Background Requirements for Linux on a
This chapter describes the base hardware and software requirements
for enabling Linux on the JavaStation
Complete Hardware Requirements
For hardware, you will need one or more JavaStation
clients and a server to feed it its Linux
image from, all networked on the same net segment.
This server you use can be any server which supports DHCP
and TFTP, and RARP. These are the
base protocols needed to perform a network boot of the
JavaStations. You may also need NFS
service as well, but it is not necessary in one type of configuration
this HOWTO describes. Also, you can get by without RARP
on both the Krups and Espresso
This document will describe how to set up serving the network
Linux OS image to the JavaStation
from a Sun server running SparcLinux. While you
do not need a Sun server to serve your Linux
image off of, a Sun SparcLinux server is recommended
should you wish to compile a kernel of your own, or prototype a new
filesystem for your JavaStations to use.
Otherwise, you will need to use prepackaged kernels and filesystems
somebody else has pre-built and made publicly available for use.
(You might also use a cross-compiler to produce the kernel images,
but prototyping a filesystem is best done on a Sun SparcLinux server.)
Reports of successful boot servers used include Sun boxes running
Sparclinux, Sun boxes running Solaris, and PCs running MS Windows.
It is only when you are building a new kernel or filesystem that a
Sun box running Linux becomes valuable.
Your network can be a simple 10 Mbps ethernet
LAN, but when you begin using more than 50
JavaStations at once, a switched
100 Mbps network becomes desirable for your server to handle
multiple concurrent boot requests.
This HOWTO includes pointers to example kernels, filesystems and a
complete out-of-the-box solution for you to use, eliminating your need for
a Linux/SPARC server, but you still need a server of
some type to feed the image to the JavaStations as
Network Service Requirements
As discussed in the last section, the JavaStation
boot cycle will make use of DHCP and TFTP
with possibly NFS and RARP. To
understand why, read up on the JavaStation boot
sequence in the next section.
Understand the JavaStation Boot Sequence
The JavaStations follow a typical
diskless workstation boot sequence.
When powered on, the JavaStation sends out a
broadcast request for its IP. It gets its IP
info via RARP or DHCP.
With a DHCP response, it gets information about the
network it is on and where to go download its boot image from via
There are subtle variations in diskless boots from one diskless machine to
the next. For instance, BOOTP may sometimes be
substituted where DHCP is, and RARP
may be eliminated in favor of either of the two. But in general, the
sequence is typically the same between the client and the server:
Who am I?
You are xxx
Where do I go for my boot image?
You go here.
Give me my image from here...Please?
Here's your image.
After the kernel is finished loading, your diskless client typically mounts
its root filesystem from the network via NFS.
Alternatively, it may load and mount it from a RAMdisk.
The original JavaOS and Hotjava Views environment, when run on a JavaStation,
required the setup and maintenance of the core services above, plus
also NIS, HTTP, DNS, POP, and NTP servers. If setting up a JavaStation boot
server seems like a lot of work, imagine adding these extra services
into the mix too.
Additional Software Requirements: Replacement Firmware
JavaStations came with two different
PROMs installed in them. Version 2.30 shipped with
the earliest Mr. Coffee models, and was
updated by latter versions of the Sun Netra J
software environment to 3.11. Krups and
Espresso came with 3.x versions of the
PROM by default.
It turns out the later 3.x series of PROMs is not
conducive to booting Linux upon.
Fortunately, a complete PROM replacement
called PROLL now exists to get by this limitation.
PROLL becomes the first image your
JavaStation grabs by TFTP. It then
will load your true kernel image and boot into Linux
No matter what PROM revision you have, get
PROLL. This can make troubleshooting new installs easier.
The current, master version of PROLL is available
The current version at the time of this writing is
PROLL can also be found mirrored on
, and also on this HOWTO's distribution site at:
(HOWTO website mirror - version 14)
Decide on your Filesystem-type: NFS-Root, or
Before you begin, you must decide upon the root-filesystem type you wish to
use for your diskless JavaStation. There are
In this setup, after the boot kernel is retrieved off the network, the
running JavaStation makes an NFS
connection for its root filesystem. The root directory
mounted off the network for the duration of the current session.
NFS-Root solution is the recommended
way to go for beginners, as it is easier to troubleshoot if there are
problems. It also makes it easier to prototype the proper filesystem,
as any changes you make on a running system can be propogated for the
next boot cycle (so long as you are in read-write mode, of course).
Drawbacks of this type of system is increased network activity as the
running JavaStations locate and execute files, plus file organization
in large environments.
In this setup, the root filesystem is loaded directly into RAM
and accessed from there.
The advantage of this setup is that there is no NFS
traffic to worry about, resulting in a clean solution.
The disadvantage of this configuration is that you can no longer do rapid
prototyping of your filesystem, as any changes you make to a running system
are lost. If you have no
NFS-Root setup available, you
develop an embedded filesystem by making small tweaks and performing
reboots to test. Other disadvantages include the requirement of fitting
the full filesystem in available RAM; due to a limitation of PROLL, this
requirement is much lower on JavaStations than expected. Still, embedded
root is the way to go for the cleanest environment.
First time users will want to set up an
configuration. When you have things stabilized, move to
Embedded-Root to take use of its advantages.
Support Sites to Check Out: Zaitcev's Linux Site
One website to keep on reference when you begin thinking about
putting Linux on your JavaStation is kernel hacker Pete Zaitcev's
throughout this document as the
ZLS site (short for
"Zaitcev's Linux Site"). Here you will find the latest version of
PROLL and many low-level details about dealing with the JavaStations.
Many items on the ZLS have been merged into this document, but not all.
Oct. 2001 update: It is in your best interest to review all the information
on Pete's site, in this document, and references pointed to, before diving
in and setting up your JavaStation with Linux. Almost all questions people
have had in setting up their systems are covered in the materials presented.