Language Selection

English French German Italian Portuguese Spanish

Using nullfs:

Filed under
HowTos

The nullfs filesystem is a passthrough filesystem. When nullfs is mounted it - literally copies the filesystem transaction. If a file is deleted, nullfs simply transmits the information down to the lower filesystem. Conversely, if a file is created, it does the same and tacks on all of the data needed for the filesystem underneath. Why is that a good thing? Where did nullfs come from and why?. What else, if anything, is it good for? The series focuses on where nullfs comes from, how it can be leveraged, a code walk and a skeloten implementation (nearly a blind copy).

Origins of nullfs

The answer to this is simple as quoted from KirkMcKusick:

The null filesystem was done in July 1992 by John Heideman when he was visiting Berkeley to add his stackable filesystem implementation to BSD. John is the person that built the framework and built nullfs to show others how to use it. Jan-Simon Pendry used that framework in February 1994 to build several new filesystem modules including the union filesystem, the kernel filesystem, the umap filesystem, and the portal filesystem.

Stackable filesystems can lay on top each other (as the name implies) but more importantly - they abstract the details of a regular filesystem.

A good example is to look at layers. While there are many more layers an abstraction of file layers might be:

Full Story.

More in Tux Machines

Leftovers: Software

  • diction: The words you choose and why
  • style: Similar idea, different direction
  • SMS based Cosmos Browser for the developing countries
    Browsing the internet has different meaning to different people. While to some the web is a source of entertainment, to others it is a valuable and source of learning. Sadly enough, the internet is not widely available and easily affordable everywhere in the globe. Slow network speed is another problem. Developer Stefan Aleksic of ColdSauce tries to find a solution in an SMS (text) based browser for the third world countries which are yet to see the internet as we know it. He has named it the Cosmos Browser. If you ever used elinks on Linux, you know how efficient and low-bandwidth text only browsing can be. Of course, it is not meant for visiting a website for downloading wallpapers, but it is more than sufficient if you want to read some information from the web. Cosmos will work on text and will not need any data plan or WiFi.
  • Keyboard Modifiers State indicator For Ubuntu: Xkbmod Indicator

today's howtos

Leftovers: Gaming

Sorry, Windows 9 Fans, This Is How Multiple Desktops Should Work – Video

The Linux platform has always taken pride in this cool feature. Having multiple desktops is a great way to increase the productivity and there are numerous means to implement it. Lots of Linux distributions have this option, which is used in various ways. Read more