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SmartZIP (tm) ZIP File Optimizer ■ Version 1.10 ■ August, 1990 Copyright 1989, 1990 ■ Joseph A. Vincent Consulting ■ All Rights Reserved If you're reading this before using SmartZIP 1.10, congratulations! Not many people are as disciplined and thorough as you are. However, please be aware that the file, "READ_ME!.NOW", is MANDATORY READING, since there are some caveats there that aren't provided here. Please review "READ_ME!.NOW" before using SmartZIP 1.10. ----------------------- >>>>> What is SmartZIP? ----------------------- SmartZIP is a ZIP file-size optimizing companion product for PKZIP 1.xx and PKZIP 0.9x, so don't throw away PKZIP 0.9x yet! SmartZIP can also take advantage of PKZIP 0.9x if that version's "Reducing" will yield better compression for a particular file. In fact, MUCH of the benefit of using SmartZIP comes from exploiting PKZIP 0.9x's Reducing algorithm. SmartZIP, working with PKZIP 1.xx and PKZIP 0.9x, will produce the absolutely, positively smallest ZIP files possible. SmartZIP is an intelligent ZIP file create/update/reZIP utility that will minimize both ZIP file size and the time required to create/update /reZIP an optimized ZIP file. It does this by using logic that will always yield the smallest possible ZIP file in a minimum number of trials. SmartZIP is shareware. That means that you are encouraged to try it to see if it meets your needs and, if you decide to keep and use the program, register it and pay a reasonable fee ($12 per copy suggested). Those who register SmartZIP will receive: - "MergZIPs", a program that will merge two existing ZIPs together without requiring any intermediate unZIPping of either or both of the two ZIPs. This program is not available as shareware. It's only available as a premium for registering SmartZIP. - The next release of SmartZIP as soon as it is released. Many hours of hard work have gone into producing SmartZIP and the accompanying documentation. I developed SmartZIP because I needed it and I use it every day. I think you'll find that SmartZIP produces an appreciable savings in disk space beyond that saved by using PKZIP alone at the expense of a nominal amount of extra time spent in doing data compression. ------------------- >>>>> Why SmartZIP? ------------------- I wrote SmartZIP based on my observation that no single compression algorithm ALWAYS yields the best compression. While one file might compress best with Imploding, another might compress best with Shrinking or Reducing. Therefore, it's not possible to obtain the smallest ZIP file by selecting a single compression algorithm to use for all files to be ZIPped. It's not even possible to obtain the smallest ZIP file using PKZIP 1.xx's "-ex" option. The ideal is to choose the best compression algorithm file by file, from PKZIP 1.xx's Imploding/Shrinking and PKZIP 0.9x's Reducing, and that's what SmartZIP does for you. You'll notice, as you run SmartZIP, that SmartZIP won't use the same compression algorithm for every file within a given ZIP file. Since it's choosing the compression algorithm file-by-file, SmartZIP might, for example, choose Imploding for one file, Shrinking for another and, if you're using the "both PKZIPs" option, one of the Reducing levels from PKZIP 0.9x might be chosen for some other file. The result is that the best compression algorithm is chosen for each FILE individually, not for the COLLECTION of files overall. Is it worth it? I think so. The following table provides statistics for a few files for which Imploding (PKZIP 1.xx's minimize-size algorithm) did NOT yield the best compression. The algorithm that yielded the best compression is marked by an "*". Statistics are from PKZIP 1.1 and PKZIP 0.92. ╔══════╤═════════╤════════╤════════╤════════╤════════╤════════╤════════╗ ║ File │ Initial │ │ │ Reduced│ Reduced│ Reduced│ Reduced║ ║ Type │ Bytes │Imploded│ Shrunk │ Level 4│ Level 3│ Level 2│ Level 1║ ╟──────┼─────────┼────────┼────────┼────────┼────────┼────────┼────────╢ ║ │ │ │ │ │ │ │ ║ ║ .TXT │1,018,954│ 352,084│*326,676│ 365,606│ 373,598│ 384,633│ 387,578║ ║ .TXT │ 80,767│ 27,762│* 27,194│ 30,133│ 30,163│ 30,750│ 31,118║ ║ .BTR │ 38,912│ 7,461│ 7,968│* 7,441│ 7,489│ 7,582│ 7,842║ ║ .TXT │ 118,360│ 4,374│ 12,991│* 4,052│ 4,101│ 4,291│ 19,485║ ║ .TXT │ 8,625│ 2,794│* 2,605│ 2,909│ 2,847│ 2,759│ 2,699║ ║ .EXE │ 55,269│ 55,389│ 55,389│* 55,255│ 55,271│ 55,274│ 55,274║ ║ .ZIP │ 5,466│ 5,582│ 5,582│* 5,458│ 5,582│ 5,582│ 5,582║ ║ .ZIP │ 6,083│ 6,002│ 6,201│* 5,713│ 5,765│ 5,797│ 5,794║ ║ .COM │ 6,360│ 5,984│ 5,922│* 5,261│ 5,288│ 5,379│ 5,394║ ║ .ASP │ 7,062│ 2,701│ 2,434│ 2,776│ 2,463│ 2,300│* 2,184║ ║ .Z00 │ 58,428│ 36,326│ 50,592│* 35,689│ 36,307│ 36,836│ 37,473║ ║ .Z00 │ 79,002│ 46,353│ 67,597│* 45,138│ 45,646│ 46,525│ 48,336║ ║ .Z00 │ 88,587│ 49,479│ 72,578│* 48,044│ 48,842│ 50,675│ 52,095║ ║ .88F │ 80,640│ 11,877│ 13,949│ 10,172│ 10,138│* 10,097│ 10,192║ ║ .ARC │ 15,593│ 15,167│ 15,711│* 14,585│ 14,685│ 14,810│ 14,933║ ║ .COM │ 9,516│ 5,508│ 5,954│* 5,199│ 5,303│ 5,343│ 5,408║ ║ .COM │ 7,777│ 6,373│ 6,715│* 5,755│ 5,756│ 5,768│ 5,856║ ║ .ZIP │ 20,608│ 20,726│ 20,726│* 20,447│ 20,649│ 20,648│ 20,674║ ║ .COM │ 6,342│ 5,992│ 5,915│* 5,256│ 5,282│ 5,368│ 5,386║ ║ .COM │ 9,516│ 5,508│ 5,954│* 5,199│ 5,303│ 5,343│ 5,408║ ║ .EXE │ 18,649│ 10,101│ 11,998│* 9,820│ 10,089│ 10,236│ 10,502║ ║ .PIC │ 64,896│ 57,906│ 65,016│ 53,792│ 53,618│ 53,446│* 53,338║ ║ .PIC │ 64,896│ 47,195│ 51,835│ 45,502│ 45,256│* 44,879│ 44,916║ ║ .PIC │ 64,896│ 52,502│ 59,491│ 49,855│ 49,518│* 49,062│ 49,072║ ║ .PIC │ 64,896│ 45,584│ 48,773│ 43,884│ 43,503│ 42,999│* 42,876║ ║ .PIC │ 64,896│ 52,084│ 58,674│ 49,126│ 48,694│ 48,347│* 48,157║ ╚══════╧═════════╧════════╧════════╧════════╧════════╧════════╧════════╝ In general, Imploding is a superior compression algorithm; it yields the best compression the majority of the time. However, there are enough cases where it doesn't to make use of SmartZIP worthwhile. Graphics files (.PICs, etc.) and database files, in particular, seem to compress best with some level of PKZIP 0.9x's Reducing algorithm. ----------------------------- >>>>> How does SmartZIP work? ----------------------------- SmartZIP ZIPs all of the files matching the file specification in the selected directory into a ZIP file using the ZIP file name specified by the user. If the ZIP file exists, it is updated. If it doesn't exist, it is created. If the reZIP ("/r") option is being used, the ZIP file must exist. For EACH of the files to be ZIPped, SmartZIP first performs PKZIP 1.xx Imploding. It then performs PKZIP 1.xx Shrinking. If you request it, SmartZIP will also perform PKZIP 0.9x Reducing level 4, and, if Reducing level 4 yields a smaller ZIP file than either Imploding or Shrinking, SmartZIP will try the other three Reducing levels, as well, searching for improved compression. If Reducing level 4 was no better than Imploding or Shrinking, no additional compression is attempted. The assumption is that, if Reducing level 4 doesn't yield better compression than Imploding or Shrinking, it is unlikely that other Reducing levels will, either. Use of this option is HIGHLY recommended. The ZIP produced using the optimum compression algorithm isolated by this process is then merged into the target ZIP file. If the compression achieved by all of the algorithms used is the same, then Shrinking (PKZIP 1.xx's minimize-compression-time algorithm) will be selected. As SmartZIP executes, it will display several things: - The name of the file being SmartZIPped. - The compression algorithm being tried. - The compression size achieved by each compression algorithm tried. - PKZIP's screen output. When the optimum compression algorithm is identified, the compressed file size achieved will be marked with an asterisk and highlighted, and an additional message will be displayed stating that SmartZIP is merging the individual ZIP into the target ZIP file and specifying the compression algorithm being used. Note that the "compression size" displayed includes the ZIP file overhead, so it won't match the compressed size of the individual file exactly; it's usually high by a hundred bytes or so. Therefore, the number displayed is only a relative size estimate suitable for the purpose. -------------------- >>>>> SmartZIP Setup -------------------- SmartZIP.EXE and PKZIP.EXE must both be in in a directory specified in your PATH. If you wish to use the option to use both PKZIP 1.xx Imploding/Shrinking and PKZIP 0.9x Reducing (HIGHLY recommended), you must rename PKZIP 0.9x's .EXE file from "PKZIP.EXE" to "PKZIP09.EXE" and place it in a directory specified in your PATH, as well. Make certain that you have ample disk space, particularly if you're using the "/r" (reZIP) option. When reZIPping, SmartZIP first unZIPs the file to be reZIPped. PKZIP further requires disk space equivalent to the final ZIP file size. Although SmartZIP has been tested and recovers elegantly from a "disk-full" situation, it's better to avoid such marginal conditions. --------------------- >>>>> SmartZIP Syntax --------------------- To run the program, key the following at the DOS prompt: SMARTZIP [path]zipname [[path]filespec] [/B [/D]] [/K | /O] [/M] [/R] "zipname" = the name of the ZIP file to be created or updated. If not specified, the file extension defaults to "ZIP". If an extension is specified, it must be "ZIP". "filespec" = an optional pattern for specifying the files to be SmartZIPped. Wild cards (* and ?) are supported. The default is to SmartZIP all files (i.e., *.*). "/B" = Use both PKZIPs. Try 1.xx Imploding/Shrinking AND 0.9x Reducing. (The default is to try only PKZIP 1.xx Imploding/Shrinking.) SEE NOTE BELOW. "/D" = "Dumb" ZIPping (with "/b" only). This will force SmartZIP to try ALL four levels of reducing for each file. "/K" = Keep existing ZIP file date. "/M" = "Move" files to the ZIP file. The default is to add files to the ZIP file. "/O" = Set ZIP date to date of latest file. "/R" = ReZIP the ZIP. NOTE: If you wish to use the "/B" option to use both PKZIP 1.xx Imploding/Shrinking and PKZIP 0.9x Reducing (HIGHLY recommended), you MUST rename PKZIP 0.9x's .EXE file from "PKZIP.EXE" to "PKZIP09.EXE" and place it in a directory in your PATH. SmartZIP has extensive logic for checking syntax and detecting errors. When SmartZIP detects an error, a high-intensity error message will be displayed along with an "information panel" showing correct syntax and brief help information. -------------------------------------- >>>>> Error Return Codes (ERRORLEVELs) -------------------------------------- SmartZIP returns an error code that can be tested within a batch (.BAT) file using the DOS "ERRORLEVEL" variable. Since SmartZIP invokes PKZIP (and PKUNZIP, if you're using the "/r" [reZIP] option), error codes from the PKWare program will be returned if the PKWare program detects an error. In order to avoid confusion between error codes returned from PKWare programs and those returned by SmartZIP, all SmartZIP error codes are greater than 100. PKWare error codes may be found in the PKWare documentation for PKZIP and PKUNZIP. SmartZIP will return one of the following ERRORLEVELs: 0 No error; normal completion. 1-100 PKZIP/PKUNZIP return codes. See PKWare documentation. 101 Nothing to do. No ZIP file or parameter specified. 102 Unrecognized option. 103 No ZIPname specified. 104 Excess parameters. 105 PKZIP.EXE not found on PATH or /B option specified and PKZIP09.EXE not found on PATH or /R option specified and PKUNZIP.EXE not found on PATH. 106 ZIP filename extension not valid (i.e., other than ".ZIP"). 107 ZIP filename not valid. 108 File specification not valid. 109 ReZIP requested and ZIP file specified does not exist. 111 No files found matching file specification. 151 Unable to allocate buffer for merge phase. Probable memory shortage. 152 Unable to open one or both merge input files during merge phase. 153 Not enough disk space to merge files during merge phase. 154 Unable to create merged output file during merge phase. 155 ZIP signature size error. Probable truncated ZIP file. 156 End central directory signature not found. Probable truncated ZIP file. NOTE: Since SmartZIP creates/updates the ZIP file "in flight", if some error is encountered (for example, insufficient space remaining on the disk) that forces SmartZIP termination, the ZIP file, if it exists, will contain only those files SmartZIPped up to the point of termination. If you're using the default ("add" to the ZIP file), you probably won't care. However, if you're using the "/M" option ("move" files to the ZIP file), you should be aware that the ZIP file contains the files that have already been moved into it and should be retained. ------------------------------------------ >>>>> SmartZIP Execution Time Optimization ------------------------------------------ Although I'm interested in optimum compression, I'm not interested in infinite execution time. Although SmartZIP will always identify the optimum compression algorithm in as few as two trials and never more than six, there are some things you can do to further minimize SmartZIP execution time: - Build the ZIP file on a RAM disk. Since SmartZIP is write- intensive, use of a RAM disk will do more to minimize SmartZIP execution time than any other single action you can take. The easiest way to do this is to change to your RAM disk (i.e., get to the point where your prompt is your RAM disk's drive letter) and execute your SmartZIP command from there. Paths may be specified for the ZIP file and filespec, as necessary. - Have a large disk cache active. Since PKZIP.EXE is invoked multiple times (and PKZIP09.EXE if you're using the "/b" option) and each file being SmartZIPped could be read multiple times, a large disk cache will also help significantly. I run SmartZIP with all temporary files residing on a RAM disk and I also have a 2048K disk cache active. This results in VERY fast runs, even on a 6-MHz PC/AT. On a 20-MHz PS/2 model 80, SmartZIP screams! --------------------- >>>>> Technical Stuff --------------------- SmartZIP was written, compiled and tested using Microsoft's Quick C. The final compilation and testing were done using the Microsoft C optimizing compiler. SmartZIP creates temporary files named "JVSMRTZP.xxx". If you terminate SmartZIP inelegantly (please don't), you might have to delete these files. ----------------------------------- >>>>> Who Am I and Do I Want Money? ----------------------------------- I'm Joe Vincent and this isn't my day job. I've put a roof over my family's heads and food on the table for 30 years as a computing professional working in large IBM mainframe installations. I consider myself one of those fortunate people who get paid for doing what they love to do. SmartZIP is shareware. That means that you are encouraged to try it to see if it meets your needs and, if you decide to keep and use the program, register it and pay a reasonable fee ($12 per copy suggested). Those who register SmartZIP will receive: - "MergZIPs", a program that will merge two existing ZIPs together without requiring any intermediate unZIPping of either or both of the two ZIPs. This program is not available as shareware. It's only available as a premium for registering SmartZIP. - The next release of SmartZIP as soon as it is released. ----------------- >>>>> Recognition ----------------- I want to recognize the significant contribution made to the computing field in general and data compression technology in particular by Phil Katz, author of PKZIP, PKUNZIP, et al. SmartZIP invokes PKZIP via the Microsoft C "spawn" command. If it weren't for the incredible efficiency and speed of PKZIP, SmartZIP wouldn't perform as well as it does. If you don't already have Phil's ZIP utilities, you can obtain them on just about any BBS or by contacting PKWare directly at: PKWARE, Inc. 7545 North Port Washington Road Glendale, WI. 53217 ---------------------------- >>>>> Disclaimer of Warranty ---------------------------- This software and documentation are distributed "as is" and without warranties as to performance or merchantability. The author makes no warranties whatsoever, either express or implied, with regard to this software and other material distributed with this software and hereby disclaims any and all implied warranties of merchantability or fitness for a particular purpose. Because of the diversity of conditions and hardware under which this software may be used, no warranty of fitness for a particular purpose is offered. The user is advised to test the software thoroughly before relying on it. The user must assume the entire risk of using the software. In no event will the author be liable for incidental or consequential damages, including, but not limited to, destruction of data or damage to your equipment. ------------------------- >>>>> Contact Information ------------------------- Registrations, suggestions, comments and reports of anomalous SmartZIP behavior should be directed to: Joe Vincent Joseph A. Vincent Consulting 805 Pine Way Anchorage, Kentucky 40223-2361 Voice: (502) 244-1541 Data: Exec-PC BBS, (414) 789-4210, PC Applications conference, File Compression topic. PKWare BBS, (414) 352-7176