From: IN%"POSTMASTER@EMBL.BITNET" "General PostMaster" 7-FEB-1990 17:24:12.75 To: HARPER@cc.Helsinki.FI CC: Subj: Automatic response to : GET SOFTWARE:BIOBIT.7 Received: from jnet-daemon by cc.Helsinki.FI; Wed, 7 Feb 90 17:23 EET DST Received: From EMBL(NETSERV) by FINUHB with Jnet id 1588 for HARPER@FINUH; Wed, 7 Feb 90 17:23 O Date: Wed, 07 Feb 90 16:06:10 From: EMBL Network File Server Subject: Automatic response to : GET SOFTWARE:BIOBIT.7 To: HARPER@cc.Helsinki.FI Reply-to: General PostMaster Organisation: European Molecular Biology Laboratory Postal-address: Meyerhofstrasse 1, 6900 Heidelberg, W. Germany 7777777777 777 7777777777 7777777777 777 7777777777777 7777777777 7777777777 7777777777 777 777 777 777 777 777 777 777 777 777 777777777 777 777 777 777777777 777 777 777777777 777 777 777 777777777 777 777 777 777 777 777 777 777 777 777 777 7777777777 777 7777777777 7777777777 777 777 7777777777 777 7777777777 7777777777 777 777 No 7 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% INDEPENDANT NEWSLETTER PRODUCED AT HELSINKI UNIVERSITY, FINLAND << EDITED BY ROBERT HARPER >> %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% After writing BIOBIT no 6 which dealt with ARC, I had a number of private letters asking about the alternatives to ARC. The most authoritative document which deals with compression is called COMPRESS.ARC. It is a HUGE file put together by ROBERT D. TOLZ. I have extracted the table of contents from the archive so you can see the wide selection of compression programmes that are available. If there is any interest in the complete document then I could upload it to NET.BIO.NET for FTP downloading. Anyway for openers, here are some interesting snippets from the original document. Hopefully they will give you an insight as to what you might come across in the future, so you can be half way prepared when a file with a strange looking extension is presented to you. %%%%%%%%%%%%%%%%%EXTRACT%%%%%%%%%%%%%%%%%%%%% TABLE OF CONTENTS INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 ABOUT COMPRESS.NW? . . . . . . . . . . . . . . . . . . . . . . . . . . 3 CURRENT EVENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 FUTURE EVENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 AN INVITATION FOR COMPRESSION AUTHORS . . . . . . . . . . . . . . . . . 4 HOW TESTING WAS DONE . . . . . . . . . . . . . . . . . . . . . . . . . 4 HOW TO READ THE TEST RESULTS . . . . . . . . . . . . . . . . . . . . . 5 QUICK SUMMARY OF RESULTS . . . . . . . . . . . . . . . . . . . . . . . 6 CAVEAT EMPTOR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 SIZE OF EXTRACTION CODE . . . . . . . . . . . . . . . . . . . . . . . . 7 OTHER FACTORS TO CONSIDER . . . . . . . . . . . . . . . . . . . . . . . 8 COMMENTS ABOUT THE PROGRAMS . . . . . . . . . . . . . . . . . . . . . . 8 ARC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 ARCA/ARCE . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 COMP16 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 DEARC7 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 DWC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 MDCD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 PAK . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 PKPAK/UNPAK . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 PKZIP/PKUNZIP . . . . . . . . . . . . . . . . . . . . . . . . . . 15 QARC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 SCRNCH . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 ST/EXP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 ZOO . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 AVAILABILITY OF PROGRAMS . . . . . . . . . . . . . . . . . . . . . . . 19 COMMENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 A WORD FROM OUR SPONSOR . . . . . . . . . . . . . . . . . . . . . . . . 22 TEST RESULTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 %%%%%%%%%%%%%END%%%%%%%%%%%%%%%%%%%%%%% As can be seen there are about 13 different compression programmes to choose from, but the "standards" that you most often come across are ARC, ZOO, or ZIP. However in the future you never now what is going to become the new "standard". You should be aware that the ARCHIVING world is in a state of ferment at the moment, and what is fashionable today is out tomorrow. When you are looking for a compression programme the two things that most people look for are percentage compression, and speed of packing and extraction. You want the files to be as small as possible, and when you extract them from the archive they should "unpack" themselves as quickly as possible. Below is a quick summary of the results. Someone was asking recently what programmes can you use to extract from "original" *.ARC files. You will find the answer below. %%%%%%%%%%%%%EXTRACT%%%%%%%%%%%%%%%%%%% ------------------------ QUICK SUMMARY OF RESULTS ------------------------ For general purpose compression/archiving programs, if you're looking for speed of compression, then check out PKZIP, DWC, PKPAK and QARC. If you're looking for degree of compression (the amount that the file shrinks) in a general purpose program, then look at PAK (not to be confused with PKPAK), PKZIP or DWC. If you're looking for the ability to extract from original format *.ARC files, then restrict your search to ARC, ARCE, PAK, PKPAK and DEARC7. If you're distributing disks and must have the absolutely greatest degree of compression regardless of the time it takes for the computer to get the job done, then investigate SCRNCH. PKZIP may also be worthy of consideration. If you want to squeeze ASCII files to the greatest degree possible, then look at ST/EXP. If you're concerned about portability (the ability for someone using a non-MSDOS system to extract files from something you compressed), then consider COMP16, DWC, ARC and ZOO. %%%%%%%%%%%%%%%%END%%%%%%%%%%%%%%%%%% One problem which many people encounter is that they receive an ARC file and they do not have a ARC programme to UNARCHIVE it. Well some developers have overcome this by producing SELF-EXTRACTING ARCHIVERS. A sender can use these to produce an EXE file which when executed "unpacks" itself, so the receiver does not have to have any programmes to do the unpacking. This is rather convenient for novices. %%%%%%%%%%%%%%%EXTRACT%%%%%%%%%%%%%%%% ----------------------- SIZE OF EXTRACTION CODE ----------------------- Software developers are likely to be concerned about how much space on a distribution disk must be devoted to the program (or self-extraction code) that is needed to extract the files from the distribution archives. Selfextraction code converts an archive into an EXE file which, when run, will extract into the archive's component files. This comparison is unlikely to be a concern for persons who are not worried about distributing files to potentially novice users who don't know an archive from an elbow. The following table illustrates the sizes of the extraction programs and the self-extraction code where available: Extraction Program Self-Extract Code ------------------ ----------------- ARC 39K 8K ARCE 7K n/a COMP16 27K n/a DEARC7 13K n/a DWC A501 46K 20K DWC A495 45K 20K MDCD 51K n/a PAK 60K 7K PKUNPAK 15K 13K PKUNZIP 16K n/a SCRNCH 0K 0K ST/EXP 100K n/a ZOO 10K (LOOZ) 2K For a rough comparison of the combined effect of a program's compression ratio and the efficiency (in size) of its self-extraction code, here's a listing of the smallest possible final size of PAL.DOC, compressed and made into a self-extracting file. These are placed in order of smallest to largest: SCRNCH 71K PAK 78K ZOO 84K PKZIP 91K ARC 93K PKUNPAK 95K DWC 100K %%%%%%%%%%%%%%%END%%%%%%%%%%%%%%%%%% And finally before you decide on what type of compression programme to use here are a few facts to keep in mind. And as a final check list the most recent versions of the various programmes are included, so you can check them against the versions that you have at the moment, and discover whether you are in step or out of step with the rest of the world. %%%%%%%%%%%%%%%EXTRACT%%%%%%%%%%%%%% ------------------------- OTHER FACTORS TO CONSIDER ------------------------- Other factors to consider in making your selection: * Licensing arrangements, cost * Source availability * Size of extraction programs * Availability of self-extraction * Ease of use * Compatibility with original *.ARC files * Portability to other operating systems * Reliability The programmes and there version number are listed below. The programs compared are: ARC version 5.32 ARCA/ARCE versions 1.28 and 3.1c, respectively COMP16 version 4.2 DEARC7 version 4.0 DWC4size version A495 optimized for size DWC4speed version A495 optimized for speed DWC5size version A501 optimized for size DWC5speed version A501 optimized for speed MDCD version 1.0 PAK version 1.51 PKPAK (old) version 3.61 (compatible with original ARC format) PKPAK/UNPAK version 3.61 PKZIP/PKUNZIP version 0.80 beta PKZIP1\ PKZIP2 \ These notations in TABLES.NW5 refer to command PKZIP3 / line switches for PKZIP which permit higher PKZIP4/ degrees of compression. QARC/ARCE versions 1.00 and 3.1c, respectively SCRNCHsize version 1.02 optimized for size SCRNCHspeed version 1.02 optimized for speed %%%%%%%%%%%%%%END%%%%%%%%%%%%%%%%%%%% Rob "I have seen the future and it is compressed" Harper