Patent Publication Number: US-2004054836-A1

Title: Method of data access by simulating an external device to be a hard disk drive

Description:
BACKGROUND OF THE INVENTION  
       [0001] 1. Field of the Invention  
       [0002] The invention relates in general to a method of data access, and more particularly to a method of data access by simulating an external device to be a hard disk drive.  
       [0003] 2. Description of the Related Art  
       [0004] Mobile phones and computers have become essential tools for modern people in trading business or official business. The data interflow or exchange between these two is also very frequent. Traditionally, a specific software is adopted to connect a mobile phone and a computer via a Universal Serial Bus (USB) port. When connecting, it is necessary to install the specific software and the USB driver every time. Then the time consumed when installing would be a waste for those businessmen who believe time is benefit.  
       SUMMARY OF THE INVENTION  
       [0005] It is therefore an object of the invention to provide a method of data access by simulating an external device to be a hard disk drive. The method enables an external device to proceed with data exchange directly with a computer, so the install operation is simplified, data access becomes faster and handier, and the product practicability is improved.  
       [0006] The invention achieves the above-identified objects by providing a method of data access by simulating an external device to be a hard disk drive. The method enables an external device to proceed with data exchange directly with a computer. The data access method comprises the following steps: firstly, the first operation system of a host detects an external device, and asks for a USB device describer from the external device. Next, the connection relationship between the host and the external device is set up in accordance with the USB device describer. An operation command is sent from the first operation system of the host to the external device, and the second operation system in the external device proceeds with data operation according to the operation command, and sends a completion message back to the host.  
       [0007] Other objects, features, and advantages of the invention will become apparent from the following detailed description of the preferred but non-limiting embodiments. The description is made with reference to the accompanying drawings in which: 
     
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
     [0008]FIG. 1 illustrates a block diagram of a data access structure by simulating an external device to be a hard disk drive according to a preferred embodiment of the invention;  
     [0009]FIG. 2A illustrates a system-control diagram in a host end according to a preferred embodiment of the invention;  
     [0010]FIG. 2B illustrates a system-control diagram in an external device end according to a preferred embodiment of the invention;  
     [0011]FIG. 3 illustrates a flow chart of a method of data access by simulating an external device to be a hard disk drive according to a preferred embodiment of the invention;  
     [0012]FIG. 4 illustrates roles of protocols according to a preferred embodiment of the invention; 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT  
     [0013] A method of data access by simulating an external device to be a hard disk drive according to the invention mainly uses the transport function of the USB Communication Protocol and the USB Mass Storage Class Protocol to enable an external device to become an external hard disk drive of a computer, and to achieve high-speed data exchange and convenient operations for users.  
     [0014]FIG. 1 illustrates a block diagram of a data access structure by imitating an external device to be a hard disk drive according to a preferred embodiment of the invention. A host  110  includes at least a first USB port  112  and a processing component  114 ; and an external device  120  includes at least a second USB port  122  and a memory module  124 . As shown in FIG. 1, a USB connecting line  130  connects the first USB port  112  of the host  110  with the second USB port  122  of the external device  120 . After the connection between the host  110  and the external device  120  is built up, the process component  114  of the host  110  can directly access data with the memory module  124  of the external device  120 , then the external device can be simulated as an external hard disk drive of the host  110 . In addition, the host  110  can be a personal computer, a notebook or other desk top computers; the external device  120  can be a mobile phone or other palm devices, such as a mobile phone with a USB port, which can proceed data exchange with a computer directly.  
     [0015] Referring to FIG. 3, a flow chart of a method of data access by simulating an external device to be a hard disk drive according to a preferred embodiment of the invention is illustrated. Please also refer to FIG. 2A and FIG. 2B, which respectively illustrate system-control diagrams in a host end and an external device end according to a preferred embodiment of the invention. As shown in FIG. 3, the method of direct data access and exchange proceeded between the external device  120  and the host  110  is illustrated as follows:  
     [0016] To start with Step  302 , the first operation system  210  of the host  110  detects an external device  120  and requests for a USB device describer from the external device  120 . The USB device describer is for indicating the characters of the USB external device, such as indications about the product and manufacturer of the external device. Next, at step  304 , the connection relationship between the host  110  and the external device  120  is set up in accordance with the USB device describer. Before the connection between the host  110  and the external device  120  is set up, the second operation system  220  of the external device  120  starts a USB Mass Storage Driver  222 , and the first operation system  210  of the host  110  loads and starts the corresponding USB Mass Storage Driver  212  after obtaining the USB device describer. After the connection between the host  110  and the external device  120  is set up, a new hard disk drive is shown on a user interface  214  by the first operation system  210 , and the data and content of the new hard disk drive can be found on the user interface  214 . The first operation system can be a windows operation system while the user interface  214  can be a Windows file manager, for example. Therefore, a user can directly operate and control the external device from the host end.  
     [0017] At step  306 , an operation command is sent from the first operation system  210  of the host  110  to the external device  120 . At step  308 , the second operation system  230  in the external device  120  proceeds with data operation on a memory module  224  via an application program interface  226  according to the operation command. The data operation on the memory module  224  includes to set up a content, to delete a content, to set up a file, to delete a file, to edit and save a file, and so on.  
     [0018] Finally, at step  310 , a completion message is sent back to the host  110  after the second operation system  230  of the external device  120  finishes the data operation, then the method of data access is completed.  
     [0019] Referring to FIG. 4, roles of protocols according to a preferred embodiment of the invention is illustrated. The USB Communication Protocol  400  is defined for identifying the high-speed communication between the USB external device  120  and the host  110 , and the USB Mass Storage Class Protocol is defined for identifying the practice of data exchange operated by the USB Mass Storage under the windows operation system. On the roles of protocols, the fundamental protocol is USB Communication Protocol  400 . In the bInterfaceProtocol field  410 , the external device  120  via its own device describer informs the host  110  that itself is a Mass Storage  412  and also assigns the Transport Protocol  422  used by the Mass Storage  412  in the bInterfaceProtocol field  420 . The Transport Protocol  422  can be Bulk-Only Transport, CBI (Control/Bulk/Interrupt protocol), or other related protocols. In addition, the Industry-standard Protocol  432  for transporting in the Mass Storage  412  is assigned in the bInterfaceSubClass field  430  to perform the data access of the new hard disk drive. The Industry-standard Protocol can be SCSI (Small Computer System Interface) Transport Command Set, or RBC (Reduced Block Commands), UFI, and other related protocols.  
     [0020] As disclosed above, a method of data access by simulating an external device to be a hard disk drive according to the invention, has the following advantages:  
     [0021] 1. Fast and convenient data access: by using the principle and protocols of a USB Mass Storage, an external device with a USB port can be simulated to be a hard disk drive for directly proceeding data exchange with a host of a computer. The high-speed and convenient data exchange is therefore achieved.  
     [0022] 2. Simplified installation: Under the window operation system for supporting a USB Mass Storage, a file manager can be adopted to directly proceed the data exchange between the external device and the host. No software installation is needed, and no time has to be spent for learning to use the related software. Such an easy operation is very convenient for users, and the practicability of products can then be improved.  
     [0023] 3. By changing a palm device to become a USB Mass Storage, a mobile palm device can be simulated to be a portable hard disk drive.  
     [0024] While the invention has been described by way of example and in terms of the preferred embodiment, it is to be understood that the invention is not limited to the disclosed embodiment. To the contrary, it is intended to cover various modifications and similar arrangements and procedures, and the scope of the appended claims therefore should be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements and procedures.