Path: utzoo!mnetor!uunet!husc6!think!ames!mailrus!umix!umich!mibte!gamma!ulysses!thumper!faline!bellcore!tness7!ninja!sys1!techsup!cpe!tif From: tif@cpe.UUCP Newsgroups: comp.sources.d Subject: Re: Standard for file transmission Message-ID: <6800015@cpe> Date: 4 May 88 19:38:00 GMT References: <292@cullsj.UUCP> Lines: 76 Nf-ID: #R:cullsj.UUCP:292:cpe:6800015:000:2937 Nf-From: cpe.UUCP!tif May 4 14:38:00 1988 Written 10:45 am May 2, 1988 by bbn.com!rsalz in cpe:comp.sources.d >If you are (sigh) going to post binaries on Usenet, DO NOT compress >them first. Many Usenet sites use compress to pack up their news >batches. Compressing a compressed file makes it larger. << I don't post often and this about as close to a flame as I've come >> But what you're compressing is text. Text can always be compressed with a significant advantage even if the text is a uuencoded compress file. In the end, the uuencode offsets most of the gains of the extra compress. If I were implementing a compressing file transfer utility which had the possibity of transfering *binary* files, I would make sure that the compress was actually profitable. Since now adays most "news" transfers are compressed, I'll give in that *if* "news" could transfer binary files, the compressing should be left to the news transfer stuff rather than be done by the poster. Since "news" can't handle binary files (at least nobody assumes that it can), the file has to be encoded in some way. I'll use my kernel as a sample binary input file and uuencode for the encoding technique. I've included the results for my /usr/dict/words file as well since postings sometimes intermix binary and ASCII files. (I couldn't figure out what order these should be in) (12 bit compresses only) Net change of transfer size transfer posted binary ASCII ------------------------------------------------------------------- uncompressed normal * no change no change compressed normal * -35% -46% uncompressed uuencoded +40% +40% uncompressed uuencoded compress -9% -25% compressed uuencoded -15% -23% compressed uuencoded compress -19% -29% (if you believe in 16 bit compresses) Net change of transfer size transfer posted binary ASCII ------------------------------------------------------------------- compressed normal * -43% -49% uncompressed uuencoded compress -20% -28% compressed uuencoded -28% -30% compressed uuencoded compress -31% -35% * These can't be posted but are provided for reference CONCLUSIONS: To transfer binary files using news software the best method in all cases is to post a uuencoded compress file. When transfering ASCII files, if you compress and uuencode, not only are you robbing a 15-20% savings from the sites that use compressed transfers, but you should be shot for making it unreadable. For the skeptics, here are the file sizes I used to build the tables: 16 bit compress 12 bit compress 234157 234157 xenix 133183 152458 xenix.Z 327860 327860 xenix.u 167759 198043 xenix.u.Z 186498 213482 xenix.Z.u 161860 190137 xenix.Z.u.Z 194192 194192 words 99725 104093 words.Z 271908 271908 words.u 135065 150047 words.u.Z 139656 145772 words.Z.u 126459 137701 words.Z.u.Z Paul Chamberlain Computer Product Engineering, Tandy Corp. ihnp4!sys1!cpe!tif