Abstract: Provided are a blockchain data storage method, a system, a device, and a readable storage medium. The method includes: obtaining, by a block file system, a target block serial number and target block contents of a target block, the block file system including a directory region and a data region, a size of each cluster in the data region being the same as a block size of blockchain, the directory region storing mapping relationships between block serial numbers and cluster addresses; sequentially allocating a target cluster address to the target block, and recording, in the directory region, a target mapping relationship between the target block serial number and the target cluster address; and sequentially writing the target block contents into the data region according to the target cluster address.

Abstract: A fan controlling circuit is provided. The fan controlling circuit includes an integral unit, an operational amplifier, a PMOS transistor, and an NMOS transistor. The integral unit transforms pulse width modulation (PWM) signals to voltages, and transmits the voltages to positive and negative input terminals of the operational amplifier. The PMOS transistor is coupled between a first PWM signal and an output terminal, and a gate of the PMOS transistor is coupled to an output of the operational amplifier. The NMOS transistor is coupled between a second PWM signal and the output terminal, and a gate of the NMOS transistor is coupled to the output of the operational amplifier. The fan controlling circuit may be formed by discrete elements and use a same voltage source as fans, so that the design cost and complexity are reduced.

Abstract: A fan controlling circuit is provided. The fan controlling circuit includes an integral unit, an operational amplifier, and an output unit. The integral unit transforms pulse width modulation signals to voltages, and then the output unit outputs one of the pulse width modulation signals having a higher operation frequency according to the comparison result between the voltages. As the fan controlling circuit may be constituted with discrete elements and use a same voltage source as fans, the design cost and complexity are reduced.

Abstract: A fan controlling circuit is provided. The fan controlling circuit includes an integral unit, an operational amplifier, and an output unit. The integral unit transforms pulse width modulation signals to voltages, and then the output unit outputs one of the pulse width modulation signals having a higher operation frequency according to the comparison result between the voltages. As the fan controlling circuit may be constituted with discrete elements and use a same voltage source as fans, the design cost and complexity are reduced.

Abstract: A fan controlling circuit is provided. The fan controlling circuit includes an integral unit, an operational amplifier, a PMOS transistor, and an NMOS transistor. The integral unit transforms pulse width modulation (PWM) signals to voltages, and transmits the voltages to positive and negative input terminals of the operational amplifier. The PMOS transistor is coupled between a first PWM signal and an output terminal, and a gate of the PMOS transistor is coupled to an output of the operational amplifier. The NMOS transistor is coupled between a second PWM signal and the output terminal, and a gate of the NMOS transistor is coupled to the output of the operational amplifier. The fan controlling circuit may be formed by discrete elements and use a same voltage source as fans, so that the design cost and complexity are reduced.

Abstract: An apparatus for preventing inappropriate removal in a multi-storage system and a method thereof are provided. The apparatus includes a plurality of expending trays, a plurality of security devices, and a monitor unit. Storage devices are selectively installed in the expending trays. Each security device is disposed in a corresponding expending tray, and is used for locking the storage device installed therein. The monitor unit is used for detecting whether the installed storages have a redundant reliability. If the installed storages do not have the redundant reliability, the monitor unit activates the security units to lock a part of or all of the storage devices for preventing data accessing failure caused by inappropriate removal of the storage devices.