초록 ▼

A RAID system that uses non-volatile random access memory (NVRAM) to greatly reduce the chance of loss of data due to an AC power failure. This RAID system has two write modes. In a normal write mode, a host computer receives a write confirmation once an array controller receives data from the host

A RAID system that uses non-volatile random access memory (NVRAM) to greatly reduce the chance of loss of data due to an AC power failure. This RAID system has two write modes. In a normal write mode, a host computer receives a write confirmation once an array controller receives data from the host computer. In a safe write mode, however, the array controller copies to NVRAM all data received from the host computer for writing to disk drives. In this safe write mode, the array controller sends the write confirmation to the host computer only after storing the data in NVRAM. To switch appropriately between the normal and safe write modes, the array controller polls a power-out flag provided by a UPS (uninterruptable power supply) to determine whether there has been an AC power failure. The array controller switches between the two write modes depending on the status of the power-out flag.

대표청구항 ▼

[ What is claimed is:] [1.] A data storage system comprising:a non-volatile memory having a plurality of segments; andan array controller for coupling to a UPS and periodically polling a power outage flag in the UPS, for coupling to a host CPU, for coupling to a power source, and for coupling to a p

[ What is claimed is:] [1.] A data storage system comprising:a non-volatile memory having a plurality of segments; andan array controller for coupling to a UPS and periodically polling a power outage flag in the UPS, for coupling to a host CPU, for coupling to a power source, and for coupling to a permanent memory, the array controller coupled to the non-volatile memory for saving write command information upon a failure of the power source.