| 摘要 |
PURPOSE:To obtain a titled device which is highly economical, accesses at a high speed and is capable of holding exactly the stored contents by backing up an RAM used as a storage medium by a magnetic tape memory, and also providing a back-up power source. CONSTITUTION:An RAM4 which executes write and read of a data to and from a main storage device is backed up by using the battery device 11 of a back-up power source, by a cassette magnetic tape device 7 controlled through a power source monitoring circuit 9. When the power source is cut off, the stored contents of the RAM4 are written in the device 7 and held, and read out of the device 7 when the power source is recovered, and written in the RAM4. According to the system using this RAM, the external storage device obtains a high economical property, accesses at a high speed and also is capable of holding exactly the stored contents. |
