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.
Peripherals are the devices external to your computer that take in information, allow the computer to put out information in visible and audible form, and perform other important tasks. Devices such as printers, scanners, audio and visual equipment and external drives allow us to make full use of the computer's resources. All of these devices hook up electronically via cables or wireless connection to the main computer, but are separate from the main operating functions of the computer.