Internal hardware devices include motherboards, hard drives, and RAM. External

hardware devices include monitors, keyboards, mice, printers, and scanners.

The internal hardware parts of a computer are often referred to as components

, while external hardware devices are usually called peripherals. Together, they 

all fall under the category of computer hardware. Software, on the other hand,

consists of the programs and applications that run on computers. Because

software runs on computer hardware, software programs often have 

system requirements that list the minimum hardware required for the software to run.

The von Neumann architecture is a family of computer architectures that use the same

storage device for instructions and for the data (unlike the Harvard architecture).

Most modern computers are based on this architecture, but may include additional devices.

Sources: http://www.techterms.com/definition/hardware

http://en.wikipedia.org/wiki/Von_Neumann_architecture

Source: http://www.techterms.com/definition/software

The OS perform basic tasks, such as recognizing input from the keyboard, sending output to the display screen, keeping track of files and directories on the disk, and controlling peripheral devices such as disk drives and printers.

Sources: http://en.wikipedia.org/wiki/Operating_system

Source: Ricardo Jurado's mind

- System virtual Machine, which is the one that provides a complete system platform, which mans that it supports the execution of a complete Operating System. The other is a Process or Lenguage virtual Machine wich is designed to run a single programm, that means it supports a single process, insteadof a complete Operating System.