KR100989692B1 - Partition View Control Method for USS Storage Devices Supporting Multiple Partitions - Google Patents

Abstract

The present invention relates to a method of controlling the hiding or showing of a specific partition in a USB storage device providing multiple partitions.

The present invention relates to a partition view control method of a USB storage device supporting multiple partitions,

Sending, by the USB host device, a command to hide or show the specific partitions to the multi-partitioned USB storage device;

The USB storage device receiving the hide or show command to hide or show the specific partitions;

Initializing the number of logic units to correspond to the number of partitions actually displayed by reflecting the setting contents by the USB storage device;

And receiving, by the USB host device, the number of initialized logic units from the USB storage device and recognizing partitions corresponding to the number of initialized logic units.

By using the present invention as described above, it is possible to implement to hide or show a specific partition of the USB storage device through the USB host device through the existing USB channel without additional hardware, secure partition ( A removable disk with a Secure Partition will be provided.

USB, Partition, LUN, Hide, Private, Host, PC

Description

Partition View Control Method of USB Storage Device Supporting Multiple Partitions

The present invention relates to a method of controlling the hiding or showing of a specific partition in a USB storage device providing multiple partitions.

A USB storage device (so-called USB memory) is a permanent removable disk drive that allows data to be moved.It can be inserted into the USB port of various devices including the PC to read data from various devices including the PC and stored in the USB storage device. It is widely used to read data from a storage device and store it in various devices including a PC, and the commercially available USB storage device can store a large amount of data of about 32G and in the future, it will be possible to store more data in the future.

However, the USB storage device includes not only a flash memory but also a USB related driver (USB MS Class Driver, USB Device Driver) and a controller as shown in FIG. 1. In addition, the EndPoint (EP) provided by the communication controller enables bulk communication between a USB host device (a device capable of connecting various USB memory devices such as a PC) and a USB storage device.

So, when USB storage device is connected to USB host device, enumeration process is performed through EndPoint0 (EP0) of host device and USB storage device, and when client driver for USB storage device is loaded into memory of USB host device, The USB storage device and the host device are ready for bulk transfer.

Bulk transfer between the host device and the USB storage device uses EndPoint 1 and 2 (EP1, EP2), so the minimum EP that the host device and the controller of the USB storage device should have is Control EP (EP0), EP1, EP2. It's three.

As a result, in the conventional USB storage device, all the created partitions are mounted with the USB host device, and the user has no choice but to delete some files to hide some files.

Alternatively, you can lock the file using the filesystem or a special Windows application, but not the file itself. In particular, if the file name can grasp the contents of the file, it is easy for others to see what is contained in the file even by looking at the file name.

Therefore, even if the user transfers the USB storage device to others, it is necessary for the other person not to know whether the user's important files (for example, important documents, images, certificates, etc.) exist.

SUMMARY OF THE INVENTION In view of the above problems of the prior art, the present invention partitions the storage area of the USB storage device so that even if the user transfers the USB storage device to another person, the file that the user does not want to disclose cannot be recognized even by the other person. It provides a way to divide each partitioned area into a public area and a private area so that it can be used.

In order to achieve the above technical problem, this invention,

In the partition view control method of a USB storage device supporting multiple partitions,

Sending, by the USB host device, a command to hide or show the specific partitions to the multi-partitioned USB storage device;

The USB storage device receiving the hide or show command to hide or show the specific partitions;

Initializing the number of logic units to correspond to the number of partitions actually displayed by reflecting the setting contents by the USB storage device;

And receiving, by the USB host device, the number of initialized logic units from the USB storage device and recognizing partitions corresponding to the number of initialized logic units.

By using the present invention as described above, it is possible to implement to hide or show a specific partition of the USB storage device through the USB host device through the existing USB channel without additional hardware, secure partition ( A removable disk with a Secure Partition will be provided.

First, a general hardware configuration of a USB storage device will be briefly described with reference to FIG. 2 to help with further explanation later.

The controller 1 present in the USB storage device is a module in which the CPU and peripheral devices are one-chip and control all operations of the USB storage device. Program code for the controller 1 for the original operation of the USB mass storage device is loaded in the program memory 2, and the data memory for the sector mapping table of the FTL (Flash Translation Layer). Have (3) Since concepts related to FTL and sectors are less general matters related to the present invention, further description will be omitted.

The external interface has a USB interface 4 for connecting to a USB host device, and has a flash interface bus 6 for interfacing with a NAND flash memory 5, which is an actual data storage location.

The program memory 2 may be a memory of a non-reprogrammable OTP (One Time Programmable) type or a reprogrammable flash type memory depending on which manufacturer's product the controller 1 is used. If the program memory 2 is a reprogrammable flash type memory, the partition-show / hide-related setting described below may be stored here. When the program memory 2 of the OTP type which cannot be reprogrammed is used, the setting information related to the partition opening / not opening is stored in the NAND flash memory 5.

Now, in the present invention, how to make some partitions private in the partitioned USB storage device will be described in earnest.

A general USB storage device is used as a single partition with a logical unit number (LUN) of 0. However, since Windows 2000 SP3, a USB mass storage driver (usbstor.sys) that supports multiple partitions is supported. The storage device can be divided into several partitions.

So if you format a USB storage device into two partitions, for example, you'll find two removable disk drives on a Windows-based PC.

By the way, the USB control signal EP0 is mainly used in the USB enumeration process, and has a low frequency of use except for transmitting special control commands from the host device.

In the present invention, as shown in Figure 3, by using the EP0 to transmit a command (Control) to adjust the number of LUNs of the USB storage device to hide (private) or re-display a specific partition of the USB storage device (public) Can be. In order to transmit User-Specific Command (Partition Show / Hide Command) through EP0, ICCD (IC Card Device) Driver must be installed in USB Host device (eg PC) and ICCD Application must be installed. These programs are not installed by default when installing Windows, so you install them directly to a USB host device. ICCD is a term used in a smart card and is used for convenience. The USB storage device must contain User-command Processing Code via ICCD driver.

First, the USB host device sends a command to the USB storage device to change the partition related setup via USB EndPoint0 (EP0). However, since EP0 is a channel for USB control, it is difficult to control EP0 directly from an application. Therefore, on the USB host device side, an ICCD driver is placed between EP0 and the application to convert the USB protocol into a serial protocol that is easy for a user to use. An application can call the ICCD Driver's API (Application Programming Interface) to construct a program. Eventually, the application connects to the ICCD driver via a virtual serial interface and sends a show / hide partition command to the USB storage device through this ICCD driver.

Next, a method related to separating a plurality of USB storage devices and making a portion private will be described in detail through various embodiments.

As a first embodiment, the case where the USB mass storage device is divided into two partitions will be described with reference to FIG.

In this case, the application defines a partition show / hide protocol as shown in FIG. Such a protocol may be arbitrarily defined and may be a data format that can be recognized between the USB host device and the USB storage device. If you separate a USB storage device into two partitions, you will see both partitions by default when you connect them to a USB host device. Eventually, hiding (private) a partition that has been shown (public) is accomplished by changing the user's settings to private with the USB storage device set so that all partitions are visible after the partition.

For simplicity, let's say the partition is the F and G drives, which are the drive letters you see on your PC. You want to use the F drive as an area that is open to everyone, and the G drive as an area that is used only by you and private to others.

Before the user hands over the USB storage device to another person, the USB Host device (PC) sends a Hide Partition (Private) command to the USB storage device according to the protocol of FIG. Then, as shown in Fig. 2, this command is physically transmitted to the USB interface 4 of the USB storage device through the USB EP0 so that the controller 1 in the USB storage device receives the command.

The controller 1 now interprets the received command, and if the command is interpreted as a hide partition command, the program hides the partition at a specific position of the program memory 2 if the program memory 2 is a flash type memory. The Hide Partition setting requires 1 bit to indicate TRUE or FALSE, so simply use 1-byte memory to represent it.

You will need to reboot the USB storage device in order for Partition Hide to take effect, so remove the USB storage device from the USB host device and reconnect it. Then, the USB storage device starts to reboot again. Before proceeding with the USB enumeration process with the USB host device, the settings for hiding / showing the partition in the specific location are first read and the LUN (Logical Unit Number) value is initialized. Since you previously set up partition hiding, LUN = 0 is initialized. If LUN = 0, then only one partition of the USB mass storage device will communicate with the USB host device.

Typically, when a USB storage device is connected to a USB host device, the USB host device sends a command to query the number of LUNs called GerMaxLun at the end of the USB enumeration. In response, the USB storage device responds with LUN = 0 and the USB host device recognizes that there is only one partition on the USB mass storage device. In fact, if you check the removable disk in Windows Explorer on your PC, you will see only one drive.

Now, in order for the user to see both partitions again, the USB host device transmits the show partition command shown in FIG. 4 to the USB storage device. If the USB storage device is already connected to a USB host device, you can transfer it in that state. In other words, you do not need to remove and reconnect the USB storage device to the USB host device for this transfer. Because the USB storage device is mounted on the USB host device and held as a removable disk, the show partition command can be transmitted via USB EP0. After sending the show command, remove the USB storage device from the USB host device and reconnect it to see the partitions.

As a second embodiment, consider a case where a USB storage device is divided into four partitions. If you divide the partition into four partitions, the USB storage device is internally set to LUN = 3. When the partition is divided into four and plugged back into the USB host device, the USB storage device will advertise LUN = 3 to the USB host device, and four removable disks will be added to Windows Explorer.

For convenience, the USB host device is called a PC, and the drive letters added as removable disks are called F, G, H, and I in order, the user uses the F and G drives as a public area, and the H and I drives as a private area. Suppose you want to use Then, when the USB host device (PC) sends a hide partition command using the same protocol as in FIG. 5, the USB storage device changes the setting to LUN = 1 internally. Now, when you plug the USB host device back into your PC, you see only the F and G drives, and the H and I drives are hidden. Naturally, after sending the show partition command, drive H and I will be visible again.

However, let's say that the user selects G and I drives as the public area and F and H drives as the private area. In order to enable such a selection, since the information in the protocol of FIG. 4 is insufficient, it is necessary to modify the protocol as shown in FIG.

A brief description of the portion of the protocol in FIG. 5 that differs from that of FIG. 4 indicates that the number of partitions = 0x02 is two partitions to be hidden. That is, two F and H drives. HIDE PARTITION number 0, 1 indicates the partition position to hide. Set F, G, H, and I to 0, 1, 2, 3 in order and display 0, 2 value corresponding to partition F, H to hide. It is. This allows the user to tell the USB storage device that it will hide two drives, F and H.

On the other hand, since the USB storage device can tell only the number of LUNs to the USB host device, it is necessary to have its own drive mapping table as shown in FIG.

The USB storage device that receives the command to hide the F and H partitions from the user creates a virtual flash physical layer as shown in FIG. Then, when you reconnect the USB storage device to your PC, you will see two removable disks in Windows Explorer. For example, the drive letters displayed are F and G. The F drive in the Windows Explorer points to the G drive area in the flash physical layer of FIG. 6, and the G drive in the Windows Explorer points to the I drive area in the flash physical layer. As a result, as shown in FIG. 6, the drive regions (G and I drive regions) shown are sequentially located in the virtual flash physical layer first, and the drive regions (F and H drive regions) hidden thereafter are sequentially located later. Now, when the USB storage device receives the show partition command again, the mapping of FIG. 6 is released and the F, G, H, and I drives are shown in the PC in order.

Finally, a third embodiment in which the second embodiment is generalized will be briefly described with reference to FIG. A user wants to create N partitions on a USB storage device, of which M will be private and N-M (where N> M) as the public.

After dividing the USB storage device into N partitions, and in accordance with the protocol shown in Fig. 7, the USB host device sends a command to the USB storage device by hiding M and showing NM commands. In front of the virtual flash physical layer of the device, there are NM disk drive areas shown and M disk drive areas hidden after the old one.

Now, when the Show Partition command is sent, you will see all N partitioned disk drives in Windows Explorer.

1 illustrates a communication scheme between a USB host and a USB storage device in the prior art.

Figure 2 shows the internal structure of a typical USB storage device.

Figure 3 illustrates a communication scheme between a USB host and a USB storage device in the present invention.

Figure 4 shows the protocol when the USB storage device is divided into two partitions and one partition is private in the present invention.

FIG. 5 shows a protocol in which the USB storage device is divided into four partitions and the two partitions are private in the present invention. FIG.

FIG. 6 illustrates a drive order mapping method in the USB storage device of the present invention of FIG.

7 is a generalization of the present invention, and shows a protocol when a USB storage device is divided into N partitions and M partitions are private.

Claims (9)

In the partition view control method of a USB storage device supporting multiple partitions, Sending, by the USB host device, a command to hide or show specific partitions to the multi-partitioned USB storage device; The USB storage device receiving the hide or show command to hide or show the specific partitions; Initializing the number of logic units to correspond to the number of partitions actually displayed by reflecting the setting contents by the USB storage device; Installing a virtual storage physical area mapped to actual storage physical areas in the USB storage device by reflecting the hiding command; The USB host device receives the initialized logic unit number from the USB storage device, obtains the actual storage physical area information from the mapping information of the virtual storage physical area, and recognizes partitions corresponding to the initialized logic unit number. And a partition view control method of a USB storage device supporting multiple partitions. delete The method of claim 1, A partitioned view control method of a USB storage device supporting multiple partitions, wherein the partitioned areas are first displayed in the virtual storage physical area in order, and then the partitioned areas are hidden in order. delete The method of claim 1, The command transmission of the partition view of a USB storage device supporting multiple partitions, characterized in that the transmission of the command is performed via the USB EP0 present in the USB host device and the USB storage device. The method of claim 1, The command may include hiding or showing selection information, information about the number of partitions to be hidden, and information about which partitions are to be hidden, wherein the partition view control method of a USB storage device supporting multiple partitions. The method of claim 1, The USB storage device includes a reprogrammable program memory for storing program code for a controller controlling the USB storage device, and a flash memory as an actual data storage location, and the setting contents are stored in the program memory. Features a partition view control method for USB storage devices that support multiple partitions. The method of claim 1, The USB storage device includes a non-programmable program memory for storing the program code for the controller controlling the USB storage device and a flash memory as an actual data storage location, and the setting contents are stored in the flash memory. Features a partition view control method for USB storage devices that support multiple partitions. The method of claim 1, The USB host device is a partition view control method of a USB storage device supporting multiple partitions, characterized in that the PC.

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