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A computer is a machine that manipulates data according to a set of instructions.

Hardware is a general term for the physical artifacts of a technology. It may also mean the physical components of a computer system, in the form of computer hardware.

Components directly attached to the motherboard include:

  • The central processing unit (CPU) performs most of the calculations which enable a computer to function, and is sometimes referred to as the “brain” of the computer. It is usually cooled by a heat sink and fan.
  • The chip set mediates communication between the CPU and the other components of the system, including main memory.
  • RAM Stores all running processes (applications) and the current running OS. RAM Stands for Random Access Memory
  • The BIOS includes boot firmware and power management. The Basic Input Output System tasks are handled by operating system drivers.

The Central Processing Unit (CPU) or the processor is the portion of a computer system that carries out the instructions of a computer program, and is the primary element carrying out the computer’s functions. This term has been in use in the computer industry at least since the early 1960s. The form, design and implementation of CPUs have changed dramatically since the earliest examples, but their fundamental operation remains much the same.

See http://www.flickr.com/photos/biwook/153062645/

One typical CPU

Inspite of some different architectures the main principle of executing commands is similar for typical commands independent of the used high-level language. There is a formalism of the Turing machine behind those modern architectures, although they have some excellent features that make execution rather fast.

In CPU the high level commands are split into atomistic machine level instructions.

For example adding the registers 1 and 2 and placing the result in register 6 is encoded:

[  op  |  rs |  rt |  rd |shamt| funct]
    0     1     2     6     0     32     decimal
 000000 00001 00010 00110 00000 100000   binary

Because typical high-level instructions can be transformed into atomic formulas, it is possible to mimic different parts of any high level command step-by-step. There are only some exception to that rule (parallelism etc).

Therefore it is possible for a tool to split high level commands into symbolic trees, which atomic parts of it as its leafs. This observation leads to a theory of source code simulation. Although partial execution of any high-level command from any part of those programs seldom can be complete, it is possible by partial evaluation to retrieve useful information from those commands to the program comprehension purpose in order to understand relations and arguments of any relevant command.

Symbolic Abstract Machine

Summary

As a conclusion in our study we were able to create a simulator for source code, which mimics CPU, but in a high abstraction level. The only components and artifacts for this work are symbols, which have been implemented as hybrid objects (see AHO). The user can create mental models by traversing information between symbols.

Hardware is a general term that refers to the physical artifacts of a technology. It may also mean the physical components of a computer system, in the form of computer hardware.

A virtual machine (VM) is a software implementation of a machine (i.e. a computer) that executes programs like a real machine.

Erkki Laitila, PhD (2008) computer engineer (1977)