Enabling Mass Computing For the Global Children
Priyadarsan Patra (dpatra@yahoo.com)
Given
below are the specifics, in a nutshell, of what is needed for a Linux terminal server project suited for
a village/small-town setting or in a school classroom. This is derived from an education
project in USA
called K12LTSP. After describing the resources needed of such
a project, we will motivate the reason for “terminal computing” as a means for
“mass computing”. Then we will delve into the mechanics of setting up the
project. I have quoted information/advice from various sources liberally.
We
need a P3 or better class of computer as a server,
while old machines (dirt cheap) such as 486’s can be good thin-clients. Server needs two ethernet cards (one to control the
thin clients or ‘dumb terminals’ and the other to connect to Internet) and an
UPS. All the basic+ software on this linux machine is free. Only recurring cost
is the Internet connection charge. We
should get the old 486 or Pentiums from businesses that are discarding them, thus
creating a win-win proposition. I have recently sent the setup software (for
that I have 3 cd-roms which include RedHat Linux 9.0) to the principal of JITM
in Gajapati, Orissa. (We are also talking to Rourkela Engineering
College with the help of
Mr. S. Dasverma.) Thus, our resource needs are:
- CPU: One P4
class. Dual-core cpu or at least hyper-threading cpu for the server is
preferred to handle many clients.
- RAM: 256MB +
(50MB for each client, more the merrier). I propose 4 to 8 clients.
- HD: ATA/SATA
30+ GB. (Hardware RAID-1
configuration gives added protection for the system when a disk fails)
- Network: two 100/base cards and a
100base switch/router or hub (4 to 8 ports)
- It’s more
fun/useful if we have an internet connection. If we don’t we don’t even
need the second Ethernet card. (Wireless configuration possible with some
effort: see wiki.ltsp.org/twiki/bin/view/Ltsp/WirelessLtsp)
- 1 uninterrupted power supply (UPS).
I have seen people use truck batteries instead.
- 4 to 8 X terminals
(thin-clients):
- The minimum usable X
terminal is a 386/sx 25mhz with 4 megs of ram. While not that fast, it
makes a usable station to run a web browser (such as Netscape). Image
will display fast enough. Scrolling won't be fast though (some wave
effect). While the machine displays slowly, the application server has no
problem feeding it. One must note that 386 computers are older than the
Linux project. We have found that few have unsupported video adaptors (or
less than capable ones). Unfortunately, finding replacement video adaptor
for those machines is not easy. Those machines are generally using ISA
slots.
- Recommended X terminal
While faster is always better, a 486 computer using a Vesa
local bus or PCI video adaptor offers a very good performance. Redrawing and
scrolling is crisp. For example a DX/2-66 with an ATI Mach32-2meg is a cool
station, running smoothly in 64k colors mode. Each terminal needs
keyboard/mouse, an Ethernet card and/or a floppy drive. Floppy drive is not
needed if the Ethernet card has the boot rom to boot from the network (served
by the server).
- The 3 software CDs that I can
send
- A good admin/teacher, a room,
and some community support J
Here is a smattering of blurbs on
Terminal Computing from various sources:
Terminal
computing Motivation
A
common question which is asked is what is meant by "terminal
computing" or a "terminal server." Simply put, terminal
computing is using a back-end server computer to power "dumb" and
cheap client terminals. The idea is that a common user is using a terminal
machine. That terminal does nothing but display output to a monitor and to
accept input via a keyboard, mouse (and possibly other input devices, e.g. a
scanner). All programs run on the server computer, using the server's memory
and processing power. To the regular user, they think they're using a regular
PC. They get a desktop, their application work as they normally do, and to
the user everything is normal. There are dramatic advantages to this idea of
computing; the advantages of terminal computing are:
· Lower
client maintenance costs
· Reduced
hardware costs by either using older hardware as clients or by buying cheaper
terminals instead of full PCs
·
Centralized administration of all clients
·
Drastically reduced overall administrative costs
Users break things. They might break their computer hardware or they might
"break" software. In a typical computer environment servers should
run for months without major maintenance. But user’s machines always need
routine maintenance. That maintenance may be reinstalling application
programs, or reinstalling the entire operating system or it may be just basic
hardware maintenance. Either way, that maintenance costs money.
Terminal computing radically reduces maintenance costs. Many
terminal computers have no moving parts (no fan, no hard drive, nothing --
remember, all computing is done on the server). Some will object that such
terminals cost almost as much as a typical cheap PC. But those people miss
the point. What you're buying is reliability and reduced maintenance costs.
Other people will use old PCs as terminals. This presents a huge cost
savings in not having to buy new hardware. With terminal computing, an old
486 or low-end Pentium computer is still a perfectly useful computer!
You also get radically reduced administrative costs with terminal
computing. To give all users an application you don't install it multiple
times on every user's computer -- you install it once on the terminal server.
So instead of 20 or 50 copies of a word processor that an administrator has
to maintain, update, and repair, the admin only has to maintain one copy.
Unix systems pioneered the idea of terminal computing and Microsoft has
recently copied the idea and produced Windows Terminal Server to export
Windows desktops to cheap terminals. However, the software costs of Microsoft's
solution are outrageous, both in sheer dollar costs and also in the
"cost" of freedom that you give up by agreeing to Microsoft's
license agreement.
Another good article
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Overview of a K12LTSP
Open Source Lab to setup our system:
A default K12LTSP installation uses two ethernet cards; eth0 and eth1.
One card connects the server to your school network. The other card creates a private
network for terminals (thin-clients). Your server and eth1 act as a gateway for
the terminals to the Internet and the rest of your network. eth1 is configured
to get its IP address via DHCP. A private DHCP server runs on eth0 to give IP
numbers to terminals. This configuration is flexible in that you can easily
have multiple LTSP servers in your building all sharing the same default
configuration. Servers are "plug and play" with little or no
configuration required. It only takes about 20 minutes to be up and running.
K12LTSP is based on Red Hat 9.0 with a full set of familiar GUI tools for
configuring your server. You have the choice of KDE or GNOME desktops and many
applications.
Software Included in the K12LTSP/K12Linux
Distribution:
Gnome Desktop
|
KDE Desktop
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OpenOffice
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We've
included a host of useful applications that will make you productive right
away.
- Nautilus
file manager
- Mozilla
browser with Java(tm) and Flash (tm) support
- Ximian
Evolution E-Mail, calendar and contact manager
- Adobe
Acrobat Reader
- OpenOffice
- K-Office
- Gimp
- AbiWord
- Auto
configuration for many PCI based sound cards
- Auto
configuration for both PXE and BOOTP clients
- File
sharing for both Windows and Macintosh networks
- Much
more...
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rdesktop
running Windows2000 Terminal Services Session
Included is the rdesktop
package that provides access to Windows2000/NT4 terminal sessions with a simple
click of an icon. This gives users a choice of operating systems as needed.
Note that this option requires a separate W2K/NT terminal server and licenses
for clients.
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Detailed info on setting up from the 3 disks: Insert “disk I” into
the cdrom of your server machine to install and configure the server. Read the
following
Ethernet Cards,
Hubs
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Classroom
Server 5+ clients
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Your server will have two ethernet
cards, one to create a private network (192.168.0.x) on a hub for terminals
and one to connect to the rest of your network.
You can install LTSP servers with just one ethernet card. They will then live
on your network and be available from all over your school. For single card
installations we've prepared a list of files to
edit to help you with your network settings.
By default the LTSP sever runs DHCP on the client's card (eth0) and
automatically gives out IP #'s upon request. It then accepts bootp and PXE
boot requests and passes on the Linux kernel to the client. The default
dhcpd.conf file will support over 200 clients. All this happens on eth0. The
LTSP server will not answer dhcp requests over eth1 (with the default
settings.)
Why do we default to a private network and 2 ethernet cards? Thin-clients and
servers can generate a lot of network traffic. By isolating this traffic on a
single hub and routing only necessary traffic out to the rest of the network
we lower the overall impact of clients on school networks that are often
substandard in the first place.
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Tip: Our classroom
LTSP servers are connected to the rest of our school via 10base ports. We NFS
mount /home over eth1 and run the clients from a hub on eth0. This works well
and gives us a configuration we can easily replicate throughout our building.
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Planning
Your Network
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It's
a good idea to gather some information before you start installing Linux. If
you simply click "Next" and "Yes" straight through the
install after selecting "LTSP Server" you'll end up with a working server
ready to go.
Not advised, but, If you are planning on using static IP addresses and/or
just one ethernet card then you'll need to gather some information on your
network. See the list
of files to edit at the end of this page.
|
You
can skip all this if you're doing a default install. Just plug eth1 into a
port and if you have DHCP running on your network your server will be up and
running. Connect eth0 to a hub for clients and you're ready to go!
One or two network cards?
DHCP or static IP numbers?
Classroom server or building/lab server?
Hostname of server?
DNS server?
Gateway?
Netmask settings?
Etc...
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Installation
Choices
|
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- LTSP - Creates
a terminal server for thin-client workstations. Server defaults to an IP
gateway/firewall when 2 ethernet cards are present.
For our
LTSP install select "LTSP."
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Create
user accounts later after system booting into linux and allowing you as the root
to login for the first time.
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Network
Configuration
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eth0 is the
interface on the thin-client side of your LTSP server. You will connect this
network card to your terminal hub. The 192.168.0.x address is designated as a
"private" IP address for internal networks. IP traffic from you
clients is routed to the Internet and the rest of your network through eth1.
Note that the server has the last available address in this range,
192.168.0.254. The first client will be assigned IP # of 192.168.0.253.
You won't have to enter hostname info or any of the information in the lower
half of the window. These settings will come from eth1.
The default for eth1 is "Configure using DHCP." If you are using
custom settings then you'll need to click on the "eth1" tab and
configure the card.
(Not recommended: If you're only
using one ethernet card then go ahead and enter the information in the bottom
part of this form)
Remember that all of this information can be edited later with the standard
Red Hat network configuration tools menu.
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Take a fast look at this
detailed ZDNet article, which does an excellent job of describing its basic
hardware and software ingredients.
OpenOffice
(the open-source alternative to Sun Microsystems' StarOffice)
works great as
Linux replacements for the spendy Microsoft
tools.
-
Sound setup and other
questions:
If there are any networking problems persisting, we can take care of them after
booting the server. The network settings
may be changed by the “root” from the Gnome desktop.
See http://k12ltsp.org/faq.html
or, if needed, write to me.
Alternatives
“Debian Edu” is another package
that is popular in Europe (Also known as
SkoleLinux).
APPENDIX
Quote from an article in the Washington
Post:
“In many ways, India is the
perfect laboratory for adapting the Internet to development needs, bringing
together abundant technological expertise with an estimated 700 million people
in 600,000 rural villages. Although telephone lines aren’t necessary,
electricity is, and unreliable power supplies leave many villages without
electricity for all but a few hours each day. And some development experts say
money used to equip villages with modems and computers could be better spent on
primary schools or health clinics.
The approach pioneered by Jhunjhunwala and his
colleagues here in the southern Indian state of Tamil Nadu aims to render that
debate irrelevant by turning over the job of connecting rural India to the
Internet to profit-minded entrepreneurs.
Central to the effort is Wireless Local Loop
technology, which provides cheap, relatively fast Internet connections to
fiber-optic cables as far as 18 miles away. Although many villages still lack
phone service, India’s
fiber-optic network is sufficiently well developed to provide wireless coverage
for up to 85 percent of the country, Jhunjhunwala said.
He and his colleagues created an independent
company, n-Logue Communications, which identifies promising kiosk owners,
trains them and provides equipment — computer, printer, battery backup and
wireless Internet antenna — for about $1,000; n-Logue helps the owners arrange
financing, which is then paid off with revenue from the kiosks. The company
makes its money from hourly connection fees.
So far, n-Logue has set up more than 500 kiosks in
Tamil Nadu and other states, with plans for 10,000 by next June.
While most kiosks are run for profit, one of the
most well-established parts of the kiosk network is a demonstration project set
up with help from Harvard
University and the
Massachusetts Institute of Technology, and financed in part by India’s ICICI
Bank. Situated in the tropical Madurai
district of interior Tamil Nadu, the Sustainable Access in India, or SARI,
project has so far set up 40 kiosks in rural villages such as this one.
The effort has not been without problems, most centering on the
failure of kiosk operators to adequately explain and promote their services,
according to Joseph Thomas, who manages the project out of a cluttered office
at the Indian Institute of Technology campus.
“You have to do a huge amount of awareness
generation, and some of these guys are just not into that — they think it’s
like setting up a betel-nut shop or cigarette shop,” Thomas said. “If it’s to
become a part of the community, it needs a person who empathizes with the
community.”