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- Path: sparky!uunet!mcsun!sun4nl!ruuinf!accucx!nevries
- From: nevries@accucx.cc.ruu.nl (Nico E de Vries)
- Newsgroups: comp.compression
- Subject: First impression, PKZIP 2.04c
- Message-ID: <3552@accucx.cc.ruu.nl>
- Date: 5 Jan 93 22:26:07 GMT
- Organization: Academic Computer Centre Utrecht
- Lines: 49
-
- I finally got the "real" PKZIP 2.04c. It is not clear to me whatever
- happened at wuarchive but to be safe I donwloaded it directly from
- compuserve.
-
- I am comparing PKZIP 2.04c with PKZIP 1.93a.
- I tried to test under OS/2 2.0 but failed to get PKZIP running, I
- tested on a 33/486, QEMM, 8Mb, PC-DOS 5.02
-
- * compression ratio
- Compression has not changes much since 1.93a. The -ex option is
- slightly better (0.3% for the calgary corpus) and so is the -en
- option (1.4% for the calgary corpus). For normal files (<> Calgary)
- improvement is 0% for -ex and 0.5% for -en.
-
- * compression speed
- For -en and -ex there is a small speed improvement. In some cases
- up to 20% faster, in some cases (e.g. Calgary -en) up to 10% slower.
- In general I believe compression is about 10% faster.
- This is except for the -es option. Here the speed has been
- dramatically improved. I have seen 50% speed improvement in
- general cases. Of cource the new -es delivers less compression
- than the old one but that is not important. The use of -es is
- speed, for compression -en and -ex are more important.
-
- * decompression speed
- I didn't detect improvements here. Stil extremely fast.
-
- * system usage
- PKZIP utilizes XMS and DPMI now. Unfortunately this implies the program
- does not seem to run under OS/2 2.0. At least not with the default
- settings. Has someone found a setting which DOES work? PKZIP works
- with all the specials disabled. PKZIP neatly reports detected
- processor, Novell netware version etc etc. I doubt if the program
- actually uses all this information but it looks nice.
-
- * multivolume support
- Unfortunately TECHNOTE has disapeared. Therefore the excact way
- this works is unclear to me. It all seems a bit primitive to me
- (being used to ARJ) but the improtant factor is that multiple
- volumes are supported.
-
- Overall impression.
-
- PKWARE did a good job here. I don't understand what took them so long
- but it all seems to work perfectly. The product is now in general
- comparable to ARJ but it is significantly faster but on the other
- hand more expensive and has less options. IMHO PKWARE has a winner
- here. Unless ARJ gets some major improvement in speed or compression
- I think many people are going to switch (back) to PKZIP.
-