PACKET RADIO: Signature Lines

Steve Wolf, W8IZ@W8IZ

(This text from the W8IZ packet radio bulletin

board. It's formatted to fit a 80 character screen.)

sb sysop@ww
Notes From A Network Friend
Just the other day I had a interesting talk with a mobile data
supplier over spectrum usage.  This fellow represents one of the
larger mobile data networks.  The network is little more than a
packet network that operates over a cellular system.  To computer
programmers, however, the system is considered quite complicated.
This fellow came to see a new usage being implemented at our
location.  The usage involved sending a single screen of text from a
central location to a mobile data terminal.
The fellow was quite polite until he saw how we were implementing the
sends to the cars.  We were using a simple message switching function
to send between 500 and 1,000 bytes to the car.  Should an update be
needed, that update would involve a complete new screen to the car.
Well, you would have thought we were the devil incarnate.  Beads of
sweat broke out over his forehead as he demanded to know why we
breached our contract.  In a gruff voice, now raised and trembling,
demanded to know how such incompetent programming can happen.  In
short, the fellow lost control.
After discussing his options (settle down, be thrown out or be
arrested) we retreated to a conference room to discuss things.
My stand on the matter involved our need to increase and expand our
use of mobile data.  I expressed our need to do photographs, long
searches and perhaps even remote file editing.  If his network could
not handle our mundane task, it will never suffice for what we have
The data supplier expressed his need to maximize the usage of his
system.  He talked in terms of hundreds or thousands of users sending
data 24 hours a day.  He was not unreasonable, he was genuinely
interested in making his system efficient.  He was, further,
interested in making his system not only efficient but squeezing
every last grain of efficiency out of any application using his
He felt that the screens could be compressed, sent and uncompressed.
He demanded that any update not be sent as a full screen but as a
minimized (and, of course, compressed) summary of the changed data.
As to the future, he reported 640x480 GIF compression to 2,500 bytes
would be acceptable.  In short, any wasted byte was cause for
TCP/IP?  He laughed ... he laughed hard.  He reports it gives
"overhead" a new meaning.
What does this have to do with amateur applications?  Look at the
text of a bulletin just received here.  The top part is the message
and the bottom part is the signature:
*** begin included text
         x xxx xx xxxxxx xxxxx
      x xxxx xxxx xxxxxxxxx xx xx xxxx xxx xxxxx x xxxxx xxxx  x xxxx xx xxxxxx
x xxxxxxx xx xx xx x xxxxxxxxxxxx xx xxxxxxxx xxxxx xxx xxxxxxxx  x xxxx xxx xx
xxxx xxx xxx xxxx xxxxxxx xxxx xx xx xxxx xxxxxxxxxxxx xx xxxxxxxx xxx xxxxx xx
x xxxxxxxxx  xxxx xxxx   x xxxxxxx xxxx x xxxx xxxx xxxx xxxx xx xxxxxx xxxxxxx
xxxx xx x xxx xx xxxxxx   x  xxxx xxx xxxxxx xxx xxx xx xxxxxxxxxxxxxxx xxxx xx
xxx xxxxxxxx   xx xxxxxx xxx xxx xxxxx xxxx xxxx xx xxxx xx x xxxxxxxx  xxxx xx
x xxxx xx xx xxxxxx xx xxxx xx x xxxxxxx  x xxxxx xxxxxxxxxx xxx xxxxxxxxxx  
/                              xxxxxx xxx xx                         \
/                                xxxx xxxx                           \
/                                \
/                                            \
/             xxxx xx xxxxx  xxxxxxxx xxxxxxxxxx xx xxx xxx          \
/                            xxxx xxxxxx xxx                         \
/                            xxx xxxxxxx xxxx                        \
/                        xxxxxxxxxx xx xxxxxxxxxx                    \
/                             xxxxx xxxxxxxx                         \
*** end included text
There are 586 bytes in the message.  There are 847 bytes in the
signature.  59% of the message is in the brag lines.
What do you think my network friend would have to say about that?
The purpose here is not to invite people to reply about our need for
high speed networks.  Look at USENET.  We want that?  The purpose is
to show that a good percentage of our network time is wasted.
I'm not sure I want to invest another $1,000.00 to up my part of our
network to a faster speed.  I can double the speed easily by not
supporting users with dopey long signature lines.
Steve, NO8M 

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