Patent Application
20090043831
A portion of the disclosure of this patent document contains material which is subject to copyright protection. The copyright owner has no objection to the facsimile reproduction by anyone of the patent document or the patent disclosure as it appears in the Patent and Trademark Office patent file or records, but otherwise reserves all copyright rights whatsoever.
This invention relates to distributing data to storage devices based on the significance of the content of the data.
With the advances of portable electronics such as portable computers and MP3 players the need for high performance, high reliability, and low cost nonvolatile storage devices is increasing rapidly. Hard disks and flash memory are the two types of nonvolatile storage devices used for storage and transfer of data between computers and other digital products. Both hard drives and flash memory have their own advantages and disadvantages. For instance, hard disks have higher data reliability and lower cost than flash memory, but have severe mechanical and electrical limitations; hard disks take a significant amount of time to respond to and complete an I/O request. Flash memory, on the other hand, offer faster read access times and better shock resistance than hard disks. Flash memory can also withstand extreme conditions with respect to temperature, pressure and humidity.
Flash memory stores information in an array of floating gate transistors called cells. Flash memory devices can be a single cell level (SLC) flash in which each cell stores only one bit of information, multiple cell level (MLC) flash, where more than one bit per cell is stored, or a combination of the two. Even though flash memory devices offer advantages over the hard disks, they have limitations with respect to the cost per byte and capacity. For instance, SLC flash has limitations with respect to capacity and has a relatively high cost per byte, while MLC flash has limitations such as performance and reliability.
As one kind of storage device does not clearly solve all the problems of performance, data reliability and low cost, new hybrid storage devices, including a wide range of storage devices, are being developed. These hybrid storage devices, as well as systems with a combination of nonvolatile storage devices, require a storage controller that can distribute data to an appropriate storage device based on the significance of the data file.
For example, a computer system may include multiple storage devices such as hard drive and a combination of MLC and SLC flash memory. If a user needs to store information that contains critical data and requires rapid access, the controller should store that data in the SLC flash memory because SLC flash memory offers high data reliability combined with speed. Similarly, if a data file does not contain critical information, the storage controller may store the data file in less expensive MLC flash memory. The user may assign data files with certain formats such as, for example, .doc, and .xls as critical and file formats such as jpeg, .bmp, .pdf, and .mp3 as non-critical.
The present invention includes a method and mechanism that distributes data to different storage devices based on the significance of data content, requirements of file access time, and frequency of file access. The significance of the data content may be determined by the format of its associated data file.
The invention may also be practiced in software.
A method and apparatus for dynamically distributing data to an appropriate storage device based on the significance of the data is described. In one embodiment the method determines the significance of a data file using the format of the data file. The method also includes identifying a storage device and memory location of the storage device to write the data.
In a software implementation, a computer system employs a filter driver and/or a device driver to identify and store data files (for the purposes of this application, the term “filter driver” also encompasses “device driver”). In a hardware implementation, a storage controller includes a state machine that initiates and executes firmware or other code. The storage controller determines data file formats and storage device locations. Identifying a file type is one method of determining the critical or non-critical nature of data files. However, it is also within the scope of this invention for software or a controller to examine other attributes such as, but not limited to, data file content, access time requirements, and frequency of access. Depending upon data file attributes, data files may be stored in an appropriate location, such as SLC flash memory, MLC flash memory, or hard disk.
The details of the present invention, both as to its structure and operation, and many of the attendant advantages of this invention, can best be understood in reference to the following detailed description, when taken in conjunction with the accompanying drawings, in which like reference numerals refer to like parts throughout the various views unless otherwise specified, and in which:
The logic of a sample disk software input/output (I/O) system is shown in
Instead, if the file extension indicates that the contents of the file in fact contain critical data, the file may be further examined to determine if access time is critical (step 86). If not, the file may be flagged for storage in a hard disk (step 88) and forwarded to the file system driver 65. If the data is time critical, the file may be flagged for storage in an SLC device (step 90), and then forwarded to the file system driver 65.
Other types of nonvolatile memory may be substituted for SLC, MLC, and hard drive devices and still be within the scope of this invention.
To determine if the data is time critical, the software may record and use the history of respective data file usage. A user or application may mark data as time critical. Or an expert or queuing system may be employed.
The invention may also reside in a controller.
The storage controller 104 may employ tables, such as Table 1 and Table 2 (see below), to determine the appropriate storage device.
To determine if the data is time critical, a user or application may flag files. Alternatively, the storage controller may record and use the history of respective data file usage. Or a fuzzy logic, expert, or queuing system may be employed.
The storage controller need not be a separate peripheral device. It may reside on a chip connected to host 101.
In one embodiment of the present invention, the appropriate storage device can be predetermined based on the format of the data file. In another embodiment, the peripheral interface 103 may include but is not limited to USB interface, IDE interface, or SATA interface. In yet another embodiment, the storage controller 104 can identify the different kinds of storage devices such as, but not limited to, memory sold under the trademarks CompactFlash, MultiMediaCard, Memory Stick, and Secure Digital Card. In fact, storage controller 104 may identify any number of different removable flash memory types, including those compatible with USB flash drives. Moreover, the storage controller 104 can distribute the data to the appropriate memory location of the storage devices.
In another embodiment, the data file includes content critical information that does not require short access time. In this case, the data may be written to the storage device 102n, hard drive. Optionally, data received by storage controller 104 can be encrypted by using an encryption key depending on the format of the data file.
Storage controller 104 may detect data file system type installed on the storage device by reading system ID field in the bootable partition located in master boot record of the storage device. A short list of typical system ID types is listed in Appendix A. Once the file system type is determined, file system structures can be located and content of critical and non-critical data files can be stored in appropriate areas. Appendix B lists one such search where a special folder is located that contains a special file.
Example table, Table 1, is a decision matrix showing how access time non-critical data may be handled. In one situation, in which there is light writing and heavy reading, data are best stored in MLC memory (step 480). If data access is medium, then hard disk would be employed (step 490). In another case, where there is frequent writing and infrequent reading, SLC would be chosen (step 470).
If at step 440, data are determined to be content critical, then another decision matrix, Table 2 for example, is employed (step 450).
Example table, Table 2, is a decision matrix showing how access time critical data may be handled. In this case, data which are lightly written and heavily read are stored in SLC memory (step 470). If data access is medium, then hard disk would be employed (step 490). In the situation in which there is heavy writing and light reading, SLC memory may be used (step 470).
In addition to determining where to store data based on file type, content, and access time requirements, another factor, frequency of access, may be employed. Appendix C describes how data may be stored depending on how often it is accessed. This may stand alone as the sole criteria for where to store data, or it may work in tandem with software or the storage controller to weigh all the factors in determining an optimal storage location. While four factors are described herein (file type, content, access time requirements, and frequency of access), additional factors may also be used to determine storage locations.
determining that the data file type is non-critical (step 700),
determining that the access time requirements are non-critical (step 710),
determining that the data file content is critical (step 720),
if data is frequently accessed (step 730), storing data in SLC memory (step 740) else
storing data in hard disk memory set 750).
As shown in
In traversing the decision tree, a number of binary decisions are made. However, it is not necessary to assign the various factors an “all or nothing” status. As suggested in Appendix D, factors may have various weights. An expert or fuzzy logic system (collectively referred to as “artificial intelligence”) may then evaluate the factors in determining storage location(s). Moreover, the contents of a data file could be spread across storage media, depending on how the factors relate to various parts of the data file.
While the particular method and apparatus as herein shown and described in detail is fully capable of attaining the above-described objects of the invention, it is to be understood that it is the presently preferred embodiment of the present invention and is thus representative of the subject matter which is broadly contemplated by the present invention, that the scope of the present invention fully encompasses other embodiments which may become obvious to those skilled in the art, and that the scope of the present invention is accordingly to be limited by nothing other than the appended claims, in which reference to an element in the singular means “at least one”. All structural and functional equivalents to the elements of the above-described preferred embodiment that are known or later come to be known to those of ordinary skill in the art are expressly incorporated herein by reference and are intended to be encompassed by the present claims. Moreover, it is not necessary for a device or method to address each and every problem sought to be solved by the present invention, for it to be encompassed by the present claims. Furthermore, no element, component, or method step in the present disclosure is intended to be dedicated to the public, regardless of whether the element, component, or method step is explicitly recited in the claims.
Information on file systems is widely available and can be found in web sites such as Wikipedia and OSData, and also in books such as File Systems: Design and Implementation by Daniel Grosshans, published by Prentice Hall, Windows XP Professional by Dan Baiter, published by Que Publishing etc.
ID Name (located at Offset 4 of each 16-byte Partition record on the MBR)
0f WIN95: Extended partition, LBA-mapped
After the firmware has successfully detected the presence of a storage device, it finds the bin file as follows:
LBA address of Root Directory=Number of hidden sectors+(Sectors per FAT*2)+Number of reserve sectors
This application claims the benefit of U.S. Provisional Application No. 60/955,341 filed Aug. 11, 2007.
| Number | Date | Country | |
|---|---|---|---|
| 60955341 | Aug 2007 | US |
