4. Has a rigid cell wall made of peptidoglycan (except for the mycoplasma). This cell wall is thick in Gram-positive bacteria and thin in Gram-negative bacteria. It is the thickness of the peptidoglycan that accounts for the ability/lack of ability to retain the crystal violet used in the Gram stain.
Computer hardware is the physical parts or components of a computer, such as the monitor, mouse, keyboard, computer data storage, hard disk drive (HDD), graphic cards, sound cards, memory, motherboard, and so on, all of which are physical objects that are tangible.
A printer is known as a peripheral device. A computer peripheral is a device that is connected to a computer but is not part of the core computer architecture. The core elements of a computer are the central processing unit, power supply, motherboard and the computer case that contains those three components.