Where and how does software meet hardware? [closed]

Answer 1

When we enter any key or give any command then small electric waves became due by pressing of key is actually we complete the circuit

Answer 2

This explanation may not be too academical but this is how i understand it (didn't go to university either).

The first step involves Boole's algebra that proved in the 19'th century that any mathematical operation can be expressed using a series of symbols and some associated operators. Thus the base 10 arithmetic with the common +, -, *, / operators can be expressed in using just two symbols (0, 1/ true, false) and logic operators (AND, OR etc) leading to the Boolean logic that is the mathematical foundation of digital computing.

The second step is Alan Turing's work that constructed a mathematical model of an imaginary machine that could process symbols. The naive description of a Turing machine would be any automaton that has memory (to store it's state), operates on a series of symbols that represent it's state and interprets another series of symbols that define the transition from one state to another.

The modern digital processor is an implementation of a Turing machine that uses Boole's logical algebra as the symbol and operator base (take a look at a How Stuff Works detailed explanation of Boole's logic at work). The reason for this is that the true/false logical states can be easily mapped to electrical signals (+ , -) and their associated operators can be implemented in transistor circuits that given a binary input (electrical signal) can output the result according to the boolean operators. So any modern computer is a machine that has memory to store it's state (encoded in binary electrical/magnetic form) and an array of circuits that accept electrical impulses and operators (the processor instructions) and output results accordingly at a very fast speed.

Thus every program written in any computer language is eventually translated by the compiler or runtime into a series of boolean operations for the processor to execute

Answer 3

Machine code, I believe, is as low-level as one can go. It is directly understood by the processor and executed without an interpreter. The processor is built with a certain set of instructions which define the machine code for a given architecture (x86, PPC, ARM, etc.).

Everything from drawing letters on the screen to calculating pi is, at its most base level, run in machine code. Drawing letters on the screen is just a matter of creating some machine code which computes letter height, color, and pixel locations and plots them on a screen using a video output device.

Answer 4

Here is the real deal. My starting point. Everything requires energy to operate. The On/Off is defined within a limit. for example if between 3 and 5 v it is on if less then 3 volt its off. A morse code concept. I am working on a thermometer so I need to make or buy a sensor. Then I need to calibrate it. Translate the signals from signal no signal or strength of signal to a temperature. This is where I am now.

Answer 5

Well, the actual point where you meet hardware depends on what you are doing, of course. But to take your (excellent) example of "displaying text":

From abstract to hardware:

• user types letters into her word processor (wp)
• wp software first stores the letters in memory as part of the document being edited
• wp software then tells the user interface library it uses that it wants to display the text being edited in a window (this happens continually, of course). The UI library will be system-dependent (the Windows API on MS Windows, X Windows or QT etc. on Linux, AWT/Swing on Java etc.)
• The UI library will pass the data through a few more abstraction layers. In particular, it will perform rasterization (convert the information "show an A" into the pixel grid that represents an A)
• Eventually, the information will be passed to the device driver of the graphic card. This is where we meet "real" hardware :-). Normally, the graphic card exposes "video memory", i.e. memory on the card that the CPU can write to. The graphic card driver (which runs on the CPU) will write the pixels for an A to video memory.
• The graphic card's circuits will read the video memory and convert the data there into a video signal that goes out the video connector on the card and to the monitor.
• The monitor will display what looks hopefully like an A :-)

Answer 6

You're getting it wrong.

Everything the computer does, be it showing letters on the screen or doing some computation, can be viewed at different (many) levels of abstraction, from the electrical current to the manipulation of abstract concepts like money on a bank account.

That said, building the circuit for a simple microprocessor is not that hard, an ALU, some registers and some control logic. Altera has this as advanced tutorials for the Cyclone II starter board, but I can't find it on the web.