Article View: comp.sys.mac
Article #29032Re: some (should-be) ground-rules f
From: gillies
Date: Sun, 12 Jun 1988 05:29
Date: Sun, 12 Jun 1988 05:29
22 lines
1564 bytes
1564 bytes
I have been reading the compress source code extensively, and the
original paper by Terry Welch. Here are some of the many non-standard
modifications to "vanilla" LZW:
(1) adaptive reset to restart compression at a certain threshold
(suggested, but not standard). I've read the code, and I suspect
the reset may always be arriving 100% too late, but I'm not positive.
(2) variable-length codes, minimum = 9 bits, max = 16, increasing
as the compression goes on. "Vanilla" LZW is 12 bits (constant).
(3) some kind of special processing for low-density bit images.
This may be a significant performance hit -- it may significantly
overuse (abuse?) the adaptive reset [HOG_CHECK code].
Someone said we should standardize compress because it's decent and
nearly every UNIX machine has it. Well, I believe that IBM PCs are
decent and nearly every business has one. So while we're at it, why
don't we just give up on the macintosh altogether? This would save
even more time!
Don Gillies {ihnp4!uiucdcs!gillies} U of Illinois
{gillies@cs.uiuc.edu}
Technical Details
Message-ID:
<76000218@uiucdcsp>Path:
arc1-ca.pugleaf.net!utzoo!attcan!uunet!husc6!bloom-beacon!bu-cs!purdue!i.cc.purdue.edu!j.cc.purdue.edu!pur-ee!uiucdcs!uiucdcsp!gilliesReferences:
<2758@utastro.UUCP>Show Full Headers
Complete Article Headers
Path: arc1-ca.pugleaf.net!utzoo!attcan!uunet!husc6!bloom-beacon!bu-cs!purdue!i.cc.purdue.edu!j.cc.purdue.edu!pur-ee!uiucdcs!uiucdcsp!gillies From: gillies@uiucdcsp.cs.uiuc.edu Newsgroups: comp.sys.mac Subject: Re: some (should-be) ground-rules f Message-ID: <76000218@uiucdcsp> Date: 12 Jun 88 05:29:00 GMT References: <2758@utastro.UUCP> Lines: 22 Nf-ID: #R:utastro.UUCP:2758:uiucdcsp:76000218:000:1082 Nf-From: uiucdcsp.cs.uiuc.edu!gillies Jun 12 00:29:00 1988