>If you are moving stuff like uncompressed text (news) there is PLENTY
>of reason to go higher. a 33.6 modem can (and does) easilly tranfer >57600
>when moving stuff that is highly compressable. Problem is more likely
>an old motherboard with unbuffered UARTS and an external modem but
>the original posting has expired from my server so I can not read it.
A friend of mine and I made some tests once. He had a new 28.8kbps
modem and I a new 14.4kbps. Using DOS and COMMO (terminal pgm), I called him
and established a connection (he used DOS and COMMO also). Using COMMO, it's
easy to change parms -- such as the pooter<=>modem rate and etc. One of us
set his to 57,600 and the other to 38,400 at first, then we both reset to
57,600, and used zmodem to tfr a pair of test files (a fairly long ASCII
text file and a ZIPed copy of DOOM.WAD).
Not only did the uncompressed ASCII text file tfr faster when both
ends were set to 57,600, but the compressed ZIP of DOOM.WAD tfr'd signif-
icantly faster too. I forget the figures, but we're talking several minutes
difference on the ZIP file. Both ways (uloading and dloading.)
I've always set this figure (pooter<=>modem bps rate) to 4x the
expected modem<=>modem rate. For 14.4kbps this works out to 57,600. The
reason is that v.42bis, the most common hardware compression protocol in use
for high-speed modems, is capable of attaining a four times compression
rate. Of course, this figure and these results aren't always seen. For
general BBS work, where unless a file is being tfr'd, the data is mostly
short bursts of uncompressed data (ANSI screens and ASCII text), it makes no
difference what speed is being used (IMHO 2400 is prob fast enough for most
BBS work that doesn't involve tfring dense ANSI screens). It is when a file
tfr is done that these speeds become meaningful.
I'm a firm b'liever in using the highest pooter<=>modem speed
possible. Now that I have a new USR Sportster 33.6 (with x2 coming rsn),
I've changed this figure to 115,200 in both my DOS and Linux modem setups.
Sure, a lower speed will work as well, but the link won't be operating at
full efficiency.
--
Eclectic Garbanzo BBS, (707) 539-1279
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