cactus used us identify Slates party to the PC!‘ on the fmm pages of pamphlets publishing international
`applications under Ihe PCT.
`
`AT
`AU
`H3
`BE
`
`Bh‘
`BJ
`ER
`
`FF
`
`Aandrm
`Aumr;:|:.1
`BurI'I.|du:
`Belgium
`Burklmx I-Aw
`Bulgaria
`Bunill
`Bnull
`('a1nauJu
`('|.‘n[r'u1 -lrrn..:u Rupuhliu
`( ‘tango
`.‘:w1I.n.'| land
`(Tm: d'iwuru
`l.'a1.m|.'ruun
`(Tn:|:hm.lnvnLi.1
`Iidsrnumy
`I)|:n|n.1r|n
`Spain
`
`'
`
`'
`
`_
`
`1-in|.mnl
`I'~r41:cu
`(rah-un
`United Kingdom
`Uuittua
`(ir|,'L'l.'L'
`Hungary
`In:|a|nd
`Iluly
`Jdflilll
`lJu:rnu¢.-r.1!'lc P¢u}IlI:'5 Rupulbliu
`of Korea
`RI.-puhlu: of Korea
`l icclilcnaluin
`bri lunka
`l.ms:ruhourg
`Muahlcti
`hLu|.'lgusL'.Ir
`
`Mali
`Muugulia
`M.mril.'1I1iu
`M.I.l-‘N-Ii
`Nulllcriunda
`Norway
`l’u|.md
`Huniallid
`Huhhiflll Federation
`Sudan
`Swt.-dell
`Sunug.-1|
`Soviet Union
`(Thad
`Tugu
`Unitud States of Anicrical
`
`'
`
`'
`
`

`
`W0 92/21224
`
`PCTI US92/ 04534
`
`OPTICAL DISK DRIVE ASSEMBLY HAVING SELECTABLE
`
`COMPRESSION AND EMULATION
`
`BACKGROUND OF THE INVENTION
`
`EIELD QF INVENTIQN
`
`The present
`
`invention relates to optical disk drives for
`
`storage of digital
`
`information. More specifically,
`
`the present
`
`invention relates to a system including an optical disk drive and
`
`associated circuitry for data compression and conversion of
`
`commands, with a capability for selection of the compression
`
`mode. emulation of a number of pre-existing systems and
`
`seiection of setup parameters. The system of the present
`
`invention may be enclosed in a housing with a size corresponding
`
`to the industry's 5.25“ full height form factor standard. with
`
`manual controls for mode. emulation, and setup selection.
`
`QESEQRIPTIQN QF RELATED AB]
`
`The capability for storage of digital data has expanded
`
`dramatically over the past twenty years. Digital
`
`information was
`
`first stored on reeis of magnetic recording tape;
`
`‘however,
`
`this
`
`storage method proved cumbersome, access to data was slow. and
`
`required many large reets of tape. The advent of the floppy disk
`
`ushered in a new era of speed and information density for digital
`
`

`
`W0 92/21 224
`
`PCTIUS92/04534
`
`. 2 .
`
`storage. Over the past few years, new products. such as the hard
`
`disk drive (often called the Winchester drive) have evolved. so
`
`that at present. storage capacities of 40 MB or more are common
`
`in hard disks internal to many personal computers, and access to
`
`much of the data is very quick.
`
`Much greater storage capacities are possible in optical
`
`disks;
`
`for example, the Maxoptix® RXT-BOOHS. available from
`
`Maxoptix® Corporation of San Jose, CA. the assignee herein. can
`
`store 786 Megabytes of information on a write once optical disk.
`
`The Maxoptixii-C RXT-BOOHS drive is available in a half-height
`
`housing. Optical drives typically allow writing only once. and are
`
`often called “WORM” drives (for write-once, read-many). Erasabie
`
`optical drives are also available.
`
`An optical disk is inserted into the disk drive for writing
`
`or reading, and the disk can be removed for archival purposes. As
`
`a space saving media. optical disks are attractive for many uses.
`
`particularly when large amounts of data must be stored.
`
`Examples of optical disks include compact disks (CD5) used for
`
`digital music recording.
`
`Other uses for optical disks includes
`
`library storage of information such as images, databases,
`
`spreadsheets, desk-top publishing. CAD files, programs. binary
`
`data, and word processing. Optical disks are useful as backup
`
`storage media for computer networks having one or more disk
`
`._ drives. Massive storage capabilities are useful
`
`in medical
`
`processes that produce a large amount of digital data. For
`
`example. imaging processes, such as MRl (Magnetic Resonance
`
`

`
`W0 92/21 224
`
`_
`
`PCTI US92/04534
`
`- 3 -
`
`imaging), output large quantities of data that must be stored
`
`quickly and efficiently. Later, when time is available , the data
`
`is processed to provide images useful for diagnosis and surgery.
`
`As discussed. optical disks are useful for storage of
`
`iarge amounts of information. However.
`
`it would be an advantage
`
`to provide an even greater storage capability than that provided
`
`by the existing optical disk systems. To increase storage
`
`capacity of other non-optical digital recording formats such as
`hard disks. data compression circuitry has been used. For
`
`example, a data compression chip, the #9703 data compression
`
`co-processor,
`
`is available from Stac Electronics, of Carlsbad,
`
`California. However, data compression has not been used with
`
`optical disk drives in any meaningful way:
`
`one so-called data
`
`"compression" system for optical disk drives provides almost
`
`negligible storage reduction (0-5%) by using simple software
`
`driven routines. For example,
`
`it this system sees a string of
`
`blanks (zeros),
`
`it simply skips the data, effectively throwing it
`
`away. To significantly and meaningfully increase storage
`
`abilities,
`
`it would be an advantage to provide a compression
`
`system for an optical disk drive that can compress data two or
`
`more times. For exampie, with a 3:1 compression ratio, a
`
`736 Megabyte drive can store 2.35 Gigabytes of
`
`information.
`
`Another problem with data compression. as applied to
`
`._ optical disk systems.
`
`is the lack of compatibility between disks
`
`recorded without compression, and disks recorded with
`
`compression. Furthermore. whether or not disks are recorded
`
`

`
`WO 92121224
`
`'
`
`PCTIUS92/04534
`
`with compression. optical disks are not fully portable between
`
`systems.
`
`In other words, an optical disk written with one system
`
`may not be usable by another.
`
`It would be an advantage to provide
`
`an optical disk system that can compress data for greater storage
`
`density, while having a capability for emulating any of a number
`
`of pre-existing disk drives. so that the system would be
`
`compatible with optical disks recorded by those pre-existing
`systems. Also,
`it would be an advantage if a user could select the '
`
`emulation parameters and the compression mode.
`
`it would be a
`
`further advantage if the user could select the emulation and
`
`compression manually from the optical disk drive housing,
`
`without accessing a computer.
`
`in the computer industry, great effort has been expended
`
`to provide faster, more powerful computers in smaller, compact,
`
`marketable packages. This effort has lead to the development of
`
`de tacto standards that enhance compatibility between products
`
`of different manufacturers. Standards have developed for
`
`communications between computers and Winchester hard disks;
`
`most present-day computers are designed with an ability for
`
`communication with a Winchester hard disk. This
`
`communications ability is embodied in both software and
`
`hardware.
`
`Further. de tacto standards include the housing size of
`
`,- disk drives; many large computer manufacturers follow the
`
`industry's standards, and have allotted an internal space the size
`
`of a standardized “full height form factor‘ for their 5.25‘ disk
`
`

`
`W0 92/ 21 224
`
`PCTIUS92/04534
`
`_ 5 -
`
`drives.
`
`This full height housing size is available from a number
`
`of OEM manufacturers of disk drives;
`
`thus. any of these DEM
`
`manufacturers’ drives can be installed successfully.
`
`Because the space for a full height housing has already
`
`been allotted by many manufacturers.
`
`it would be an advantage if
`
`an optical disk drive were available in a full height form factor
`
`package, and it would be a further advantage if the package were
`
`compatible with the Winchester drive communication links that
`
`are standard in most computers. As stated above, write once
`
`optical disk drives are available in the half height form factor
`
`size. However, these drives inherently have different
`
`communication requirements than the Winchester drives.
`
`in order
`
`to achieve compatibility with this type of optical drive,
`
`the
`
`computer must be re-programmed with a software driver that
`
`converts to the appropriate commands for interfacing with the
`
`optical disk drive. However, software-based conversion is
`
`relatively slow, and far greater speeds are possible by using an
`
`available hardware-based conversion circuit. An example of a
`
`conversion circuit containing hardware specifically designed to
`
`perform the conversion at high speed is the Optical Conversion
`
`Unit
`
`(OCUTM) available from Ten X Technology Corporation of
`
`Austin, Texas. The OCUT” acts as an interface to connect the
`
`Winchester communications systems with the optical disk drive.
`
`._
`
`in one configuration,
`
`the OCUT” is available in a half height form
`
`factor package. A front panel display is provided that supports
`
`entry of data at
`
`initialization and displays information about
`
`the
`
`

`
`W0 92/21224
`
`PCI‘/US92!04534
`
`- 5 -
`
`operation of the unit.
`
`If a iull form package were available.
`
`it
`
`would be a further advantage if
`
`it included data compression
`
`circuitry for increasing the data storage capacity. and it the data
`
`compression could be controlled from the front panel for
`
`effective and convenient user interface.
`
`It would be an additional advantage if the system
`
`contained error detection and correction circuitry to ensure that
`
`the compressed data is written correctly to the disk, and that the
`
`data is read correctly from the disk.
`
`it would also be an
`
`advantage if errors were corrected in the instance when the data
`
`is incorrectly read from the disk.
`
`It would be an even further
`
`advantage if the error correction were provided after data
`
`compression during a write, and before data decompression during
`
`a read.
`
`

`
`WO 92/21224
`
`PCTI U592!04534
`
`- 7 .
`
`SUMMARY QF IHE INVENHQE
`
`The system of the present invention provides an optical
`
`disk drive system that
`
`includes data compression to achieve
`
`storage capacities much greater than previously available.
`
`in
`
`addition. the compression mode and the emulation parameters can
`
`be selected to achieve compatibility with a large number of
`
`pre-existing optical disks and optical disk systems. The user can
`
`also select setup parameters in order to achieve compatibiiity
`
`with a variety of host computers. A number of preset seiections
`
`(presets) are avaiiable for the user to select,
`
`in a single stroke,
`
`the setup parameters for some common host computers. The
`
`system can be enclosed in a standard size housing, the industry's
`
`5.25" full height form factor size.
`
`that
`
`is easily installed in most
`
`standard computers.
`
`Furthermore, the system is compatible with
`
`most hard drive communication capabilities provided by standard
`
`computers.
`
`The present invention provides a system for storing data
`
`on, and receiving data from, an optical disk. The data may be
`
`produced by a host computer or any other appropriate digital
`
`device. The system of the present invention comprises an optical
`
`disk drive sub-assembly and a circuit for compressing data
`
`transmitted into the sub-assembly, and for decompressing data
`
`transmitted from the sub-assembiy.
`
`The
`
`compressionrdeoompression circuit communicates with the
`
`optical disk drive sub-assembly via a standard communications
`
`bus that transmits data between the optical disk drive sub-
`
`

`
`W0 92/21224
`
`PCTIU592!04534
`
`- 3 .
`
`assembly and the compressionldecompression circuit. Control
`
`circuitry is provided for operating the
`
`compressionfdecompression circuit
`
`in any of a number of
`
`available compression modes and emulations.
`
`in one compression mode, the
`
`compressionldecompression circuit
`
`is activated and operates to
`
`compress or decompress the data as much as possible within its
`
`capabilities.
`
`In another mode. a ‘bypass’ mode, the
`
`compressionfdecompression circuit
`
`is de-activated (bypassed) so
`
`that no compression or _decompression occurs.
`
`In still another
`
`mode, a "target ratio“ mode, a target compression ratio is
`
`selected before a writing operation. The target ratio may be
`
`selected from a number of available options. During operation,
`
`the compression/decompression circuit
`
`is controlled so that
`
`compression occurs only if the target ratio is attainable;
`
`if the
`
`target
`
`ratio is not attainable,
`
`then the compression circuit
`
`is
`
`bypassed and the data is written in its uncompressed form.
`
`In the
`
`writing process,
`
`the existence of compression is associated with
`
`each partition block of data on the optical disk by writing this
`
`information to the optical disk. Thus, when the data is to be read,
`
`the existence of data compression is first determined by reading
`
`this information from the disk, and then the process control
`
`circuit accordingly either bypasses or sets the decompression.
`
`. Some compression modes may be used with specific emuiations
`
`of other optical disk drives.
`
`

`
`W0 92/21224
`
`PCT/US92/04534
`
`- 9 -
`
`The compression modes may be selected by user
`
`manipulation of manual controls such as buttons electrically
`
`connected to the system's selection circuitry.
`
`Similarly,
`
`the
`
`emulations for the hard disk may be selected by the buttons. Also
`
`the setup parameters can be selected by the buttons,
`
`in order to
`
`provide flexibility for
`
`interfacing with any of a variety of
`
`computers. A number of preset selections (presets) are available
`
`for the user to select,
`
`in a single stroke, the setup parameters
`
`for some common computers. Alternately,
`
`the modes. emulations.
`
`and setup parameters may be selected through the computer's
`
`interface with the system's circuitry. when the system is
`
`positioned in a housing. the modes. emulations, and setup
`
`parameters may be selected by manual controls accessible from
`
`outside the housing. A front panel on the housing may include a
`
`front panel having a display viewable by a user, and buttons
`
`accessible to a user.
`
`The system of present invention includes a conversion
`
`circuit for converting commands to be compatible with any of a
`
`number of standard computers. Most standard computers include
`
`a SCSI bus that provides disk drive commands for controlling
`
`random access disks, such as the Winchester hard disk that can be
`
`written over. However. an optical disk drive sub-assembly during
`
`writing is responsive to commands suitable for a sequential
`
`_. access disk, and a WORM (write-once. read-many) disk is not
`
`rewriteable. During reading, the optical disk can be accessed
`
`randomly, but access requires use of a directory built previously
`
`

`
`W0 92/21224
`
`PCTIUS92l04534
`
`_
`
`1 O -
`
`during sequential recording. Furthermore. the size of the basic
`
`storage units are different;
`
`a hard drive generally has sector
`
`sizes of 512 or 1024 bytes while an opticai drive may have larger
`
`sector sizes ranging from 512 to 4096 bytes.
`
`including 512.
`
`1024, 2048, and 4096 bytes.
`
`On the front panel of the housing, the display can show
`
`the emulation selected, as well as other information relating to
`
`the optical disk such as the amount of storage remaining
`
`available for recording. During writing operations,
`
`the display
`
`may be selected to show the average compression ratio. or the
`
`free space, updated continuously. During reading operations.
`
`the
`
`display may be selected to show the average compression ratio
`
`attained when the data was written to the disk. Positioned on the
`
`front panel, buttons may be provided for user selection of the
`
`emulation and other user requirements.
`
`For example. the
`
`controller may be operated in a "bypass" mode wherein the data
`
`compression stage is bypassed in order to read disks previously
`
`recorded without data compression. The display and the selection
`
`buttons may also allow direct selection of data compression
`
`parameters such as the target ratio of data compression;
`
`for
`
`example, the user may choose from several target ratios.
`
`in other
`
`embodiments. the computer may select the data compression
`
`parameters and the type of emulation.
`
`For avoidance of errors,
`
`parity checks are provided at communication links. Error
`
`correction circuitry is provided to correct errors occurring during
`
`writing to the optical disk, and reading from the opticai disk.
`
`

`
`WO 92121224
`
`PCTIUS$12!M534
`
`The present invention provides several advantages. One
`
`advantage is the large storage capability, and another related
`
`advantage is the savings in computer time. Optical disks are
`
`useful
`
`in archiving, or storing large amounts of
`
`information.
`
`Information stored in its compressed form occupies much less
`
`physical space on a disk, and writing and reading compressed data
`
`takes much less time than writing uncompressed data. This
`
`means that,
`
`to store a given amount of information, fewer disks
`
`are necessary, and less computer time (and operator time, as
`
`well) is used up. Fewer disks means less cost and less time for
`
`an operator who must wait, and insert and remove disks during
`
`writing and reading operations. For example, a 10:1 compression
`
`ratio can increase disk capacity by ten times, saving the cost of
`
`ten separate disks, and reducing expensive time spent by the
`
`computer and the operator by as much as a factor of ten.
`
`As an additional advantage. the user has substantial
`
`control over the writing process. During writing operations,
`
`the
`
`display shows the compression ratio updated continuously;
`
`because the compression ratio varies dependent upon the data to
`
`be compressed. this information may be beneficial to a user.
`
`Before writing, a user may select the type of emulation, the data
`
`compression mode. and the setup parameters by manual control
`
`using the buttons positioned on the front panel. Thus, for
`
`.«compatit:iility with a number of different computers and optical
`
`disk systems, the setup parameters, compression mode, and
`
`emuiation can be selected easily. As an example. disks previously
`
`

`
`WO 92121224
`
`PCI‘/US92/04534
`
`. 12 .
`
`recorded by the RXT-BOOHS can be read in the "bypass" mode,
`
`wherein the data compression step is bypassed. For additional
`
`flexibility in application,
`
`the computer can issue emulation
`
`commands directly to the controller through the SCSI bus. so that
`
`the emulation or the compression ratio can be adjusted
`
`automatically,
`
`if desired, without manual selection.
`
`Furthermore. selection of a specific data compression mode may
`
`have additional advantages to a user. For example,
`
`if data to be
`
`written has been previously compressed. then that data should
`
`not be compressed further.
`
`In that instance, the user may select
`
`the bypass mode so that the data bypasses the compression
`
`process. As another example. a user may wish to completely
`
`bypass the compression process for one reason or another, and
`
`therefore this user would choose the bypass mode even though
`
`compression is available to him.
`
`As an additional feature. the user can select the
`
`termination of the communications buses remotely,
`
`from the
`
`front panel. This feature provides an advantage in convenience
`
`for the user who.
`
`if he had followed conventional methods. would
`
`directly connect a jumper wire to make the termination. Using
`
`the selectable termination option. the user can easily choose to
`
`terminate the communications bus as appropriate, without using
`
`jumper wires.
`
`As another advantage,
`
`the compressionldecompression
`
`circuit
`
`interfaces better with the optical disk's larger sector
`
`size than with the smaller sector size of a hard disk. A standard
`
`

`
`W0 92/2] 224
`
`PCT/ U392!04534
`
`hard disk has a sector size of 512 bytes, while an optical disk
`
`can, and typically does, have a larger sector size, such as 2048
`
`bytes, or even 4095 bytes. The compressionidecompression
`
`circuit functions well with a boundary of 4096 bytes, which can
`
`be obtained directly from a sector size of 4096 bytes, or can be
`
`obtained if 2-2048 byte sectors are combined.
`
`In comparison to
`
`obtain 4096 bytes in a hard disk format requires that eight 512
`
`byte sectors be combined. As an additional advantage,
`
`in the
`
`optical disk,
`
`the relativeiy fewer number of
`
`large size sectors (2)
`
`provides better storage control, and simplified and faster storage
`
`operations.
`
`Furthermore. a larger sector size makes more
`
`efficient use of the disk storage space. By using larger sectors.
`
`more data can be stored on the disk in a continous string;
`
`the
`
`boundaries are larger, and less space is used recording the
`
`boundaries and other file information.
`
`The compression ratio will vary widely, dependent upon
`
`the data; data such as programs may compress at a ratio around
`
`2.5, but other data such as black and white images may compress
`
`at a ratio around 20. At the present time, compression ratios of
`
`up to 29:1 have been observed for black and white pixel images
`
`(grey scale).
`
`As a further advantage, the system of the present
`
`invention is suitable for “plug and play” installation by computer
`
`_ manufacturers.
`
`Particularly easy installation in a wide variety
`
`of computers is afforded when the system is packaged in a full
`
`height form factor housing.
`
`The form factor standards are
`
`

`
`W0 92/21224
`
`1 4
`
`PCI"/US92/04534
`
`followed by most computer manufacturers. and thus this housing
`
`can be easily instaiied in pre-existing computer siots.
`
`Additionally, most computers are designed to operate a
`
`Winchester hard drive. The conversion circuit can make the
`
`opticai disk emulate a hard drive,
`
`thus providing compatibility
`
`with a wide variety of computers.
`
`

`
`W0 92/21 224
`
`PCTI U592!04534
`
`IP
`
`N
`
`F
`
`AW
`
`Figure 1
`
`is diagrammatic illustration of a system for
`
`writing to. and reading from, an optical disk.
`
`Figure 2 is a perspective view of a full height form
`
`factor housing for the writing/reading system,
`
`including a front
`
`panel having a display and manual buttons. the housing being
`
`suitable for
`
`installation in a computer.
`
`Figure 3 is a perspective view of a housing for the
`
`readinglwriting system, positioned in'a computer with the
`
`housing's front panel facing outward and accessible to a user.
`
`Figure 4 is a block diagram of a system for writing to,
`
`and reading from, an optical disk,
`
`illustrating more detail
`
`than
`
`Figure 1.
`
`Figure 5 is a flow chart
`
`illustrating operation during a
`
`data-in process wherein data from a computer is compressed and
`
`written to an optical disk.
`
`Figure 6 is a flow chart
`
`illustrating operation during a
`
`data-out process wherein data is read from the optical disk,
`
`decompressed, and transmitted to the computer.
`
`Figure 7 depicts a series of displays that are shown on
`
`the front panel LCD display in a preferred embodiment.
`
`Figure 8 depicts a series of options available to a user in
`
`a preferred embodiment.
`
`Figure 9 is a table that shows the available compression
`
`modes and emulations in a preferred embodiment.
`
`

`
`W0 92/21224
`
`PCTI US92f04534
`
`Figure 10 is a table that shows preset configurations for
`
`setup parameters in the preferred embodiment.
`
`

`
`W0 92/21224
`
`PCTIUS92/04534
`
`-
`
`1 7 -
`
`E RIPTIN FT
`
`V
`
`N
`
`The invention is best understood by reference to the
`
`figures wherein like parts are designated with like numerals
`
`throughout.
`
`Fieterence is made to Figure 1, which illustrates,
`
`in block
`
`diagram form, a system for storing data on. and receiving data
`
`from, an optical disk. Figure 4,
`
`in comparison.
`
`is a block diagram
`
`that
`
`illustrates additional features, and these more specific
`
`features are described with reference thereto. Referring back to
`
`Figure 1, a host computer 10. or another appropriate digital
`
`device. originates appropriate data and commands, which are
`
`transmitted to a controller 12. The controller 12 may respond
`
`with its own data and commands, which are transmitted‘ back to
`
`the host computer 10. The controlier 12 includes a
`
`compressionldecompression circuit 13 that can compress data
`
`transmitted irom the host computer 10. The compressed data is
`
`transmitted to an optical disk drive sub-assembly 14 along a data
`
`link 16. The optical disk drive sub-assembly 14 is a
`
`‘commercially available package that includes an optical disk
`
`drive unit and associated electronics described later with
`
`reference to Figure 4.
`
`In a write of compressed data to the disk
`
`sub-assembly 14, the data link 16 transmits compressed data to
`
`the sub-assembly 14.
`
`in a read oi compressed data from the sub-
`
`assembly 14,
`
`the data link 16 transmits compressed data to the
`
`compression/decompression circuit 13, which decompresses the
`
`data. Thus.
`
`the inputted compressionfdecompression circuit 13
`
`

`
`W0 92/21224
`
`PCTI US92/04534
`
`.
`
`1 3 -
`
`compresses data which is to be transmitted into the sub-
`
`assembly 14, and it decompresses data transmitted from the sub-
`
`assembly 14.
`
`The controller 12 also includes a process control
`
`circuit 17, which can control operation in one of a number of
`
`available modes of operation of the compression/decompression
`
`circuit 13, as well as provide a specific emulation by controlling
`
`a converter circuit 27 in conjunction with the
`
`compressionldecompression circuit 13. The process control
`
`circuit 17 can also be programmed with setup parameters to
`
`provide communications with a variety of host computers 10. The
`
`available modes of operation. the emulations, and the setup
`
`parameters are discussed more fully with reference to Figures 7,
`
`8, and 9. The particular mode and emulation may be selected by
`
`the host computer 10 or the user;
`
`i.e., the process control circuit
`
`17 may be responsive to commands from the computer 10. or it
`
`may be responsive to commands from manual controls 18 that are
`
`accessible to a user. A display 19, such as a LCD display, may
`
`provide visual access to information for user verification of
`
`parameters and selection of modes.
`
`Reference is now made to Figure 2, which illustrates a
`
`housing for a system for writing to, and reading trom, a optical
`
`disk. The system is enclosed in a housing illustrated generally at
`
`20.
`
`in the block diagrams of Figure 1 and 4, the system that is
`
`included in the housing 20 is shown enclosed within a box also
`
`labelled 20. Referring now to Figure 2. a front panel 21 has a slot
`
`22 for inserting and removing a conventional optical disk
`
`

`
`WO 92121224
`
`PCT! US92/04534
`
`- 19 _
`
`cartridge (not shown). The tront panel 21 also includes an
`
`ejection button 23 for ejecting an inserted optical disk. The
`
`manual controls 18 are presented on the front panel 23,
`
`in a
`
`position proximate to the display 19 for ease of user interface.
`
`The manual controls 18 include buttons 24,25 for scrolling
`
`selections that may be shown on the display 19;
`
`specifically,
`
`the
`
`selection button 24 scrolls up. and the selection button 25
`
`scrolls down. The controller 12 (Figure 1)
`
`transmits a series of
`
`verifications and user options to the display 19 that will be more
`
`_fully described with reference to Figures 5-8. The manual
`
`controls 18 allow the user to move through the series of
`
`verifications and select options. One of the user options is
`
`selection of the emulation in which the system is operating, so
`
`that the user can select the emulation corresponding to the disk
`
`that he is inserting for proper reading and writing operations.
`
`Other options include setup parameters. which allow the user to
`
`setup the system for operation with any of a variety of
`
`computers.
`
`For example. the controller 12 may be operated with
`
`a RXT-800 emulation to read a disk previously recorded without
`
`data compression, using a Macintosh computer as a host. The
`
`process control circuit 17 may also allow direct selection of a
`
`data compression mode. such as a compression "on" mode. a
`
`bypass mode, or a target ratio mode.
`
`In some embodiments. the
`
`,_ computer 10 may be programmed to select data compression
`
`modes. setup parameters, and emulations. either alone or in
`
`conjunction with the user.
`
`

`
`WO 92121224
`
`PCI'fUS92/04534
`
`- an -
`
`The housing 20, made in the industry's standard full
`
`height form factor size,
`
`is compatible with any of a number of
`
`standard computers. The industry's form factor standards for
`
`disk drives are -followed by many computer manufacturers. As
`
`illustrated in Figure 3,
`
`the full height form factor housing 20 is
`
`readily inserted in the space available on a PC (personal
`
`computer) 26. The industry's standards for the full height form
`
`factor are approximately:
`
`a depth of 8.DD"iD.63. a height of
`
`3.25".-tO.D3, and a width of 5.75"i0.U3.
`
`Eight screw holes are
`
`provided. four on the bottom, and two on each side. Four of the
`
`holes are provided at a distance from the front of 1.87" 10.02.
`
`and the other four holes are at an additional distance of
`
`3.12"iD.D2 from the front. The front bottom two holes, spaced
`
`evenly from the sides. are separated by a distance of
`
`5.50“-£0.02.
`
`Similarly.
`
`the back bottom two holes. spaced
`
`evenly from the sides, are separated by a distance of
`
`5.5U"i0.U2. All four side holes are spaced a distance of
`
`0.86":0.D2 from the bottom. The screw holes are 6-32 INC x
`
`0.31 deep.
`
`Most computers 10, such as the PC 26. are manufactured
`
`or programmed with disk drive commands for controlling random
`
`access disks. such as the Winchester hard disk. Reference is
`
`again made to Figure ‘I,
`
`particularly the controller circuit 12,
`
`which includes the converter circuit 27.
`
`The converter circuit
`
`27 and the optical disk drive sub—assembly 14 communicate
`
`through a command link 28. The converter circuit 27 translates
`
`

`
`W0 921"21224
`
`PCT/ US92/04534
`
`commands from the computer 10 into commands usable by the
`
`optical disk drive sub-assembly 14. The optical disk sub-
`
`assembly 14 requires commands suitable for a sequential access
`
`disk;
`
`thus,
`
`the converter circuit 27 is designed to quickly and
`
`efficiently make the conversion in either direction of command
`
`flow. The process control circuit 12 may control
`
`the converter
`
`circuit 27 as well as the compressionldecompr