Final answer:
Hardware specifications commonly include RAM and CPU but do not include DNS or OS, as these are related to network services and software, respectively.
Step-by-step explanation:
Hardware specifications refer to the detailed description of the physical components of a computer or computing device. Hardware specs typically include the Random Access Memory (RAM) and Central Processing Unit (CPU). RAM is a type of computer memory that can be accessed randomly; it is where a computer stores data it is actively using so that it can be accessed quickly. The CPU is the brain of the computer where most calculations take place. Conversely, DNS (Domain Name System) is a network service that translates human-friendly domain names to IP addresses which is not a hardware component. OS (Operating System) is the software that manages hardware and software resources, also not considered hardware.