Diskless Nodes HOW-TO document for Linux

Diskless Nodes HOW-TO document for Linux
Robert Nemkin [email protected] , Al Dev (Alavoor
Vasudevan) - Maintainer of this HOWTO [email protected] ,
Markus Gutschke [email protected] , Ken Yap
[email protected] , Gero Kuhlmann [email protected]
v18.0, 25 Jan 2001

This document describes how to set up a diskless Linux box. As tech�
nology is advancing rapidly, network-cards are becoming cheaper and
much faster - 100 MBits ethernet is standard now and in about 1 to 2
years 1000 MBits i.e. 1GigBits ethernet cards will become an industry
standard. With high-speed network cards, remote access will become as
fast as the local disk access which will make diskless nodes a viable
alternative to workstations in local LAN. Also diskless nodes elimi�
nates the cost of software upgrades and system administration costs
like backup, recovery which will be centralized on the server side.
Diskless nodes also enable "sharing/optimization" of centralised
server CPU, memory, hard-disk, tape and cdrom resources. Diskless
nodes provides mobility for the users i.e., users can log on from any
one of diskless nodes and are not tied to one workstation. Diskless
Linux box completely eliminates the need for local floppy disk, cdrom
drive, tape drive and hard-disk. Diskless nodes JUST has a network
card, 8MB RAM, a low-end cpu and a very simple mother-board which does
not have any interface sockets/slots for harddisks, modem, cdrom,
floppy etc.. With Diskless linux nodes you can run programs on remote
Linux 64 CPU SMP box or even on Linux super-computer! Diskless nodes
lowers the "Total Cost of Ownership" of the computer system. This
document is copy�righted by Robert Nemkin and other authors as listed
above. Copyright policy is GPL. Thanks to Bela Kis bkis@car�
tan.math.klte.hu for translating this initial document v0.0.3 (which
was a mini-howto) to English.
______________________________________________________________________

Table of Contents

1. Buying is cheaper than building!

2. Diskless Computer for Microsoft Windows 95/NT !!

2.1 VMWare package
2.2 VNC package from AT and T

3. Advantages of Diskless Computer

4. Quick Steps to implement Diskless Nodes

4.1 Linux Terminal Server Project - LTSP

5. Building EEPROM Burner

5.1 What is this ?
5.2 Construction
5.3 Parts List
5.4 Usage
5.5 Schematic Diagram

6. EPROM Burners and Memory chips

6.1 Non-Volatile Memory chips
6.2 List of EEPROM Burner manufacturers

7. Introduction to Network Booting and Etherboot

7.1 What is Network booting?
7.2 How does it work
7.3 Netbooting in Practice
7.3.1 Bootp
7.3.2 Tftp
7.3.3 NFS root filesystem
7.3.4 Burn EPROM
7.4 Uses of Network booting
7.5 For more information

8. Redhat Linux configuration

8.1 X-terminal

9. LanWorks BootWare PROMs

10. Etherboot

11. Netboot

11.1 Introduction
11.2 Mailing list
11.3 Netboot useful links

12. Related URLs

13. Copyright Notice

14. Other Formats of this Document

15. Topics for Academics and Universities

______________________________________________________________________

1. Buying is cheaper than building!

Sometimes, buying a diskless linux computer will be cheaper than
building!! Checkout the following commercial sites, which are selling
diskless linux network-cards and diskless computers. These companies
do mass production of Linux Diskless computers selling millions of
units and thereby reducing the cost per unit. Each and every fortune
1000 companies in USA will be replacing the MS Windows PCs with
diskless computers in near future as diskless linux computers can run
both Linux and MS Windows 95 programs (via VMWare BIOS software).
VMWare <http://www.vmware.com> is NOT a emulator but has BIOS which
allows you to install Windows 98/NT as guest OS to linux. You can use
the 'xhost' command and DISPLAY environment from diskless node to run
Windows95/Linux programs. See 'man xhost' on linux. You can also use
Virtual Network Computing (VNC) to run Windows95/NT programs on linux
diskless nodes. Get VNC from <http://www.uk.research.att.com/vnc>

� Linux Systems Labs Inc., USA <http://www.lsl.com> Click on "Shop
On-line" and than click on "HardWare" where all the Diskless
computers will be listed. Phone 1-888-LINUX-88.

� Diskless Workstations Corporation, USA
<http://www.disklessworkstations.com>

� Unique Systems of Holland Inc., Ohio, USA <http://www.uniqsys.com>

Even if you buy diskless linux computer, you may be very much
interested in reading this entire document.

2. Diskless Computer for Microsoft Windows 95/NT !!

Since Microsoft Windows 95/NT DOES NOT support diskless nodes, there
is an intelligent work-around to overcome this short coming.
Microsoft corporation will be surprised !!

2.1. VMWare package

Use the VMWare <http://www.vmware.com> BIOS software with Linux which
can host the Windows 95/98/NT. Linux will be the "host" OS and
Windows 95/NT will be the "guest" OS. VMWare <http://www.vmware.com>
is NOT a emulator but has BIOS which allows you to install Windows
95/98/NT as the guest OS to linux. Install the VMWare on Linux server
and than install Windows 95/NT on VMWare.

You can use the 'xhost' command and DISPLAY environment from any
diskless node. See 'man xhost' on linux. At diskless node give -

______________________________________________________________________
export DISPLAY=server_hostname:0.0
where server_hostname is the name of the server machine. And start X-terminal with
xterm
______________________________________________________________________

Using VMWare <http://www.vmware.com>, Diskless linux computers can run
both Linux and MS Windows 95 programs. VMWare is at
<http://www.vmware.com>.

2.2. VNC package from AT and T

You can also use the VNC (Virtual Network Computing) Technology from
the telecom giant AT & T. VNC is GPLed and is a free software. Using
VNC you can run Windows 95/NT programs on diskless linux computer but
actually running on remote Windows95/NT server. VNC is at
<http://www.uk.research.att.com/vnc>

3. Advantages of Diskless Computer

Diskless linux computer will become immensely popular and will be the
product of this century and in the next century. The diskless linux
computers will be very successful because of the availability of very
high-speed network cards at very low prices. Today 100 Megabit per
second (12.5 MB per sec transfer rate) network cards are common and in
about 1 to 2 years 1000 MBit (125 MB per sec transfer rate) network
cards will become very cheap and will be the standard.

In near future, Monitor manufacturers will place the CPU, NIC, RAM
right inside the monitor to form a diskless computer!! This
eliminates the diskless computer box and saves space. The monitor will
have outlet for mouse, keyboard, network RJ45 and power supply.

The following are benefits of using diskless computers -

� Diskless Linux computers can run BOTH MS Windows 95/NT and linux
programs.

� Total cost of ownership is very low in case of Diskless computers.
Total cost of ownership is cost of initial purchasing + cost of
maintainence. The cost of maintainence is usually 3 to 5 times the
cost of initial computer purchase and this cost is recurring year
after year. In case of Diskless computers, the cost of
maintainence is completely eliminated!!

� All the backups are centralized at one single main server.

� More security of data as it is located at server.

� No need of UPS battery, air-conditioning, dust proof environment
for diskless clients, only server needs UPS battery, A/C and dust
proof environment.

� Noise is completely eliminated since diskless computer does not
have Fan motor, and local harddisk. Only server makes lots of noise
but it is enclosed in a server room.

� Protection from Virus attack - Computer virus cannot attack
diskless computers as they do not have any hard disk. Virus cannot
do any damage to diskless computers. Only one single server box
need to be protected against virus attack. This saves millions of
dollars for the company by avoiding installtion of vaccines and
cleaning the hard disks!!

� Server can have large powerful/high performance hard disks, can
optimize the usage of disk space via sharing by many diskless
computer users. Fault tolerance of hard disk failure is possible
by using RAID on main server.

� Server can have 64 bit CPU SMP box having many CPUs or even linux
super-computers. CPU power can be shared by many diskless computer
users

� Sharing of central server RAM memory by many diskless computer
users. For example, if many users are using web browser than at
server RAM there will be only one copy of web browser in the RAM.
In case Windows 95 PCs, many users need to have individual copy of
web browser in local RAM and hence there is wastage of RAM space.

� Diskless computers are extremely fast because program loading time
is completely eliminated. For example, if the server loads the
StarOffice suite into memory due to request from one diskless user
then if another diskless user wants to use the StarOffice suite
then loading time is avoided since StarOffice is already loaded.

� Diskless linux computers can run programs on multiple servers using
the "xhost" and DISPLAY environment.

� Very few system administrators required to maitain central server
unlike Windows 95 PC clients which need many administrators.

� Zero administration at diskless client side. Diskless computers are
absolutely maintainence free and troublefree.

� Long life of diskless clients - more than 300 years without any
hardware or software upgrades.

� Eliminates install/upgrade of hardware, software on diskless client
side.

� Eliminates cost of cdrom, floppy, tape drive, modem, UPS battery,
Printer parallel ports, serial ports etc..

� Can operate in places like factory floor where a hard disk might be
too fragile.

4. Quick Steps to implement Diskless Nodes

An overview to build diskless nodes is as follows:

� Download/Install redhat RPM packages from LTSP org
<http://www.ltsp.org>

� Test with floppy disk (1.44MB) having the PROM program.

� Next you have to make the Network card which has the bootable prom

� Either purchase NIC ready with prom or

� Purchase the eproms

� (or) Purchase Eprom burner to burn your own eproms. Transfer the
tested program from floppy to prom via eprom burner

� Visit <http://www.disklessworkstations.com> to buy eprom burners
and see also ``List of EPROM Burner'' manufacturers, ``Build EEPROM
burner''

4.1. Linux Terminal Server Project - LTSP

LTSP is an open source code project to build diskless linux computers.

At LTSP site you will find RPM packages for Redhat Linux and packages
for Debian Linux which will save you lots of time. The subsequent
chapters given in this document are for academic purposes only, which
you can read them if you have more time.

Visit the LTSP and related sites at :-

� <http://www.ltsp.org>

� <http://www.disklessworkstations.com>

� <http://www.slug.org.au/etherboot>

� <http://metalab.unc.edu/Linux/HOWTO/XFree86-Video-Timings-
HOWTO.html>

Related topics worth seeing -

� NCD X-terminal <http://www.linuxdoc.org/HOWTO/mini/NCD-X-
Terminal.html>

5. Building EEPROM Burner

5.1. What is this ?

This chapter is written by Abhijit Dasgupta and is reproduced here
from <http://www.nnaf.net/~abhijit/eep>. Abhijit's email :
[email protected]

A photo of the burner is at -
<http://www.nnaf.net/~abhijit/pictures/eeprom-burner.jpg>

This is an eeprom burner for the 2816/2864 type of eeproms. There are
various designs available, but the main goal was to have something
which

� is cheap (less than $35)

� is easy to build and uses only commonly available parts

� works with linux

This one uses a handful of 74HCTxx logic chips all available at the
local Radio Shack store! It uses the PC parallel port interface, and
Abhijit wrote the driver code for Linux only, but it should be easy to
modify it for other PC operating systems.

This was used to burn netboot PROMs for ethernet cards, which were
used to make diskless linux boxes. See the netboot/etherboot packages
for details of how to do that. You can also use it for building
microcontroller systems with external ROM (e.g. 8031).

5.2. Construction

WARNING: It is easy to destroy the parallel port of your PC by
connecting things to it. It is also possible to damage or destroy the
whole PC, its attachments, peripherals, and people near it by improper
connections and electrical accidents. USE EXTREME CAUTION.

Disclaimer: Use at your own risk. There is absolutely no warranty of
any kind here.
The programmer can be built on a breadboard, but use a protoboard for
a more permanent version. Use 0.1uF power-bus bypass capacitors
generously. The 5V power source can be obtained from the PC itself,
but be careful here.

5.3. Parts List

� ICs: 74HCT123, 74HCT132, 74HCT138, 74HCT157, 74HCT574 (1
ea), and 2 74HCT259s.

� Resistors: 100K, 10K, 1K, and 390 ohms (1 ea).

� Capacitors: 100pF, 1uF, (1 ea) and 3 0.1uF power-bus bypass
capacitors.

� Misc: 1 LED, 1 SPST switch, 25-conductor ribbon cable with
DB25 male connector, 28 pin ZIF socket (small breadboard can be
used instead), jumper pins.

5.4. Usage

Download the software from
<http://www.nnaf.net/~abhijit/eep/eeprom.tar.gz>. To build the
software, just cd to the src directory and type `make';

______________________________________________________________________
readrom
-------
readrom will read a specified number of bytes from a 2816/2864 eeprom
starting at a given offset, and send it to the standard output in
either binary (raw) or ascii-hex listing format.

Usage:

readrom -b|-t offset size

where

-b output binary (raw) bytes
-t output text (ascii-hex) listing
offset start address of eeprom, 0..8191
size number of bytes to output, 0..8192

Examples:

# read the contents of a 2864 in binary (raw) form and save it in a file:
readrom -b 0 8192 > contents.bin

# list 80 bytes starting at offset 32:
readrom -t 32 80

writerom
--------

writerom will read a given number of bytes from the standard input and
write them into a 2816/2864 eeprom starting at a specified offset.
writerom verifies the eeprom byte-by-byte as it writes into it.

Usage:

writerom offset size

where

offset start address of eeprom, 0..8191
size number of bytes to output, 0..8192

Example:

# Write 8192 bytes from the file ne.lzrom into the eeprom:
writerom 0 8192 < ne.lzrom
______________________________________________________________________

5.5. Schematic Diagram

The schematic is in ascii, but a PostScript version which looks better
is available from
<http://www.nnaf.net/~abhijit/eep/eeprom/schematic.ps>

______________________________________________________________________
+-------+
+5-------|RST | +5---o o o J1 +-----------+
+5--o----|/CLR1 | 10K | | |
| | |-----o--/VVV\-- +5 +----------|26 +5(NC) |
+------+ | |1/2 123| | +----------->|27 NC(/WE) |
16 o-|/CS2 | | | |--||-+ | +--------->|23 /WE(A11)|
| CS1|----o----|B1 | 100pF | | | |
| | | /Q1|---------->---------o o o J2 | ZIF28 |
| Y1|---------|/A1 | | | socket |
| 138 | +-------+ _ 1/2 74HCT132 | | for |
| | +5 --| \ __ | | 2816(2864)|
| Y2|--------------------------| O--| \ | | |
8 o-|A2 | +-------+ |_/ | O-------------->|/OE |
7 o-|A1 Y4|--------------->|EN Y7|-----o-|_/ | | |
6 o-|A0 Y3|----+ +5-----|RST | | | | |
| Y0|-+ | | Y6|--+ | | | |
| /CS3| | | | 259 | | | | | |
+------+ | | | Y4|--|--|-----------|------->|2 NC(A12) |
| | | | Y3|--|--|-----------+ | |
5 o--->---|--|--|--------o--|D Y2|--|--|------------------->|A10 |
4 o--->---|--|--|------o-|--|A2 Y1|--|--|------------------->|A9 |
3 o--->---|--|--|----o-|-|--|A1 Y0|--|--|------------------->|A8 |
2 o--->---|--|--|--o-|-|-|--|A0 | | | | |
| | | | | | | +-------+ | | +5------------|28 NC(+5) |
| | | | | | | | | +5----/VVV\---|1 NC(RDY) |
| | | | | | | +-------+ | | 1K | |
| | | | | | | | Y7|--|--|------------o------>|A7 |
| | +---------->|EN |--|--|-----------o|------>| |
| | | | | | | |--|--|----------o||------>| |
| | | | | | | 259 |--|--|---------o|||------>| |
| | | | | | | |--|--|--------o||||------>| |
| | | | | | | |--|--|-------o|||||------>| |
| | | | | +--|D |--|--|------o||||||------>| |
| | | | +----|A2 Y0|--|--|-----o|||||||------>|A0 |
| | | +------|A1 | | | |||||||| | |
| | +--------|A0 RST| | | |||||||| | ZIF28 |
| | +-------+ | | +------------+ | for |
| | | | | | data in | | 2816/64 |
| | +5 | +-->|/OE | | |
| | | | 574 | | |
| +------------------------------->|CLK | | |
| | | data out | | |
| V +------------+ | |
+----+ +------------+ |||||||| | |
| | SEL | |||||||| | |
| | B3|<----|||||||o------|D7 |
11 o---<-----------------------|Y3 B2|<----||||||o-------| |
12 o---<-----------------------|Y2 B1|<----|||||o--------| |
13 o---<-----------------------|Y1 157 B0|<----||||o---------| |
15 o---<-----------------------|Y0 A3|<----|||o----------| |
| | A2|<----||o--- data---| |
| | A1|<----|o---- bus ---| |
| GND----|/OE A0|<----o-------------|D0 |
+5--o--+ | +------------+ | |
| | __ o---------------------------------------------->|/CE |
100K +-| \ | __ +-----------+
sw1 | | O-o-| \ 1/2 74HCT132
o-->o----|__/ | O---390ohm--+
| | +-|__/ |
| --- 1uF | LED
| --- +5--+ |
| | |
+---o----------------------------o- GND
______________________________________________________________________

Notes:

1. Pin numbers on the left margin are for DB25 parallel port.

2. Pin numbers in the right box are for the _ZIF28 socket_, not the
IC.

3. A 2816 should be low-justified in the ZIF28 socket.

4. J1 and J2 are single-row 3-pin jumpers. For both jumpers, the left
two pins should be jumpered for a 2816, the right two for a 2864.

5. The signal labels for a 2864 (if different from 2816) in the ZIF28
socket box are given in parentheses. E.g. pin 23 of the ZIF 28 is
labeled "23 /WE(A11)", so it is /WE for a 2816, and A11 for a 2864.

6. Sw1 needs to be open to enable operation of the programmer.

6. EPROM Burners and Memory chips

Below is the information about EPROM and various types of memory
chips.

6.1. Non-Volatile Memory chips

Here is the brief descriptions of memory chips and their types.

� PROM: Pronounced prom, an acronym for programmable read-only
memory. A PROM is a memory chip on which data can be written only
once. Once a program has been written onto a PROM, it remains there
forever. Unlike RAM, PROMs retain their contents when the computer
is turned off. The difference between a PROM and a ROM (read-only
memory) is that a PROM is manufactured as blank memory, whereas a
ROM is programmed during the manufacturing process. To write data
onto a PROM chip, you need a special device called a PROM
programmer or PROM burner. The process of programming a PROM is
sometimes called burning the PROM. An EPROM (erasable programmable
read-only memory) is a special type of PROM that can be erased by
exposing it to ultraviolet light. Once it is erased, it can be
reprogrammed. An EEPROM is similar to a PROM, but requires only
electricity to be erased.

� EPROM: Acronym for erasable programmable read-only memory, and
pronounced e-prom, EPROM is a special type of memory that retains
its contents until it is exposed to ultraviolet light. The
ultraviolet light clears its contents, making it possible to
reprogram the memory. To write to and erase an EPROM, you need a
special device called a PROM programmer or PROM burner. An EPROM
differs from a PROM in that a PROM can be written to only once and
cannot be erased. EPROMs are used widely in personal computers
because they enable the manufacturer to change the contents of the
PROM before the computer is actually shipped. This means that bugs
can be removed and new versions installed shortly before delivery.

A note on EPROM technology: The bits of an EPROM are programmed by
injecting electrons with an elevated voltage into the floating gate
of a field-effect transistor where a 0 bit is desired. The
electrons trapped there cause that transistor to conduct, reading
as 0. To erase the EPROM, the trapped electrons are given enough
energy to escape the floating gate by bombarding the chip with
ultraviolet radiation through the quartz window. To prevent slow
erasure over a period of years from sunlight and fluorescent
lights, this quartz window is covered with an opaque label in
normal use.

� EEPROM: Acronym for electrically erasable programmable read-only
memory. Pronounced double-e-prom or e-e-prom, an EEPROM is a
special type of PROM that can be erased by exposing it to an
electrical charge. Like other types of PROM, EEPROM retains its
contents even when the power is turned off. Also like other types
of ROM, EEPROM is not as fast as RAM. EEPROM is similar to flash
memory (sometimes called flash EEPROM). The principal difference is
that EEPROM requires data to be written or erased one byte at a
time whereas flash memory allows data to be written or erased in
blocks. This makes flash memory faster.

� FRAM: Short for Ferroelectric Random Access Memory, a type of non-
volatile memory developed by Ramtron International Corporation.
FRAM combines the access speed of DRAM and SRAM with the non-
volatility of ROM. Because of its high speed, it is replacing
EEPROM in many devices. The term FRAM itself is a trademark of
Ramtron.

� NVRAM: Abbreviation of Non-Volatile Random Access Memory, a type of
memory that retains its contents when power is turned off. One type
of NVRAM is SRAM that is made non-volatile by connecting it to a
constant power source such as a battery. Another type of NVRAM uses
EEPROM chips to save its contents when power is turned off. In this
case, NVRAM is composed of a combination of SRAM and EEPROM chips.

� Bubble Memory: A type of non-volatile memory composed of a thin
layer of material that can be easily magnetized in only one
direction. When a magnetic field is applied to circular area of
this substance that is not magnetized in the same direction, the
area is reduced to a smaller circle, or bubble. It was once widely
believed that bubble memory would become one of the leading memory
technologies, but these promises have not been fulfilled. Other
non-volatile memory types, such as EEPROM, are both faster and less
expensive than bubble memory.

� Flash Memory: A special type of EEPROM that can be erased and
reprogrammed in blocks instead of one byte at a time. Many modern
PCs have their BIOS stored on a flash memory chip so that it can
easily be updated if necessary. Such a BIOS is sometimes called a
flash BIOS. Flash memory is also popular in modems because it
enables the modem manufacturer to support new protocols as they
become standardized.

6.2. List of EEPROM Burner manufacturers

For a list of EPROM burner manufacturers visit the Yahoo site and go
to economy->company->Hardware->Peripherals->Device programmers.

� Yahoo URL for EPROMs is at
<http://dir.yahoo.com/Business_and_Economy/Companies/Computers/Hardware/Peripherals/Device_Programmers/>

� Advanced Research Technology B.V <http://www.artbv.nl/ > -
development, production and sales of electronic programmer
equipment; development of hardware and software.

� Advin Systems Inc. <http://www.advin.com > - PC-based device
programmers that support the latest in package types and device
technologies.

� Andromeda Research Labs <http://www.arlabs.com > - manufactures a
portable eprom and device programming system.

� B and C Microsystems, Inc <http://www.bcmicro.com/> - offers test
and duplication/programming equipment for PCMCIA (PC) Cards,
ISA/PCI Cards, SIMMs, Memory Devices (including FLASH), PLDs.
� BP Microsystems <http://www.bpmicro.com/ > - Device Programmers.

� Bytek <http://www.bytek.com > - designs, develops, manufactures and
markets micro-processor-based, modular electronic systems used to
program and test semiconductor devices. Product line includes the
ChipBurner.

� Concentrated Programming Ltd <http://www.logicaldevices.com/ > -
offers a full range of device programming solutions.

� Dataman Programmmers Ltd. <http://www.dataman.com/ > - manufacture
of hand-help EPROM programmer/emulator. Also sell PC-based
programmers, and Gang-Pro programmers.

� General Device Instruments <http://www.generaldevice.com/ > - IC
Device programmers. Universal and Gang programmers for Pld, Flash,
microcontrollers, Proms, EEproms, Memory, Epld, Mach and many other
ic devices.

� HI-LO System Research Co., Ltd. <http://hilosystems.com.tw > -
manufacturer of universal and gang device programmers.

� ICE Technology <http://www.icetech.com/ > - EPROM and universal
device programmers which support memories, microcontrollers, and
programmable logic devices.

� Iceprom <http://www.inabyte.com/iceprom.html > - in-circuit
erasable programmable read-only memory.

� Incept Ltd. <http://www.incept.ie >

� International Microsystems Inc <http://www.imtest.com > - High
speed reliable gang programmer. (PROM, FLASH, Microcontroller,
PCMCIA memory card).

� JED Microprocessors Pty. Ltd. <http://www.jedmicro.com.au > - plugs
into a PC printer port D25 connector, and programs any 28-pin or
32-pin EPROM and FLASH device.

� Logical Devices, Inc <http://www.logicaldevices.com > - device
programming for PLDs, FPGAs, PROMs, microcontrollers. Producers of
CUPL compiler for programmable logic and the ALLPRO and Chipmaster
device programmer.

� MCL Systems <http://www.mcl.dk > - new method not only for
programming but also for developing your new hardware with
Integrated Controller Unit. And you don't need to be an expert.

� MQP Electronics <http://www.mqp.com > - manufacturer of universal
device programmers, gang programmers, production software, and
package converters. High thoughput and reliability.

� Needham's Electronics <http://www.needhams.com> - manufacturer of
device programmers.

� NP Programming Services <http://www.npps.com/ > - provides
programming for memory and logic parts.

� Program Automation, Inc. <http://www.progauto.com > - independent
service company specializing in high volume PROM programming,
including flash I/Cs.

� Stag Programmers Inc <http://www.stagusa.com > - manufacturer of
prom and logic programmers, production handling equipment and UV
erasers.

� Sunrise Electronics <http://www.sunriseelectronics.com > -
universal device programmers, gang and in-circuit programmers with
life time support.

� System General Co. <http://www.sg.com.tw > - Device Programmer,
EPROM Writer and IC Tester

� Tribal Microsystems <http://www.tribalmicro.com > - universal and
gang device programmers, 8051 and EPROM emulators, test and burn-in
sockets and production sockets.

� Universal Device Programmers <http://www.xeltek.com/ >

7. Introduction to Network Booting and Etherboot

This chapter is written by Ken Yap [email protected] and explains how to
bootstrap your computer from a program stored in non-volatile memory
without accessing your hard disk. It is an ideal technique for
maintaining and configuring a farm of linux boxes.

7.1. What is Network booting?

Network booting is an old idea. The central idea is that the computer
has some bootstrap code in non-volatile memory, e.g. a ROM chip, that
will allow it to contact a server and obtain system files over a
network link.

7.2. How does it work

In order to boot over the network, the computer must get

1. an identity

2. an operating system image and

3. usually, a working filesystem.

Consider a diskless computer (DC) that has a network boot ROM. It may
be one of several identical DCs. How can we distinguish this computer
from others? There is one piece of information that is unique to that
computer (actually its network adapter) and that is its Ethernet
address. Every Ethernet adapter in the world has an unique 48 bit
Ethernet address because every Ethernet hardware manufacturer has been
assigned blocks of addresses. By convention these addresses are
written as hex digits with colons separating each group of two digits,
for example - 00:60:08:C7:A3:D8 .

The protocols used for obtaining an IP address, given an Ethernet
address, are called Boot Protocol (BOOTP) and Dynamic Host
Configuration Protocol (DHCP). DHCP is an evolution of BOOTP. In our
discussion, unless otherwise stated, anything that applies to BOOTP
also applies to DHCP. (Actually it's a small lie that BOOTP and DHCP
only translate Ethernet addresses. In their foresight, the designers
made provision for BOOTP and DHCP to work with any kind of hardware
address. But Ethernet is what most people will be using.)

An example of a BOOTP exchange goes like this:

DC: Hello, my hardware address is 00:60:08:C7:A3:D8, please give me my
IP address.

BOOTP server: (Looks up address in database.) Your name is aldebaran,
your IP address is 192.168.1.100, your server is 192.168.1.1, the file
you are supposed to boot from is /tftpboot/vmlinux.nb (and a few other
pieces of information).

You may wonder how the DC found the address of the BOOTP server in the
first place. The answer is that it didn't. The BOOTP request was
broadcast on the local network and any BOOTP server that can answer
the request will.

After obtaining an IP address, the DC must download an operating
system image and execute it. Another Internet protocol is used here,
called Trivial File Transfer Protocol (TFTP). TFTP is like a cut-down
version of FTP---there is no authentication, and it runs over User
Datagram Protocol (UDP) instead of Transmission Control Protocol
(TCP). UDP was chosen instead of TCP for simplicity. The
implementation of UDP on the DC can be small so the code is easy to
fit on a ROM. Because UDP is a block oriented, as opposed to a stream
oriented, protocol, the transfer goes block by block, like this:

DC: Give me block 1 of /tftpboot/vmlinux.nb.
TFTP server: Here it is.
DC: Give me block 2.

and so on, until the whole file is transferred. Handshaking is a
simply acknowledge each block scheme, and packet loss is handled by
retransmit on timeout. When all blocks have been received, the network
boot ROM hands control to the operating system image at the entry
point.

Finally, in order to run an operating system, a root filesystem must
be provided. The protocol used by Linux and other Unixes is normally
Network File System (NFS), although other choices are possible. In
this case the code does not have to reside in the ROM but can be part
of the operating system we just downloaded. However the operating
system must be capable of running with a root filesystem that is a
NFS, instead of a real disk. Linux has the required configuration
variables to build a version that can do so.

7.3. Netbooting in Practice

Net Loader is a small program that runs as a BIOS extension, usually
on an EPROM on the NIC. It handles the BOOTP query and TFTP loading
and then transfers control to the loaded image. It uses TCP/IP
protocols but the loaded image doesn't have to be Linux. The loaded
image can be anything, even DOS. They can also be loaded from a
floppy for testing and for temporary setups.

Besides commercial boot ROMs, there are TWO sources for free packages
for network booting. Free implementations of TCP/IP net loaders are -

1. ETHERBOOT <http://www.slug.org.au/etherboot/> and

2. NETBOOT <http://www.han.de/~gero/netboot.html>

Etherboot uses built-in drivers while Netboot uses Packet drivers.
First you have to ascertain that your network card is supported by
Etherboot or Netboot. Eventually you have to find a person who is
willing to put the code on an EPROM (Erasable Programmable Read Only
Memory) for you but in the beginning you can do network booting from a
floppy.

To create a boot floppy, a special boot block is provided in the
distribution. This small 512 byte program loads the disk blocks
following it on the floppy into memory and starts execution. Thus to
make a boot floppy, one has only to concatenate the boot block with
the Etherboot binary containing the driver for one's network card like
this:

______________________________________________________________________
# cat floppyload.bin 3c509.lzrom > /dev/fd0
______________________________________________________________________

Get the nfsboot package (the package is available from your favourite
linux mirror site in the /pub/Linux/system/Linux-boot directory). It
contains a booteprom image for the network cards (like wd8013) which
can be directly burned in. See also the LTSP site at
<http://www.ltsp.org>

Before you put in the network boot floppy, you have to set up three
services on Linux -

1. BOOTP (or DHCP)

2. TFTP and

3. NFS.

You don't have to set up all three at once, you can do them step by
step, making sure each step works before going on to the next.

7.3.1. Bootp

Install Bootp. See bootp*.rpm on Redhat linux cdrom. See also LTSP
site for RPM packages at <http://www.ltsp.org>. See also unix manual
pages 'man 5 bootptab', 'man 8 bootpd', 'man 8 bootpef', 'man 8
bootptest'. You then have to ensure that this server is waiting for
bootp requests. The daemon can be run either directly by issuing
command

______________________________________________________________________
bootpd -s
______________________________________________________________________

Or by using inetd edit the file /etc/inetd.conf and put a line like
this:

______________________________________________________________________
bootps dgram udp wait root /usr/sbin/in.bootpd bootpd
______________________________________________________________________

Insert or uncomment the following two lines in /etc/services:

______________________________________________________________________
bootps 67/tcp # BOOTP server
tftp 69/udp # TFTP server
______________________________________________________________________

If you had to modify /etc/inetd.conf, then you need to restart inetd
by sending the process a HUP signal.

______________________________________________________________________
kill -HUP <process id of inetd>.
______________________________________________________________________

Next, you need to give bootp a database to map Ethernet addresses to
IP addresses. This database is in /etc/bootptab. You must modify it
by inserting the IP addresses of your gateway, dns server, and the
ethernet address(es) of your diskless machine(s). It contains lines
of the following form:

______________________________________________________________________
aldebaran.foo.com:ha=006008C7A3D8:ip=192.168.1.100:bf=/tftpboot/vmlinuz.nb
______________________________________________________________________

Other information can be specified but we will start simple.

Another example of /etc/bootptab is :

______________________________________________________________________
global.prof:\
:sm=255.255.255.0:\
:ds=192.168.1.5:\
:gw=192.168.1.19:\
:ht=ethernet:\
:bf=linux:
machine1:hd=/export/root/machine1:tc=global.prof:ha=0000c0863d7a:ip=192.168.1.140:
machine2:hd=/export/root/machine2:tc=global.prof:ha=0800110244e1:ip=192.168.1.141:
machine3:hd=/export/root/machine3:tc=global.prof:ha=0800110244de:ip=192.168.1.142:
______________________________________________________________________

global.prof is a general template for host entries, where

� sm field contains the subnet mask

� ds field contains the address of the Domain Name Server

� gw field contains the default gateway address

� ht field contains the lan media hardware type

� bf field contains the name of the boot file

After this, every machine must have a line:

� the first field contains the host name,

� hd field contains the directory of the bootfile,

� the global template can be included with the tc field,

� ha field contains the hardvare address of the ethernet card,

� ip field contains the assigned ip address.

Now boot the DC with the floppy and it should detect your Ethernet
card and broadcast a BOOTP request. If all goes well, the server
should respond to the DC with the information required. Since
/tftpboot/vmlinux.nb doesn't exist yet, it will fail when it tries to
load the file. Now you need to compile a special kernel, one that has
the option for mounting the root filesystem from NFS turned on. You
also need to enable the option to get the IP address of the kernel
from the original BOOTP reply. You also need to compile the Linux
driver for your network adapter into the kernel instead of loading it
as a module. It is possible to download an initial ramdisk so that
module loading works but this is something you can do later.

You cannot install the zImage resulting from the kernel compilation
directly. It has to be turned into a tagged image. A tagged image is a
normal kernel image with a special header that tells the network
bootloader where the bytes go in memory and at what address to start
the program. You use a program called mknbi-linux to create this
tagged image. This utility can be found in the Etherboot distribution.
After you have generated the image, put it in the /tftpboot directory
under the name specified in /etc/bootptab. Make sure to make this file
world readable because the tftp server does not have special
privileges.

7.3.2. Tftp

For TFTP, see tftp*.rpm on Redhat Linux cdrom. TFTP (Trivial File
Transfer Protocol) is a file transfer protocol, such as ftp, but it's
much simpler to help coding it in EPROMs. TFTP can be used in two
ways:

� Simple tftp: means that the client can acces to your whole file
system. It's simpler but it's a big security hole (anyone can get
your password file via tftp).

� Secure tftp: the tftp server uses a chroot.2 system call to change
it's own root directory. Anything outside the new root directory
will be completely inaccessible. Because of the chroot dir becomes
the new root dir, the hd filed in the bootptab must reflect the new
situation. For example: when using insecure tftp, the hd field
contains the full path to the boot directory:
/export/root/machine1. When using secure tftp whith /export as
root dir, then /export becomes / and the hd field must be
/root/machine1.

Tftpd is normally started up from inetd with a line like this in
/etc/inetd.conf.

______________________________________________________________________
tftp dgram udp wait root /usr/sbin/tcpd in.tftpd -s /tftpboot
#tftp dgram udp wait root /usr/sbin/in.tftpd tftpd /export
______________________________________________________________________

Again, restart inetd with a HUP signal and you can retry the boot and
this time it should download the kernel image and start it. You will
find that the boot will continue until the point where it tries to
mount a root filesystem. At this point you must configure and export
NFS partitions to proceed.

7.3.3. NFS root filesystem

For various reasons, it's not a good idea to use the root filesystem
of the server as the root filesystem of the DCs. One is simply that
there are various configuration files there and the DC will get the
wrong information that way. Another is security. It's dangerous to
allow write access (and write access is needed for the root
filesystem, for various reasons) to your server's root. However the
good news is that a root filesystem for the DC is not very large, only
about 30 MB and a lot of this can be shared between multiple DCs.

Ideally, to construct a root filesystem, you have to know what files
your operating system distribution is expecting to see there. Critical
to booting are device files, files in /sbin and /etc. You can bypass a
lot of the hard work by making a copy of an existing root filesystem
and modifying some files for the DC. In the Etherboot distribution,
there is a tutorial and links to a couple of shell scripts that will
create such a DC root filesystem from an existing server root
filesystem. There are also troubleshooting tips in the Etherboot
documentation as this is often the trickiest part of the setup.

The customised Linux kernel for the DC expects to see the root
filesystem at /tftpboot/(IP address of the DC), for example:
/tftpboot/192.168.1.100 in the case above. This can be changed when
configuring the kernel, if desired.

Now create or edit /etc/exports (see 'man 5 exports' and 'man 8
exportfs') on the server and put in a line of the following form:

______________________________________________________________________
/tftpboot/192.168.1.100 aldebaran.foo.com(rw,no_root_squash)
______________________________________________________________________

The rw access is needed for various system services. The
no_root_squash attribute prevents the NFS system from mapping root's
ID to another one. If this is not specified, then various daemons and
loggers will be unhappy.

Start or restart the NFS services (rpc.portmap and rpc.mountd) and
retry the diskless boot. If you are successful, the kernel should be
able to mount a root filesystem and boot all the way to a login
prompt. Most likely, you will find several things misconfigured. Most
Linux distributions are oriented towards disked operation and require
a little modification to suit diskless booting. The most common
failing is reliance on files under /usr during the boot process, which
is normally imported from a server late in the boot process. Two
possible solutions are -

1. Provide the few required files under a small /usr directory on the
root filesystem, which will then be overlaid when /usr is imported,
and

2. Modify the paths to look for the files in the root filesystem. The
files to edit are under /tftpboot/192.168.1.100 (remember, this is
the root directory of the DC).

You may wish to mount other directories from the server, such as /usr
(which can be exported read-only).

7.3.4. Burn EPROM

When you are satisfied that you can boot over the network without any
problems, you may wish to put the code on an EPROM.

7.4. Uses of Network booting

X-terminals are one natural use of network booting. The lack of a disk
in the terminal makes it quieter and contributes to a pleasant working
environment. The machine should ideally have 16MB of memory or more
and the best video card you can find for it. This is an ideal use for
a high-end 486 or low-end Pentium that has been obsoleted by hardware
advances. Other people have used network booting for clusters of
machines where the usage is light on the DC and does not warrant a
disk, e.g. a cluster of classroom machines.

7.5. For more information

Your first stop should be the Etherboot home page:
<http://www.slug.org.au/etherboot/>

There you will find links to other resources, including a mailing list
you can subscribe to, where problems and solutions are discussed.

Related documents

� NFS-root Mini Howto at /usr/doc/HOWTO/mini or on Linux cdrom.

� Linux Networking-HOWTO by Terry Dawson, at /usr/doc/HOWTO or on
linux cdrom [email protected]

� NET-3-Howto at /usr/doc/HOWTO or on Linux cdrom.

� /usr/src/linux/README about configuring and compiling new kernels

8. Redhat Linux configuration

The DC requests to mount /tftpboot/< IP address of DC > (in Linux
Kernel 2.1 and above it is - /tftpboot/< name of DC in bootptab > ) as
its root directory '/' by NFS from server. You must export this from
the server (rw, no_root_squash) because the DC wants to write on it
(log files, etc).

The root directory / must contain /sbin, /bin, /lib, /etc, /var, /tmp,
/root, /dev and /proc.

/sbin, /bin, /lib can be a copy of an existing Redhat Linux system.
They can be shared between all DCs. But hard links only. By the way,
don't link to server originals.

/etc, /var and /dev should be non-sharable copies. Customise
/etc/sysconfig/network, /etc/sysconfig/network-scripts/ifcfg-eth0,
/etc/fstab, /etc/conf.modules, and others. Turn off all network
services you don't need. Remove all stuff you don't need from /var,
e.g. RPM db, lpd files.

/root and /proc should just exist. /tmp should exist and be mode 1777.

You probably want to create /usr and /home mount points. /usr can be
mounted ro (read-only).

About 10 MB per DC plus about 15 MB of shared files should be
sufficient. By the way, if your DCs are quite similar, the kernel
image can also be shared.

Here is an illustrative script to create the first root filesystem.

______________________________________________________________________
#!/bin/sh
if [ $# != 1 ]
then
echo Usage: $0 client-IP-addr
exit 1
fi

cd /

umask 022

mkdir -p /tftpboot/$1

# just make these ones
for d in home mnt proc tmp usr
do
mkdir /tftpboot/$1/$d
done

chmod 1777 /tftpboot/$1/tmp

touch /tftpboot/$1/fastboot
chattr +i /tftpboot/$1/fastboot

# copy these ones
cp -a bin lib sbin dev etc root var /tftpboot/$1

cat <<EOF
Now, in /tftpboot/$1/etc, edit

sysconfig/network
sysconfig/network-scripts/ifcfg-eth0
fstab
conf.modules

and configure

rc.d/rc3.d
EOF
______________________________________________________________________

Here is an illustrative script to duplicate the root filesystem

______________________________________________________________________
#!/bin/sh
if [ $# != 2 ]
then
echo Usage: $0 olddir newdir
exit 1
fi

cd /tftpboot

if [ ! -d $1 ]
then
echo $1 is not a directory
exit 1
fi

umask 022

mkdir -p $2

# just make these ones
for d in home mnt proc tmp usr
do
mkdir $2/$d
done

chmod 1777 $2/tmp

touch $2/fastboot
chattr +i $2/fastboot

# link these ones
for d in bin lib sbin
do
(cd $1; find $d -print | cpio -pl ../$2)
done

# copy these ones
for d in dev etc root var
do
cp -a $1/$d $2
done

cat <<EOF
Now, in /tftpboot/$2/etc, edit

sysconfig/network
sysconfig/network-scripts/ifcfg-eth0
fstab (maybe)
conf.modules (maybe)

and configure

rc.d/rc3.d
EOF
______________________________________________________________________

8.1. X-terminal

On the server, make sure the DC is matched by a clause in
/etc/X11/xdm/Xaccess and comment out the :0 in /etc/X11/xdm/Xservers.
Then make sure that xdm is run from the init scripts.

On the client, run X -query server

You will get the xdm login box and then all your X clients will run on
the server.

For other applications use - you could use diskless technique for
netboot routers, print servers (but should not be spooling print
server), standalone apps, etc.

9. LanWorks BootWare PROMs

This information may save you time. In order to make LanWorks
BootWare(tm) PROMs to correctly start up a Linux kernel image, the
"bootsector" part of the image must be modified so as to enable the
boot prom to jump right into the image start address. The net-
bootable image format created by netboot/etherboot's `mknbi-linux'
tool differs and will not run if used with BootWare PROMs.

A modified bootsector together with a Makefile to create a BootWare-
bootable image after kernel compilation can be found at -

� Bwimage package
<ftp://ftp.ipp.mpg.de/pub/ipp/wls/linux/bwimage-0.1.tgz>

� See also <http://www.patoche.org/LTT/net/00000096.html>

� LanWorks BootWare Boot ROMs <http://www.3com.com/lanworks>

Refer to the README file for installation details. Currently, only
"zImage"-type kernels are supported. Unfortunately, kernel parameters
are ignored.

This section courtesy of Jochen Kmietsch email to -
[email protected] for any questions.

10. Etherboot

Etherboot is a package for creating ROM images that can download code
over the network to be executed on an x86 computer. Typically the
computer is diskless and the code is Linux, but these are not the only
possibilities.

This document is at the Etherboot Home Page
<http://www.slug.org.au/etherboot/>. This document explains how to
install, configure and use the Etherboot package.

11. Netboot

Netboot was written by Zur�ck zu Gero. The main site is at
<http://www.han.de/~gero/netboot.html>.

11.1. Introduction

The following list shows just a few examples of what Netboot can be
used for:

� Printer spooler

� Terminal server

� X11 terminal

� Data logging system

� Network-Computer (NC)

� Some more ....

For the bootrom to find the kernel image it uses the BOOTP protocol as
defined in ``'' and ``'' to get the necessary boot information, and
then loads the actual image using the TFTP protocol as defined in
``''.

The exact specifications for this netboot process can be found
<http://www.han.de/~gero/netboot/english/spec.html>.

11.2. Mailing list

There exists a mailing list devoted to network booting. To subscribe
simply send a mail with the line

subscribe netboot

in it's body to [email protected]

The subject in the mail header doesn't matter. After subscribing to
it, you can send messages into the list by writing a mail to
[email protected].

11.3. Netboot useful links

Netboot mailing list archive is at
<http://www.han.de/~gero/netboot/archive/maillist.html>

� 3com drivers at <http://support.3com.com/infodeli/tools/nic>

� Accton drivers at here
<http://www.accton.com/accton/drivers/adapter.html>

� Artisoft <http://www.artisoft.com>

� CNET <http://www.cnet.com.tw>

� Compaq <http://www.compaq.com/support/networking>

� D-Link <http://www.dlink.com>

� Microdyne <http://www.mcdy.com/marketin/prodman/prodcat.htm>

� Many NE2000 PCI cards are based on Realtek chipsets. Get drivers
here <http://www.realtek.com.tw/cn/driver/driver.htm>

� Standard Microsystems Corp <http://www.smc.com/support.html>

� Surecom <http://www.sure-com.net>

� Thomas Conrad corp
<http://www.compaq.com/support/networking/OutOfProduction.html>

� Winbond <http://www.winbond.com.tw>

� Xircom <http://www.xircom.com>

� Webopaedia page <http://www.sandybay.com/pc-
web/network_interface_card_NIC.htm> on network cards

� Jargon's driver page
<http://www.evitech.fi/~jarnomn/files/drivers/net_d.html> with many
drivers for older network cards.

� Etherboot <http://www.slug.org.au/etherboot/> This is a project
similar to Netbot but based on the BSD bootrom code.

� How to make an X Window Terminal
<http://www.menet.umn.edu/~kaszeta/unix/xterminal/index.html> out
of your old or outdated PC.

� List of jumper settings <http://www.slug.org.au/NIC/index.html> for
various network cards. This page also contains many other good
links.

� Freefire <http://sites.inka.de/lina/freefire-l/tools.html> is the
home page of the Freefire project, which lists many resources for
network security issues.

12. Related URLs

� See 'Diskless-root-NFS-HOWTO' at
<http://metalab.unc.edu/LDP/HOWTO/Diskless-root-NFS-HOWTO.html>

� Linux goodies <http://www.aldev.8m.com> and mirrors at webjump
<http://aldev.webjump.com>, angelfire
<http://www.angelfire.com/nv/aldev>, geocities
<http://www.geocities.com/alavoor/index.html>, virtualave
<http://aldev.virtualave.net>, bizland <http://aldev.bizland.com>,
theglobe <http://members.theglobe.com/aldev/index.html>, spree
<http://members.spree.com/technology/aldev>, infoseek
<http://homepages.infoseek.com/~aldev1/index.html>, bcity
<http://www3.bcity.com/aldev>, 50megs <http://aldev.50megs.com>

13. Copyright Notice

Copyright policy is GNU/GPL as per LDP (Linux Documentation project).
LDP is a GNU/GPL project. Additional restrictions are - you must
retain the author's name, email address and this copyright notice on
all the copies. If you make any changes or additions to this document
than you should intimate all the authors of this document.

14. Other Formats of this Document

This document is published in 11 different formats namely - DVI,
Postscript, Latex, Adobe Acrobat PDF, LyX, GNU-info, HTML, RTF(Rich
Text Format), Plain-text, Unix man pages and SGML.

� You can get this HOWTO document as a single file tar ball in HTML,
DVI, Postscript or SGML formats from -
<ftp://sunsite.unc.edu/pub/Linux/docs/HOWTO/other-formats/> and
<http://www.linuxdoc.org/docs.html#howto>

� Plain text format is in:
<ftp://sunsite.unc.edu/pub/Linux/docs/HOWTO> and
<http://www.linuxdoc.org/docs.html#howto>

� Single HTML file format is in:
<http://www.linuxdoc.org/docs.html#howto>

� Translations to other languages like French, German, Spanish,
Chinese, Japanese are in
<ftp://sunsite.unc.edu/pub/Linux/docs/HOWTO> and
<http://www.linuxdoc.org/docs.html#howto> Any help from you to
translate to other languages is welcome.
The document is written using a tool called "SGML-Tools" which can
be got from - <http://www.sgmltools.org> Compiling the source you
will get the following commands like

� sgml2html CVS-HOWTO.sgml (to generate html file)

� sgml2rtf CVS-HOWTO.sgml (to generate RTF file)

� sgml2latex CVS-HOWTO.sgml (to generate latex file)

LaTeX documents may be converted into PDF files simply by producing a
Postscript output using sgml2latex ( and dvips) and running the output
through the Acrobat distill ( <http://www.adobe.com>) command as
follows:

______________________________________________________________________
bash$ man sgml2latex
bash$ sgml2latex filename.sgml
bash$ man dvips
bash$ dvips -o filename.ps filename.dvi
bash$ distill filename.ps
bash$ man ghostscript
bash$ man ps2pdf
bash$ ps2pdf input.ps output.pdf
bash$ acroread output.pdf &
______________________________________________________________________

Or you can use Ghostscript command ps2pdf. ps2pdf is a work-alike for
nearly all the functionality of Adobe's Acrobat Distiller product: it
converts PostScript files to Portable Document Format (PDF) files.
ps2pdf is implemented as a very small command script (batch file) that
invokes Ghostscript, selecting a special "output device" called
pdfwrite. In order to use ps2pdf, the pdfwrite device must be included
in the makefile when Ghostscript was compiled; see the documentation
on building Ghostscript for details.

This howto document is located at -

� <http://sunsite.unc.edu/LDP/HOWTO/CVS-HOWTO.html>

Also you can find this document at the following mirrors sites -

� <http://www.caldera.com/LDP/HOWTO/CVS-HOWTO.html>

� <http://www.WGS.com/LDP/HOWTO/CVS-HOWTO.html>

� <http://www.cc.gatech.edu/linux/LDP/HOWTO/CVS-HOWTO.html>

� <http://www.redhat.com/linux-info/ldp/HOWTO/CVS-HOWTO.html>

� Other mirror sites near you (network-address-wise) can be found at
<http://sunsite.unc.edu/LDP/hmirrors.html> select a site and go to
directory /LDP/HOWTO/CVS-HOWTO.html

In order to view the document in dvi format, use the xdvi program. The
xdvi program is located in tetex-xdvi*.rpm package in Redhat Linux
which can be located through ControlPanel | Applications | Publishing
| TeX menu buttons. To read dvi document give the command -

xdvi -geometry 80x90 howto.dvi
man xdvi

And resize the window with mouse. To navigate use Arrow keys, Page
Up, Page Down keys, also you can use 'f', 'd', 'u', 'c', 'l', 'r',
'p', 'n' letter keys to move up, down, center, next page, previous
page etc. To turn off expert menu press 'x'.

You can read postscript file using the program 'gv' (ghostview) or The
ghostscript program is in ghostscript*.rpm package and gv program is
in gv*.rpm package in Redhat Linux which can be located through
ControlPanel | Applications | Graphics menu buttons. The gv program is
much more user friendly than ghostscript. Also ghostscript and gv are
available on other platforms like OS/2, Windows 95 and NT, you view
this document even on those platforms.

� Get ghostscript for Windows 95, OS/2, and for all OSes from
<http://www.cs.wisc.edu/~ghost>

To read postscript document give the command -

gv howto.ps
ghostscript howto.ps

You can read HTML format document using Netscape Navigator, Microsoft
Internet explorer, Redhat Baron Web browser or any of the 10 other web
browsers.

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15. Topics for Academics and Universities

This section is for academic interest only - for universities or
research institutes. If you have plenty of time then you can read it.
These links are to RFCs and to the history of diskless nodes.
Students will find these links interesting to read the history of
development of diskless workstations.

Word of Caution: The information and data given by these URLs may be
old.

� Install Instructions at <http://www.aldev.8m.com/disklesshowto-
install.html> Mirror : <http://aldev.webjump.com/disklesshowto-
install.html>

� Troubleshoot Problems <http://www.aldev.8m.com/disklesshowto-
RFC-951.html> Mirror : <http://aldev.webjump.com/disklesshowto-
RFC-951.html>

� RFC 951 <http://www.aldev.8m.com/disklesshowto-RFC-1350.html>
Mirror : <http://aldev.webjump.com/disklesshowto-RFC-1350.html>

� RFC 1533 <http://www.aldev.8m.com/disklesshowto-RFC-1533.html>
Mirror : <http://aldev.webjump.com/disklesshowto-RFC-1533.html>

� RFC 1350 <http://www.aldev.8m.com/disklesshowto-Troubleshoot.html>
Mirror : <http://aldev.webjump.com/disklesshowto-
Troubleshoot.html>