Linux is one of several Unix like implementations.
Linux features a customizable kernel and generally uses GNU commands and shells. For eBook readers and PDA's it can be cut down to a very small footprint to allow it to run on smaller low power devices.
As with all operating systems Linux provides a framework for applications to use. It is the application that actually provides the eBook reader functionality. There are several applications available for Linux systems depending on the desired eBook format. The application must be compiled for the particular Linux implementation hardware that you are interested in so not all Linux applications are available for all hardware configurations.
Linux was begun August 25, 1991 by Linus Torvalds who posted his famous message announcing the project, claiming that Linux was "just a hobby, won't be big and professional like gnu." However, Linux has surpassed GNU which now uses Linux as its kernel. The popularity of Linux is largely due to its modularity and the fact that it is not a commercial product.
 User Front End
Linux, like Unix, is a base OS that has a basic kernel which is consists of a set of system calls to and from a User Interface and manages the work being done by the computer. However, the user only really sees the User Interface which can vary the look and feel depending on the implementation. It can be a command line using a shell but is more likely to be a Graphical User Interface (GUI). Some GUI user interface packages include:
- Gnome a Desktop package from Gnome
- Qtopia an API for custom versions of embedded Linux from Trolltech
- X window system from MIT (also used in regular Unix/Linux):
- Also KDE, LXDE and Xfce
 Linux variants
Ubuntu is a community developed, Linux-based operating system that is perfect for laptops, desktops and servers. It contains all the applications you need - a web browser, presentation, document and spreadsheet software, instant messaging and much more. A special Mobile version exists for MID devices. See http://www.ubuntu.com/
On June 24, 2008 Ubuntu Linux released the first developer's version of its new Ubuntu Mobile Internet Device (MID) Edition 8.04 operating system, which is aimed at device manufacturers that build Internet-ready handheld devices based on Intel Corp.'s Atom processors.
Based on Ubuntu's Desktop Edition operating system, the MID Edition 8.04 was developed by the Ubuntu Mobile and Embedded community, in cooperation with the Intel http://Moblin.org community, according to Ubuntu.
 Ubuntu Touch
Ubuntu Touch is a mobile version of the Ubuntu operating system, designed primarily for touchscreen mobile devices such as smartphones and tablet computers.  Unstable ISO Images are available via cdimages.ubuntu.com.
 Red Hat
Red Hat is a commercially supported variant for enterprise users.
Fedora is a Linux-based operating system that showcases the latest in free and open source software. Fedora is always free for anyone to use, modify, and distribute. It is built by people across the globe who work together as a community. It is backed by Red Hat.
 Linpus LINUX Lite
Linpus Linux Lite is the latest OS development for low-cost PCs like UMPC, OLPC, Classmate PC, MID and other consumer mobile devices. This new version of Linpus Linux distribution is designed to run smoothly and reliably on a lower-end hardware with processing power as low as 500 MHz, 128MB of DRAM and 512MB of storage space. With Linpus Linux Lite, you can surf the web, edit documents and photos, read e-book and email, play the music and games, enjoy the GPS navigation and VoIP service, etc.
 Palm webOS
Palm webOS is a mobile operating system running on the Linux kernel with proprietary components developed by Palm including a touchscreen interface.
Debian is a totally free operating system. Currently this is Linux or FreeBSD based but other bases are being worked on most notably GNU/Hurd is available for download. A large portion of the basic tools are GNU based. Debian comes with over 37500 packages (precompiled software that is bundled up in a nice format for easy installation on your machine).
 Raspberry Pi
Raspberry Pi is a very small hardware module that uses a version of Linux downloadable from their web site. These downloads are installed on an SD card which is then inserted into the hardware. They have several images depending on the needs of the user.
 Embedded systems
Most eBook readers use an embedded Linux system. The largest companies in this business are Wind River and MontaVista. MontaVista is the one used on the Sony Reader.
JTAG (Joint Test Action Group) tools can be used to debug the embedded Linux kernel.
 For more information
- See eBook software for programs that will work on this platform.
- See ADE 2.0.1 Linux to install ADE.
- Linux web site
- http://www.embedded.com for embedded information.
- http://www.handhelds.org/ for Handheld PDA and Palmtop versions.
- Debian Linux on a Kobo
- Running X apps on Kindle Touch
- http://freeengineer.org/learnUNIXin10minutes.html learn Unix/Linux basics in 10 minutes
- http://www.ee.surrey.ac.uk/Teaching/Unix/ Another tutorial, a bit more complete