Abstract:
A network storage device having a network controller card and a data storage device is described herein the card and storage device are either enclosed in a small from factor unit or assembled together to fit within a standard hard disk drive bay in a computer. The combination of a controller card and storage device is designed to transfer files from and to a network using standard network file protocols. As the network storage device does not process the files, much of the computational overhead of a network server can be eliminated, resulting in a simpler device capable of faster file exchange.

Description:
BACKGROUND OF THE INVENTION 
     This invention is in the field of mass storage devices for use with computers and computer networks. More particularly it relates to mass storage devices directly coupled to computer networks. 
     The Internet, a collection of publicly accessibly computer networks, and Intranets, collections of privately accessibly business computer networks, are known. Both have witnessed explosive growth in the last few years. In 1996, the number of users of the Internet was estimated to be doubling every two months. This explosive growth has fueled an equally explosive demand for mass storage devices capable of supporting both Internet and Intranet applications. 
     FIG. 1 is a block diagram showing a common architecture for supporting Internet/intranet operations. Individual clients  1  using either personal computers or workstations are coupled through a network  3  to one or more servers  5 . Each server is typically a general purpose computer, which computer uses either the Unix or Windows NT operating system. The server in turn is coupled to a plurality of mass storage devices  7 , which may include hard disk drives (“HDD”s), archival tape storage devices, here shown as Digital Linear Tape drives, or any other known form of mass storage devices. 
     This architecture has several disadvantage. All data must travel through a general purposes server before it can be sent to a client from a data storage device or written to a data storage device from a client, which slows data transfer. The client/server architecture is also expensive to purchase and to maintain. Scaling this architecture requires adding both additional processors and additional memory. Installation of either memory or processors is almost never a straightforward process and any upgrades of the system require that the servers be shut down. 
     As these disadvantages of the client/server architecture are known, attempts have been made either to correct or simply avoid them. One commercially available product is a thin file server through which storage devices are connected for direct network attached access via Unix or Windows clients. The file server/controller couples disk drives and RAID arrays to a network, without the need for a server. Although this device allows for some improvement on the known client/server architecture, it still requires both a separate controller and a storage device. The controller itself also requires a full  3 . 5 ″ disk drive bay for installation. Thus, the combination of the file server/controller and a storage device requires at least two bays in either a rack-mounted configuration or two of the internal bays found in most personal computers and network servers. 
     The meridian Data System Inc. Snap! Server incorporates an HDD with a network controller card into a single unit. However, the device&#39;s controller card uses an X86 microprocessor, which is expensive, uses more power than desirable in this application, and is somewhat slower in operation than other commercially available microprocessors. 
     The controller card and HDD are not well integrated, the package itself is large and a “Y”-connector cord is required to provide power to both the controller card and the HDD. 
     SUMMARY OF THE INVENTION 
     A first embodiment of the present invention is a single device combining a HDD and a network controller card. The combination, hereinafter called a network storage device, can be coupled to network, which networks operate using standard Ethernet protocols. The network storage device has an extremely small form factor which fits into a standard disk drive storage bay (4″×5.75″×1.625″ or 1.0″). Two embodiment of the network storage device are described herein. A first embodiment comprises a network controller card and a HDD, integrated together as a single package. A plurality of units of this first embodiment could then be rack-mounted and collectively powered from a single source of DC power and provided with individual network connections. In a second embodiment, the network controller card, one or more HDDs, and power supply are integrated within a housing and the housed, finished unit requires only a network connection and an AC power source connection. 
     This combination of storage device and network controller device offers many advantages. A single package of small size can supply the functionality of two separate devices, the single device having lower overall power consumption and smaller physical footprint, typically within the form factor of a standard HDD. Internal power connection is simplified, with a single external power input to the network controller card which in turn provides power to the HDD. The combination is also less expensive than the separate controller unit and storage device shown by the prior art. 
    
    
     BRIEF DESCRIPTION OF THE ILLUSTRATIONS 
     FIG. 1 is a block diagram of client-server computer system (Prior Art); 
     FIG. 2 is a diagram of a computer network with a plurality of clients and a server, wherein data storage is additionally provided by a network storage device; 
     FIG. 3 is an exploded isometric drawing illustrating the relative placement of the network controller card and HDD in a first preferred embodiment of the network storage device; 
     FIG. 4 is a block diagram of the network storage device&#39;s network controller card in a first embodiment; 
     FIG. 5 is a block diagram of the network storage device&#39;s network controller card in a second preferred embodiment; 
     FIG. 6 is a block diagram of the network storage device&#39;s electronics in a third preferred embodiment; and 
     FIG. 7 is a block diagram of the network storage device&#39;s electronics in a fourth preferred embodiment. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The proposed architecture for the first embodiment of the present invention is shown in FIG.  2 . Client PCS  11  and NT server  14  are coupled together through network hub  13 . Several peripherals such as tape backup storage  16  and printer  18  are also connected to the network. Network storage device  15  is also attached to the network through hub  13 . 
     Network storage device  15  is comprised of a network controller card  17  (see FIG. 3) for receiving and transmitting network compatible files over the network and storage device  19  (see FIG.  3 ), which stores the files received from network controller card  17 . In this first embodiment the network is an Ethernet network, the storage device is a hard disk drive (“HDD”), and the controller card accepts files in both a Microsoft compatible format (SMB/CIFS) or in a Unix compatible format (NFS). 
     This architecture allows one network storage device to serve many clients without the expense and complication of an additional layer created by a server computer. When servers are used primarily for data storage, the server is very rarely used to process the data being sent to it from the clients coupled to it and the server microprocessor is underutilized and therefore unnecessary overhead. This first embodiment substitutes a controller card optimized to transfer files of data between a storage device and clients for the sever computer. As the microprocessor does not process the data contained in the files, it can be simpler, more efficient device designed for this particular purpose, rather than the general purpose computer that comprises most servers. 
     FIG. 3 is an exploded isometric drawing of network storage device  15 . Network storage device  15  contains two main assemblies: network controller card  17  and HDD storage device  9 . The two components are coupled together internal frame  23 . Standard machine screws  25  attach HDD  19  and controller card  17  to frame  23 . Two short connectors  27  and  29  couple controller card  17  and HDD  19  together and carry, respectively, data/addresses and power from the network controller card  17  to HDD  19 . Assembled network storage device  15  typically fits within a standard HDD computer bay. 
     In the second preferred embodiment, the combination of both card  17  and HDD storage device  19 , after being mounted together on frame  23 , would be placed in a housing, the housing also containing a power supply for card  17  and device  19 . The design and operation of such a power supply is known in the art. 
     In another embodiment, more than one HDD may be attached to the network controller card and installed in a single housing. In this embodiment, the multiple HDDs could be mounted one atop another or one on either side of the network controller card. The data and power buses could be daisy-chained to the additional HDDs in a manner similar to the first preferred embodiment. The mounting of the additional HDDs and the coupling of the data and power busses to the additional HDDs are matters of straightforward mechanical engineering. 
     FIG. 4 is a block diagram of network controller card  17 . In this first preferred embodiment, RJ 45 connector  101  couples controller card  17  to a 10 or 100 Mb auto-Ethernet network. RJ 45 connector  101  protrudes slightly beyond the physical outline of the HDD to allow flush mounting within the enclosure. Transceiver  133  is in turn coupled to connector  101  and controls file flow into and out of the network storage device. ICS 1890A PHY  131  and DEC 21143-A PCI-to-Ethernet media independent interface  115  are coupled together and provide a network interface. Mac address  113  is coupled to interface  115  and provides a unique address for each individual network storage device. Digital 21285  109  is a PCI bridge and provides memory support and glue logic for controller card operation. Digital SA 110  105  is the controller&#39;s microprocessor, regulating file flow from the storage device&#39;s PCI bus to the network&#39;s Ethernet bus. Crystal  107  is coupled to processor  105  and provides a timing signal. 
     RAM memory  103  and Flash EEPROM  111  are coupled to PCI Bridge  109 . PCI bridge  109  is in turn coupled to PCI bus  132 , as well as serial port  122 . Real time clock  117  with battery back-up  119  is also coupled to PCI bus  132  and provides time and date information for file stamping purposes. PCI to Ultra ATA-33 controller  127  and  129  control actual data transfer to a storage device using the Ultra ATA-33 protocol through interface  135 . Power system  120 , comprising power input  121 , connectors  123  and  125 , and power bus  126 , provides power to both controller card  17  and storage device  19 . 
     Controller card  17  provides known functionality and its individual components are commercially available. Power system  120  is designed so that the printed circuit board traces can carry ample current for both controller card  17  and storage device  19 , and allows connection of power to both devices without modification of a standard disk drive or use of a “Y”-connector power cord. In operation, the HDD requires 12 V and the controller card  17  requires 5 V. Both network controller card  17  and storage device  19  are low power devices, using approximately 10 watts, reducing the demands on power bus  126  and minimizing thermal dissipation problems within the assembled unit, particularly if the unit is placed in a housing. 
     In FIGS. 5,  6 , and  7 , components whose structure and function has not changed retain the same part numbers assigned to them previously herein and shown in FIG.  4 . 
     In a second preferred embodiment of the present invention&#39;s network controller card  17 , illustrated in FIG. 5, the functions performed by individual units  109 ,  115 ,  117 ,  127 ,  129 , and  131  are now performed by a single custom Application Specific Integrated Circuit (“ASIC”)  151 . This simplifies the design of the printed circuit board, as well as reducing fabrication difficulties and overall thermal load. In a yet further development of network controller card  17 , shown now in FIG. 6, another level of functionality is moved into an ASIC by incorporating a microprocessor into ASIC  155 , thereby further eliminating separate blocks  105  and  107  (see FIGS.  4  and  5 ). 
     FIG. 7 illustrates yet another embodiment of network controller card  17  wherein the board area freed by the integration of most controller card functions into a single ASIC is used to advantage by moving the controller card electronics onto the HDD&#39;s circuit board. As the components and functions of an HDD&#39;s circuit board are known, they are not further described herein. 
     In order to store and retrieve files sent to it from the network, network storage device  15  is provided with a real time operating system for low level functions such as scheduling and memory management. In the first preferred embodiment, the operating system is a VX Works operating system, commercially available from Wind River Systems, Inc. A file system is needed to allow network storage device  15  to store files of data. In this first embodiment, the file system is called File System Stack OS, which is commercially available from Programmed Logic Corp. Programmed Logic Corp also provides the Network File System Layer, which enables network storage device  15  to save files transmitted over the network. This Layer may be either Unix compatible format (Network File System or NFS), or a Microsoft compatible format (Server Message Block or SMB/Common Internet File System or CIFS). Finally, to enable network storage device  15  to communicate over the network, a Network TCP/IP Protocol Stack is also provided. This Stack is also a commercially available product. As these software products are known and commercially available, their design and operation requires no further description herein. 
     In operation, after network storage device  15  is coupled to a network through connector  101  (see FIG. 4) and power supplied at connection  121 , an installation program is run. Running the installation program does not require a rebooting of the managing computer. 
     The installation program analyzes the network to which device  15  is coupled and recommends a particular IP address for device  15 . The system manager can also specify the device&#39;s name, the network manager&#39;s name and password, as well as device  15 &#39;s physically location and user and administrative e-mail addresses for future notification of problems. After completion of the installation process, device  15  appears as an icon on the various computer systems coupled to the network, the icon indicating that the device is an available storage device on the network. 
     If more than one network storage device  15  is coupled to a given network, it is possible for devices  15  to be operated in an automatic backup mode. After a file is written to the first device  15 , its operating program may automatically make a copy of the file and send it to a second device  15 . If first device  15  fails, then a complete copy of the files on the failed device can be found on the second device  15 . In these cases, if the second device  15  detects a failure in first device  15 , it can send an e-mail message to the system administrator. If a third device  15  is then coupled to the network to replace the first failed device  15 , then the second device  15  will automatically copy all its files to the third device  15 , reestablishing a backup file capacity.