Beyond WinZIP
John R. Joyce, Ph.D.
If you work in the MS Windows world you no doubt have encountered ZIP files, normally recognized by their ‘zip’ file extension. These files are used for a variety of purposes and have an ancestry extending back into the ‘prehistory’ of the DOS world. While these files can simply serve as an envelope to consolidate a number of related files, in most instances they are also used to deflate, or compress, the contained files so that they can be stored more efficiently. While this is still an important use today, with multi-megabyte applications, it was even more critical in DOS days, with only 360 KB floppy disks to store and move data around -- even less if you only had the original single-sided single-density drives.
Phil Katz (1962-2000)1 created the original format in 1989 as a response to efforts to keep the ARC compression format, created by Thom Henderson, proprietary. Phil formed the company PKWARE to develop and sell a file compression program based on this format, which he called PKZIP.2 Over the years, additional compression protocols were added so that instead of having to maintain a suite of programs to compress and decompress files, you frequently only had to have one. With the advent of Microsoft Windows, Nico Mak Computing released the program WinZip as a graphic interface shell for PKZip and has continued to enhance this application over the years since its original release, with later versions adding their own compression algorithms, so that PKZip was no longer required.3 While there are now many file compression and decompression utilities available, WinZip continues to be one of the best known, so much so that the company, now owned by Corel, changed its name to WinZip. For those interested in the technical details of this file format, you can download a copy of it from the PKWARE Web site.4 The WinZip application has a single user retail price of $29.95.
ZIP files are not the only file compression scheme around, but they are still probably the most common one in the Windows world and the format has made inroads elsewhere. You will also find these files around hiding under a variety of pseudonyms. For example, the envelope files that Agilent’s OpenLAB Scientific Data Management System (SDMS) uses to store its data are ZIP files, albeit with a slightly modified name. If you are involved with Java, you have no doubt used their JAR files, which are specified around the ZIP format. Since 1998 it can be found within versions of Microsoft Windows under the name ‘compressed folders.’ Versions of Mac OS X 10.3 and above also directly handle ZIP files. This remains true today, although some systems I’ve seen, feature a trial version of the WinRAR compression utility as well. In fact, with the ZIP file association redirected to the WinRAR program, you might think that the native ZIP support has been removed. However, it still seems to be there, you just have to go into Windows Explorer and re-associate the ZIP extension with the Windows Explorer application (alternately, when in Windows Explorer, right click on a ZIP file and select “Open With”, allow Windows to suggest an application, and select “Windows Explorer” and check the box that says “Always use the selected program to open this kind of file.” Currently supported extraction file types include RAR, ZIP, CAB, TAR, GZIP, UUE, JAR, Z, BZIP2, 7-ZIP, ISO, IMG and ZIPX.
Despite the obvious container association, the term ‘zip’ was apparently not selected for an analogy of zipping a bag closed to represent a containing file. Rather, this term was apparently suggested by Robert Mahoney, a friend of Katz, for its suggestion of speed,2 as one of their driving design criteria was to develop a faster compression system than those currently extant. This desire to keep improving the process is probably one of the major factors driving things today, both within WinZip and their official product and all of the other developers who have created competing utilities. The details will vary with the specific developer, but some appear to be driven by increasing the number of compression file types supported, others by the usability of the interface, and, I suspect, some just to see if they can do it. Whatever the reason, today you have many alternatives to using the WinZip application itself. Some of these are distributed as Shareware, others as standard commercial applications, and some as Freeware. The following describes just a few of the other file compression utilities currently available. Please check the vendors Web site for additional information.
Depending on who you talk with, one of the better competitors is the command line program RAR and its Windows scion WinRAR. This utility currently can compress and extract files from compressed RAR, ZIP, CAB, ARJ, LZH, ACE, TAR, GZip, UUE, ISO, BZIP2, Z and 7-Zip files.5 On the fun side, it includes multiple themes that can be used to customize its appearance, ranging from Disney’s Aladdin to Medieval, with just about every possible permutation between. More importantly, for most people, are versions of the UnRAR utility for operating systems ranging from the PowerPC, to various Linux, Sparc, and AIX implementations (among others). It should be noted that RAR is a closed specification, meaning that many programs can uncompress a RAR archive, only RAR, WinRAR, and other applications that license the technology are allowed to create a RAR archive. Single user price is $29.
 |
| 7-Zip |
7-Zip v.9.2.0
6 is a free open source file archiver and file manager developed by Igor Pavlov. It currently can generate compressed archives in 7z, XZ, BZIP2, GZIP, TAR, ZIP and WIM formats, as well as extract files from over 30 different archive formats. Localizations are available in 79 languages and it is available in both installable and portable versions. The installed version provides strong integration with the Windows shell. You do need to be aware that when performing wild card operations, it interprets wild cards somewhat differently than the traditional DOS and Windows handling. Specifically, if you use the wild card ‘*.*’, it will only process files that have both a name and an extension, it will not process files without an extension. Depending on what you are trying to do, to process all files, whether they have an extension or not, use the wild card ‘*’ or do not insert any wild card at all.
 |
| PeaZip |
PeaZip v.3.8
7 is the free open source file archiver and file manager that I currently find myself using most often. It actually originated as a graphical front-end developed by Giorgio Tani that integrates a number of command line driven archive packages, but now includes support for a native archiving format as well. Among the integrated archive utilities are Igor Pavlov’s 7z executable and Bulat Ziganshin’s FreeArc.
8 This version can create compressed archives in the 7Z, ARC, BZ2, GZ, *PAQ, PEA, QUAD/BALZ, TAR, UPX, WIM, XZ and ZIP formats and can extract files from a total of 133 archive types. It can be installed as an integrated Windows application, in place of the existing Windows Explorer file manager, or it can be run as a PortableApp, without installing anything in Windows at all. Of particular interest to some of you who are tired of hearing about Windows applications, PeaZip is also available in both installable and portable versions for Linux as well, with a Mac OS version under development. It is currently localizable to 27 different languages. I find its ‘Flat View’ particularly useful for recovering files from multiple archives that have been archived together.
 |
| IZArc |
Developed by Ivan Zahariev,
9 IZArc is a free closed source, proprietary file compression and archiving utility for Windows. As of v.4.1.2, IZArc can extract files from over 45 different compression formats, is localizable in over 40 different languages, and, as of v.4, provides Unicode support in file names. A portable version, IZArc2Go, is also available. While I have not used this particular utility, one of its more interesting features is support for extraction of files from within ISO disk images.
All of the above programs support strong encryption with those formats for which it is allowed, as well as drag-and-drop file transfer. Any of them would likely meet your needs in terms of processing your more commonly encountered archive formats, whether in Windows or Linux, though you would have to forgo use of a GUI with some of the Linux ports. So, as it so often does, selection of the ‘best’ option for you comes down more to the look and feel of the application, rather than its technical capabilities, as they can all do the job. If you just look at the screen shots, they could well look very similar as well. In this case, as all of these applications are either free or have extended trial periods, I recommend checking out their lists of supported archives, to ensure any of the more esoteric ones you might have to deal with are on there, then download those that do and give them a try.
For that matter, as their interfaces should all have a somewhat different ‘feel’ to them, you may discover that you like different apps for the different tasks you have to perform. If that’s the case, then keep the ones that make your job easiest. The best tool is the one that makes the job easiest to perform, not the tool that can do everything so-so. You may find that you prefer using one of these tools over Windows Explorer as well. If so, great! If everything else is equal, then the fewer interfaces you have to learn, the easier your job will be.
1. Founder Phil Katz | About Us | Security Software Company | PKWARE. at <http://www.pkware.com/about-us/phil-katz>
2. ZIP (file format). Wikipedia, the free encyclopedia at <http://en.wikipedia.org/wiki/Zip_file>
3. WinZip - Wikipedia. Wikipedia, the free encyclopedia at <http://en.wikipedia.org/wiki/WinZip>
4. File: APPNOTE.TXT - .ZIP File Format Specification. at <http://www.pkware.com/documents/casestudies/APPNOTE.TXT>
5. WinRAR download and support: WinRAR. WinRAR at <http://www.win-rar.com/rarproducts.html>
6. 7-Zip. 7-Zip at <http://www.7-zip.org/>
7. PeaZip - Free file and archive manager - 7Z RAR TAR ZIP... PeaZip at <http://www.peazip.org/>
8. PeaZip. Wikipedia, the free encyclopedia at <http://en.wikipedia.org/wiki/Peazip>
9. IZArc. Wikipedia, the free encyclopedia at <http://en.wikipedia.org/wiki/IZArc>
John Joyce is a laboratory informatics specialist based in Richmond, VA. He may be reached at editor@ScientificComputing.com.
