# Patent

## Title
System and method for creating virtual disk images for use with remote computer

## Abstract

A system and method is disclosed for creating and exposing virtual disk images to a host server, during a KVM session, using an HTML5 KVM virtual media client running in the Web browser of a user's device (e.g., PC workstation). The host server is able to select all or specific portions of the virtual disk image for use, whereupon the bytes representing the selected data content are packaged by the HTML5 KVM virtual media client and transmitted to the host server. Using the HTML5 KVM virtual media client to create and expose virtual disk images eliminates the problem of the Web browser not being able to directly access physical media (e.g., disks) on the user's device.

## Background
CROSS-REFERENCE TO RELATED APPLICATIONS
This application claims priority to U.S. Provisional Application No. 61/709,468, filed Oct. 4, 2012. The entire disclosure of the above application is incorporated herein by reference.


FIELD
The present disclosure relates to systems and methods for creating virtual disk images, and more particularly a system and method for creating virtual disk images of selected data that can be used by a remotely located host server, during a KVM session, just as if a physical device with the selected data had been directly connected to the host server.
BACKGROUND
The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
Present day keyboard, video and mouse (KVM) appliances and baseboard management controllers (BMCs) allow a user to access remote servers and other devices by passing the keyboard, video and mouse signals between the user's device (typically a laptop, PC, tablet, smartphone, etc.) and the KVM appliance or BMC. For the purpose of discussion, the following examples will make reference only to a KVM appliance, but it will be appreciated that they are equally applicable to communication with a BMC. The keyboard and mouse signals received by the KVM appliance are typically received in some network protocol, for example Ethernet protocol packets, and then converted to a format (e.g., USB) that the remote device can accept.
With the recent development of the HTML5 technology, an HTML5 KVM/virtual media client is now able to run in the Web browser of a user's device when a KVM session is established by the user. Currently HTML5 is supported by several web browsers including Apple Corporation's SAFARI® Web browser, Mozilla's FIREFOX® Web browser, the Google CHROME® Web browser, and the INTERNET EXPLORER® version 10 Web Browser from Microsoft Corp. The ability to run the HTML5 KVM/virtual media client in the user's Web browser is a significant advantage because the user typically is highly familiar with using a Web browser. As such, this implementation provides the user with a comfortable, easy to use means for conducting a KVM session with a remote KVM device (e.g., KVM appliance or BMC).
The running of an HTML5 KVM/virtual media client in the user's Web browser does, however, present some significant limitations. For one, the Web browser does not allow the KVM/virtual media client access to the physical disks of the client device on which the Web browser is running (e.g., PC workstation, laptop, computing tablet, smartphone, etc.). This limitation did not exist with a KVM/virtual media client that did not run in the user's Web browser. The technology previously used, such as Java or ActiveX, allowed access to the physical media devices such as disk drives, and thus a disk image was not required to access the data files on the user device. When using a Web browser, however, the Web browser provides a “sandbox” into which the JavaScript engine that runs in the Web browser can bring files into the sandbox. But the JavaScript engine still is not allowed to write out the files, nor is it allowed direct access to the physical media devices on the user's device, such as disk drives, typically used in virtual media implementations. As a result, a new system and method is needed for accessing the data files stored on the user's device or physically connected to the user's device, when using an HTML5 KVM/virtual media client running in the Web browser of the user's device.
SUMMARY
In one aspect the present disclosure relates to a method for creating and exposing virtual disk images to a host server, during a KVM session, using an HTML5 KVM/virtual media client running in the Web browser of a user's device. The method may comprise sending a selection to the host server of a specific virtual media device to be mapped on the host server. The HTML5 KVM/virtual media client may be used to package selected content using a selected format to create a disk image of the selected content in a sandbox of the Web browser. The host server may be notified of an available virtual disk image and exposing the virtual disk image for use to the host server. The host server may be used to obtain the virtual disk image and then to send a request to the HTML5 KVM/virtual media client for a portion of the data of the virtual disk image to retrieve. The HTML5 KVM virtual media client may be used to translate the request into at least one specific file that makes up the virtual disk image, and to send bytes of data corresponding to the at least one specific file to the host server. The host server may receive the bytes of data corresponding to the at least one specific file.
In another aspect the present disclosure relates to a method for creating and exposing virtual disk images to a host server during a KVM session. The method involves using an HTML5 KVM/virtual media client running in the Web browser of a user's device. The method may comprise sending a selection to the host server of a specific virtual media device to be mapped on the host server. The HTML5 KVM/virtual media client may then be used to package selected content using a selected format to create a disk image of the selected content in a sandbox of the Web browser. The host server may be notified of an available virtual disk image and the virtual disk image may be exposed for use to the host server. The host server may then be used to obtain the virtual disk image. The host server may be used to send a request to the HTML5 KVM/virtual media client with a starting block number and number of blocks of data of the virtual disk image to retrieve. The HTML5 KVM virtual media client may be used to implement a reverse lookup operation to translate the request into at least one specific file that makes up the virtual disk image, and to send bytes of data corresponding to the at least one specific file to the host server.
In still another aspect the present disclosure relates to a system for creating and exposing virtual disk images to a host server during a KVM session, while using an HTML5 KVM/virtual media client running in the Web browser of a user's device. The system may comprise a user device having a Web browser running thereon, with the Web browser having a sandbox for temporary storage of data. An HTML5 KVM virtual media client may be included which runs in the Web browser. The HTML5 KVM virtual media client may be configured to perform a plurality of operations including: packaging selected content using a selected format to create a disk image of the selected content in a sandbox of the Web browser; notify the host server of an available virtual disk image and exposing the virtual disk image for use to the host server; responding to a request from the host server for data corresponding to a portion of the virtual disk image; and using the HTML5 virtual media client to implement a reverse lookup operation to translate the request for data into at least a portion of at least one specific file makes up the virtual disk image. The HTML5 KVM virtual media client may then send bytes of data corresponding to the at least a portion of one specific file to the host server for use.



BRIEF DESCRIPTION OF THE DRAWINGS
The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present disclosure in any way.
FIG. 1 is a high level block diagram of a system in accordance with an example of the present disclosure for creating virtual disk images of content on the user's device, that may be used by a remote host server during a KVM session when an HTML5 KVM/virtual media client is running in the Web browser of the user's device; and
FIGS. 2A and 2B represent a flowchart illustrating one example of a sequence of communications between an HTML5 KVM/virtual media client and a remote Host server by which a virtual disk image is created for use by the Host server, and the contents of the virtual disk image is supplied to the Host server.



DETAILED DESCRIPTION
The following description is merely exemplary in nature and is not intended to limit the present disclosure, application or uses. It should be understood that throughout the drawings, corresponding reference numerals indicate like or corresponding parts and features.
Referring to FIG. 1, a system 10 is shown in which a user device, in this example a workstation computer 12 having a Web browser 14 running thereon, is used to conduct a KVM session with a remotely located Host server 16 at a Data Center 17. A KVM device, in this example a KVM appliance 18, connects the user workstation 12 with the Host server 16. However, it will be appreciated that a BMC could just as readily be implemented in place of a KVM appliance. For the purpose of discussion, however, reference will be made to the KVM device as being a KVM appliance.
The Web browser 14 may have an HTML5 KVM/virtual media client 20 running in it. The Web browser 14 also provides a “sandbox” 22, which is dedicated memory space into which a JavaScript engine running in the Web browser 14 can bring files or portions of files. However, as noted above, the JavaScript engine is not able to write the files out, nor is it permitted direct access to any of the physical devices (disk drive, flash drive) that are contained within the workstation 12 or physically connected to the workstation.
The HTML5 KVM/virtual media client 20 communicates with the Host server 16 via the KVM appliance 18, a virtual media connection device 24 inside the KVM appliance 18, a USB port 26 of the Host server 16, and a wide area network connection (e.g., the Internet). Messages, for example and without limitation AVMP messages, are communicated between the HTML5 KVM/virtual media client 20 and the Host server 16 when virtual disk images are created on the workstation 12 and exposed to the Host server 16, and when status updates (e.g., number of bytes transferred) are sent from the HTML5 KVM/virtual media client to the Host server 16. Creating virtual disk images of files and/or directories on the disk drives of the workstation 12, and exposing the virtual disk images to the Host server 16, provides a means for allowing the Host server 16 to access the contents on any of the disks of the workstation 12, as well as any virtual media device (e.g., flash drive, portable memory device, etc.) that may be physically connected to the workstation 12.
Referring now to FIGS. 2A and 2B, a flowchart 100 illustrating an example of a sequence of operations between the HTML5 KVM/virtual media client 20 and the Host server 16 will be presented. Initially at operation 102 (FIG. 2A) the user establishes a KVM session with the Host server 16 via the HTML5 KVM/virtual media client 20 running in the user's Web browser 14. At operation 104 the KVM appliance 18 sends the HTML5 KVM/virtual media client 20 a list of virtual media devices available for mapping on the Host server 16. At operation 106 the user selects the Host server device to be mapped, and then selects specific content to be mapped via a virtual disk image. The content to be mapped may be a specific file or possibly a directory or subdirectory.
At operation 108 the HTML5 KVM/virtual media client 20 packages the selected content using a selected format (e.g., FAT32 or ISO9660) to create a virtual disk image of the selected content in the browser's sandbox 22. At operation 110 the HTML5 KVM/virtual media client 20 sends a message to the Host server 16 notifying the Host server of the available virtual disk image, and exposes the virtual disk image to the Host server 16 for use. Regarding the message that may be sent, it will be appreciated that any messaging protocol may be employed, but in one preferred form AVMP (Avocent Virtual Message Protocol) messages may be used. The Avocent Virtual Messaging Protocol is a proprietary protocol of Avocent, Inc., an Emerson Network Power company.
At operation 112 the Host server 16 obtains the virtual disk image and then sends a message (e.g., AVMP message) back to the HTML5 KVM/virtual media client 20 with the starting block number and number of blocks of data to retrieve. At operation 114 the HTML5 KVM/virtual media client 20 translates the request into the specific files that make up the virtual disk image and the specific content from those files (i.e., offset into the file and number of bytes to read from the file). It will also be appreciated that creating the virtual disk image involves creating the structural elements of a disk image such as the boot sector and FAT tables. The data of a disk image typically stored in files within the disk image is not part of the virtual disk image. Instead, the present system and method keeps references to the files so that when a request for a certain data block (or set of blocks) is received, a reverse lookup may be performed. The reverse lookup determines which files contain the requested data, and then an operation may be performed to go and retrieve that data from the client workstation. The data is retrieved by copying those portions of the required files into the sandbox 22 and then transmitting the data to the Host server 16. The files which make up the disk image are not brought into the sandbox 22 until their data is needed, and then only those portions of the files that are needed are brought into the sandbox. Accordingly, this methodology forms a type of “on-demand” system.
At operation 116 the HTML5 KVM/virtual media client 20 sends the data represented by the selected bytes to the Host server 16. At operation 118 the Host server 16 receives the transmitted bytes. It will be appreciated that the bytes received by the Host server 16 are from certain blocks on the virtual disk image. However, the Host server 16 does not know that the bytes are from a disk image. To the Host server 16 it appears that it is obtaining the bytes of data from a physical device connected to its USB port 26.
Referring to FIG. 2B, at operation 120 the Host server 16 determines if additional bytes are needed. If so, the Host server 16 requests the additional bytes, as indicated at operation 122. A check is then made if the additional bytes can be sent by the USB device to the HTML5 KVM/virtual media client 20, as indicated at operation 124, and if so, the requested additional bytes are sent to the Host server 16, as indicated at operation 126. If the check at operation 124 indicates that the USB device cannot send any additional bytes, then the USB device responds with a message to the Host server 16 that additional bytes cannot be read, as indicated at operation 128. The Host server 16 treats this condition as an error, as indicated at operation 130.
If the check at operation 120 indicates that no additional bytes are needed, then the user may end the KVM session by unmapping the virtual disk from the HTML5 KVM/virtual media client 20, or alternatively by “ejecting” it from the Host server 16, as indicated at operation 132. By “ejecting” it will be understood that the Host server 16 “sees” the virtual disk image as a physical connection to a physical device, for example a disk drive on the workstation 12. As such, the Host server 16 can disconnect from the virtual disk image, for example by selecting an “Eject” command, just as if it was disconnecting from a physical virtual media device coupled to its USB port 26. At operation 134 the KVM appliance 18 firmware receives the ejection notice and sends a message (e.g., AVMP message) to the HTML5 KVM/virtual media client 20, which then unmaps the virtual disk image.
By using the HTML5 KVM/virtual media client 20 to create virtual disk images, and to expose the virtual disk images to the Host server 16, the inability of the Web browser to directly access the physical disks on the workstation 12 is at least partially overcome. However, the ability of the Host server 16 to boot off of the physical disks on the client workstation is lost because the sandbox 22 will not allow the HTML5 KVM/virtual media client 20 to read the boot section of the physical device. Essentially any data content stored on the disks of the workstation 12 as files, as well as any virtual media device accessible to the workstation 12 through a physical connection with the workstation, is accessible to the Host server 16. Being able to run the HTML5 KVM/virtual media client 20 in the Web browser 14 also significantly adds to the ease of use for the user because of the user's familiarity with using the Web browser.
While various embodiments have been described, those skilled in the art will recognize modifications or variations which might be made without departing from the present disclosure. The examples illustrate the various embodiments and are not intended to limit the present disclosure. Therefore, the description and claims should be interpreted liberally with only such limitation as is necessary in view of the pertinent prior art.

## Claims

1. A method for creating and exposing virtual disk images to a host server, during a KVM (Keyboard, video and mouse) session, using an HTML5 KVM (Keyboard, video and mouse) virtual media client running in the Web browser of a user's device, the method comprising:
sending a selection to the host server of a specific virtual media device to be mapped on the host server using the HTML5 KVM (Keyboard, video and mouse) virtual media client to package selected content using a selected format to create a disk image of the selected content in a sandbox of the Web browser;
notifying the host server of an available virtual disk image and exposing the virtual disk image for use to the host server;
using the host server to obtain the virtual disk image;
using the host server to send a request to the HTML5 KVM (Keyboard, video and mouse) virtual media client for a specific data block or set of data blocks a portion of the data of the virtual disk image to retrieve;
using the HTML5 KVM (Keyboard, video and mouse) virtual media client to maintain references to specific files that correspond to the at least one of a specific data block or the set of data blocks, and
using a reverse lookup operation to determine which specific ones of the files of the disk image correspond to the specific data block or the set of data blocks being requested, and transmitting bytes of data corresponding to those portions of files stored on the user's device into a sandbox of the Web browser of the user's device; and
using the HTML5 KVM (Keyboard, video and mouse) virtual medial client to send the bytes of data brought into the sandbox to the host server; and
using the host server to receive the bytes of data.

2. The method of claim 1, further comprising:
using the host server to request additional bytes of data;
making a determination if the additional bytes of data can be presented to a USB device associated with the host server; and
using the HTML5 KVM (Keyboard, video and mouse) virtual media client to send the additional bytes of data to the host server.

3. The method of claim 1, further comprising responding to a command from the user device to unmap the virtual disk image from the HTML5 KVM (Keyboard, video and mouse) virtual media client.

4. The method of claim 1, further comprising responding to a command from the user device to eject the virtual disk image from the host server.

5. The method of claim 1, further comprising sending a status update message from the HTML5 KVM (Keyboard, video and mouse) virtual media client to the host server regarding the number of bytes transferred to the host server.

6. The method of claim 1, further comprising using the HTML5 KVM (Keyboard, video and mouse) virtual media client to package the selected content using at least one of:
an FAT32 format; and
an IS09660 format.

7. The method of claim 1, wherein creating the virtual disk image further comprises creating structural elements of a virtual disk image including a boot sector and FAT tables.

8. A method for creating and exposing virtual disk images to a host server, during a KVM (Keyboard, video and mouse) session, using an HTML5 KVM (Keyboard, video and mouse) virtual media client running in the Web browser of a user's device, the method comprising:
sending a selection to the host server of a specific vMedia virtual media device to be mapped on the host server;
using the HTML5 KVM (Keyboard, video and mouse) virtual media client to package selected content using a selected format to create a disk image of the selected content in a sandbox of the Web browser;
notifying the host server of an available virtual disk image and exposing the virtual disk image for use to the host server;
using the host server to obtain the virtual disk image;
using the host server to send a request to the HTML5 KVM (Keyboard, video and mouse) virtual media client with a starting block number and number of blocks of data of the virtual disk image to retrieve;
using the HTML5 KVM (Keyboard, video and mouse) virtual media client to implement a reverse lookup operation to translate the request into at least one specific file that makes up the virtual disk image, and transmitting only bytes of data associated with the at least one specific file stored on the user's device that correspond to requested blocks of data into the sandbox of the Web browser running on the user's device, and to send the bytes of data corresponding to the at least one specific file to the host server.

9. The method of claim 8, further comprising using the host server to receive the bytes of data corresponding to the at least one specific file.

10. The method of claim 8, further comprising using at least one of a KVM (Keyboard, video and mouse) appliance or a baseboard management controller (BMC) to transmit to the HTML5 KVM (Keyboard, video and mouse) virtual media client a list of virtual media devices available for mapping on the host server.

11. The method of claim 8, further comprising sending status messages to the host server including information on a number of bytes transferred pursuant to each specific request for data made by the host server.

12. The method of claim 11, wherein said sending status messages comprises sending status messages in accordance with an Avocent Messaging Protocol (AVMP).

13. The method of claim 11, wherein the reverse lookup operation comprises using the HTML5 KVM (Keyboard, video and mouse) virtual media client to maintain references to specific files that correspond to at least one of a specific data block or set of data blocks requested by the host server, and using a reverse lookup operation to determine which specific ones of the files of the disk image correspond to the requested blocks of data.

14. The method of claim 8, further comprising using the HTML5 KVM (Keyboard, video and mouse) virtual media client to respond to one or more subsequent requests of data from the host server, and informing a USB device associated with the host server if additional bytes of data are not available.

15. The method of claim 8, further comprising at least one of:
unmapping the virtual disk image from the HTML5 KVM (Keyboard, video and mouse) virtual media client; and
ejecting the virtual disk image from the host server.

16. A system for creating and exposing virtual disk images to a host server, during a KVM (Keyboard, video and mouse) session, using an HTML5 KVM (Keyboard, video and mouse) virtual media client running in the Web browser of a user's device, the system comprising:
a user device having a Web browser running thereon, the Web browser having a sandbox for temporary storage of data;
an HTML5 KVM (Keyboard, video and mouse) virtual media client running in the Web browser, the HTML5 KVM (Keyboard, video and mouse) virtual media client configured to:
package selected content using a selected format to create a disk image of the selected content in a sandbox of the Web browser;
notify the host server of an available virtual disk image and exposing the virtual disk image for use to the host server;
respond to a request from the host server for data corresponding to a portion of the virtual disk image; and
use the HTML5 KVM (Keyboard, video and mouse) virtual media client to implement a reverse lookup operation to translate the request for data into at least a portion of at least one specific file makes up the virtual disk image, and transmitting only those portions of files stored on the user's device that correspond to requested blocks of data into a sandbox of the Web browser of the user's device, and to send bytes of data corresponding to the at least a portion of one specific file to the host server for use.

17. The system of claim 16, wherein the lookup operation implemented by the HTML5 KVM (Keyboard, video and mouse) virtual media client comprises using the HTML5 KVM (Keyboard, video and mouse) virtual media client to maintain references to specific files that correspond to at least one of a specific data block or set of data blocks requested by the host server, and using determining which specific ones of the files of the disk image correspond to the requested data.

18. The system of claim 16, wherein the HTML5 KVM (Keyboard, video and mouse) virtual media client is further configured to at least one of:
unmap the virtual disk image from the HTML5 KVM (Keyboard, video and mouse) virtual media client; and
eject the virtual disk image from the host server.