System and method for accessing storage devices attached to a stateless client

• US 7,996,631 B1
• Filed: 02/17/2004
• Issued: 08/09/2011
• Est. Priority Date: 02/17/2004
• Status: Active Grant

• Current Assignee: Oracle America, Inc. (Oracle Corporation)
• Original Assignee: Oracle America, Inc. (Oracle Corporation)
• Inventors: Bender, Michael S., Wijeyeratnam, Aloysius C. Ashley
• Primary Examiner(s): Farrokh; Hashem
• Application Number:
  US10/780,270
• Time in Patent Office: 2,730 Days
• Field of Search: 711/154, 709/203
• US Class Current: 711/154
• CPC Class Codes: G06F 3/0617 in relation to availability
• CPC Class Codes: G06F 3/0632 by initialisation or re-initialisation of storage systems
• CPC Class Codes: G06F 3/0659 Command handling arrangements, e.g. command buffers, queues, command scheduling
• CPC Class Codes: G06F 3/067 Distributed or networked storage systems, e.g. storage area networks [SAN], network attached storage [NAS]

Abstract

A system and method for accessing storage devices attached to a stateless client. In one embodiment, the system may include a server configured to execute an application and a stateless client coupled to the server, whereby a user interacts with the application. The system may further include a storage device locally coupled to the stateless client, where the storage device is accessible by the user via the server. In various specific implementations of the system, the storage device may be a solid-state mass storage device or a mass storage device employing magnetic or optical media. In another specific implementation of the system, the storage device may be locally coupled to the stateless client via an interface such as Universal Serial Bus (USB) or IEEE 1394 (e.g. FireWire).

Claims

1. A system, comprising:

a memory; and

a processor of a server coupled to the memory and configured to execute instructions to;

detect the presence of a mass storage device locally coupled to a stateless client; and

interface said mass storage device to an application executable on the server, wherein the server is configured to implement a multithreaded execution environment, wherein to interface the mass storage device to the application, the processor is further configured to execute the instructions to implement a device interface through which the mass storage device is visible to the application, and wherein the device interface is implemented by a corresponding device thread that is separately schedulable from other device threads for execution by the server;

wherein said mass storage device is accessible via said server by a user who interacts with said application via said stateless client; and

wherein the processor is further configured to execute the instructions to store data to said mass storage device via said stateless client in response to said user'"'"'s interaction with said application.

2. The system as recited in claim 1, wherein said mass storage device is locally coupled to said stateless client via a Universal Serial Bus (USB) or IEEE 1394 interface.

3. The system as recited in claim 1, wherein said mass storage device employs magnetic media, optical media, or solid-state storage media.

4. The system as recited in claim 1, wherein the server is configured to detect a hotplugging event generated in response to disconnection of the mass storage device from the stateless client.

5. The system as recited in claim 4, wherein in response to detecting the hotplugging event, the server is configured to mark resources associated with the mass storage device as deleted or stale, such that disconnection of the mass storage device is visible to the application.

6. The system as recited in claim 1, wherein said server is further configured to provide a kernel execution mode and a user execution mode, and wherein said server is further configured to execute a storage service daemon, wherein said storage service daemon executes in user execution mode.

7. The system as recited in claim 1, wherein said mass storage device comprises one or more unit interfaces, wherein each unit interface comprises one or more logical units (LUNs), and wherein each logical unit comprises one or more partitions.

8. A method, comprising:

detecting the presence of a mass storage device locally coupled to a stateless client;

interfacing said mass storage device to an application executable on a server, wherein the server is configured to implement a multithreaded execution environment, wherein the server is configured to implement a device interface through which the mass storage device is visible to the application, and wherein the device interface is implemented by a corresponding device thread that is separately schedulable from other device threads for execution by the server;

wherein said mass storage device is accessible via said server by a user who interacts with said application via said stateless client,

storing data to said mass storage device via said stateless client in response to said user interacting with said application.

9. The method as recited in claim 8, wherein said mass storage device is locally coupled to said stateless client via a Universal Serial Bus (USB) or IEEE 1394 interface.

10. The method as recited in claim 8, wherein said mass storage device employs magnetic media, optical media, or solid-state storage media.

11. The method as recited in claim 8, further comprising disconnecting the mass storage device from the stateless client.

12. The method as recited in claim 11, further comprising indicating a hotplugging event to the server in response to disconnection of the mass storage device, wherein upon processing of the hotplugging event by the server, disconnection of the mass storage device is visible to the application.

13. The method as recited in claim 8, wherein said server is further configured to provide a kernel execution mode and a user execution mode, and wherein said server is further configured to execute a storage service daemon, wherein said storage service daemon executes in user execution mode.

14. The method as recited in claim 8, wherein said mass storage device comprises one or more unit interfaces, wherein each unit interface comprises one or more logical units (LUNs), and wherein each logical unit comprises one or more partitions.

15. A computer-accessible storage medium that stores program instructions, wherein the program instructions are executable by a server to:

detect the presence of a mass storage device locally coupled to a stateless client; and

interface said mass storage device to an application executable on said server, wherein the server is configured to implement a multithreaded execution environment, and wherein to interface the mass storage device to the application, the program instructions are executable by the server to implement a device interface through which the mass storage device is visible to the application, and wherein the device interface is implemented by a corresponding device thread that is separately schedulable from other device threads for execution by the server;

wherein said mass storage device is accessible via said server by a user who interacts with said application via said stateless client; and

wherein the program instructions are executable by the server to further store data to said mass storage device via said stateless client in response to said user'"'"'s interaction with said application.

16. The computer-accessible storage medium as recited in claim 15, wherein said mass storage device is locally coupled to said stateless client via a Universal Serial Bus (USB) or IEEE 1394 interface.

17. The computer-accessible storage medium as recited in claim 15, wherein said mass storage device employs magnetic media, optical media, or solid-state storage media.

18. The computer-accessible storage medium as recited in claim 15, wherein to detect the presence of the mass storage device, the program instructions are executable by the server to detect a hotplugging event generated in response to coupling of the mass storage device to the stateless client.

19. The computer-accessible storage medium as recited in claim 18, wherein in response to detecting the hotplugging event, the program instructions are executable by the server to create the device interface through which the mass storage device is visible to the application.

20. The computer-accessible storage medium as recited in claim 15, wherein said server provides a kernel execution mode and a user execution mode, and wherein said program instructions the program instructions are executable by the server to implement:

a storage service daemon, wherein said storage service daemon executes in user execution mode;

a kernel interface that executes in kernel execution mode and is configured to provide to applications that execute on the server a public interface to the mass storage device coupled to the stateless client; and

a daemon interface that executes in kernel execution mode and is configured to convey device access requests from the kernel interface to the storage service daemon, wherein the interface between daemon interface and the storage service daemon is private with respect to applications that execute on the server.

21. The computer-accessible storage medium as recited in claim 20, wherein the storage service daemon comprises:

a plurality of device threads, each corresponding to a respective device interface, and each device thread being separately schedulable from other device threads for execution by the server;

a remote disk driver that, upon receiving an access request from a particular device thread, is configured to assemble a command for the mass storage device according to a command set implemented by the mass storage device;

a protocol driver that is configured to assemble one or more commands received from the remote disk driver into a transaction for the mass storage device according to a peripheral interface with which the mass storage device is coupled to the stateless client.