dricejb@drilex.UUCP (Craig Jackson drilex1) (08/17/90)
I've been experimenting with MNP5 to several of our host computers, and
I've noticed that there doesn't seemt to be enough compression to stop
the output from being choppy at 4800 bps when reading news. However,
when working with our mainframe, which likes to output in all caps,
the choppiness seems to be a good deal less. I remember that there are
people out there who are familiar witht the MNP5 scheme--is it really
compressing more on all-caps? This would be a useful thing to know.
--
Craig Jackson
dricejb@drilex.dri.mgh.com
{bbn,axiom,redsox,atexnet,ka3ovk}!drilex!{dricej,dricejb}s8925188@mqcomp.mqcc.mq.OZ (Philip Craig) (08/20/90)
In article <14862@drilex.UUCP> dricejb@drilex.UUCP (Craig Jackson drilex1) writes: >When working with our mainframe, which likes to output in all caps, >the choppiness seems to be a good deal less. I remember that there are >people out there who are familiar witht the MNP5 scheme--is it really >compressing more on all-caps? This would be a useful thing to know. MNP5 maps the most frequently occuring characters into tokens that have a short number of bits, and less frequent characters into tokens of longer length. The shortest token is 4 bits, and the longest is 11 bits. When a machine talks only in all caps, then the character set it is using has 26 less characters in it. This means that other characters can move up the table and use the shorter length tokens. The compression has nothing to do with the all-caps nature, but the one-case nature is what is important. The same effect would be achieved if the machine used only lower case (and it'd be a lot more readable, I reckon!) ----------------------------------------------------------------- Are you sure you want to remove SUN microsystems [yes/no]? ACSnet ( s8925188@mqcomp.mq.oz ) UUCP ( uunet!munnari!mqcomp.mq.oz!s8925188 ) Internet ( s8925188%mqcomp.mq.oz@uunet.uu.net )