KV9U wrote:
> If it is the same protocol as B1F, was the reason for developing it,
> that the B1F did not have the needed exchange to work with Winlink 2000?
I'm not really sure what that means, and I'm pretty sure I didn't say
B2F is the same protocol as B1F. Only the compression is the same.
> So it is basically an extended version to do more "things" that they
> need to have it do?
It's just the internal format for handling email messages on the Winlink
2000 system, and the protocols for the systems handling the emails to
negotiate the transfer.
> I don't think that I am fully understanding what your code is being
> written for? Are you writing what would be considered an open source
> version of B2F so that it could be used across all platforms to access
> the Winlink 2000 system through the internet?
"What would be considered"? It *is* an open source cross-platform
Winlink 2000 client, released under the GNU General Public License
(GPL). Why not have a look for yourself?
"Through the internet"? No, that's just the first step to having a
working client; eventually it will work over the radio. In fact it has
been on the air a few times, but not really in a fully functional way.
The code in the sourceforge repository has a very brainless TNC driver,
which needs to be rewritten from scratch to use WA8DED hostmode and/or KISS.
In fact, if there are any TNCs out there that are binary transparent in
command mode, the existing driver could probably be used on the air
today. My SCS PCT-IIpro is not, and the documentation I have suggests
that hostmode is the way to get binary transparency.
When will it be fully functional? When I get around to it, or when
someone else pitches in some help, which was my primary motivation for
making it open source.
> Is there any way to improve interoperability between say, a PSKmail
> system and Winlink 2000 system?
I don't really know much about PSKmail. It sounds like an interesting
system, but I've never looked at it beyond a cursory glance. One of
these years I'll find the time, I'm sure.
But one of my motivations for releasing my code as open source was to
promote interoperability with WL2K. It would be great if someone used
my work to figure out how to add WL2K compatibility to a system like
JNOS2. Since JNOS2 can already talk to several TNCs, and my code can
talk to the WL2K servers, the marriage of the two would be a very good
thing.
> On a separate note, how feasible is it to incorporate L-Z/Huffman
> combined compression in any data mode, including keyboard mode?
It isn't very well suited to compression of single characters or tiny
sequences of characters. To get good compression ratios, it needs to
have a substantial stream of characters to work with. Otherwise the
overhead for the compressed stream will be greater than the compression
savings.
For example, if I put my callsign (followed by a linefeed) in a file and
compress it, the original file is 5 bytes and the compressed file is 12
bytes. But when I put my callsign in a file 100 times, the compression
savings is significant, with the 500 byte file shrinking to 30 bytes:
Script started on Sat Jan 13 17:17:03 2007
[501]~/sourceforge.net/work/paclink-unix $ echo n2qz > text.txt
[502]~/sourceforge.net/work/paclink-unix $ ./lzhuf_1 e1 test.txt
test.txt.lzh
5
In : 5 bytes
Out: 6 bytes
Out/In: 1.200
CRC: 3a10
[503]~/sourceforge.net/work/paclink-unix $ wc -c test.txt*
5 test.txt
12 test.txt.lzh
17 total
[504]~/sourceforge.net/work/paclink-unix $ yes n2qz | head -100 > test.txt
[505]~/sourceforge.net/work/paclink-unix $ ./lzhuf_1 e1 test.txt
test.txt.lzh
61
In : 500 bytes
Out: 24 bytes
Out/In: 0.048
CRC: fdce
[506]~/sourceforge.net/work/paclink-unix $ wc -c test.txt*
500 test.txt
30 test.txt.lzh
530 total
[507]~/sourceforge.net/work/paclink-unix $ exit
Script done on Sat Jan 13 17:18:28 2007
--
73 de Nick N2QZ
Section Traffic Manager, Eastern New York Section
Net Manager, NYS/E
FISTS #11469
SKCC #1027
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