Question

What is the fastest storage unit ina usual memory hierarchy?

Answer 1

In a computer, a register is the fastest memory. Register a part of the computer processor which is used to hold a computer instruction, perform mathematical operation as storage address, or any kind of data. The register memory indicates the capacity of the register to hold the size of data it can hold. The capacity varies on the design of the processor and varies for example a 32 bit microprocessor can have 8 bit register giving memory size 256 bits.

Answer 2

Processor registers – the fastest possible access (usually 1 CPU cycle). ...
Cache. ...
Main memory (Primary storage) – Gigabytes in size. ...
Disk storage (Secondary storage) – Terabytes in size.