Abstract: A computer that controls a temperature of its file bays includes a ventilation opening in a wall of the computer, a first file bay that contains a first file unit having its own ID, a second file bay that contains a second file unit having its own ID and that is arranged near the first file bay, a fan that dissipates heat from the first and second file units and that is arranged close to the ventilation opening, a bay identifying circuit that recognizes operation assuring temperatures of the first and second file units by referring to their IDs and that determines a blowing direction of the fan; and a fan control circuit that controls the blowing direction of the fan as determined by the bay identifying circuit.

Abstract: A data terminal apparatus includes a basic unit, a plurality of units, a power supply circuit, switching units and a controller. The basic unit realizes a basic function of the data terminal apparatus and requires a basic quantity of DC power. Each of the plurality of units realizes a specific function of the data terminal apparatus and requires quantities of DC power. The power supply circuit receives DC power from a power supply source, and can supply the DC power to the basic unit and the plurality of units. The switching units are provided for the plurality of units, and each of the switching units selectively supplies the DC power from the power supply circuit to a corresponding one of the plurality of units in response to a switching control signal. The controller selectively outputs the switching control signals to the switching units based on the DC power of the power supply source.

Abstract: To provide a computer having function for controlling temperature of file bays, the computer includes a ventilation opening which is formed on a wall of the computer, a first file bay which contains a first file unit having own ID, a second file bay which contains a second file unit having own ID and is arranged near the first file bay, a fan which dissipates heat of the first and second file units and is arranged close to the ventilation opening, a bay identifying circuit which recognizes operation assuring temperature of the first and second file units by referring to the IDs and determines blowing direction of the fan; and a fan control circuit which controls blowing direction of the fan determined by the bay identifying circuit.

Abstract: When a first bus master device issues a bus request on a first request signal line, a centralized arbitration circuit in a system bus manage circuit issues a bus grant signal on a first grant signal line if the bus is available for use. This causes the first bus master device having gained the ownership of the bus to issue a read request to a first slave device. At this time a first signal line is designated. Even before the sending of the read data constituting a response to this read request to the first bus master device, a bus request from a second bus master device can be accepted if the data bus is unoccupied. Thus, the centralized arbitration circuit in the system bus manage circuit issues a grant signal on a second grant signal line. This causes the second bus master device having gained the ownership of the bus to designate a second end signal line, and to issue a read request to a second slave device.