The ALU of a computer normally contains a number of high-speed storage elements called

The high-speed storage elements inside the ALU are called registers.

Semiconductor memory is a broader term for chip memory, not these ALU elements.

Hard disks are slow secondary storage, not fast ALU elements.

Magnetic disks are likewise slow storage rather than registers.

Registers briefly hold operands and results during calculations.

They are the fastest storage locations in a computer.