[TUHS] Re: "Webster's Second on the Head of a Pin"?

[Douglas McIlroy <douglas.mcilroy@dartmouth.edu>]

Gnu lzip -9  got a 3.92 compression factor , while Morris-Thompson got 4.52.

According to the lzip man page, lzip has integrity checks, which must
take some space. It is also said to be a "simplified" L-Z, though the
only simplification that is mentioned--bounding the size of the
dictionary--can only happen on much bigger files than Webster. If you
still wonder how well "pure" L-Z does, I'll be happy to try your
favorite implementation.

 It did not surprise me that lzip lost to M-T, for it has to discover
over and over again that the dictionary is lexicographically
ordered--a fact that gives M-T most of its leverage. The dictionary is
definitely not generated by a Markov process!

Doug

On Mon, Mar 10, 2025 at 6:56 PM James Johnston <audioskeptic@gmail.com> wrote:
>
> Doug, do you know how much better Ziv-Lempel does? I'm guessing "a little bit"?
>
> On Mon, Mar 10, 2025 at 3:52 PM Douglas McIlroy <douglas.mcilroy@dartmouth.edu> wrote:
>>
>> I have sent a copy to Warren for the Unix archives.
>>
>> Doug
>>
>> On Sat, Dec 28, 2024 at 9:54 PM Royce Williams <royce@techsolvency.com> wrote:
>> >
>> > Someone I know is seeking the original version of an internal Bell Labs memo from 1974 titled "Webster's Second on the Head of a Pin" by Morris and Thompson. The topic appears to be related to improving the speed of lookups or search. It's cited in a few papers as "Unpublished Technical Memo, Bell Laboratories, Murray Hill, NJ 1974." All I can find online is citations. Any leads appreciated!
>> >
>> > --
>> > Royce
>
>
>
> --
> James D. (jj) Johnston
>
> Former Chief Scientist, Immersion Networks