A computer power supply of the present disclosure comprises a housing, a circuit board disposed inside the housing and a fan assembly for dissipating heat from the circuit board, and the fan assembly is disposed obliquely with respect to a surface of the circuit board. In one example, a programmable logic device includes a decryption key memory with a number of decryption-key fields and, for each key field, an associated error-correction-code field. A drive system includes a plurality of drive segments coupled together so that the skin engaging unit of the drive segment frictionally moves the inner layer of the torus skin relative to the outer layer of the torus skin.