Abstract:
A method and system of recovering a system that has experienced a fault includes a backup device to enable access of a network through the interface in response to the fault. The system includes a main operational portion that controls operation of the system under normal conditions. However, if a fault occurs, then the backup device can be selected to take over control of the system so that data can be retrieved from a backup storage to recover the system. The backup device includes software and/or hardware components to enable the system to access a network even though the main operational portion may not be functioning properly.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This is a continuation of U.S. patent application Ser. No. 09/706,960, entitled “Recovering a System that has Experienced a Fault,” filed Nov. 6, 2000, now U.S. Pat. No. 7,089,449, which is hereby incorporated by reference. 
     
    
     TECHNICAL FIELD 
       [0002]    The invention relates to recovery of systems that have experienced faults. 
       BACKGROUND 
       [0003]    Improvements in technology have provided users with a wide variety of devices to perform various tasks. Examples of such devices include desktop computer systems, portable computer systems, personal digital assistants (PDAs), mobile telephones, and so forth. The devices are relatively sophisticated devices that include processing elements (e.g., microprocessors or microcontrollers) and storage devices (e.g., hard disk drives, dynamic random access memorys or DRAMs, and so forth). 
         [0004]    A typical device includes an operating system (e.g., a WINDOWS® operating system, a UNIX operating system, a LINUX operating system, etc.) that is loaded when the device is started. Application software is also loaded into the device to provide useful functions for users. Example applications include word processing applications, electronic mail applications, web browsing applications, calendar and address book applications, and so forth. 
         [0005]    Despite improvements in technology, failures in various components of a device remains a persistent problem. When a component of a device, such as a hard disk drive, fails, the user may be left with an inoperational device. One option for the user is to take the device to a repair shop where an attempt may be made to recover the failed component, such as the failed hard disk drive. In some cases, data on the hard disk drives may be recovered so that loss of data is minimized. However, in many other cases, the data stored on the hard disk drive is lost, unless the user has diligently backed up the data. 
         [0006]    Conventionally, recovery of the failed component such as the hard disk drive is an arduous process that often is frustrating for the user. A need thus exists for an improved method and apparatus for recovering a device to an operational state after a failure has occurred. 
       SUMMARY 
       [0007]    In general, according to one embodiment, a system comprises an interface to a network and a first operational element to perform one or more tasks in the system. A storage element contains a flag to indicate if a fault has occurred with the first operational element. A backup device enables access to the network through the interface in response to the flag indicating failure of the first operational element. 
         [0008]    In general, according to another embodiment, a system comprises a main storage device, a backup storage device, and a routine executable to boot from the backup storage device in case of a system fault. The backup storage device enables access over a network to retrieve data from a network node to recover the system. 
         [0009]    Other features and embodiments will become apparent from the following description, from the claims, and from the drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]      FIG. 1  is an embodiment of a network system including a network, various nodes coupled to the network, and a backup storage system. 
           [0011]      FIG. 2  is a block diagram of components of a node of  FIG. 1 , in accordance with an embodiment. 
           [0012]      FIG. 3  is a flow diagram of tasks performed for a failure recovery in the node of  FIG. 2 , in accordance with an embodiment. 
       
    
    
     DETAILED DESCRIPTION 
       [0013]    In the following description, numerous details are set forth to provide an understanding of the present invention. However, it will be understood by those skilled in the art that the present invention may be practiced without these details and that numerous variations or modifications from the described embodiments may be possible. 
         [0014]    Referring to  FIG. 1 , a network system  10  includes a network  12  that is coupled to network nodes  14 ,  16 , and  18 . Examples of the nodes  14 ,  16 , and  18  include desktop computer systems, portable computer systems, and other types of systems having access to the network  12  (over either wired or wireless connections). Examples of the network  12  include local area networks (LANs), wide area networks (WANs), the Internet, and so forth. 
         [0015]    A backup storage system  20  accessible over the network  12  stores data to be used to recover nodes  14 ,  16 , and  18  in case of a fault (such as a component experiencing an error or failure) occurring in the nodes. The data stored in the backup storage system  20  includes user data, such as user-created documents or files, electronic mail messages, calendar and address book files, and so forth. The data stored in the backup storage system also includes software, such as operating system and application software that are stored and executed in each of the nodes. In one embodiment, the user data and software are stored as image data  30 ,  32 , and  34  that correspond to nodes  14 ,  16 , and  18 , respectively. Thus, in case of a fault in node  14 , the image data  30  is retrieved from the backup storage system  20  and communicated to the node  14 , with the image data used to recover the node  14 . Similarly, image data  32  and  34  are used to recover nodes  16  and  18 , respectively. 
         [0016]    As illustrated, the node  18  includes a main hard disk drive  24 , a backup storage device  22 , and a backup routine  26  executable in the node  18 . The backup routine  26  is initially stored on the backup storage device  22  and is executable to enable the node  18  to access the backup storage system  20  over the network  12  in case one of several predetermined faults occurs in the node  18 . Examples of such predetermined faults include failure of the hard disk drive, an unrecoverable error occurring on the hard disk drive, corrupted software and files associated with the software (e.g., library files, etc.), and so forth. The backup routine  26  and the backup storage device  22  may be collectively be referred to as the “backup device  25 .” In the illustrated embodiment, the backup routine  26  is a software routine loaded from the backup storage device  22  for execution on a processing element in the node  18 . Alternatively, the backup device is a hardware component that performs backup tasks in response to detection of certain types of faults. 
         [0017]    More generally, the node  18  includes a main operational portion, which in one embodiment contains the main hard disk drive  24  for some other type of storage element). The main operational portion controls operation when the node  18  functions normally. The main hard disk drive  24  stores the operating system and application software, which are loaded into the node  18  to perform useful tasks. In case of some predetermined faults, the backup device  25  is used to enable access over the network  12  to the backup storage system  20  to retrieve data to recover the main operational portion of the node  18 . 
         [0018]    The backup storage device  22  can be implemented in a number of different ways. For example, the backup storage device  22  can be a bootable mini-drive that is mounted inside the chassis of or on a motherboard in the node. The mini-drive can be a hard disk drive having a relatively small storage capacity for reduced cost. Alternatively, the mini-drive can be other types of non-volatile memory, such as flash memory, electrically erasable and programmable read-only memory (EEPROM) devices, and so forth. Instead of a separate component in the chassis of each node, the mini-drive can also be integrated onto the motherboard of the node if its size permits. Alternatively, the backup storage device  22  can be a full form factor drive. 
         [0019]    The backup storage device  22  can also include a compact disk (CD) or digital video disk or digital versatile disk (DVD) drive in which a CD or DVD is loaded. The CD or DVD contains the necessary software to enable the node  18  to access the network  12 . Alternatively, the backup storage device  22  includes a partition on the main hard disk drive  24 . It is likely that only one part of the hard disk drive  24  is corrupted while another portion is not corrupted. The backup storage device  22  can also include other bootable cartridges or drives. 
         [0020]    An example of the backup routine  26  is a browser that is capable of executing on a processor in each node to gain access to the network  12 . To avoid having to load a large operating system such as the WINDOWS® operating system, the browser can be a reduced version browser that does not need standard full-scale computer operating systems to run. Examples of such “mini-browsers” include browsers that run in PDAs and other handheld devices. Alternatively, mini-browsers can be designed to operate in a DOS operating system, a WINDOWS® CE operating system, or other “lite” operating systems. 
         [0021]    Referring to  FIG. 2 , an example of the node  18  (which has a similar arrangement as nodes  14  and  16 ) is illustrated. The node  18  includes a central processing unit (CPU)  100  that forms the processing core of the node  18 . A host bridge  102  is connected over a host bus to the CPU  100 . The host bridge  102  is also connected to a system bus  104 , such as a Peripheral Component Interconnect (PCI) bus. Additionally, the host bridge  102  contains control elements to interface a main memory  103  and a video controller  116  that controls presentation of images on a display  114 . The system bus  104  is connected to a network interface  112  that manages communications to the network  12  through a port  110 , 
         [0022]    Other components of the node  18  include a south bridge  123  coupled to the system bus  104 . The south bridge  123  is in turn coupled to a disk controller  124  that is connected to the main disk drive  24 . The disk controller  124  can also manage communications with a CD and/or DVD drive  126 . An input/output (I/O) controller  118 , which is connected to a floppy disk drive  120  and to a mini-drive  122 , is also coupled to the south bridge  123 . 
         [0023]    When the node  18  first starts up, a basic input/output system (BIOS) routine  108  is loaded to perform boot and initialization tasks. The BIOS routine  108  is stored in a non-volatile memory  106 , which can be a flash memory, EEPROM, and other like memory devices. Access to the non-volatile memory  106  is provided through the south bridge  123 . 
         [0024]    The backup storage device  22  of  FIG. 1  can be one or more of the following elements in the node  18 : the mini-drive  122 , the CD or DVD drive  126 , the floppy drive  120 , the backup partition  130  in the main hard disk drive  24 , or an additional drive like the main chive  24 , 
         [0025]    Although not shown, the node also includes various layers and stacks to enable communications over the network  12 . For example, a network stack can include a TCP/IP (Transmission Control Protocol/Internet Protocol) or a UDP/IP (User Datagram Protocol/Internet Protocol) stack. TCP is described in RFC 793, entitled “Transmission Control Protocol,” dated September 1981; and UDP is described in RFC 768, entitled “User Datagram Protocol,” dated August 1980. One version of IP is described in Request for Comments (RFC) 791, entitled “Internet Protocol,” dated September 1981; and another version of IP is described in RFC 2460, entitled “Internet Protocol, Version 6 (IPv6) Specification,” dated December 1998. TCP and UDP are transport layers for managing connections over an IP network. 
         [0026]    Also, various services enable the communication of requests over the network  12 , such as requests between a node and the backup storage system  20 . One such service is the Hypertext Transport Protocol (HTTP) service, which enables requests sent from one network element to another and responses from the destination network element to the requesting network element. 
         [0027]    Referring to  FIG. 3 , the failure recovery process performed in one of the nodes  14 ,  16 , and  18  is illustrated. The operating system  134  determines (at  202 ) if the node has experienced a fault. If so, the operating system  134  sets (at  204 ) a fail flag  132  (in the main hard disk drive  24 ) to an active state. Alternatively, the fail flag can be stored in the non-volatile memory  106 , the mini-drive  122 , or another memory storage element in the node. 
         [0028]    Next, either in response to a user request to restart or automatically upon detection of the fault, the node is rebooted (at  206 ). When the node starts up, the BIOS routine  108  is loaded to perform boot tasks. One of the tasks performed by the BIOS routine  108  is to determine if the fail flag  132  has been set (at  208 ). If not, a normal boot process is performed (at  210 ) by the BIOS routine  108 . If the fail flag  132  is set, then the BIOS routine  108  accesses (at  212 ) the backup storage device  22 . Alternatively, instead of automatically checking for the fail flag  132 , the boot from the backup storage device  22  can be performed manually by a user through the BIOS (such as by selecting the boot drive). Software on the storage device  22 , including the backup routine  26 , is loaded (at  214 ) into the node for execution on the CPU  100 . As noted above, the backup routine  26  can be a mini-browser that enables communications over the network  12 . 
         [0029]    The backup routine  26  presents an indication of the fault (at  216 ), such as displaying a warning on the display  114 . The backup routine  26  then waits (at  218 ) for a user request to recover. If a request to recover the node is received, then the backup routine  26  accesses (at  220 ) the remote backup system  20  over the network  12 . Image data ( 30 ,  32 , or  34 ) is retrieved from the backup storage system  20  and downloaded (at  222 ) into the node, where the image data is used to recover the node. A scan disk operation may be performed to determine portions of the hard disk drive that are defective. The image data can then be copied to the remaining portions of the hard disk drive  24  to enable normal operation of the node. 
         [0030]    The various software routines or modules described herein may be executable on various processing elements. Such processing elements include microprocessors, microcontrollers, processor cards (including one or more microprocessors or microcontrollers), or other control or computing devices. As used here, a “controller” can refer to either hardware or software or a combination of the two. 
         [0031]    The storage units include one or more machine-readable storage media for storing data and instructions. The storage media include different forms of memory including semiconductor memory devices such as dynamic or static random access memories (DRAMs or SRAMs), erasable and programmable read-only memories (EPROMs), electrically erasable and programmable read-only memories (EEPROMs), and flash memories; magnetic disks such as fixed, floppy and removable disks; other magnetic media including tape; or optical media such as CDs or DVDs. Instructions that make up the various software routines or modules when executed by a respective processing element cause the corresponding node to perform programmed acts. 
         [0032]    The instructions of the software routines or programs are loaded or transported into the node in one of many different ways. For example, code segments including instructions stored on floppy disks, CD or DVD media, a hard disk, or transported through a network interface card, modem, or other interface device are loaded into the system and executed as corresponding software routines or modules. In the loading or transport process, data signals that are embodied in carrier waves (transmitted over telephone lines, network lines, wireless links, cables, and the like) communicate the code segments, including instructions, to the node. Such carrier waves may be in the form of electrical, optical, acoustical, electromagnetic, or other types of signals. 
         [0033]    While the invention has been disclosed with respect to a limited number of embodiments, those skilled in the art will appreciate numerous modifications and variations therefrom. It is intended that the appended claims cover all such modifications and variations as fall within the true spirit and scope of the invention.