Digital Communication


Digital Communication

IPO model: what is Input Processing Output?


Data processing by computers or humans always follows the same process with input, processing and output steps (Input Processing Output in English). Therefore, in the context of electronic data processing, we also speak of the universally applicable IPO model. This principle also describes the way computers operate and work.

IPO model: the basis of data processing

The acronym IPO comes from the English “Input Processing Output”, which translates into French as “Entry, Processing, Output”. This conceptual model turns out to be intuitive and explicit in its meaning, since it outlines the fundamental steps of data processing in a sequential manner:

  1. Data is initially fed into processing units, such as computers, through appropriate input devices.
  2. These data are then subjected to processing operations in accordance with previously defined rules.
  3. Finally, the processed data is displayed or transmitted through different output devices to end users.

The IPO model thus represents a essential basic structure in the field of computing. It does not matter whether the data is entered by a computer or by a human being, because what matters is the sequential order of data processing. This model can be applied to both global systems and subsystems. For example, in a complex computer system, data may be fed in bulk to be processed and distributed to various parts of the system later.

Why is Input Processing Output so important?

One could argue without thinking that the EVA principle only describes what is already obvious. However, it is of great importance when it comes to the hardware and software development. It is only when the fundamentals of data processing match the model that one can be sure that the input, processing, and output processes are aligned consistently with the desired operation.

Below we explain the importance of the IPO model for hardware and software development:


When designing hardware, it is essential to determine precisely what types of input signals that hardware should be capable of processing. The input units to be used depend on this. Likewise, the necessary processing units are defined according to the requirements of the processing to be carried out. Finally, the choice of output units to use for display or output is conditioned by the desired actions after input.


Software development also follows the IPO model. A program must be developed upstream by taking into account the input data in order to understand how it should process it. Therefore, for software such as word processing programs or operating systems, the process of input, data processing and output differs from that of graphic design software or a media player . Depending on the input command, it may be necessary to use other output units and devices. The programming paradigms and algorithms used in software development therefore also depend on the IPO model.

How does the principle of input, processing and output work?

As a universal and applicable guideline for everyone, the order and flow of data processing according to the IPO model can be explained as follows:

Input (“E”)

Data entry represents a command or instruction to the device or system. Entry can be done by different devices depending on the needs. This could be:

  • Computer keyboard
  • Mouse
  • Microphone
  • Touch screen
  • Touchpad
  • To scan
  • Webcam
  • Eye control
  • Virtual keyboard
  • Game controller/joystick

Input devices allow commands and data to be entered in different forms and ways. These can be letters, numbers, clicks, symbols, Windows shortcuts, voice commands, touch commands, visual data or document scans. Data is processed differently depending on the device and program you are working with.

Treatment (“V”)

The processing or calculation of the entered data is carried out by units designed for this purpose. The most important are the processor (CPU)there random access memory (RAM) and the graphics card (GPU). The most important unit for processing is the processor and RAM module: during this phase, the input data is analyzed, the instructions are executed, and simultaneously, the data is stored and buffered.

For storage, we use hard drives, RAM, Cloud storage, DVDs and USB keys. It is important to note that memory is distinct from processing units and occupies a separate position in the IPO sequence. It is the algorithm that dictates which output units are activated and how the data is processed, which is of great importance in this process.

Output (“A”)

To output the processed data as desired, computers or electronic devices have corresponding output units. These ensure that the processed data is, for example, displayed on a monitor/screen or disseminated by speakers, printer, projector or headphones. Thus, even the movement of the mouse pointer on the screen is considered output according to the IPO model, as is the appearance of typed letters or the printing of documents.

In which areas is the IPO model applicable?

Being a universal guideline, the IPO model finds application in any situation where input signals drive results. An eloquent example is that of “input devices” of the human body, whether it is the eyes, ears, nose, mouth or skin. Our interaction with the outside world is both passive, through receiving information such as smells, sounds and the visible environment, and active, through our actions such as reading, watching watching movies, listening to music or tasting our favorite dish. These signals are then processed, and the results are generated by our senses and processing units, such as the brain, organs, bones, muscles and tendons. Results include things like images, colors, flavors, meanings, smells or conversations.

When developing functional hardware and software, Input Processing Output plays a decisive role, especially from the point of view of error diagnosis and performance optimization. It prescribes test sequences to identify situations where an input signal does not lead to the expected results. Thus, it makes it possible to identify and correct errors, incompatibilities between input and output devices, as well as malfunctions in processing units. In this way, it is also possible to determine, for example, whether data processing in the processors should take place in parallel on several cores by multithreading or hyperthreading and which parts of the operating system kernel are required.

IPO model: examples of data processing

Examples of the IPO operating principle can actually be found in every data entry on a PC, smartphone, tablet, printer, scanner or Bluetooth devices. For example, if you enter a word on the keyboard, the keyboard signals are displayed on the screen as a word by processing units such as the CPU, RAM and word processing programs. If you click on a video link, the browser calls up the corresponding website, the computer’s audio units start audio playback, and the video is displayed on the monitor.

The same applies when you make presets on a printer regarding the format, print color and number of copies, start printing and then the documents print. Any machine performing a certain function therefore in principle applies the principle of data input, processing and output, whether it is the dispensing of cash or the display of the account balance of an ATM , a scanner for scanning documents, a games console with a connected screen and game controllers or a hi-fi system with speakers.

In summary

Input Processing Output constitutes an important guideline for guarantee flawless and efficient data processing. It ensures that errors between input and output are identified and corrected and allows data processing processes to be organized as continuously and resource-efficiently as possible.

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