Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Posting-Version: version B 2.10.2 9/18/84; site rosevax.UUCP
Path: utzoo!watmath!clyde!cbosgd!ihnp4!stolaf!mmm!rosevax!hogan
From: hogan@rosevax.UUCP (Andy Hogan)
Newsgroups: net.micro.mac
Subject: Re: Re: Shrink To Fit (STF) Mac data compression.
Message-ID: <308@rosevax.UUCP>
Date: Mon, 17-Feb-86 18:01:41 EST
Article-I.D.: rosevax.308
Posted: Mon Feb 17 18:01:41 1986
Date-Received: Wed, 19-Feb-86 01:00:12 EST
References: <678@aicchi.UUCP> <736@astrovax.UUCP>
Distribution: net
Organization: Rosemount Inc., Eden Prairie, MN
Lines: 36

>In net.sources.mac <678@aicchi.UUCP> David B. (Ben) Burch writes about stf,
>a compression program that gives, for his examples, compression of 16% and 18%.
>Has anyone yet ported the Unix compress program to the Macintosh?  That program
>is getting to be very common on Unix systems and in my experience tends to give
>about 50% compression on text.
>-- 
>Bill Sebok			Princeton University, Astrophysics

I did a quick test on 13 binhex'd files with compress, and got an average 
compression of 29.5%.  This would indicate that we could save a quarter to
a third of the length of these postings using a good compression algorithm.
But before porting compress to the Mac, let me suggest two alternatives:
  
  *  use "compress" on binhex'd files before posting and "uncompress"
     after recieving.  Would depend on whether "all" sites have the
     programs and if compressed files are mailable.  Uncompress-ing is
     a lot more bearable on a VAX than a Mac.

  *  incorporate a compress-style packing algorithm in a new version
     of binhex.  Keep backward compatibility, of course, and keep postings
     of the new format down until "all" sites had successfully gotten
     the new binhex.  (Wasn't this the difference between two of the
     binhex versions?  Some data compression, I mean?)  This could be an
     option, like the line feed filtering.

Is either of these feasible/desirable?  It's not that I don't think the
basic idea is good; I just hate taking more time to do the uncompression
than necessary.  You can fire up a whole bunch of uncompress-ing in the
background of a UNIX box and do something else (like read news), but Mac
just spins the disk for a while on one file at a time......


-- 
Andy Hogan   Rosemount, Inc.   Mpls MN
path: ...ihnp4!stolaf!umn-cs!mmm!rosevax!hogan
Working is not a synonym for Quality.