Xref: utzoo comp.sources.d:2003 comp.binaries.ibm.pc.d:58
Path: utzoo!mnetor!uunet!lll-winken!lll-tis!ames!amdahl!nsc!voder!cullsj!jeff
From: jeff@cullsj.UUCP (Jeffrey C. Fried)
Newsgroups: comp.sources.d,comp.binaries.ibm.pc.d
Subject: Re: Standard for file transmission
Message-ID: <296@cullsj.UUCP>
Date: 3 May 88 21:42:53 GMT
References: <292@cullsj.UUCP> <55@psuhcx.psu.edu> <537@csccat.UUCP>
   I would like to clear up a couple of notions that have been expressed over
Organization: Cullinet Software, San Jose, CA
Lines: 41
Keywords: protocol compression source


  1) COMPRESS is a text only compression routine.  It will not now, or ever,
     help in the compression of binary files.

  2) ARITH is a more general compression routine using adaptive arithmetic 
     coding.  It will compress binary files where there is redundancy, but
     when it fails (on an extremely random file) the result increases very
     little (under 1% in my experience).  It compresses better than HUFFMAN,
     but it is NOT faster than SQ/UNSQ which are written in assembler whereas
     ARITH is written in C.
     (Once again, i will post it if there is sufficient interest.)

  3) The source for ZOO, PKARC, and the others is NOT available.  Therefore
     we are at the whims of whomever is currently supporting (or not supporting)
     them.

  4) COMPRESS works faster and better on text files then the ARC routines
     because they use 12 bit compression, where 13-bit (and more) are possible
     under even the PC for COMPRESS (i've tried it on ans AT-clone).

  5) On the weak side, there is as yet, no CRC or checksum for any of these,
     but adding it would be someithing i am willing to take responsibility
     for should enough people decide they would like to take the approach
     which i'm currently suggesting.
     Also, there no directory support provided with these tools.  They work
     on only one file at a time.  This is also correctable since the source
     is available.

  5) LASTLY: I am not trying to criticize the ARC routines, rather i am trying
     to offer an alternative which i feel will reduce the time for transmission
     of files, as well as, providing us with portability.  COMPRESS, ARITH, 
     UNSHAR and UUENCODE are all available at the source level.  COMPRESS and
     ARITH have been tried in at least three different environments: UNIX (BSD),
     VMS and PC/MS-DOS.
     Remember, for those of us who are NOT using the NET at the expense of a
     university, the cost of communication, and therefore the time required
     to transmit a file, are VERY important.

   If this sounds like a flame, then please assign my apparent bad attitude to
poor methodology rather than a desire to upset people.  This is provided in the
spirit of adding to what i hope will become a meaningful dialog with a very
practicle result.