| 摘要 |
<p>A data protection system for protecting the data stored in a memory (10) in a data processing system having at least a channel system, a device controller (2) and an external storage device (6), includes: a memory (10) provided in the device controller and supplied to a power source voltage from a power source (1), and temporarily storing a data to be transferred; a battery (12) connected to the power source (11) and the memory (10), and charged by the power source (11) when the power source (11) is normal, and supplying a battery voltage to the memory (10) when the power source is accidentally interrupted. The data protection system also includes a first voltage check circuit (13) connected to the battery (12) which compares the battery voltage with a first reference voltage and generates a battery error signal when the battery voltage is lower than the first reference voltage and, a second voltage check circuit (14) connected to the battery (12), which compares the battery voltage with a second reference voltage and generates a battery charging signal when the battery voltage lies between the first reference voltage and the second reference voltage. The data protection system also includes a control circuit (2) for selectively determining two modes, one mode being a write-back mode for transferring the data from the memory to the external storage device after the data is stored in the memory, and the other being a write-through mode for directly transferring the data from the channel system to the external storage device (6) not through the memory (10) when the battery error signal and/or the battery charging signal is input to it.</p> |
