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TimeSys Linux Install HOWTO

Trevor Harmon


Revision History                                                             
Revision 1.0            2005-04-05             Revised by: TH                
first official release                                                       

  This document is a quick-start guide for installing TimeSys Linux on a
typical desktop workstation.

Table of Contents
1. Introduction
    1.1. Background
    1.2. Copyright and License
    1.3. Disclaimer
    1.4. Feedback
2. Requirements
3. Install the packages
4. Prepare the source directories
5. Configure the kernel
6. Compile the kernel
7. Prepare for rebooting
8. Rebooting
9. Further Information

1. Introduction

1.1. Background

  TimeSys Linux is a derivative of Linux created by []
TimeSys Corporation. It includes a fully preemptible kernel, a constant-time
scheduler, fully schedulable interrupt handlers, fully schedulable soft-IRQs,
and reduced interrupt disable times. These features reduce latency to a point
where TimeSys Linux can be used as a Real-Time Operating System (RTOS).

  TimeSys Linux comes in four flavors:

��*�  TimeSys Linux/GPL ?? The basic TimeSys Linux kernel; offers full
    preemption at the kernel level, prioritized interrupt handlers, and so
��*�  TimeSys Linux/Real-time ?? Makes Linux a true RTOS by adding priority
    inheritance and a POSIX-based high-resolution timer API.
��*�  TimeSys Linux/CPU ?? Adds support for CPU reservation, which gives a
    thread, process, or process group exclusive use of the CPU.
��*�  TimeSys Linux/Net ?? Adds support for network bandwidth reservation,
    guaranteeing that your thread or process will get the bandwidth it
    requires, regardless of network activity in other processes.

  This document deals with the first variant, GPL, as it is the only one
available for free. The GPL version is unsupported by TimeSys Corporation
(unless you purchase a support contract, of course), and thus the
documentation for it is a bit lacking.

To be fair, the documentation for installing TimeSys Linux onto an embedded
board and cross-compiling code for it is fairly good. The problem is that
TimeSys charges for the toolchains necessary for cross-compiling, and even
then, many first-time users may not wish to start compiling for a target
board right away. They may just want to try out TimeSys Linux, or they may
not even have an embedded board to begin with. TimeSys Corporation's
documentation does not help these users.

  In this mini-HOWTO, I try to rectify this situation somewhat by explaining
how to install TimeSys Linux/GPL onto a typical "beige box" desktop
workstation. Although this is clearly not the intended platform for TimeSys
Linux, installing the kernel onto a plain-vanilla desktop is an easy way to
get started quickly and play around with some real-time applications, such as
the [] RTSJ []
Reference Implementation.

1.2. Copyright and License

  This document, TimeSys Linux Install mini HOWTO, is copyrighted (c) 2005 by
Trevor Harmon and is licensed under the Creative Commons
Attribution-Sharealike 2.0 License. Terms and conditions for distribution can
be found at [] http://

  TimeSys is a registered trademark of TimeSys Corporation.

  Linux is a registered trademark of Linus Torvalds.

1.3. Disclaimer

  No liability for the contents of this document can be accepted. Use the
concepts, examples and information at your own risk. There may be errors and
inaccuracies that could be damaging to your system. Proceed with caution, and
although this is highly unlikely, the author does not take any

  All copyrights are held by their by their respective owners, unless
specifically noted otherwise. Use of a term in this document should not be
regarded as affecting the validity of any trademark or service mark. Naming
of particular products or brands should not be seen as endorsements.

1.4. Feedback

  Feedback is welcome for this document. Send your additions, comments, and
criticisms to <>.

2. Requirements

  For this HOWTO, I assume that you have the following:

��*�  [] Red Hat Linux 9 [1]
��*�  []
    TimeSys Linux 4.1 Build 155 for the generic Pentium [2]
��*�  Pentium-class computer capable of running Red Hat Linux 9

3. Install the packages

  Your first task is to install Red Hat Linux 9 on the desktop computer that
will be running TimeSys Linux. If you already have a computer with RHL9 on it
(or even just a boot partition that has it), you can skip this step, but a
clean installation is always best. Be sure to choose the Workstation
installation option so that all of the development packages get installed.

Next, make sure that the kernel-source package is installed. You can do this
by typing:
        # rpm -q kernel-source                                               

If it's not installed, retrieve it by whatever means you prefer, such as
downloading the binary RPM from Red Hat's [
linux/9/en/os/i386/RedHat/RPMS/] FTP site, then install it with:
        # rpm -Uvh kernel-source-2.4.20-8.i386.rpm                           

  Copy the TimeSys Linux distribution archive to the computer running RHL9
and extract it. Switch to the TimeSys-x86bsp directory that was created and
run ./install as root. This will put all of the TimeSys Linux files into /opt

4. Prepare the source directories

  Before compiling the TimeSys Linux kernel, you need to set up the source
directories so that the kernel knows about all the drivers and things on your
system. To do so, issue the following commands:
        # cd /usr/src                                                                 
        # mv linux linux.old   # Only if the linux directory already exists           
        # mv linux-2.4 linux-2.4.old                                                  
        # ln -s /opt/timesys/linux/4.1/x86bsp/src/2.4.21-timesys-4.1/kernel linux     
        # ln -s /opt/timesys/linux/4.1/x86bsp/src/2.4.21-timesys-4.1/kernel linux-2.4 

  Note that in the above commands, you may need to change x86bsp and the
version numbers as needed for the TimeSys Linux package that you downloaded.

5. Configure the kernel

  You are now ready to compile the TimeSys Linux kernel. Begin by executing
these commands:
        # cd linux                                                           
        # make menuconfig                                                    

  Note that you cannot skip the above step and edit the .config file
yourself. Running the configuration utility and saving your changes generates
files that are necessary for compiling the kernel.

  If you had performed a clean install of Red Hat Linux 9, then most likely
you don't need to change any of the configuration options that appear.
However, if you have any strange hardware or just want to perform a "sanity
check", you should walk through the menus and enable whatever drivers and
options you need. For instance, you may need to add Ethernet drivers for
whatever network card you have. If you are installing to a laptop, don't
forget to enable General Setup --> PCMCIA/CardBus Support before going to the
Network device support page so that you can see the PCMCIA Ethernet drivers.
If you have a USB keyboard or mouse, be sure USB devices are enabled. You
should also make sure that Block Devices --> Loopback device support is
enabled. And it wouldn't hurt to check other likely prerequisites, such as 
Networking options --> IP: DHCP support.

  When you are satisfied with the configuration, exit and save.

6. Compile the kernel

  The next step is to compile TimeSys Linux:
        # make dep                                                           
        # make bzImage [3]                                                   
        # make modules                                                       
        # make modules_install                                               
        # make install                                                       

  The make install should have put the kernel into /boot and even added a 
TimeSys entry into GRUB for you. If you want the new kernel to boot by
default, edit /etc/grub.conf and change the default line to the appropriate
zero-based index corresponding to the TimeSys kernel entry. (This will
probably be 0).

7. Prepare for rebooting

  At this point, the kernel is prepped and ready, but if you reboot now, your
system won't come back up due to device file system errors. The problem is
that TimeSys Linux depends on the devfs file system.

  To solve this problem, install [
linux/daemons/devfsd/devfsd-v1.3.25.tar.gzdevfsd] devfsd from [http://] Richard Gooch's site. Extract the tar
file, then copy it to /usr/src/redhat/SOURCES/. Switch to the directory where
the file extracted to, then run:
        # rpmbuild -ba rpm.spec [4]                                          

  This should build the devfs package and place it in /usr/src/redhat/RPMS/
i386/. You can then install this RPM by typing:
        # rpm -Uvh /usr/src/redhat/RPMS/i386/devfsd-1.3.25-1.i386.rpm        

  Normally, you would now need to add the line /sbin/devfsd /dev into /etc/
rc.d/rc.sysinit, but Red Hat Linux 9 should already have done this for you
during installation.

8. Rebooting

  Congratulations! You're done! You can now reboot into the TimeSys Linux/GPL

9. Further Information

  Here are some web sites related to TimeSys Linux that you may find useful:

��*�[] TimeSys Linux/GPL on
    SourceForge ?? an independent project that hosts TimeSys Linux/GPL
��*�[] Review of TimeSys Linux/RT by
    Linux Journal ?? a brief look at the RT version (not GPL) of TimeSys


[1]  Other Linux distributions are compatible with TimeSys Linux, but I find 
     that RHL9 is the most TimeSys-friendly.                                 
[2]  Other versions should work, of course, but this is the one I tested.    
     Note, too, that TimeSys may occasionally update its kernel with security
     fixes, so obtaining the most recent build is recommended.               
[3]  If you get errors about not finding i586-linux-gcc, edit the Makefile   
     and comment out the line about CROSS_COMPILE.                           
[4]  If your system can't find rpmbuild, you may need to install the         
     rpm-build package first.                                                

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