This is a new protocol proposed for the purpose of facilitating fast
Linux CD/DVD ISO downloads through the DTH type satellite medium. A
Linux satellite having a footprint over Asia and Africa will help in
providing the latest Linux distributions to even the remotest areas of
these regions. The broadcasts will be sequential and timed for every
.iso file, just like regular television programmes with their respective
timings. The number of transponders, frequency etc. is not discussed
here. The main purpose of this writeup is to create a transmission
protocol for error free unidirectional file downloads via satellite. A
single broadcast should be received by un-limited number of receivers
anywhere in Asia and Africa.
As satellite transmission is prone to disturbances, any error in the ISO
file being downloaded will render the entire process useless. Since it
is going to be a unidirectional broadcast that cannot receive feedback
from the receiving units, certain correction features need to be added
to the broadcast.
The proposed protocol will be called Unidirectional File Broadcast (
UFB-15 ) Protocol. The number 15 denotes the 15 second delay feature
added for correction. This can vary from 1 second to 60 seconds or more
as per the users' choice.
The UFBP-15 will broadcast data packets in groups of 1 second each.
These packets will contain their parity check sequence interlaced to
check downloaded packet integrity. After the first 15 packet groups of
one second each are broadcast, the next one second will contain the
first packet group re-broadcast. The next second will have the 16th
packet group. The next one to follow will be the 2nd packet group
re-broadcast. So every second a new packet group and its 15 second
earlier packet group is alternately broadcast. This provides the
receiver a 15 second delay to re-load the packets if they got corrupted
in the first attempt. An illustration is placed below. 'P' denotes the
packet group per second and its timing sequence. They are broadcast
P1 --> P15 --> P1 --> P16 --> P2 --> P17 --> P3 --> P18 --> P4 --> P19
--> P5 --> P20 --> P6 --> P21 --> P7 --> P22 --> P8 --> P23 --> P9 -->
P24 --> P10 --> P25 --> P11 --> P26 --> P12 --> P27 --> P13 --> P28 -->
P14 --> P29 --> P15 --> P30
As you can see, after every 15 seconds a re-broadcast of old packets
takes place to help the receiver catch up with broken packets. The delay
time can be chosen after experimenting with different time delays. This
will reduce the bandwidth by half but offer a self correction for
unidirectional broadcasts. To increase bandwidth, a higher transmission
frequency can be chosen. The proposed UFB-15 Protocol is free to anyone
to modify and correct for better transmission quality. The only
condition is that it should be released under the GPL license so that
anyone can make use of it freely.
Another method of reducing reception errors is to avoid transmitting an
ISO file as a whole. Instead, it can be transmitted as a set of files
just as they exist on the CD/DVD. Individual files being smaller, can be
corrected easily and will not disturb the entire ISO file block. An
executable script file transmitted along with the download assembles all
the components back into an single ISO file in the receiving unit.
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I was comparing rates for broadband internet for downloading linux
distro isos and find that over a period of one year, the rates are still
high, compared to the number of cds/dvds that can be downloaded. For
example a 600/- per month NU plan becomes 7200/- per year. How many CDs
or DVDs would a person actually download in one year for 7200/-? Plus,
many places in India, Asia as well as Africa are still undeveloped and
broadband is not available.
The World Space satellite radio is a technology that was meant to spread
radio to the whole of Asia and Africa. The receivers now start at a Rs.
1500/- one time investment.
So can the world Linux community come together and launch its own
satellite with multiple channels, each channel representing a linux
brand, like Debian, Fedora, Mandriva, Ubuntu, Gentoo etc. The downloads
will be in the form of serial broadcasts in the form of a programme
schedule. A timer in the receiver records the ISO download at that time.
A mini HDD inside the receiver can record the data. This helps those who
don't have facilities to mount antennas or don't face the satt. They can
take the receiver and antenna outside, download and then come back in to
transfer it to their pcs. At high one way speeds, downloads should be
very fast. The entire service should be free of cost to download.
How much would such a satellite cost and which country has the minimum
taxes for such a launch? The entire linux community could contribute for
this, along with donations from big distro companies and some Govts. It
should last us for 15 years. Technically what would be the maximum
download speed available for one way broadcasts?
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Saturday, Feb 24, 2007's meeting at Goa Science Centre focussed on these issues:
* Demo of LUGRadio programmes via a Chinese-clone of the iPod.
Feedback: difficulty in following the programmes, and a bit of
"excessive laughter" on the episode we were tuned into.
* Talking about devices, Arvind suggested the OpenMoko phone
Notice to Developers
If you are interested in developing Free Software applications for the
OpenMoko platform, please send information regarding embedded Linux
projects you have contributed to, and the work you have done to
We had some hardware issues that set us back about a month. But now
we're back on track and should start shipping in February. All of our
efforts are focused on getting the device out, so please forgive our
delays in replying to your emails.
* Queries about web-to-SMS international gateways. Some suggested
using Yahoo (only Windows compatible). BSNL is offering SMS
within India for 40 paisa per SMS.
* Brief discussion about using 'sleep' mode under GNU/Linux, while transporting
laptop with a GNU/Linux distro.
* Fedora and its marketing strategies.
* Debate about new distros. Stanley is on the search for some.
* Some of us remembered Prakash Advani, earlier with FreeOS.com and now
with Novell. He has an interesting photo blog. See:
* We also thought of the photography work of Tariq Sani (Nagpur) and
Kalyan Varma (Bangalore), two other FLOSS techies.
* We had a brief discussion on the Simputer and also the plans of Geodesic,
where Atul Chitnis is now vice-president
The visit of Dr Vinay Deshpande to Goa was remembered too.
There was a debate over the $100 computer (OLPC), and whether the it was
really unsuted to India, or whether the opposition to it could be from
those eager to block the spread of Free Software/Open Source among
the younger generation.
See http://www.laptop.org/ or http://wiki.laptop.org/go/Home
* Someone raised the question about the Mobilis.
The Mobilis, is Encore's inexpensive mobile PC
* Arvind was keen to get access to the book 'Linux Kernel: In A Nutshell'
Apologies to the lady who missed our meeting, because we started late! Ashwin
Naik phoned, and was eager to come to meetup (at the bhel-puri informal
meet-up following the indoors meet at the Goa Science Centre, Panjim). FN
FN M: 0091 9822122436 P: +91-832-240-9490 (after 1300IST please)
7500+ sharable pics from Goa http://www.flickr.com/photos/fn-goa/
> Hi, I too have written a report on a similar hardware. Except I had a
> PATA drive instead of a SATA. I have a PATA DVD RW too. Anyway, I have
> the i386 install. It is stable. No issues till now. I have Xen
> virtualization enabled as well. The only difference between our
> installation methods is I guess I installed the distro without Xen
> virtualization and then used the system-config-packages to add Xen and
> the Xen kernel. The system was stable all throughout. 2.6.18-SMP kernel
> updated to 2.6.19-SMP and 2.6.18-Xen updated to 2.6.19-Xen.
I have created a wiki entry based on my experience on the ilug-bom site
in the HOWTO section as per some suggestions I received. Maybe you could
also update the wiki with your experiences.
I'm currently following my CCNA (Cisco certified network associate) course.
I'm almost done with it. I want to support my networking course with some
programming skills. Where to start from ?? I have been to NIIT & already
checked with them about language course, they said "C" & "C++" will be
covered in a period of 2 months.
I personally do not feel that 2-months time is sufficient for those two
languages. Also, i keep reading about 'RUBY' & 'Python' and i gather that
RUBY is much easy to learn for beginner like me.
So, any experts out there can please point me to any institute which offers
courses in RUBY / Python ? Is there any pre-requisite for learning those
languages (like familiarity with syntax of "C" or any other language for
that matter) ??
Please note that i have already been to Eric Raymond's site and have read
his opinion about programming.
i m wrkng with a embeded system which makes use of arm linux
pls provide some references for arm linux............
Don't be flakey. Get Yahoo! Mail for Mobile and
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[Please pardon the cross posting. I felt that this mail is not
off topic for any of the mailing lists I have posted it to,
and it is about time we had a technical, as opposed to
sentimental or loyalty based look at the .deb and .rpm file
formats, I have read the acceptable use policies of all three
lists, and I think this is not in violation of any of them. I
apologize if I am mistaken]
It might be instructive to compare package file formats on a
purely technical level: http://kitenet.net/~joey/pkg-comp/
This is a fairly authoritative document, and well worth understanding.
Here follows commentary on the major points of difference oj
just the rpm and deb format (please read the URL for details
regarding other package formats).
1) Data unpack-able by standard tools, meta-data accessible by
standard tools, and ability to create a .deb with standard (non
distribution specific) tools: .debs are just ar archives of
tar-balls, and can be unpackaged, inspected, and created using cp,
chmod, ar and tar. rpm's need a special tool. Now, why is this
important at all? Well, think of a classified environment, where
you do not want to rely on the packaged tool to help you with
forensics; but you have a trusted solaris box.
2) Package relationships: The .deb format has a more nuanced set of
relationships, incorporating recommendations and suggested
packages, and orders packages by priority as well as group.
rpm does not have the nuanced relationship, nor priority, but it
does have file based dependencies, and easily extract-able
copyright information so it is easier to marshal packages by
Personally, I am of the opinion that file dependencies are a mixed
bag; they complicate the package dependency graph with edges that
are different from a package dependency; added to the less
nuanced dependency and priority information, they make the
installation ordering of rpm's far less sophisticated.
dpkg goes through a song and dance ordering packages with
topological sorting of the graph, breaking installation into
chunks to ensure that no conflicting packages ever are unpacked at
the same time, unpacking and configuring packages in dependency
order, and rolling back failed installation. rpm does
installations on a best effort basis, and thus failures at
critical stages leave the system in an untenable state.
3) rpm can mark documentation files (makes it easier to find docs),
and has ghost files, files which are not shipped in the package
but are registered as being owned by the package. For
documentation, Debian relies on convention; all package
documentation is found in /usr/share/doc/$package; but ghost files
are clearly a plus for rpms.
4) Debian packages may run binaries at install and un-install times.
I am not sure if this is a major plus.
5) Package verification and triggers -- rpm has them, and package
verification is one of the major features missing in a .deb.
triggers, well, there is a technical proposal currently being
debated about adding triggers to dpkg, but obviously, Debian is
playing catch-up here.
6) New sections in the package format: .debs were designed to be
extensible, and whole new sections can be added to the package by
adding yet another tar-ball or the ar archive. Some of the future
additions being planned are detached signatures by various keys;
developers key, build daemon maintainer key, archive maintainers
key, release manager key, mirror master key, -- in a new section
of the package file. So, new data sections, compiled binaries
for more than one sub-arch, or 32 and 64 bit binaries -- they can
be added easily to a new section, and dpkg be told how to deal
with the new sections by inspecting the .deb format version.
rpm's can't as easily cope with unseen new requirements.
"Nuclear war can ruin your whole compile." Karl Lehenbauer
Manoj Srivastava <srivasta(a)acm.org> <http://www.golden-gryphon.com/>
1024D/BF24424C print 4966 F272 D093 B493 410B 924B 21BA DABB BF24 424C
Koustubha Kale wrote:
>> I have a Tata Indicom VDATA PCMCIA card for internet access when out of office.
>> Is it possible to use this with Fedora core 6? Any pointers please.
>I have used the Huawei EC321 data card on FC6.x86_64. Setting it up
>using wvdial was a breeze. If you want, I can provide you the wvdial
>settings that I used.
>Vivek J. Patankar
I got it working with wvdial. Also got the modprobe to do it automagically as described in the blog. Just one problem I have a default gateway since I use the laptop at office too. wvdial/pppd does not put in a default route for the new connection. I tried the defaultroute option in the /etc/ppp/options and /etc/ppp/peers/wvdial files but no avail. Can u tell me a tric by which I can have the defaultroute inserted when i connect with wvdial and my office route put back when i disconnect?
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