[comp.arch] Compress, LZW and LZ...

mtr@geech.ai.mit.edu (Michael Rowan) (07/26/90)

[ disclaimer: if this is the wrong place for this post blah blah blah...]

It turns out that the LZ and LZW (Lempel-Ziv and Lempel-Ziv & Welch) 
algorithms, that are used compress, are patented.  Unisys Corp holds 
the patent and are currently making money from license fees (it is
being used in current modem technology.)

This patent is on the algorithm, not on code (unlike a copyright) so 
any program that produces compressed or uncompresses files using LZ 
or LZW are covered under the patent.   Unisys is actively pursuing 
the licensing of compress.

So... FSF is looking for alternative algorithms to use in lieu of
compress.  We were told of a new algorithm recently published that 
beats LZ and LZW on compression rates.  Does anyone know anything
about this?    Also someone mentioned Shannon-Fano trees; does anyone
have any references to this?   

Any information that is relevant to this would be highly appreciated.
Drop me a line with anything at all related to this, as I don't read
news that often (If I did, I wouldn't get *any* hacking in...)

mtr