SYSTEM FILE EXTENSIONS  What are they and types? ▷ 2020

A system file is any file that, as its name indicates, necessary to operate this. They are really important and therefore need to differentiate themselves very well from the rest, for which the system file extension is used.

This is the nomenglature that we give to each of these files to be able to differentiate them. Its importance is such that if we move them around, modify or, obviously, eliminate them, our OS will malfunction and may even stop doing so.

As you can see, we are not talking about something insignificant or meaningless, so knowing everything about this resource can keep our team safe. Do not hesitate, then, to take a look at this post and put it in a safe place because in it you will discover not only what exactly are file system extensions but, more importantly, which are, so that you can always keep an eye on them.

What is the extension of a file or system file and what is it really used for?

system file extension

We have already seen that the system files are those that are related to the operation of this. That means that a new computer will already include them, it is not something that we are going to download.

In addition, these, in general, remain hidden in their corresponding folders precisely so that the inexperienced user does not access them and modify them, with its corresponding and negative consequence.

As we have already seen in other posts about extensions, these are nothing more than, at first glance, a little lyrics and / or numbers (between two and four) accompanying the name of each of our files. These are placed behind a dot, immediately after the file name, without spaces.

With this alphanumeric set we are indicating that said file isprecisely of the system and not of any other type (text, video, image, etc). Within these we find icons, libraries, device drivers or themes.

In addition, and very important, we also say what kind of OS it belongs to each one as these files are incompatible between systems; each OS has its own.

Types of system file extensions and their associated programs to open them

Although, as we have said, system files are, in general, hidden, it does not hurt to know very well what they are, identifying their extension or format, so that if, for whatever reason, they are exposed, we know how to recognize them and, of course, not modify them in any way.

So, let’s finish by looking at what the system file formats are in this case:

Extension Characteristics Program


  • Virtual device driver.
  • Access to kernel memory, execution processes, and hardware.
  • Its installation occurs with the operating system.
  • It does not need to be opened; Windows makes it work


  • It is a file of the operating system.
  • Check that its operation is correct.
  • They shape this, differentiating it from other versions and other OS.
  • System updates modify them


  • Windows registry file.
  • Saves information (modification, addition or subtraction of values ​​and keys) about the installed applications.
  • Registry editor on double click
  • Editing with right click opens with Notepad


  • They are dynamic link libraries.
  • Modules for publishing controls and functions of Windows programs.
  • It requires registration in the system, although this is usually automatic.
  • Development platforms for Windows such as Visual Basic
  • Macro languages
  • Script languages
  • Embedded in files with support for OLE


  • Start file.
  • It includes all kinds of configuration information about everything that starts with it.
  • Windows system boot
  • Boot for some GNU / Linux environments

.fon, .otf or .ttf

  • They are font files (text).
  • They come with the system and can be downloaded to get different fonts.
  • They are installed in the OS by button
  • Font viewer


  • Driver file for devices connected to the board by bus or cable.
  • Define parameters of these to synchronize them and communicate with the OS.


  • They are dynamic link libraries, files that can be run loaded by order of the operating system.
  • They are required to run both software pre-installed on the system and third-party software, giving them the ability to share resources.


  • It has data in binary and is used by various non-text software without us noticing.
  • Your information is processed, in part, as text (translating without formatting), but most of it is formatting and other functionalities.


  • Batch processing file.
  • They are plain text (MS-DOS instructions).
  • The work is group work, carried out sequentially to achieve automation.


  • Executable file.
  • Very simple structure.
  • Direct and linear storage of the memory image of each software (single segment)
  • Windows, OS / 2, QDOS, MS-DOS, CP / M and PC-DOS


  • Executable file of relocatable code, with relative memories.
  • Source code with header and segments.
  • It enables the operation of a program but is not part of it.
  • Native use on Windows, ReactOS, DOS and OS / 2


  • OS configuration file.
  • It is created with the execution of an INF
  • It does not need to be opened; is stored in OS directory


  • It is a device driver that enables communication between the device and the system.
  • It is a previous denomination of the current .vxd. There are (were) many others.
  • It does not need to be opened; systems make it work


  • Android apps and games.
  • Android Application Package.
  • Android operating system with activation of “Unknown sources”
  • With APK emulators for PCs

* If you are viewing the web from your smartphone, slide the table to the right to see all the data

Do you know other extensions that you think are important? Leave them in the comments and we will add them to the list, it will surely be of great value to other readers!

If you have any questions, leave them in the comments, we will answer you as soon as possible, and it will also be of great help to more members of the community. Thank you! 😉

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