Solid state storage devices with changeable capacity

• US 7,975,105 B1
• Filed: 12/03/2007
• Issued: 07/05/2011
• Est. Priority Date: 12/03/2007
• Status: Active Grant

• Current Assignee: Chemtron Research LLC (Intellectual Ventures LLC)
• Original Assignee: Guozhong Sun
• Inventors: Sun, Yingju, Zheng, Joe
• Primary Examiner(s): BATAILLE, PIERRE MICHE
• Application Number:
  US11/949,748
• Time in Patent Office: 1,310 Days
• Field of Search: 710/74, 710/62, 710/72, 710/313, 711/103, 711/115, 711/112, 711/E12.001, 711/114, 739/131, 713/2
• US Class Current: 711/115
• CPC Class Codes: G06F 1/187 Mounting of fixed and removable disk drives
• CPC Class Codes: G06F 3/0607 by facilitating the process of upgrading existing storage systems, e.g. for improving compatibility between host and storage device
• CPC Class Codes: G06F 3/0658 Controller construction arrangements
• CPC Class Codes: G06F 3/0688 Non-volatile semiconductor memory arrays

Abstract

A reconfigurable type of flash memory-based storage device is disclosed. According to one aspect, a flash SSD comprises a data bridge and a plurality of flash memory cards. The data bridge includes necessary interfaces, a data buffer and a data management module to facilitate data exchange between a host and these flash memory cards. Each of the flash memory cards, such as an SD flash memory card, functions perfectly by itself. To facilitate the need of upgrading in terms of storage capacity, the SSD provides a plurality of slots to receive these flash memory cards As the storage capacity of the flash memory cards is increased over the time, so does the SSD by replacing only the flash memory cards.

Claims

1. A flash-based storage device comprising:

an enclosure including a plurality of openings;

a main board, housed in the enclosure, including at least a host interface, a buffer, a data management module and a plurality of card interfaces;

a number of mechanisms respectively coupled to the card interfaces, each of the mechanisms directing towards one of the openings, each of flash memory cards being inserted into one of the mechanisms through one of the openings and coupled to one of the card interfaces, wherein the each of the flash memory cards independently works with a device that provides a slot to receive the each of the flash memory cards for data exchange, wherein the data management module is configured to manage how to store data on the flash memory cards when there are at least two of the flash memory cards inserted respectively in the mechanisms, and indicates so when one of the at least two of the flash memory cards holds some of the data but becomes no longer available, and wherein the host interface facilitates data exchange between the flash-based storage device and a host device, the buffer is provided to buffer data being exchanged between the host device and the flash-based storage device, data received from the host device is first buffered in the buffer before the buffered data is distributed among the inserted flash memory cards; and

wherein a storage capacity of the flash-based storage device is upgraded when one of the flash memory cards is replaced.

2. The flash-based storage device as recited in claim 1, wherein at least one of the openings is designed to be flexible enough to accommodate commonly used memory cards in different form factors.

3. The flash-based storage device as recited in claim 1, wherein the buffer provides a space to reassemble retrieved data respectively stored in some or all of the flash memory cards before the retrieved data is transported from the flash-based storage device to the host device via the host interface.

4. The flash-based storage device as recited in claim 3, wherein the data management module is configured to remember which of the at least two flash memory cards is used to store at least part of the data.

5. The flash-based storage device as recited in claim 1, wherein a utility application is included in one of the flash memory cards and activated to allow a user to cause the flash-based storage device to move data stored in one of the flash memory cards to another one of the flash memory cards, the utility application provides a graphic interface to show the capacity and usage of each of the memory cards.

6. The flash-based storage device as recited in claim 1, wherein each of the card interfaces is designed to comply with a standard that allows one of the flash memory cards to work with other than the flash-based storage device.

7. The flash-based storage device as recited in claim 6, wherein each of the memory cards is one or more of a USB (Universal Serial Bus) flash drive, a Secure Digital (SD) cards, a Multi-Media Card (MMC), a SmartMedia card, and a CompactFlash card (CF card) or a commonly used flash memory card.

8. The flash-based storage device as recited in claim 1, wherein the data management module is configured to perform one or more of operations of:

notifying which one of the at least two flash memory cards soon reaches an end of working life so that a replacement is necessary;

moving data stored in a relatively old flash memory card to another flash memory card to prepare for a replacement of the relatively old flash memory card, wherein the relatively old flash memory card is one of the at least two flash memory cards; and

ensuring that data is evenly distributed among the at least two flash memory cards or creating a redundant copy to prevent possible loss of the data.

9. The flash-based storage device as recited in claim 1, wherein the data management module is configured to ensure that frequently updated data is to be stored in Single-Level Cell (SLC) flash core and less frequently updated data is to be stored in Multi-Level Cell (MLC) flash core when any of the at least two flash memory cards is made of MLC flash cores.

10. A flash-based storage device comprising:

a case designed in shape substantially similar to a traditional hard disk drive so that the flash-based storage device is used to replace the traditional hard disk drive to work directly with a host, wherein the case with a plurality of openings includes a data bus and an integrated circuit designed to provide functions of a host interface, a buffer, a data management module and a plurality of card interfaces, the case further includes a plurality of identical slots, each directing towards one of the openings, a number of flash memory cards in identical shape are inserted respectively into the identical slots through the openings so that the flash memory cards are coupled to the integrated circuit via the card interfaces, wherein each of the flash memory cards independently works with a device for storage; and

the data management module is configured to buffer data from the host in the buffer and distribute the buffered data to be stored among some or all of the flash memory cards and reassemble in the buffer stored data from some or all of the flash memory cards to be read by the host, and wherein each of the flash memory cards is removable from the flash-based storage device.

11. The flash-based storage device as recited in claim 10, wherein each of the flash memory cards comes in a form factor that is suitable for a commonly used portable device, and wherein a manufacturer of the flash-based storage device produces such a flash-based storage device without having to test or verify storage functions of the flash-based storage device but provides a flexibility of increasing or decreasing storage capacity of the flash-based storage device by a user any time.

12. The flash-based storage device as recited in claim 11, wherein the data management module is configured to move data stored in a relatively old flash memory card to another flash memory card before the relatively old flash memory card is replaced with a new flash memory card.

13. The flash-based storage device as recited in claim 12, wherein the data management module is configured to ensure the new flash memory card to be used more frequently than other of the flash memory cards that have not been replaced.

14. A flash-based storage device comprising:

a main board including at least a host interface, a buffer, a processor, a data management module and a plurality of card interfaces;

a housing, to house the main board, with a plurality of openings on one side of the housings to receive a number of flash memory cards inserted externally, the flash memory cards being coupled to the main board via the card interfaces respectively, wherein each of the flash memory cards works independently with a device for storage; and

wherein the host interface facilitates the flash-based storage device to work directly with a host device to store data of an operating system (OS), the data management module configured to ensure that the data stored in some or all of the flash memory cards is reassembled in the buffer before booting the host from the flash-based storage device, an overall storage capacity of the flash-based storage device is upgradeable anytime by replacing any one of the flash memory cards.

15. The flash-based storage device as recited in claim 14, wherein the capacity of the flash-based storage device is readily increased by adding new memory cards of larger capacity without changing the flash-based storage device.

16. The flash-based storage device as recited in claim 15, wherein the data management module is configured to perform one or more of operations of:

notifying which one of the flash memory cards soon reaches an end of working life so that a replacement is necessary;

moving data stored in a relatively old flash memory card to another flash memory card to prepare for a replacement of the relatively old flash memory card, wherein the relatively old flash memory card is one of the at least two flash memory cards; and

creating a redundant copy to prevent possible loss of the data.

17. The flash-based storage device as recited in claim 15, wherein the data management module is caused to provide a graphic interface to show respective statuses of the memory cards.

18. The flash-based storage device as recited in claim 15, wherein the processor is configured to determine characteristics of other data to be stored, when the other data is frequently used or updated, the other data is caused to be retained in a first type of flash memory in some or all of the flash memory cards, when the other data is less frequently updated, the data is caused to be retained in a second type of flash memory in some or all of the flash memory cards.

19. The flash-based storage device as recited in claim 18, wherein the other data that is frequently used or updated pertains to the operating system (OS), and the other data that is less frequently updated includes audio, image and video data.

20. The flash-based storage device as recited in claim 18, wherein the first type of flash memory is based on Single-Level Cell (SLC) flash core, and the second type of flash memory is based on Multi-Level Cell (MLC) flash cores.