churchh@ut-emx.UUCP (Henry Churchyard) (08/25/90)
In the recent post of GnuDiff, the ZOO archiver had packed the
34,557 byte DIFF.EXE file into a 46,648 byte archive. When I asked
ZOO to recompress the DIFF.EXE file, I got exactly the same result!
This is data _compression_?! Perhaps it's time to switch to .ZIP.
--Henry Churchyard churchh@emx.cc.utexas.eduralphs@halcyon.wa.com (Ralph Sims) (08/25/90)
churchh@ut-emx.UUCP (Henry Churchyard) writes: > In the recent post of GnuDiff, the ZOO archiver had packed the > 34,557 byte DIFF.EXE file into a 46,648 byte archive. When I asked > ZOO to recompress the DIFF.EXE file, I got exactly the same result! > This is data _compression_?! Perhaps it's time to switch to .ZIP. > It may be possible that one of the *.exe-shrinkers was applied prior to compression (lexe, exepack, etc.). On rare occasions archives can be larger than their components. -- No matter who you elect, the Government still gets in.
davidsen@sixhub.UUCP (Wm E. Davidsen Jr) (08/28/90)
In article <36726@ut-emx.UUCP> churchh@ut-emx.UUCP (Henry Churchyard) writes: | | In the recent post of GnuDiff, the ZOO archiver had packed the | 34,557 byte DIFF.EXE file into a 46,648 byte archive. When I asked | ZOO to recompress the DIFF.EXE file, I got exactly the same result! | This is data _compression_?! Perhaps it's time to switch to .ZIP. This was a special case, in which the file was packed with something or other. Hopefully a new version of zoo will be forthcoming with better compression. The only other candidate is LHARC, since zip fails two requirements for "official" archiver, in that it (a) doesn't run on UNIX, and (b) is shareware. If a new zoo doesn't come out I may either add comments to lharc or port dwc to unix. -- bill davidsen - davidsen@sixhub.uucp (uunet!crdgw1!sixhub!davidsen) sysop *IX BBS and Public Access UNIX moderator of comp.binaries.ibm.pc and 80386 mailing list "Stupidity, like virtue, is its own reward" -me
davidsen@sixhub.UUCP (Wm E. Davidsen Jr) (08/28/90)
In article <36726@ut-emx.UUCP> churchh@ut-emx.UUCP (Henry Churchyard) writes: | | In the recent post of GnuDiff, the ZOO archiver had packed the | 34,557 byte DIFF.EXE file into a 46,648 byte archive. Out of curiosity, what compression did ZIP get? -- bill davidsen - davidsen@sixhub.uucp (uunet!crdgw1!sixhub!davidsen) sysop *IX BBS and Public Access UNIX moderator of comp.binaries.ibm.pc and 80386 mailing list "Stupidity, like virtue, is its own reward" -me
roy@cs.umn.edu (Roy M. Silvernail) (08/29/90)
davidsen@sixhub.UUCP (Wm E. Davidsen Jr) writes: > This was a special case, in which the file was packed with something > or other. ISL reported that GNUDIFF was compressed with LZEXE. > Hopefully a new version of zoo will be forthcoming with better > compression. I noted that PKZIP will store a file if the compressed version is no smaller than the original. This would be a valuable addition to Zoo, since files already compressed rarely will shrink further, and would avoid this problem in the future. > If a new zoo doesn't come out I may either add comments to lharc or > port dwc to unix. What's dwc? I thought I'd seen most all the available archivers for DOS, but that's a new one on me. -- Roy M. Silvernail |+| roy%cybrspc@cs.umn.edu |+| #define opinions ALL_MINE; main(){float x=1;x=x/50;printf("It's only $%.2f, but it's my $%.2f!\n",x,x);} "This is cyberspace." -- Peter da Silva :--: "...and I like it here!" -- me
davidsen@sixhub.UUCP (Wm E. Davidsen Jr) (08/30/90)
In article <N72mo1w162w@cybrspc> cybrspc!roy@cs.umn.edu (Roy M. Silvernail) writes: | What's dwc? I thought I'd seen most all the available archivers for DOS, | but that's a new one on me. Once upon a time there was a BBS where Rahul Dhesi was posting new versions of zoo, Dean W Cooper was posting DWC, and Phil Katz was posting whatever he was doing at the time. DWC is a small fast compressor, which gives good results slightly larger than zip in most cases. The source was release for DOS but not (yet) ported to UNIX. I believe that Dean gave Phil Katz some help with zip, but I don't recall for sure. It's a single program like zoo rether than a multipart thing like zip. -- bill davidsen - davidsen@sixhub.uucp (uunet!crdgw1!sixhub!davidsen) sysop *IX BBS and Public Access UNIX moderator of comp.binaries.ibm.pc and 80386 mailing list "Stupidity, like virtue, is its own reward" -me
alexande@dri.com (Mark Alexander) (09/06/90)
In article <N72mo1w162w@cybrspc> cybrspc!roy@cs.umn.edu (Roy M. Silvernail) writes: >I noted that PKZIP will store a file if the compressed version is no >smaller than the original. This would be a valuable addition to Zoo, >since files already compressed rarely will shrink further, and would >avoid this problem in the future. The version of ZOO I use (1.71) does have this feature. After it has written the compressed data for a single file to the ZOO file, it checks to see if it has written more bytes than are in the original file. If this is the case, it seeks back to the start of the compressed data in the ZOO file, truncates the ZOO file, then does a straight copy. This should result in a file that is the size of the original, plus a little bit for headers. I suspect that the version of ZOO that was used to create the offending file being discussed in this thread may have had a broken zootrunc() function (the system-dependent function that truncates a file). The result would be that the ZOO file contained some unused data at the end. This is especially likely if the archive contained a single file; otherwise, later files might have overwritten the unused data. Unfortunately, I didn't save a copy of this ZOO file, so I can't check my theory. -- Mark Alexander (uunet!drivax!alexande or alexande@dri.com)