Build an embedded Linux distro from scratch
Before you start
This tutorial shows you how to install Linux on a target system. Not a prebuilt Linux distribution, but your own, built from scratch. While the details of the procedure necessarily vary from one target to another, the same general principles apply.
The result of this tutorial (if you have a suitable target) is a functional Linux system you can get a shell prompt on.
About this tutorial
The tutorial begins with a discussion of cross-compilation issues, then discusses what the components of a Linux system are and how they are put together. Both the building and the installation and configuration of the target system are covered.
The specific target discussed, a Technologic Systems TS-7800, imposes its own default boot and bring-up behaviors; other systems will have other mechanics, and this tutorial does not go into great detail about every possible boot loader.
Prerequisites and system requirements
Developers who are interested in targeting embedded systems, or who just want to learn more about what Linux systems are like under the hood, will get the most out of this tutorial.
The host environment used is Ubuntu, but other systems work as well. Users are assumed to have basic familiarity with UNIX® or Linux system administration issues. The tutorial assumes root access to a host system.
This tutorial assumes that your shell is a Bourne shell derivative; if you use a C shell derivative, the prompt will probably look different, and you will need to use different commands to set environment variables.
For cross-compiling (which is useful when targeting embedded systems), I used crosstool-ng version 1.1.0, released in May of 2008. You may download it from the distribution site (see Related topics). Details follow on installing and configuring it.
About the target and architecture
The target I chose is a Technologic Systems TS-7800 (see Related topics for more detail). This is a small embedded ARM system, with both built-in and removable flash storage, as well as a SATA controller. This tutorial walks you through configuring this system to boot to a login prompt, without relying on prebuilt binaries.
I chose the ARM architecture to make it a little easier to check whether a given binary is host or target, and to make it easy to see when host pollution might be occurring. It is also nice having a machine that consumes a total of about 5W of power and runs completely silently.
What is cross-compiling?
Cross-compiling is using a compiler on one system to develop code to run on another. Cross-compilation is relatively rare among casual UNIX users, as the default is to have a compiler installed on the system for use on that system. However, cross-compilation becomes quite common (and relevant) when targeting embedded systems. Even when host and target are the same architecture, it is necessary to distinguish between their compilers; they may have different versions of libraries, or libraries built with different compiler options, so that something compiled with the host compiler could fail to run, or could behave unexpectedly, on the target.
Obtaining cross-compilation tools
It is, in theory, quite possible to build a cross-compiler yourself, but it is rarely practical. The series of bootstrap stages needed can be difficult and time-consuming, and it is often necessary to build a very minimal compiler, which is used to partially configure and build libraries, the headers of which are then used to rebuild the compiler so it can use them, and so on. A number of commercial sources for working cross-compilers for various architecture combinations are available, as well as several free cross-compilation toolkits.
Dan Kegel's crosstool (see Related topics for details) collects a variety of expertise and a few specialized patches to automatically build toolchains for a number of systems. Crosstool has not been updated in a while, but the new crosstool-ng project builds on this work. For this tutorial, I used crosstool-ng version 1.1.0, released in May of 2008. Download it from the distribution site (see Related topics).
Crosstool-ng has a
configure script. To
configure it, just run the script using
--prefix to set a location. For instance:
$ ./configure --prefix=$HOME/7800/ctng
Once you have configured it, build it using
make and then
make install. The build process creates a
ctng directory in the 7800 working
directory that holds the crosstool-ng build scripts. Add the
ctng/bin subdirectory to your path:
Crosstool-ng uses a
.config file similar to
those used by the Linux kernel. You need to create a configuration
file matching your target to use crosstool-ng. Make a working
directory for a crosstool-ng build:
$ mkdir toolchain-build
$ cd toolchain-build
Now, copy in a default configuration. It's possible to manually configure crosstool-ng, but one of the sample configurations happens to fit the target perfectly:
$ cp ../ctng/lib/ct-ng-1.1.0/samples/arm-unknown-linux-uclibc/* .
Finally, rename the
$ mv crosstool.config .config
This copies in a configuration file that targets an armv5te processor, the model used on the TS-7800. It builds with uClibc, a libc variant intended for embedded systems. However, the configuration file does need one modification.
Fixing the configuration path
The default target directory for a crosstool-ng build is
$HOME/x-tools/$TARGET. For instance, on
this build, it would come out as
x-tools/arm-unknown-linux-uclibc. This is
very useful if you are building for a lot of targets, but not so
useful if you are building for only one. Edit the
.config file and change
Building the toolchain
To build the toolchain, run the
build argument. To improve
performance, especially on a multi-core system, you may want to run
with multiple jobs, specified as
build.#. For example, this command
builds with four jobs:
$ ct-ng build.4
This may take quite a while, depending on your host system. When it's
done, the toolchain is installed in
$HOME/7800/toolchain. The directory and its
contents are marked read-only; if you need to delete or move them, use
chmod u+w The
ct-ng script takes other arguments, such as
help. Note that
ct-ng is a script for the standard
make utility, and as a result, the output
--help is just the standard
make help; use
ct-ng help to get the help for
If you haven't seen this trick before, it's a neat one. Modern
UNIX systems interpret an executable file in which the first line
#! as a script, specifically, a
script for the program named on the rest of the line. For instance,
many shell scripts start with
The name of the file is passed to the program. For programs that treat
their first argument as a script to run, this is sufficient. While
make does not do that automatically, you
can give it a file to run with using the
flag. The first line of
#!/usr/bin/make -rf. The
-r flag suppresses the built-in default
construction rules of
make, and the
-f flag tells it that the following word
(which is the script's file name) is the name of a file to use instead
of one named
Makefile. The result is an
executable script that uses
instead of shell syntax.
Using the toolchain
For starters, add the directory containing the compiler to your path:
With that in your path, you can now compile programs:
$ arm-unknown-linux-uclibc-gcc -o hello hello.c
$ file hello
hello: ELF 32-bit LSB executable, ARM, version 1 (SYSV), for
GNU/Linux 2.4.17, dynamically linked (uses shared libs), not stripped
Where are the libraries?
The libraries used by the toolchain to link binaries are stored in
toolchain directory. This directory
forms the basis of an eventual root file system, a topic we'll cover
under Filesystems, once the kernel is built.
The kernel distribution tree provided by the vendor is already
configured for cross compilation. In the simplest case (which this
is), the only thing you have to do to cross compile a Linux kernel is
to set the
CROSS_COMPILE variable in the
top-level Makefile. This is a prefix that is prepended to the names of
the various programs (gcc, as, ld) used during the build. For
instance, if you set
arm-, the compile will try to find a
arm-gcc in your path. For
this build, then, the correct value is
arm-unknown-linux-uclibc. Or, if you don't
want to rely on path settings, you can specify the whole path, as in
CROSS_COMPILE ?= $(HOME)/7800/toolchain/bin/arm-unknown-linux-uclibc-
Building the kernel
Downloading the source
Download Technologic's Linux source and TS-7800 configuration files and unzip them in a suitable location.
A complete discussion of kernel configuration is beyond the scope of
this tutorial. In this case, the
ts7800_defconfig target gave me a default
usable configuration for the 7800, with one small hiccup: the
CONFIG_DMA_ENGINE setting ended up off when
it should have been on.
Tweaking the kernel
It is usually best to edit the kernel using
menuconfig, which offers a
semi-graphical interface to kernel configuration. This interface is
navigated using arrow keys to move the cursor, the Tab key to select
options from the bottom of the screen, and the space or Enter keys to
select options. For instance, to exit without changing anything, press
Tab until the <Exit> at the bottom of the screen is
highlighted, then press Enter. Running
menuconfig again reopens the
Changing the default console
The TS-7800 normally boots silently, because the default kernel
configuration specifies a null console device to keep the display
quiet. To change this, use the arrow keys to navigate down to "Boot
options," and press Enter. The third line shows the default kernel
options, which select the ramdisk, the startup script, and the
console. Use the arrow keys to navigate down to this line, press
Enter, and change
console none to
console ttyS0,115200. Then, press Tab to
move the cursor to the <Ok> at the bottom of the panel,
and press Enter. Now press Tab to select <Exit> and
press Enter, bringing you back to the main menu.
For the goal of booting as fast as possible, the console device isn't useful, and indeed, even at a high baud rate, sending kernel messages can take a noticeable fraction of the time the system takes to boot. For debugging and playing around, though, you want the console.
Enabling the DMA engine
Navigate down to "Device drivers" and press Enter. This list is longer than the usual display, so you will have to scroll down to the very end to reach the option for "DMA Engines." Navigate to that with the arrow keys, and press Enter. There are two options at the top of this page that have square brackets indicating a boolean option. The second, "Support for DMA engines," was not enabled by default in the download I started with. Navigate to it with the arrow keys, and press space to toggle its state. Now use Tab and Enter to select <Exit> from each screen to navigate out to the top level of the program, and then <Exit> one more time to leave the program. When asked whether you wish to save your new kernel configuration, tab to <Yes> and press Enter.
Compiling the kernel
make. Yes, it really is that simple.
This builds a kernel, as well as a collection of modules. Once again,
multi-core users might want multiple jobs; try
-j 5. For the purposes of this
project, I'm going to ignore kernel modules, and favor compiling-in
any needed features. The bootstrap ramdisk technique used to get
needed drivers into the kernel early seems excessive, and building a
root file system is already complicated enough. This, of course,
brings up the question of how to get a kernel booting, the subject of
the next section.
What is a boot loader?
A boot loader (or bootstrap loader) is a program that loads another program. The boot loader is a small and specialized hunk of code, specific to a target system, that has just enough complexity to find the kernel and load it without being a full-featured kernel. Different systems use a variety of different boot loaders, from the huge and complicated BIOS programs common on desktop PCs, to very small and simple programs more common on embedded systems.
A simple boot loader
The TS-7800 uses an unusually simple boot loader, which simply picks up
the kernel from a predetermined partition of the SD card or on-board
flash. A jumper determines whether the board looks first at the
on-board flash, or at the SD cards. There are no other configuration
settings. More complicated boot loaders (such as
grub, commonly used on desktop PCs) have
options for configuring kernel options and so on at boot time. On this
system, the kernel's default options must be compiled in, as described
The decision to compile in kernel options is a typical example of a choice that makes some sense in an embedded system, but would be uncomfortably limiting on a desktop.
There are a variety of formats in which kernels are stored. The initial
Linux kernel binary, named
rarely the file that a boot loader will work with. On the TS-7800, the
boot loader can use two files, either
These files are created in the
arch/arm/boot directory within the kernel
People often describe the
zImage kernel as a
compressed kernel, and so expect the boot loader to need to provide
decompression. In fact, it's rather more clever. The
zImage kernel is an uncompressed
executable, which contains a particularly large static data object
which is a compressed kernel image. When the boot loader loads and
zImage executable, that executable
then unpacks the kernel image and executes it. This way, you get most
of the benefit of compression without imposing additional effort on
the boot loader.
Setting up the SD card
The SD card needs an MBR table containing DOS-style partition information. A sample MBR table is available for download from Technologic's site; this is for a 512MB card, but it is easy to edit the fourth partition to a size suiting whatever size card you want to use. The first three partitions are 4MB each; the first is unused on smaller cards, and the second and third hold the kernel and initial ramdisk image respectively.
For my purposes, I used the
which is not always recommended but has the desirable trait of
trusting me when I ask it to create a partition that does not align on
a partition boundary.
Installing the initial kernel
The kernel for the TS-7800 is dumped directly into the second partition
of the SD card. The exact path to the card depends on how you are
accessing it; typically, if you have the card on a USB card reader, it
will be detected as a SCSI device. Note that there is no file system
access involved; the raw kernel is just dumped into the partition. The
dd command copies raw data from one source
to another, as in this example:
$ dd if=zImage of=/dev/sdd2 bs=16k
93+1 records in
93+1 records out
1536688 bytes (1.5 MB) copied, 0.847047 s, 1.8 MB/s
This command dumps raw data from the
file to the second partition of
using 16KB blocks.
A bit about block sizes
The output of this command is a little cryptic (as are its inputs,
dd runs, it copies data in
"records," which are by default 512-byte blocks; this command
specifies a block size of 16k (which
understands to mean 16*1024).
dd command reports the amount of data
copied first in blocks; the number after the plus sign is the number
of partial blocks copied. In this case, because 1,536,688 is not an
exact multiple of the block size, the remaining bytes of the file are
read (and written) separately as a partial block. This information is
harmless for most modern devices but crucial to diagnosing problems
with some older ones.
The ability to control block sizes (and reblock data when transferring it) was exceptionally useful for working with tape devices and other specialized media that required writes to be of particular fixed sizes, and also helps for performance and reliability reasons with flash devices.
While the kernel device representing flash media can often take writes of arbitrary sizes, it is common for the underlying device to work only in full blocks, often of somewhat larger sizes (4KB or larger). To do a partial write, the flash device must extract the current contents of the full block, modify them with the input data, and flash the whole block back. If a device uses 4KB blocks, and you write to it in 512-byte blocks, each device block gets rewritten eight times for a single copy. This is bad for the device's longevity, and also bad for performance. (A 512-byte write of the same file was half as fast on the flash card I used.)
Booting the kernel
Booting the kernel is simple enough. Set the jumper for an SD boot, put the card in the system, and power it up. If you started with a blank card, this produces a predictable result:
Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block(1,0)
This cryptic message indicates that the kernel has been unable to find its root filesystem. That means it's about time to create one.
Normally, Linux has only a single root filesystem. However, during boot, it is common to use a temporary root filesystem to load and configure device drivers and the like, and then obtain the real root filesystem and switch to it. The TS-7800 uses this temporary filesystem (called an initial ramdisk, or initrd) for the SD driver and for a variety of configuration options. In fact, the ramdisk is used for many of the things (such as determining the final root filesystem to use) that might be handled by the boot loader on another system.
A general caveat applies: most filesystem operations require root
privileges. There are some exceptions and some workarounds. The most
notable is the
which allows you to build applications with "fakeroot support." This
allows the manipulation of a virtual root filesystem with control over
ownership, permissions, and so on. However, the permissions and
related material are maintained in a separate database, and no actual
privileged operations are needed. This allows a non-root user to
manipulate directory hierarchies with virtual root privileges, and
ultimately create archives or filesystem images containing files that
the user hasn't got the privileges to create. For this tutorial,
however, I assume root privileges.
chroot command, while certainly part of
the story, is not sufficient to change the root filesystem. The tool
for this is
pivot_root, which makes one
named directory the new root directory, and "moves" (really, changes
the mount point of) the old root directory to another name.
A not-so-initial root
For the purposes of this tutorial, I'm assuming that the default initrd image provided with the board is adequate. Linux kernel distributions have some support for generating suitable initrd images, and the details of this one are not crucial to an understanding of building an actual distribution. I'll just introduce the key things needed to get the system moving, then focus on what goes on the real root filesystem.
Most Linux users are familiar with files containing images of ISO
CD-ROM or DVD filesystems. Linux supports the creation and use of
images of other types of filesystems. In fact, any file can be treated
as though it were a disk partition, using the
loop option to
mount. For instance, while researching
this, I made a copy of the initrd image used by the TS-7800:
$ dd if=/dev/sdd3 of=initrd.dist bs=16k
$ cp initrd.dist initrd.local
With this file available, it's possible to mount the filesystem to have
a look at it. The copy named
is the local version to edit; the copy named
initrd.dist is a safe pristine copy in case
something gets broken later.
$ mount -o loop initrd.local /mnt
What does the initrd do?
The initrd provides a very basic initial filesystem used to bootstrap
the device by finding and mounting the real root filesystem. The
default kernel configuration is hard-wired to use an initrd
/dev/ram0) as root, and run the
linuxrc script on startup. There are
several provided variants of this script for different root file
systems. The obvious choice is to look at the
linuxrc-sdroot program tries to
configure the system to use an SD card as root. Assuming a correctly
configured SD card with an ext3 filesystem on the fourth fdisk
partition, the script mounts that filesystem and runs
/sbin/init on it. This looks like a good
strategy. So, a couple of small changes are needed to the initrd
image. The first is to change the
symlink to point to
second is to update the script to work with the uClibc build instead
of the Debian build it was configured for.
The SD driver
The SD driver for the TS-7800 includes a proprietary module, so the
tssdcard.ko file simply has to be manually
copied in, and loaded at runtime. The file on the distribution initrd
works fine with the new kernel, so no change is needed.
Switching bootstrap routines
The kernel simply runs the program called
linuxrc. By default, this is a symbolic
link to the program
comes up quickly to the initrd root filesystem. Removing the link, and
linuxrc instead to
linuxrc-sdroot, causes the system to try to
boot from the last partition on the SD once the drivers are loaded.
Changing the bootstrap routine
The script checks for errors, and if it finds any, mounts from the
internal flash. If it does not, it mounts the filesystem from the SD
card and then tries to change to it. The bootstrap routine actually
has a small quirk that affects this build; it tries to use its own
mount utility, rather than the rootfs one,
for the last cleanup work after calling
pivot_root. This works well with the
provided Debian install, but fails with the minimalist uClibc install.
The solution is to change the lines following the
pivot_root command at the end of the file
else clause) as follows:
pivot_root . ./initrd
/bin/mount -n --move ./initrd/dev ./dev
/bin/mount -n --move ./initrd/sys ./sys
/bin/mount -n --move ./initrd/proc ./proc
exec /sbin/init < $CONSOLE > $CONSOLE 2>&1
This causes the script to run the new (uClibc, statically linked) executables that you are about to create, instead of trying to run dynamically linked executables from another system. (If you were doing this without a tutorial, you probably wouldn't know this until after you'd set everything else up and started getting cryptic error messages).
Unmount the disk image
Unmount the initrd disk image like so:
$ umount /mnt
Populating the root file system
What goes into a root filesystem?
The root filesystem needs an
will do whatever it is we want done. This can be a custom program
rather than a conventional UNIX-style init, but it is easier to work
with the system if you provide a working environment complete with
console shell and everything.
Basic libraries and headers
crosstool-ng build created a default
system root providing library code and headers. Make a copy of it:
$ cp -r toolchain/arm-unknown-linux-uclibc/sys-root rootfs
Note that no effort is being made to fix permissions right now; for a real distribution, you'd probably want to correct this, but it's harmless enough for demonstration purposes. This gets you the first basic parts of a root filesystem, containing only the libraries (and headers) future builds will use.
When it comes to embedded root filesystems, busybox is probably the best starting point. Busybox offers a reasonably complete set of core system utilities all built into a single binary, which uses the name it gets invoked with to determine what function to perform. This, coupled with a lot of links, allows dozens of the main system programs to be bundled into small amount of space. This isn't always necessary, but it is convenient for our purposes.
Busybox can be downloaded from its downloads page (see Related topics). The archive is just a standard tarball and can be unpacked in a build directory. I used version 1.10.2.
Busybox is built around similar configuration tools to those used for
crosstool-ng and the Linux kernel. To build
a default configuration, run
make defconfig. This creates the default
configuration. A following
allows you to change settings; under "Busybox Settings," the "Build
Options" menu allows you to specify a static build. Do that, because
crosstool-ng build of uClibc
requires it. You might sometimes prefer a dynamically linked binary,
to reduce the size of the executable, but the size problem isn't such
a big deal on a system where nearly every binary is just a symbolic
link. As with the kernel, the top-level
Makefile has a
CROSS_COMPILE variable which holds the
prefix to use on the names of compiler tools. Set it to the same value
you used before.
To build busybox, just run
Surprisingly, there was a compilation problem during the build, which
required me to add
<linux/types.h> to the main
libbb.h header. With that out of the way,
the compile completed quite quickly.
To install busybox, you need to run
make install, but specify the root
$ make CONFIG_PREFIX=$HOME/7800/rootfs install
This copies in the
busybox binary and
creates all of the necessary links. This root filesystem now has
libraries and all the common UNIX utilities. What's missing?
You need device nodes. There are two ways to provide device nodes for a
root file system. One is to statically create all the device nodes you
plan to have, the other is to use something like
udev, which provides an automatic current
device node tree for the current kernel. While
udev is extremely elegant, it can also be
fairly slow, and embedded systems have the luxury of being able to
predict their hardware components.
Creating the needed device nodes
Many programs depend on access to device nodes, such as
/dev/null. Device nodes are typically made
at runtime on ARM systems, using the mdev utility, part of busybox. In
fact, this has already been done by the initrd filesystem; one of the
changes above was to move the already populated
/dev mount point onto the new root
filesystem. You can manually create key device nodes, but it is
usually not worth the trouble;
Several mount points are required. The
/proc mount points are used to move the
sysfs and procfs virtual filesystems. The
/dev directory is used as a mount point for
a tmpfs filesystem, populated by
These directories do not need any other contents:
$ cd $HOME/7800/rootfs
$ mkdir sys proc dev
The /etc directory, while not strictly necessary to get to a shell
prompt, is very useful to get to a useful shell prompt. The most
important part during initial booting is the
init.d subdirectory, which
init searches for system startup files.
Create a trivial
rcS script and give it
execute permissions for initial system startup:
$ mkdir rootfs/etc/init.d
rootfs/etc/init.d/rcS file with
the following contents:
echo "Hello, world!"
Now mark it executable:
$ chmod 755 rootfs/etc/init.d/rcS
Creating a disk image
Make a large empty file
You can create a file system image by copying blocks from
/dev/zero into a file, or just by copying
an existing image. Whatever size space you have available (remembering
that 12MB are already reserved for the first three partitions), you
can create a file of that size with
This creates a nice roomy 64MB root filesystem:
$ dd if=/dev/zero of=rootfs.local bs=1M count=64
Format the file
mkfs utilities can be run on
files, not just on disks. To build an ext3 root filesystem (the kind
the initrd looks for), run
your disk image:
$ mkfs.ext3 rootfs.local
mkfs utility prompts you as to whether
or not to proceed even though the file is not a block special device:
rootfs.tmp is not a block special device.
Proceed anyway? (y,n) y
Mount the new disk image
To mount the disk image, use the
option to the
mount command again to mount
the image somewhere.
$ mount -o loop rootfs.local /mnt
Copy the rootfs files to the mounted disk
pax utility is particularly good at
$ cd 7800/rootfs
$ pax -r -w -p e . /mnt
This copies the directory tree you've just created to
/mnt, preserving symlinks and special files
(except for sockets, but you can live without the log socket).
Unmount the image
Once again, having finished work on the image, unmount it:
$ umount /mnt
Getting the images back on the card
Copying files back
You might wonder why the above procedure didn't just use the card as a filesystem. The answer is that, in general, it is better not to use flash filesystems very heavily, because flash devices have much shorter life expectancies than hard drive media under heavy load. Thus, the complicated edits and copies are done to disk images, then the disk images are copied back as a single write operation.
Copy in the initrd
Copy the initrd image in to the third partition of the SD card:
$ dd if=initrd.local of=/dev/sdd3 bs=16k
Copy in the root filesystem
Likewise, copy the filesystem image in to the fourth partition of the SD card.
$ dd if=rootfs.local of=/dev/sdd4 bs=16k
Wait for device access
Do not yank the SD card out of the reader right away. Sometimes it can take a few extra seconds for the system to finish writing. Wait until any activity lights have stabilized, then wait a few seconds longer just to be sure.
The boot process reviewed
What does init do?
init program manages system startup, and
then keeps the system running. For instance, when processes die,
init is the program that collects their
exit status values so the kernel can finish unloading them. The exact
startup procedure varies from one version of Linux to another. In this
case, it is the busybox version of
that will be booting our test system.
You may have wondered why the previous startup script uses
exec /sbin/init rather than just invoking
init. The reason is that the startup script
was the previous
init, and had the special
process ID 1. The
init program does not
become the system's startup daemon unless its process ID is 1;
exec causes it to take over the calling
shell's process ID, rather than acquiring a new one.
The init program starts by running the first system startup script,
/etc/init.d/rcS. (If there is no such file,
it prints a warning message and continues without it.) After this, it
runs according to the instructions in
/etc/inittab, if it exists. In the absence
init runs a shell on the console, and deals
gracefully with reboot and halt requests.
Bringing it together
With your own kernel, a slightly customized initrd, and your own root
filesystem, you should now be able to boot the system to a shell
prompt. If you created the
rcS file, the
system should greet you on boot. Now you have a working, if rather
minimal, Linux system, built entirely from source, and assembled by
What you do next is up to you. I suggest installing some video games, but you could always configure the system for a database server or a Web server. If you plan to do anything that will produce a lot of disk activity, consider using an external hard drive attached via USB.
- Get the complete Linux source and configuration files for the TS-7800 from Technologic's FTP server.
- Download the crosstool-ng sources and documentation to build your own cross compiler.
- Download the Busybox source code to get a complete Linux system in a tiny little package.
- Check out this introduction to the Linux boot process (developerWorks, May 2006).
- Learn more about Dan Kegel's crosstool on its original site.
- Read about Linux initial RAM disks and how to use them (developerWorks, July 2006).
- Learn more about the Technologic Systems TS-7800 single-board computer.
- In the developerWorks Linux zone, find more resources for Linux developers, and scan our most popular articles and tutorials.
- See all Linux tips and Linux tutorials on developerWorks.