PATENT DOCUMENT

Publication Number: US-7415545-B1
Application Number: US-14203005-A
Country: US
Kind Code: B1

Title: Method and apparatus for dynamic link driver configuration

Abstract:
A method and apparatus embodied in transaction layer software suitable for use with serial bus devices, such as IEEE standard 1394 serial bus devices for supporting multiple link device drivers. The invention acquires or otherwise ascertains the capabilities of link devices and provides link device driver configurations to such link devices based on the link device&#39;s capabilities and behaviors, among other factors.

Claims:
1. A method for configuring a link driver for a link device in a serial bus device, comprising:
 a) querying said link driver for its capabilities by way of a transaction layer process; 
 b) receiving said capabilities of said link device; and 
 c) determining whether said link device exhibits a first behavior, and generating a first link driver configuration if said link device exhibits said first behavior, said first link driver configuration based at least in part on said capabilities of said link device; otherwise 
 d) generating a second link driver configuration, said second link driver configuration based at least in part on said capabilities and a second behavior of said link device. 
 
     
     
       2. The method of  claim 1 , wherein said first behavior comprises an asynchronous communication behavior. 
     
     
       3. The method of  claim 1 , wherein said second behavior comprises an isochronous communication behavior. 
     
     
       4. The method of  claim 1 , further comprising receiving user-defined configuration data for said link device before said generating said first or second link driver configuration, wherein said generating of said first or second link driver configuration further uses said user-defined configuration data. 
     
     
       5. The method of  claim 1 , wherein said serial bus device comprises an IEEE Standard 1394 device. 
     
     
       6. The method of  claim 1 , wherein said first and said second behaviors comprise the type of communication carried about by said serial bus device. 
     
     
       7. The method of  claim 6 , wherein said first link driver configuration is configured for an asynchronous communication type. 
     
     
       8. The method of  claim 7 , wherein said second link driver configuration is configured for an isochronous communication type. 
     
     
       9. The method of  claim 1 , wherein said received capabilities of said link device comprise at least one of:
 a maximum sync packet capability; 
 a support capability for busy mode; 
 a cycle accuracy capability; 
 a cycle master capability; and 
 a CSR-ROM support capability. 
 
     
     
       10. The method of  claim 1 , further comprising storing information relating to said capabilities in a storage device. 
     
     
       11. The method of  claim 1 , wherein said act of querying is performed substantially in response to the detection of said link device. 
     
     
       12. An apparatus that supports multiple link driver device configurations, comprising:
 a) a transaction layer software unit operating in a serial bus device; and 
 b) at least one link layer service unit operatively coupled to said transaction layer software, said transaction layer software unit configured to ascertain capabilities and behaviors of said link layer service unit and to provide at least a first link driver configuration and/or a second link driver configuration for said link layer service unit; 
 wherein said transaction layer software unit provides either said first link driver configuration or said second link driver configuration based at least on said capabilities and behaviors. 
 
     
     
       13. The apparatus of  claim 12 , wherein said behaviors comprise the type of communication carried about by said serial bus device. 
     
     
       14. The apparatus of  claim 13 , wherein said first link driver configuration is configured for an asynchronous communication type. 
     
     
       15. The apparatus of  claim 13 , wherein said second link driver configuration is configured for an isochronous communication type. 
     
     
       16. A method for configuring link drivers for a plurality of link devices in a serial bus device, comprising:
 a) querying each said link driver for its capabilities by way of a transaction layer process; 
 b) receiving said capabilities of each said link device; and 
 c) determining whether each said link device exhibits a first behavior or a second behavior; and 
 d) generating a first link driver configuration if individual ones of said link devices exhibit said first behavior, said first link driver configuration based at least in part on said capabilities of said link device; otherwise 
 e) generating a second link driver configuration, said second link driver configuration based at least in part on said capabilities and a second behavior of individual ones of said link devices. 
 
     
     
       17. The method of  claim 16 , further comprising receiving user-defined configuration data for each said link device before said generating said first link driver configuration or said second link driver configuration;
 wherein said generating of said first and second link driver configurations further uses said user-defined configuration data. 
 
     
     
       18. The method of  claim 16 , wherein at least one of said plurality of link drivers is provided said first link driver configuration, said first link driver configuration being configured for asynchronous communication. 
     
     
       19. The method of  claim 16 , wherein at least one of said plurality of link drivers is provided said second link driver configuration, said second link driver configuration being configured for isochronous communication. 
     
     
       20. A program storage device readable by a machine, tangibly embodying a program of instructions executable by the machine to perform a method for configuring link drivers for at least one link device in a serial bus device, said method comprising:
 a) querying said link driver for its capabilities by way of a transaction layer process; 
 b) receiving said capabilities of said link device; and 
 c) determining whether said link device exhibits a first behavior, and generating a first link driver configuration if said link device exhibits said first behavior, said first link driver configuration based at least in part on said capabilities of said link device; otherwise 
 d) generating a second link driver configuration, said second link driver configuration based at least in part on said capabilities and a second behavior of said link device. 
 
     
     
       21. The program storage device of  claim 20 , wherein said method further comprises receiving user-defined configuration data for said link device before said generating of said first link driver configuration or said second link driver configuration, wherein said generating said first and second link driver configuration further uses said user-defined configuration data. 
     
     
       22. The program storage device of  claim 20 , wherein said program storage device readable by a machine is selected from the group consisting of:
 a magnetic media; 
 an optical media; and 
 a semiconductor media. 
 
     
     
       23. A method for dynamically configuring a link device driver, comprising:
 determining one or more capabilities and behaviors of a link device by sending one or more requests to a link device driver associated with said link device; 
 generating configuration information for said link device driver based at least in part on said one or more capabilities and behaviors; and 
 configuring said link device driver with a first link driver configuration if said link device exhibits a first behavior, said first link driver configuration based at least in part on said one or more capabilities of said link device; otherwise 
 configuring said link device driver with a second link driver configuration, said second link driver configuration based at least in part on said capabilities and a second behavior of said link device. 
 
     
     
       24. The method of  claim 23 , wherein said acts of determining and generating are performed substantially by a transaction layer process. 
     
     
       25. The method of  claim 23 , further comprising storing information relating to said one or more capabilities in a storage device. 
     
     
       26. The method of  claim 25 , wherein said storage device comprises a BIOS. 
     
     
       27. The method of  claim 23 , wherein said act of determining is performed substantially in response to the detection of said link device. 
     
     
       28. Apparatus for configuring a link driver for a link device in a serial bus device, comprising:
 means for querying said link driver for its capabilities by way of a transaction layer process; 
 means for receiving said capabilities of said link device; and 
 means for determining whether said link device exhibits a first behavior or a second behavior; 
 means for generating a first link driver configuration if said link device exhibits said first behavior, said first link driver configuration based at least in part on said capabilities of said link device; and 
 means for generating a second link driver configuration if said link device does not exhibit said first behavior, said second link driver configuration based at least in part on said capabilities and said second behavior of said link device.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is a continuation of U.S. patent application Ser. No. 09/431,703, filed on Nov. 1, 1999 now U.S. Pat. No. 6,959,343, which is hereby incorporated by reference as if set forth herein. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention pertains generally to link driver configuration for IEEE Standard 1394 nodes. More particularly, the invention is a method for dynamic link driver configuration of link driver architecture for IEEE Standard 1394 modules. 
     2. The Prior Art 
     The Institute of Electrical and Electronics Engineers, Inc. (IEEE) defines the IEEE Standard 1394-1995 serial bus architecture in the document “IEEE Standard for a High Performance Serial Bus” published Aug. 30, 1996 which is incorporated herein by reference. In IEEE 1394, the serial bus architecture is defined in terms of nodes. In general, a node is an addressable entity (i.e., a logical entity with a unique address), which can be independently reset and identified. More than one node may reside on a single module, and more than one unit may reside in a single node. 
     A module is a physical device, comprising one or more nodes that share a physical interface. The address space provided by a node can be directly mapped to one or more units. A unit is a logical entity, such as a disk controller, which corresponds to unique I/O (input/output) driver software. On a multifunction node, for example, a processor and I/O interfaces could be different units on the same node. 
     During initialization (startup) of a module, certain hardware devices of the module are checked and appropriate drivers are loaded as is known in the art. For example,  FIG. 1  illustrates a typical module device  1  having first and second nodes  2   a ,  2   b . Nodes  2   a ,  2   b  include respective link layer services (LINK)  3   a ,  3   b  and physical layer services (PHY)  4   a ,  4   b . During the start up of module  1 , link driver  5   a  is loaded to configure LINK  3   a , and link driver  5   b  is loaded to configure LINK  3   b . The link drivers  5   a ,  5   b  provide necessary configuration information which allows the LINKs  3   a ,  3   b  to carry out its link layer services. The prior art implementation provides a static link driver which is configured identically for each node  2   a ,  2   b  without regard for the type of communication that will be carried out by the node. Thus, link driver  5   a  is configured the same way as  5   b , even though node  2   a  may carry out different communication than node  2   b.    
     The prior art implementation of providing a static configuration for link drivers is not always optimal. For example, in IEEE 1394 communication, nodes may carryout asynchronous and isochronous communication. In asynchronous communication such as SBP (serial bus protocol), it would be advantageous to have a link device configured for data pumping to provide optimum performance for such asynchronous transfers. On the other hand, in isochronous communication such as AV/C (audio/video control), no advantage is provided if the link device is configured for data pumping, since AV/C commands do not have high bandwidth requirements. Rather, AV/C communication would benefit if the link device is configured for transferring isochronous data. Thus, the current implementation of providing a static configuration link driver for all LINKS ( 3   a ,  3   b , for example) is a disadvantage. 
     As an example, LINK  3   a  may be able to receive and process 2054 byte packet sizes, while LINK  3   b  may be able to receive and process only 512 byte packet sizes. The prior art implementation would configure link device drivers  5   a ,  5   b  to handle 512 byte packet sizes, even though LINK  3   a  is able to handle larger (2054 byte) sizes. Thus, the capabilities of LINK  3   a  are not fully utilized where static link driver configurations are provided as is carried out in the prior art. 
     Accordingly, there is a need for a method which provides multiple link device driver configurations based on the capabilities of the link device and based on the specific behaviors of the link device. The present invention satisfies these needs, as well as others, and generally overcomes the deficiencies found in the background art. 
     An object of the invention is to provide a method for configuring link device drivers which overcomes the deficiencies of the prior art. 
     Another object of the invention is to provide a method for configuring link device drivers based on the capabilities of the link device. 
     Another object of the invention is to provide a method for configuring link device drivers based on the specific behaviors of the link device. 
     Another object of the invention is to provide a method for configuring link device drivers by ascertaining the capabilities of link devices before providing the configuration information for the link device drivers. 
     Further objects and advantages of the invention will be brought out in the following portions of the specification, wherein the detailed description is for the purpose of fully disclosing the preferred embodiment of the invention without placing limitations thereon. 
     BRIEF DESCRIPTION OF THE INVENTION 
     The present invention is a method and apparatus embodied in transaction layer software suitable for use with serial bus devices, such as IEEE standard 1394 serial bus devices for supporting multiple link device drivers. In its most general terms, the invention acquires or otherwise ascertains the capabilities of link devices and provides link device driver configurations to such link devices based on the link device&#39;s capabilities and behaviors, among other factors. 
     The invention further relates to machine readable media on which are stored embodiments of the present invention. It is contemplated that any media suitable for retrieving instructions is within the scope of the present invention. By way of example, such media may take the form of magnetic, optical, or semiconductor media. The invention also relates to data structures that contain embodiments of the present invention, and to the transmission of data structures containing embodiments of the present invention. The method and operation of the invention may be carried out by a conventional processor within the serial bus device as is known in the art. 
     In general the invention may be used to configure one or more link device drivers in a module of a serial bus device according to the capabilities of the link devices, the behavior of the link devices, and other criteria. 
     In a first system embodiment, the invention operating in the transaction layer of the module is operatively coupled for communication to one or more link devices for the configuration of the link device drivers for the link devices. In a second system embodiment, the invention operating in the transaction layer of the module is operatively coupled for communication to a device driver service which is operatively coupled for communication with one or more link devices. The device driver service provides messaging between the transaction layer and the link devices for the configuration of the link device drivers. In general, the invention and the link devices communicate via driver control commands. 
     The link devices which for which the invention provides link driver configuration may comprise the same or different types. In cases where the link devices are the same type, the invention configures the link driver for each link device according to the behavior of the link device (e.g., the type of communication carried out by the link device) as well as the capabilities of the link device. For example, in a module having first and second nodes, each node having a link device, first node may be configured for asynchronous communication, while the second node may be configured for isochronous communication. Even though the link device in the first node is identical to the link device in the second node, the invention may provide link driver configuration optimized for asynchronous data transfer to the link device in the first node and link driver configuration optimized for isochronous data transfer to the link device in the second node to thereby support the behavior carried out by each respective module. 
     Other criteria may be used to configure link devices including, for example, user defined input criteria provided by a user of the module. 
     In operation, during initialization, link drivers are “installed” or loaded according to the type of system involved. For embedded systems, the method for installing device drivers will vary depending on the needs of the implementation. Device drivers for locally resident drivers may be pre-compiled into a ROM image. Under this arrangement, at boot time the drivers would be called to perform initialization thereof. 
     The transaction layer software of the present invention then queries each of the link drivers to ascertain each link device&#39;s capabilities via a driver control command. In the preferred embodiment, the transaction layer requests the link&#39;s capabilities as soon as it becomes aware of the link device. In response, the link drivers transmit its respective capabilities to the transaction layer software. The capabilities of the link device may be staticly provided in a resident storage device, such as a BIOS (basic input/output system), for example. The transaction layer software may receive additional configuration data such as user-defined configuration, which may define specific behaviors of the module. The transaction layer software then generates link driver configuration data according to the link device capabilities and the other configuration data for each link device. The generated link driver configuration is then transmitted to the respective link device driver and loaded therein. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention will be more fully understood by reference to the following drawings, which are for illustrative purposes only. 
         FIG. 1  is a functional block diagram of serial device module which carries out device driver configuration according to the prior art. 
         FIG. 2  is a functional block diagram of an illustrative link data structure suitable for use with the present invention. 
         FIG. 3  is a functional block diagram of a first embodiment serial device module which carries out device driver configuration according to the present invention. 
         FIG. 4  is a functional block diagram of a second embodiment serial device module which carries out device driver configuration according to the present invention. 
         FIG. 5  is a flow chart showing generally acts for configuring link drivers according to the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Persons of ordinary skill in the art will realize that the following description of the present invention is illustrative only and not in any way limiting. Other embodiments of the invention will readily suggest themselves to such skilled persons having the benefit of this disclosure. 
     Referring more specifically to the drawings, for illustrative purposes the present invention is embodied in the apparatus shown  FIG. 2  through  FIG. 4  and the method outlined in  FIG. 5 . It will be appreciated that the apparatus may vary as to configuration and as to details of the parts, and that the method may vary as to details and the order of the acts, without departing from the basic concepts as disclosed herein. The invention is disclosed generally in terms of a method and system which provides multiple link device driver configurations based on the capabilities of the link device and based on the specific behaviors of the link device, although numerous other uses for the invention will suggest themselves to persons of ordinary skill in the art. 
     Referring first to  FIG. 2 , there is depicted a block diagram of an illustrative link data structure  10  suitable for use with the present invention. It will be appreciated that the data structure depicted in  FIG. 2  and described herein is only exemplary and that other data structures may be used in conjunction with the present invention, such as database tables and trees, for example. 
     Link data structure  10  is a link list of link device nodes  12   a  through  12   n , and is maintained by the transaction software (TNF kernel) of the present invention. Each link device node  12   a  through  12   n  represents a link device in the module and includes information about the link device. For example, in a module having two link devices, the first link device would be represented by node  12   a  and the second link device would be represented by node  12   b.    
     A main pointer  14  provides a link to the link data structure  10 . Link devices nodes  12   a  through  12   n  further may include a peer pointer  16   a  through  16 ( n− 1) to thereby allow TNF kernel to navigate the link data structure  10  for each link device of the module. Thus, node  12   a  includes a peer pointer  16   a  to node  12   b , node  12   b  includes a peer pointer  16   b  to node  12   c , etc. Since the last node  12   n  does not have additional peers to point to, node  12   n  does not include a peer pointer, shown as a null pointer  18 . 
     Each node  12   a  through  12   n  further includes a corresponding link configuration data structure  22   a  through  22   n  and a corresponding link capabilities data structure  24   a  through  24   n . The link configuration data structure  22   a  through  22   n  is used by the TNF kernel to instruct the link device how it should be configured. For example, the link configuration data structure  22   a  through  22   n  controls how the link behaves on the serial bus, among other things. The link capabilities data structure  24   a  through  24   n  provides the TNF kernel with information about the link device. For example, the link capabilities data structure  24   a  through  24   n  may provide such information about the corresponding link device as the link device&#39;s maximum sync packet capabilities, support or non-support for busy mode, cycle accuracy, capability for cycle master, CSR-ROM support, and other like capabilities. 
     Referring now to  FIG. 3 , there is shown a functional block diagram of a first exemplary embodiment serial device module  26  which carries out device driver configuration according to the present invention. Module  26  includes three nodes  28   a  through  28   c , each having a respective link layer (LINK) device  30   a  through  30   c  connected to a respective physical layer (PHY) devices  32   a  through  32   c . LINKS  30   a  through  30   c  provide the link services for the module  26  as is known in the art, and PHY devices  32   a  through  32   c  provide the physical layer services for the module  26  as is known in the art. Each PHY device  32   a  through  32   n  is connected to serial bus  34  through a conventional serial interface connection. 
     The module  26  further includes one or more unit architectures  36  to present to other devices on the serial bus. Unit architectures  36  may comprise conventional units, such as a disk controller or some other storage device and a scanner controller, for example. 
     The unit architectures  36  and the LINKS  30   a  through  30   c  are operatively coupled for communication to TNF kernel  38 . The TNF kernel  38  provides transactional services for module  26  and the method of the invention as described herein and in further detail in conjunction with  FIG. 5 . 
     In operation, when module  26  is initialized, Link drivers  40   a  through  40   c  are loaded (initialized) for respective LINKS  30   a  through  30   c . As noted above, drivers are loaded according to the type of module involved. For embedded systems, the method for installing device drivers will vary depending on the needs of the implementation. Device drivers for locally resident drivers may be pre-compiled into a ROM image. Under this arrangement, at boot time the drivers would be called to perform initialization thereof. Under either arrangement, or other suitable arrangements, a signal is transmitted to the TNF kernel to communicate the initialization of the link drivers. Link drivers  40   a  through  40   c  are then configured as described below. For each LINK  30   a  through  30   c , the TNF kernel  38  creates link device nodes ( 12   a  through  12   c ) using the link data structure  10  as described above in conjunction with  FIG. 2 . As noted above, other data structures may be used without departing from the spirit and scope of the present invention. 
     The TNF kernel  38  then queries each link driver  40   a  through  40   c  for the link capabilities of the LINKS  30   a  through  30   c . In the preferred embodiment, the TNF kernel  38  requests each link&#39;s capabilities as soon as it becomes aware of the link device. In response, link drivers  40   a  through  40  provides the capabilities of respective LINKS  30   a  through  30   c  by providing link capabilities data, which is stored into data structure  24   a  through  24   c  for respective nodes  12   a  through  12   c . The TNF kernel  38  may also receive other link configuration data provided by a user. The TNF kernel  38  evaluates the link capabilities of LINKS  30   a  through  30   c  and the other link configuration data, if any, to generate appropriate link driver configurations according each LINK&#39;s capabilities and user-defined configuration. The link configuration generated by TNF kernel  38  is then stored to link configuration data structure  22   a  through  22   c  associated with respective nodes  12   a  through  12   c  in link data structure  10  and is communicated to link drivers  40   a  through  40   c  for configuration therein. 
     Referring now to  FIG. 4 , there is shown a functional block diagram of a second exemplary embodiment serial device module  42  which carries out device driver configuration according to the present invention. Module  42 , like module  26 , includes three nodes  28   a  through  28   c , each having a respective link layer (LINK) device  30   a  through  30   c  connected to a respective physical layer (PHY) devices  32   a  through  32   c . LINKS  30   a  through  30   c  provide the link services for the module  42 , and PHY devices  32   a  through  32   c  provide the physical layer services for the module  42 . Each PHY device  32   a  through  32   n  is connected to serial bus  34  via conventional serial interface connection. 
     The module  42  also includes one or more unit architectures  36  to present to other devices on the serial bus. The unit architectures  36  are operatively coupled for communication to TNF kernel  38 . The TNF kernel  38  provides transactional services for module  42  and the link driver configuration of LINKS  28   a  through  28   c  as described above and in conjunction below with  FIG. 5 . 
     The module  42  further includes device driver services (IO coordinator  44 ) operatively coupled to the TNF kernel  38  and the LINKS  30   a through  30   c . The IO coordinator  44  provides, among other things, event notification to TNF kernel  38  of LINKS  30   a  through  30   c.    
     In operation, when module  42  is initialized, Link drivers  40   a  through  40   c  are loaded (initialized) for respective LINKS  30   a  through  30   c . In response to the Link drivers  40   a  through  40   c  being loaded, the IO coordinator  44  communicates to the TNF kernel  38  that Link drivers  40   a  through  40   c  have been initialized for LINKS  30   a  through  30   c.    
     For each LINK  30   a  through  30   c , the TNF kernel  38  creates link device nodes ( 12   a  through  12   c ) using the link data structure  10  as described above in conjunction with  FIG. 2 . As noted above, other data structures may be used without departing from the scope of the present invention. 
     The TNF kernel  38  then queries each link driver  40   a  through  40   c  for the link capabilities of the LINKS  30   a  through  30   c . In response, link drivers  40   a  through  40  provides the capabilities of respective LINKS  30   a  through  30   c  by providing link capabilities data, which is stored into data structure  24   a  through  24   c  for respective nodes  12   a  through  12   c . The TNF kernel  38  may also receive other link configuration data provided by a user. The TNF kernel  38  evaluates the link capabilities of LINKS  30   a  through  30   c  and the other link configuration data, if any, to generate appropriate link driver configurations according each LINK&#39;s capabilities and user-defined configuration. The link configuration generated by TNF kernel  38  is then stored to link configuration data structure  22   a  through  22   c  associated with respective nodes  12   a  through  12   c  in link data structure  10  and is communicated to link drivers  40   a  through  40   c  for configuration therein. 
     While the above illustrative embodiments (module  26  and module  42 ) were described using three nodes  28   a  through  28   c , the method of the invention may also be carried out with a module having one or more nodes. As illustrated, the method of the invention may be carried out with or without device driver services (IO coordinator  44 , or other like messaging services). 
     The method and operation of the invention will be more fully understood by reference to the flow chart of  FIG. 5 , as well as  FIG. 2  through  FIG. 4 .  FIG. 5  illustrates generally the actions associated with providing dynamic configuration ROM using double image buffers in accordance with the present invention. The order of operation as shown in  FIG. 4  and described below are only exemplary, and should not be considered limiting. 
     At box  100 , the TNF kernel  38  has become aware of one or more link drivers (and corresponding link devices) which need to be configured according each respective link device&#39;s capabilities, behaviors, as well as other user-defined configuration data. The TNF kernel  38  may recognize the link devices using various methods, such as via a device driver notification service, for example, as described above in conjunction with  FIG. 4 . For each link device, the TNF kernel  38  transmits a “get link capabilities” driver control command to each link driver initialized for the link devices. As noted above, the TNF kernel maintains the link device information in a data structure (for example, data structure  10 ). For each link device, the TNF kernel creates a data record for recording the capabilities of the link device. Box  110  is then carried out. 
     At box  110 , the link driver receives the “get link capabilities” driver control command from the TNF kernel  38 . As noted above, the capabilities of a link device may be staticly provided in a resident storage device, such as a BIOS (basic input/output system, for example. The link driver ascertains these capabilities and transmits the capabilities to the TNF kernel  38 . Box  120  is then carried out. 
     At box  120 , the TNF kernel  38  receives the link device&#39;s capabilities transmitted by the link driver from box  110 . The link device capabilities may include such information as maximum sync packet capabilities, support or non-support for busy mode, cycle accuracy, capability for cycle master, CSR-ROM support, and other like capabilities. The TNF kernel  38  may also receive additional configuration data such as user-defined configuration, which may define specific behaviors of the link device. Box  130  is then carried out. 
     At box  130 , the TNF kernel  38  evaluates the link device&#39;s capabilities and behaviors and provides link driver configuration accordingly. Box  140  is then carried out. 
     At box  140 , the TNF kernel  38  communicates the link driver configuration generated from box  130  to the link driver for configuration therein. As noted above, the TNF kernel uses the link data structure  10  and the associated link configuration data structure  22   a  through  22   n  to instruct the link driver how it should be configured. The data structure  22   a  through  22   n  is used to control how the link behaves on the IEEE Standard 1394 bus, among other things. Box  150  is then carried out. 
     At box  150 , the link driver configures itself according the configuration provided by the TNF kernel  28  in the link driver data structures  22   a  through  22   n.    
     Accordingly, it will be seen that this invention provides a method which provides multiple link device driver configurations based on the capabilities of the link device and based on the specific behaviors of the link device. Although the description above contains many specificities, these should not be construed as limiting the scope of the invention but as merely providing an illustration of the presently preferred embodiment of the invention. Thus the scope of this invention should be determined by the appended claims and their legal equivalents.

Metadata:
Filing Date: 20050531
Publication Date: 20080819
Grant Date: 20080819
Priority Date: 19991101
Inventors: BROWN STEVEN W.
Assignee: APPLE INC
CPC Classifications: [{"code": "G06F13/102", "inventive": true, "first": true, "tree": "[]"}, {"code": "G06F13/102", "inventive": true, "first": true, "tree": "[]"}]
Family ID: 35115403