O
`
`(12) United States Patent
`Phillips et al.
`
`USOO6438368B1
`(10) Patent No.:
`US 6,438,368 B1
`(45) Date of Patent:
`Aug. 20, 2002
`
`(54) INFORMATION DISTRIBUTION SYSTEM
`AND METHOD
`(75) Inventors: Robert C. Phillips, Northbrook; Caitlin
`B. Bestler, Lisle, both of IL (US)
`(73) Assignee: Ikadega, Inc., Northbrook, IL (US)
`(*) Notice:
`Subject to any disclaimer, the term of this
`patent is extended or adjusted under 35
`U.S.C. 154(b) by 0 days
`a --
`y U dayS.
`
`(21) Appl. No.: 09/579,574
`(22) Filed:
`May 26, 2000
`
`Related U.S. Application Data
`visional application No. 60/193,729, filed on Mar. 30,
`
`(60)
`
`(51) Int. Cl. ............................................... H04M 11/10
`(52) U.S. Cl. ....................... 455/412; 455/414; 455/417;
`370/300; 370/409; 370/428; 370/397; 725/92
`(58) Field of Search ................................. 455/412,414,
`455/417, 3.04, 3.01; 340/539; 342/457;
`370/300, 409, 338, 428, 397, 396; 725/91,
`92,93, 94
`
`(56)
`
`References Cited
`U.S. PATENT DOCUMENTS
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`5,414,455 A * 5/1995 Hooper et al. ................. 348/7
`5,442,390 A 8/1995 Hooper et al.
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`9/1995 Dan et al.
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`1/1996 Logston et al.
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`55: A 3. E. s
`t al
`5,751,883 A 5/1998 Ottesen et al.
`5,761,417 A 6/1998 Henley et al.
`5,778,186 A 7/1998 Funaya
`
`2 : 1
`
`- 2
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`7/1998 Sangveraphunsiri et al.
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`5,787,482 A 7/1998 Chen et al.
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`SSR A R 85 nea
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`2/1999 Ozden et al.
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`5,920,709 A
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`5.948,092 A 9/1999 Crump et al.
`5,973,722. A 10/1999 Waikai et al.
`5,983,069 A 11/1999 Cho et al.
`5.990.959 A * 11/1999 Case .......................... 348/409
`6,067,451 A * 5/2000 Campana, Jr. et al.
`455/412
`6,091,736 A * 6/2000 Hayashi ...
`370/428
`6,092,080 A * 7/2000 Gustman ....
`707/103
`6,167.253 A 12/2000 Farris et al. ...
`... 455/412
`6,188.887 B1
`2/2001 Joong et al. ................ 455/417
`6,199,060 B1
`3/2001 Gustman ....................... 707/3
`
`
`
`* cited by examiner
`
`Primary Examiner Edward F. Urban
`Assistant Examiner Marceau Milord
`(74) Attorney, Agent, or Firm-Gardner Carton & Douglas
`(57)
`ABSTRACT
`An information distribution System with an architecture that
`facilitates efficient distribution of a plurality of information
`asset data to a plurality of different requesting users Sub
`Stantially simultaneously. Fundamental components of the
`System include a plurality of mass Storage devices that Store
`information assets, mass Storage device interface units, a
`Switching unit, a centralized control unit and a gateway to
`the users. Information transfer between various components
`f the SVStem i
`lished through a plurality of
`OI line system is accomplisned unrougn a plurality of com
`munication channels according to a circuit Switching pro
`tocol. According to one embodiment of the invention, a
`plurality of communication channels are provided between
`the mass Storage devices and the Switching unit Such that
`information asset data may be transferred, in Substantially a
`Single format and according to Substantially a single
`protocol, from the mass Storage devices directly through the
`Switch and to the requesting user.
`
`29 Claims, 4 Drawing Sheets
`
`A
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`YSEP- YSE: DESRINTiPACE
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`

`

`U.S. Patent
`US. Patent
`
`Aug. 20, 2002
`002
`one
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`U.S. Patent
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`Aug. 20, 2002
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`Aug. 20, 2002
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`U.S. Patent
`
`Aug. 20, 2002
`
`Sheet 4 of 4
`
`US 6,438,368 B1
`
`
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`
`
`
`
`RECEIVE REQUEST
`FROM USER
`
`DELIVER REQUEST TO
`SYSTEM CONTROLLER
`
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`
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`
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`REPLY WITH HANDLE
`SWITCH SETUP
`
`LOCATE INFORMATIONASSET
`ONAVAILABLE DISKDRIVE
`
`ORDER PENDING REQUESTS
`FOR DISKDRIVE
`
`TRANSMIT REQUEST
`TO DISKINTERFACE UNIT
`
`DATA REQUEST COMMAND
`TO DISKDRIVE
`
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`TO USER
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`
`

`

`US 6,438,368 B1
`
`1
`INFORMATION DISTRIBUTION SYSTEM
`AND METHOD
`
`CROSS-REFERENCE TO RELATED
`APPLICATIONS
`This application claims the benefit of U.S. Provisional
`Application Serial No. 60/193,729 filed Mar. 30, 2000.
`FIELD OF THE INVENTION
`The present invention relates generally to an information
`distribution System and method, and, more particularly, to a
`system and method for distributing “on demand” a plurality
`of Substantially fixed information assets to a plurality of
`different users Substantially simultaneously.
`
`15
`
`2
`computer System or WorkStation, it Suffers from Similar
`limitations and deficiencies that will preclude the System
`from effectively performing as an information-on-demand
`System. The Dulac et al. System proposes fiber channel
`cables that deliver Video data by computer technology to a
`conversion unit that converts the video data to ATM tele
`phony technology for transmission to a network. The con
`ventional computer technology associated with the Video
`Storage devices will result in a bottleneck that will Substan
`tially limit the performance of the System for delivering
`multiple Simultaneous information Streams. For example,
`FIG. 1 teaches using a large number of Storage devices, all
`of which Supply data to a multi-port Switch through a single
`data path connection. This arrangement will require com
`plex sharing of a Single communication channel among
`many different Storage devices, resulting in a bottleneck and
`Similar problems characteristic of the deficiencies and limi
`tations encountered in bus-based Systems.
`SUMMARY OF THE INVENTION
`The present invention overcomes the deficiencies and
`limitations of Such prior art Systems by providing a unique
`architecture that is particularly beneficial for performing
`information-on-demand distribution of information assets.
`One of the advantages of the present invention is realized by
`the use of a circuit Switching technique for the transfer of
`information between various elements of the System. Since
`the information transfer technique is Substantially consistent
`throughout the System, complex and burdensome data con
`version is not necessary. This feature also facilitates conve
`nient information asset transfer from mass Storage devices to
`requesting users or to other mass Storage devices, and also
`facilitates the System receiving new information assets for
`Storage on mass Storage devices.
`Another advantage of the present invention is realized by
`providing a plurality of communication channels to accom
`modate a transfer of data between a plurality of mass Storage
`devices. Such a plurality of communication channels elimi
`nates the communication channel bottleneck and contention
`deficiencies of prior art Systems.
`Another advantage of the present invention is realized by
`providing a centralized control unit that receives requests
`from users for various information assets. Such a centralized
`control feature allows the System to reorder the requests into
`a Sequence that will allow much greater efficiency of reading
`information asset information from any particular mass
`Storage device. Such a feature is possible because the
`centralized control unit contains information relating to
`which mass Storage device or devices contain the requested
`information asset and where that information asset is located
`on the mass Storage device. Additional advantages are also
`realized through Such a centralized control unit, Such as
`allowing the System to monitor information asset usage,
`mass Storage device usage and performance, as well as a
`great number of other features relating to housekeeping and
`System maintenance.
`Another advantage of the present invention is that, while
`the information asset requests are centrally managed, the
`information asset information does not flow through the
`central control unit. Instead, information asset information is
`transmitted directly from mass Storage devices through a
`Switch and to the appropriate destination-without the need
`for conversion to a different data format. In other words, the
`Same data transmission format and protocol is used Substan
`tially throughout the System to facilitate extremely efficient
`transfer of a plurality of different information assets at high
`Speed and high Volume and Substantially simultaneously.
`
`BACKGROUND OF THE INVENTION
`There is a growing need to provide distribution of elec
`tronically stored information to a variety of different users
`Simultaneously and “on demand.’ Traditionally, electroni
`cally stored information could be utilized by individuals by
`obtaining a copy of the information Stored on a fixed
`medium, Such as an audiotape, videotape, floppy disk or CD
`ROM, and viewing or playing the information with an
`asSociated device, Such as a tape player, VCR, CD player or,
`25
`once loaded onto a computer System hard drive, the com
`puter System.
`With the massive information content presently available
`and with rapidly growing content development, Such a
`physical distribution System is no longer feasible. Moreover,
`in particular environments, it is also not desirable. For
`example, in-room movies at hotels are a Source of additional
`income for the hotel and an expected convenience for hotel
`guests. Instead of accommodating each room with Separate
`Video playerS and managing the physical distribution of
`Videocassettes, Some hotels have established a network
`whereby a bank of Video playerS may continuously play a
`predetermined set of Videocassettes and Several guests may
`Simultaneously view the same Video.
`This, however, is not a true "on demand” System because
`guests must join in Viewing a Video at the particular Segment
`in which it is currently playing. Furthermore, providing a
`plurality of Separate Video players-one for each different
`Video Selection-is a cumberSome, costly and technologi
`cally inefficient System, requiring frequent and costly main
`tenance as well as Substantial human intervention.
`Various information distribution systems have been
`proposed, but Such Systems are based upon conventional
`architectural concepts and Suffer from limitations that pre
`vent them from effectively delivering a plurality of different
`information assets Substantially simultaneously.
`One such prior art system is disclosed in U.S. Pat. No.
`5,414,455 to Hooper et al., assigned to Digital Equipment
`Corporation. AS can be seen from FIG. 2, that System is
`based upon a conventional computer and WorkStation archi
`tecture where shared control and data buses are provided
`between the various elements of the system. While such an
`architecture may be beneficial for typical data processing
`tasks, it does not effectively perform an information-on
`demand information distribution function. The shared data
`and control buses quickly limit and degrade information
`distribution performance, and moreover, Such a System
`requires complex data buffering Schemes.
`Another prior art system is disclosed in U.S. Pat. No.
`5,625,405 to Dulac et al. While the DuLac patent discloses
`an architecture that differs from that used in a conventional
`
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`US 6,438,368 B1
`
`3
`BRIEF DESCRIPTION OF THE DRAWINGS
`The foregoing and additional features and advantages of
`the present invention will be apparent from the following
`detailed description in conjunction with the drawings, in
`which:
`FIG. 1 is a schematic block diagram that illustrates
`various features of the architecture of the information dis
`tribution System of the present invention;
`FIG. 2 is a more detailed Schematic block diagram of one
`embodiment of an information distribution System accord
`ing to the present invention; and
`FIG. 3 is a flow diagram that illustrates the steps that may
`be performed in connection with the architecture of the
`present invention to deliver information asset data requested
`by users.
`
`DETAILED DESCRIPTION OF THE
`INVENTION
`Turning to FIG. 1, there is shown a schematic block
`diagram that illustrates various basic components and the
`general arrangement of the architecture of an information
`distribution system 10 in accordance with one embodiment
`of the present invention. The information distribution sys
`tem 10 receives requests for the distribution of particular
`information assets from any number of various users 12. In
`response to the requests, the System locates the information
`assets and distributes the particular information assets to the
`requesting user(s).
`According to an important aspect of the present invention,
`the System may operate as an “information-on-demand”
`System where any of the information assets may be distrib
`uted to any of the users at any time, even in the case where
`the same information asset is distributed to a plurality of
`users Simultaneously. It should be understood that, particu
`larly in connection with this latter situation, distribution of
`a particular information asset to Several users Simulta
`neously may require distributing the asset at a particular
`distribution rate for each user. Further complexity is intro
`duced when, as may typically be the case, the information
`asset is large in Size and multiple users have requested the
`asset at different times, so distribution of the asset will be
`proceeding Simultaneously but at different points within the
`asset. One useful example of Such a situation is the Simul
`taneous distribution of a plurality of video information
`assets. Video information assets may be extremely large files
`which are usually distributed in Segments as the information
`is viewed (or partially buffered) by the user. This is a process
`that is more commonly known as “streaming of Video
`information. While some users may have some buffering
`capability, usually the System will be required to distribute
`Video information in Segments, Such as blocks of a prede
`termined size requested by the user, until the entire Video
`asset is distributed or the user issues an instruction to
`discontinue the distribution.
`A great plurality of information assets, Such as files
`containing video, audio, image, text or other data, is Stored
`on a plurality of mass Storage devices 14. According to one
`embodiment of the invention, the mass Storage devices 14
`may be hard disk drives. ASSociated with each mass Storage
`device 14 is a mass Storage device interface 16 that issues
`appropriate instructions to the mass Storage device 14 to
`retrieve the information desired. The interface unit 16 of
`each of the mass Storage devices 14 is communicatively
`connected to a system Switch 20 to allow transmission of
`data and information between the Switch and the interface
`
`4
`16. The system switch 20 is also communicatively con
`nected to the users 12 of the system 10. Information and
`instructions transmitted between the system 10 and the users
`12 are Sent through the System Switch 20. According to the
`illustrated embodiment of the invention, for each of the
`interface units 16, there is provided a first transmission line
`for transmitting information from the Switch 20 to the
`interface unit 16, and a Second transmission line for trans
`mitting information from the interface unit 16 to the Switch
`20. Although it may be possible to implement an
`information-on-demand System in accordance with the
`present invention with only a single transmission line
`between the Switch and each interface unit 16 that handles
`bi-directional transmissions, the illustrated architecture may
`be preferable because it will allow transmission of informa
`tion to the users while Simultaneously providing the inter
`face unit 16 with additional instructions or information.
`Another important element of the fundamental architec
`ture of the illustrated embodiment of the invention is a
`system controller 26. The system controller 26 is generally
`responsible for receiving requests from users for information
`assets, organizing the requests and forwarding them through
`the Switch 20 to appropriate interface units 16 which will
`retrieve the requested information from the associated mass
`Storage device 14 and transmit the information through the
`Switch 20 and directly to the user or a gateway associated
`with the user 12. The system controller 26 will also be
`responsible for various “bookkeeping duties with the sys
`tem 10. For example, the system controller 26 may maintain
`an up-to-date library of information assets available on the
`mass Storage devices 14, may monitor usage Statistics of
`various information assets, may move various information
`assets between different mass storage devices 14, and per
`form numerous other administrative functions.
`According to an important aspect of the present invention,
`information which is distributed by the system 10 may be
`transmitted directly through the Switch 20 to the users. In
`contrast, conventional prior art information distribution SyS
`tems have been commonly based upon a decades-old com
`puter System architecture having three common bus
`elements—one for data, one for address information and one
`for control information. Although Such an architecture may
`be very useful for Some applications, it results in tremendous
`inefficiencies and complexities for an information-on
`demand System. For example, Since Such conventional prior
`art Systems have one common data bus, complicated bus
`contention protocols must be provided and, moreover, only
`one mass Storage device can be placing information on the
`data bus at a time. Many other complications, inefficiencies
`and problems are encountered when attempting to utilize
`Such a conventional architecture to perform an information
`distribution function. In this regard, the present invention
`represents a Substantial improvement and overcomes defi
`ciencies inherent in prior art Systems by providing a plurality
`of data transmission lines 22, 24, each of which may be
`independently and Simultaneously transmitting information
`asset data to users. Such an architecture Substantially
`increases the performance, flexibility and capacity of the
`System to Simultaneously deliver multiple Streams of infor
`mation asset data to a plurality of users, i.e., to effectively
`operate as a genuine information-on-demand System.
`Although the invention is illustrated in FIG. 1 such that
`there is a Single mass Storage device 14 associated with each
`interface unit 16, according to an alternative embodiment,
`the architecture may be modified to accommodate multiple
`mass Storage devices 14 for a single interface unit 16. For
`example, the amount of information Storage for the System
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`S
`may effectively be doubled by provided two disk drives for
`each disk interface unit. Such an implementation may be
`readily realized based upon the fundamental architecture
`illustrated in FIG. 1, particularly if an effective data trans
`mission protocol is utilized, as will be described in greater
`detail below. Thus, when a request for information is
`received by a disk interface unit 16, the disk interface unit
`16 examines the request to determine which of a plurality of
`disk drives 14 the request is directed to. In response, the disk
`interface unit 16 will direct the information request to the
`appropriate disk drive 14 associated with the disk interface
`unit 16, receive the requested information from the disk
`drive 14, and transmit the information through the Switch 20
`to the requesting Source which, in most cases, will be a user.
`AS will be readily apparent to one of skill in the art, the
`present invention as illustrated by the example architecture
`of FIG. 1 represents a Substantial improvement over con
`ventional Systems because, among other things, it is not
`limited to the traditional bus-based architecture. Further
`efficiencies and advantages of the present invention may be
`realized by utilizing particularly effective data transmission
`protocols. According to a preferred embodiment of the
`invention, a messaging or cell-based protocol for transmis
`Sion of data and information between various elements of
`the System may be utilized. In this regard, instructions and
`information may be transmitted through the System in units
`Such as a cell, message or packet that typically will contain,
`in addition to the data or information, a header that may be
`used to identify the Source as well as the destination for the
`unit of information. Using Such a protocol, a request for an
`information asset from a user may initially be directed
`through the Switch 20 to the system controller 26, which will
`determine if the information asset is available and where it
`resides on the System. Once the System controller 26 deter
`mines that the particular information asset exists on the
`System 10, the System controller 26 may, as appropriate,
`generate one or more requests to the appropriate interface
`unit 16.
`The requests for an information asset from a user may be
`handled on a Session basis. For example, when an initial
`request from a user for a new information asset is received
`by the system controller 26, the system controller 26 may
`establish a new Session, and generate a unique handle to
`identify the session. When a new session is established,
`virtual circuits within the system Switch 20 may be set up to
`handle communications for the new Session. For example,
`the System Switch 20 may, based upon the circuit identifier,
`route information for a particular Session from the appro
`priate interface unit 16 to the requesting user 12 via the
`Virtual circuit Set up when the Session was established. The
`System controller 26 may set up multiple virtual circuits
`between the same end points, but each traversing a different
`path through the system switch 26. When doing so the
`circuits will be configured So that information arrive at the
`destination as though it was a Single circuit. The System
`controller 26 may Select which circuit to use on a packet by
`packet basis, ensuring that at most one of the circuits is
`actually in use for any specific packet. In a similar manner,
`a virtual circuit within the system Switch 20 may be set up
`to handle communications from the System controller 26 to
`the interface unit 16 associated with the mass Storage device
`14 that contains the information asset requested. Typically,
`these virtual circuits will remain in place for the entire
`session. However, it is possible that the routing of the virtual
`circuit, or simply the Selection amongst the already provi
`Sioned circuits, may be changed in the case of certain events
`within the System. According to one embodiment, the Set of
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`Virtual circuits that may be used for a given Session will have
`a collective identifier, or handle. For example, in the event
`that a mass Storage device 14 which is Supplying a requested
`information asset experiences a technical problem, Such a
`fault may be communicated to or Sensed by the System
`controller 26 which, in response, may establish or Select a
`different virtual circuit under the same handle which will
`allow the same information asset on a different mass Storage
`device 14 to be transmitted to the user through the Switch.
`AS may be appreciated, this Same approach may be used in
`the case of other events that might compel the changing of
`which of the mass Storage device 14 that contain a particular
`information asset are used to deliver that asset to a user.
`Because of the unique design of the System, Such a change
`in the Supplying mass Storage device 14 will be transparent
`to the requesting user.
`In general, the present invention may be advantageously
`implemented with a Self-routing Switching technique, also
`Sometimes referred to as a Self-routing "Switching fabric'.
`The term “Switching fabric' means, for example, the com
`bination of hardware and Software that moves data coming
`into the System Switch out to the correct port or communi
`cation channel, which in turn may provide the data to
`another network. With a self-routing Switching fabric, the
`path a packet or cell takes through the fabric is determined
`by a circuit identifier in the packet or cell header. The
`originating port alone is insufficient to determine the routing
`of the cell or packet.
`Further characteristics of a Self-routing Switching fabric
`are that all packets or cells Sent with the same circuit
`identifier at a given port will arrive at the same target port.
`All cells that arrive will arrive in the same order, and cells
`may be dropped, but not re-ordered. All of these cells will
`have the same circuit identifier. This may be changed during
`transit through the fabric, but any Such changes will apply to
`all cells that Successfully transit the System. In Some cases,
`this path is referred to as a “virtual circuit”. Typically, the
`circuit must be set up prior to the first cell or packet being
`transmitted.
`Such a Self-routing Switching fabric differs from Setting
`up an actual circuit, where all packetS or cells from a given
`port will always be delivered to the same destination without
`need for headers. However, Such an actual circuit arrange
`ment would not Support use of a single port to interleave
`output for many destinations over a short period of time.
`A Self-routing Switching fabric also differs from tech
`niques such as Internet Protocol (IP) routing where there is
`no pre-determined route for each packet. Under Such a
`protocol, the packets are labeled with the desired
`destination, rather than by the circuit they should follow. At
`each Step, or hop, over the fabric, the router merely makes
`its best effort to Send the packet closer to the packet's final
`destination. Different packets may take different paths, and
`hence could arrive out of order. While this form of routing
`may be preferable for Sporadic messages of Short duration,
`it is far less efficient for large transferS and is typically
`especially inefficient for long Streaming operations.
`According to a preferred embodiment of the invention,
`the ATM (asynchronous transfer mode) dedicated
`connection Switching protocol may be used to transmit
`information between various components of the System.
`Other Switching technologies may be equally as applicable.
`The preferred selection of ATM reflects primarily the cost
`tradeoffs in the design rather than a necessity for a specific
`Switching protocol. Of course, a Standard disk drive inter
`face may be used to handle communication between the disk
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`interface unit and the disk drive or drives which are asso
`ciated with the disk interface unit. According to the ATM
`protocol, 53-byte cells may be transmitted between various
`components of the System. AS will be explained in greater
`detail in the following examples, the particular characteris
`tics of the ATM protocol make it very effective for
`information-on-demand performance, especially when
`implemented in connection with the unique System archi
`tecture of the present invention.
`Turning now to FIG. 2, there is illustrated a preferred
`embodiment of the invention that depicts various features of
`the information-on-demand System in greater detail. For
`ease of illustration, there is illustrated only one disk interface
`unit. However, it should be understood that it is contem
`plated that the System may include many disk interface units
`and many disk drives that contain information assets. In
`addition, it is contemplated that each disk interface unit may
`interface with one or more disk drives.
`Illustrated in FIG. 2 are all of the similar components
`illustrated in FIG. 1, including the system Switch 30, system
`controller 32, disk interface unit 34 and disk drive 36. In
`addition, the users of FIG. 1 have been depicted, by way of
`example, as various encoding 38 and decoding 40 units. The
`system Switch 30 is a Switch that follows the ATM conven
`tion of direct connection Switching. The Switch 30 has a
`plurality of different input ports 42 and a plurality of output
`ports 44. In addition, the Switch 30 includes an input CRC
`(cyclical redundancy check) checker 46 and an output CRC
`generator 48 for ensuring there are no errors in the data cells
`transmitted or received in accordance with the ATM proto
`col. In addition, there is provided an ATM cell memory 50
`and an ATM VCI cell memory table 52, which are used by
`the Switch 30 to determine appropriate routing for various
`cells that are transmitted through the Switch 30 according to
`the ATM protocol.
`The system controller 32, as illustrated in the embodiment
`of FIG. 2, is comprised of Several elements including, for
`example, an ATM interface 54, a CPU 56, memory 58, a
`ROM 60, a control bus 62 interface and a local bus interface
`64. The ATM interface 54 is used to extract the data, control
`or other information transmitted to the system controller 32
`through the Switch 30 which originated from another com
`ponent of the System. In Some cases, Several ATM cells may
`be used to transmit command or data information Since,
`generally, the ATM protocol involves cell sizes of only 53
`bytes in size. The CPU 56 operates a control program that is
`initially loaded from the ROM 60 upon system start-up, and
`uses the memory 58 for processing and Storage of local
`variables and data. For example, the memory 58 may be
`used by the System to at least temporarily Store information
`relating to information asset requests from users for particu
`lar disk drives 36 for the purpose of re-ordering those
`requests in a manner that the disk drives 36 may efficiently
`retrieve Such information asset data, as will be explained in
`greater detail. When a Series of information asset requests
`are ordered for a particular disk drive, the information asset
`requests, which request particular information asset data
`from a particular disk drive to be delivered to a particular
`user, are transmitted from the controller 32