PE> The files we were using had only "X" in them.

RS> Well, thats hardly surprising then is it ?  And completely
RS> irrelevant to whether it would help with the speed of my PKTs.

BG> Quite so, and in fact, these fake test files full of Xs are
BG> the worst possible example to use.  Sure, they compress better
BG> than anything else under BTLZ (something you'd never see in the
BG> real world anyway, as you know), but the real shock comes when
BG> you PRE-compress such a file before sending.  Tried it myself
BG> once, and a 100Kb file of Xs Zipped down to less than 1Kb!

Yeah, the BTLZ is fundamentally crippled by the fact that it
only sees quite small chunks of the file at a time. So it does
very badly even on those files compared with a standalone archiver
which can analyse the whole file.

BG> So at say 3:1 compression in the modem, it transmits in around
BG> 20 seconds, but if compressed first, it reaches the other end
BG> in under 1 second!  Why anybody bothers with uncompressed data
BG> is beyond me, except for relatively small (say <100Kb) files.

The main situation where it can be handy is with stupids who will
stuff it up if they have to archive it first. Particularly if they
dont actually pay for the connect time, coz its a local call. Can
be operationally convenient in that situation.

Corse you can argue that the comms app should just transparently
archive it first and dearchive it again at the other end, but you
dont see too much of that.

PE> Ok, I'll get Paul to try it again sometime.

RS> Well, use real files, PKTs, because it is possible
RS> for artificial files with just one byte repeated etc
RS> to exceed the 38400 capability in some circumstances.

BG> Sure.  Marginally better than 3:1 measured here, but Paul
BG> will never see anything like this much compression in real
BG> life, and like you, I simply cannot see any purpose in locking
BG> the port at any more than twice the modem's highest available
BG> link rate (57600 in my case, 38400 in yours and Paul's).

Its actually a fascinating commentary on human nature, it really is
quite amazing the sorts of people who cant really grasp it. Essentially
what they are doing is not really grasping the engineering and they
just use their gut reaction instead, and its wrong. You see a similar
thing with simple stats, people say 'my BIL had a holden and the
engine fell out' as if that proves a damned thing about reliability.

Still, we are getting better, not too many people sacrificed their
children to the gods to make the drought go away this time around.

--- PQWK202