In order for a computer to make calculations and process jobs, it must have a designated location to store, read and write the information that it is being manipulated. The most integral part of a computer’s internal memory is called primary memory, which has generally been in the form of Random Access Memory (commonly known as RAM) since 1968. When a computer is engaged in processing a task, data is stored in the computer’s primary memory. A computer’s primary memory only holds the data for as long as the computer is powered up with a steady flow of electrical current - it is lost when the computer is shut down.

Another form of memory that is very important to the modern computer is called secondary memory. Secondary memory is different from primary memory in the speed of access, the duration of the memory, and the total capacity. It is generally slower than primary memory, which makes it a poor choice for processing jobs. However, secondary memory is usually higher capacity and does not need a constant current running through it to retain its memory, so it useful for long-term storage. Modern versions of secondary memory storage hardware range from hard disk drives to floppy disk drives to flash drives, as well as to optical discs such as CD-ROMs and DVDs.

The Central Processing Unit (CPU) is also a very necessary component of computer hardware. The CPU, known colloquially as the computer's 'brain', processor, or central processor, conducts all of the data calculations and processes for the data held in the computer’s memory. The CPU is housed in a silicon chip called a microprocessor. These components understand the basic computer instructions that are provided by the computer's software. Even though CPUs are often physically small, they can contain millions of parts.

Storage devices (such as disk drives), display devices (such as computer monitors or screens), output devices (printers, speakers), input devices (keyboards, mice, joysticks, scanners) and other peripherals (modems and network cards) are all considered types of hardware - that is, computer components that can actually be physically touched.