Method and apparatus for the protection of write data in a disk array
First Claim
1. In a data storage system wherein write data received from a host is written into a transfer buffer and a write complete status signal is provided by the data storage system to the host prior to said write data being written to a permanent storage device within said data storage system, a method for preventing the loss of data residing in said transfer buffer comprising the steps of:
- transferring the data residing in said transfer buffer to a low power non-volatile storage device upon an occurrence of a data storage system failure and, in the absence of said data storage system failure, not transferring the data residing in said transfer buffer to said low power non-volatile storage device and in which said low power non-volatile storage device receives the data from said transfer buffer after the data has been received by said transfer buffer upon occurrence of said data storage system failure and the data transferred to said low power non-volatile storage device being the same data that is to be transferred to said permanent storage device, wherein said low power non-volatile storage device is different from said permanent storage device and in which less power is utilized in transferring data residing in said transfer buffer to said low power non-volatile storage device than power utilized in transferring data residing in said transfer buffer to said permanent storage device.
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Accused Products
Abstract
A transfer memory backup system for a RAID level 5 disk array storage system which includes a transfer buffer, wherein write data received by the array is written into a transfer buffer, and a write complete status signal generated, prior to the write data being written to the disk drives within the array. The transfer memory backup system includes a low power, industry standard PCMCIA (Personal Computer Memory Card International Association) device along with a small, temporary voltage source made up of a small rechargeable battery or a high capacitance gold capacitor. Upon the detection of a disk array storage system failure, low power logic provides continuous refresh for the transfer buffer as well as power to the components included in the transfer memory backup system upon a disk array storage system failure. A low power CMOS microprocessor with self contained microcode (mask programmable ROM) controls the transfer of data from the transfer buffer to removable storage medium within the PCMCIA device.
130 Citations
31 Claims
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1. In a data storage system wherein write data received from a host is written into a transfer buffer and a write complete status signal is provided by the data storage system to the host prior to said write data being written to a permanent storage device within said data storage system, a method for preventing the loss of data residing in said transfer buffer comprising the steps of:
transferring the data residing in said transfer buffer to a low power non-volatile storage device upon an occurrence of a data storage system failure and, in the absence of said data storage system failure, not transferring the data residing in said transfer buffer to said low power non-volatile storage device and in which said low power non-volatile storage device receives the data from said transfer buffer after the data has been received by said transfer buffer upon occurrence of said data storage system failure and the data transferred to said low power non-volatile storage device being the same data that is to be transferred to said permanent storage device, wherein said low power non-volatile storage device is different from said permanent storage device and in which less power is utilized in transferring data residing in said transfer buffer to said low power non-volatile storage device than power utilized in transferring data residing in said transfer buffer to said permanent storage device. - View Dependent Claims (2, 3)
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4. In a data storage system wherein write data received from a host is written into a transfer buffer and a write complete status signal is provided by the data storage system to the host prior to said write data being written to a permanent storage device within said data storage system, a method for preventing the loss of data residing in said transfer buffer comprising the steps of:
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monitoring the operation of said data storage system to detect an occurrence of a data storage system failure; providing a low power non-volatile storage device; providing a low power backup transfer circuitry for transferring the data residing in said transfer buffer to said low power non-volatile storage device, wherein said low power backup transfer circuitry is different from write circuitry within said data storage system that is used to transfer the data residing in said transfer buffer to said permanent storage device and in which said low power backup transfer circuitry utilizes less power than said write circuitry to transfer the data residing in said transfer buffer; providing a small voltage source for temporarily supplying power to said transfer buffer, said low power backup transfer circuitry, and said low power non-volatile storage device upon the occurrence of a data storage system failure; and using said low power backup transfer circuitry to transfer the data residing in said transfer buffer to said low power non-volatile storage device upon the occurrence of a data storage system failure. - View Dependent Claims (5, 6, 7, 8, 9)
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10. A memory backup system for a data storage system, the data storage system including a transfer buffer, write circuitry, and a permanent storage device and receiving power from a main power source, wherein write data received from a host is written into the transfer buffer and a write complete status signal is provided by the data storage system to the host prior to the write circuitry writing said write data to the permanent storage device, said memory backup system comprising:
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a low power non-volatile storage device connected to transfer data with the transfer buffer; a small voltage source for temporarily supplying power; and low power backup transfer circuitry responsive to the receipt of a signal from the data storage system indicating the occurrence of a data storage system failure for controlling the operation of said small voltage source to provide power to said low power non-volatile storage device, the transfer buffer, and said low power backup transfer circuitry, for controlling said low power non-volatile storage device and the transfer buffer to transfer data residing in the transfer buffer to said low power non-volatile storage device, and for substantially electrically isolating said small voltage source from the main power source, the permanent storage device, and the write circuitry so as to reduce the power provided by said small voltage source during the transfer of data residing in the transfer buffer to said low power non-volatile storage device, wherein said low power backup transfer circuitry is different from the write circuitry and utilizes less power than the write circuitry to transfer data residing in the transfer buffer. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 29, 30, 31)
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18. A data storage system for storing data received from a host system, said data storage system comprising:
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a first non-volatile storage device for the storage of data received from the host system; a transfer buffer connected between the host system and said first non-volatile storage device, wherein data received from the host system is written into said transfer buffer and a right complete status signal is provided by said data storage system to the host prior to said data being written to said first non-volatile storage device; and a memory backup system including a second non-volatile storage device that is different from said first non-volatile storage device and in which said second non-volatile storage device utilizes less power to write data residing in said transfer buffer than the power utilized by said first non-volatile storage device when writing data residing in said transfer buffer, and transfer means, connected with said transfer buffer, for transferring data residing in said transfer buffer to said second non-volatile storage device in response to an occurrence of a data storage system failure, said transfer means comprising a low power microprocessor for operating in a first power mode when transferring data from said transfer buffer to said first non-volatile storage device and a second power mode when transferring data from said transfer buffer to said second non-volatile storage device, wherein said low power microprocessor utilizes less power when operating in said second power mode than when operating in said first power mode. - View Dependent Claims (19, 20, 21, 22, 23, 24, 25, 26, 27, 28)
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Specification