File-Compression Programs


This article was published by ComputorEdge, issue #2836, 2010-09-03, as the cover article, in both their PDF edition (on pages 6-12) and their website.

Ever since personal computers became commonly used in businesses and homes, most of the components inside the desktop PC have changed little in their physical size. While motherboards have gradually become smaller, the same cannot be said for media components, such as hard drives and optical drives. This has been the case primarily because years ago, the major manufacturers of computer hardware developed media size standards that generally have worked quite well, and those firms and their distributors eventually found themselves locked into the inertia of selling replacement parts of a certain size — as well as complete systems whose parts might need to be replaced or supplemented later. Perhaps the only instance of a distinct and radical change in component size, was achieved by Apple, when it replaced 5.25-inch floppies with 3.5-inch diskettes — possible only because of the company's monopoly on the manufacture of Mac hardware.

As for hard drives within desktop computers, the 3.5-inch form factor became a worldwide standard in little time, and shows no sign of relinquishing that position. (In laptops, 2.5-inch drives are the norm, because of the limited space within each unit.) So when people refer to the size of a hard drive, they are not referring to its physical dimensions, but instead to its capacity, i.e., how much data can be stored inside the drive. Nowadays, many hard drives can store more than one terabyte of data, which is a remarkable one million million bytes of information. This is a thousand times more than what the early hard drives could offer, and has allowed people to locally store much more complex and visually rich operating systems and applications, as well as music, movies, and other forms of multimedia.

Given these massive hard drive capacities, one might think that there would no longer be a need for people to save space on their hard drives by compressing files (also sometimes referred to as "archiving files", since oftentimes the individual's intent is to set aside files that she probably won't need in the near term, but may want to reference at a much later date). But data compression is being utilized more than ever before, for several reasons. Firstly, in the case of file compression (more on that in a moment), it is the most efficient way to group together and e-mail multiple files. Secondly, people are storing ever larger quantities of media files on their computers, and some of these are huge (e.g., movies). Thirdly, even though the average bandwidth of Internet connections has increased substantially, file sizes are growing just as fast, if not more so, and thus compression speeds up Web page performance and reduces bandwidth costs for companies hosting large files.

Data compression can be roughly divided into two types: drive compression (in which all of the files on a particular drive/partition are automatically compressed when written, and uncompressed when read) and file compression (which deals with individual files on an uncompressed drive). File compression has become such a ubiquitous and accepted capability that the major operating systems now include it as a built-in feature. For instance, Microsoft introduced native file compression with version XP of their flagship operating system — specifically, for partitions that have been formatted using the NTFS file system. Apple's Mac OS X boasts similar functionality. But if the typical user already has file compression built into his operating system, is there any further need for standalone file compression programs? Apparently there is, given the unflagging popularity of such applications. This is largely because these programs tend to produce smaller compressed files, support more archival formats, and offer encryption, among other valuable options.

As with just about every other software category, there are both commercial and free compression programs available. The most popular products from the former category include PowerArchiver, WinRAR, and WinZip. While these are all well-respected products, one may wonder how they can survive commercially given the availability of equally-capable free alternatives — a couple of which will be discussed below (for the Windows platform).


Even though all of the free programs should be more than adequate for everyday file compression, my personal favorite is 7-Zip, for a number of reasons. It is free, open source, and supports a wide variety of data compression formats — specifically, it is able to create and of course also read 7z, ZIP, GZIP, BZIP2 and TAR archive files, and it is able to read (but not create) ARJ, CAB, CHM, CPIO, DEB, DMG, HFS, ISO, LZH, LZMA, MSI, NSIS, RAR, RPM, UDF, WIM, XAR and Z files. It naturally offers full support for 7z, a native compression format that receives high marks.

7-Zip homepage
Figure 1. 7-Zip homepage

Even though the 7-Zip interface is just as spartan as the product's website, countless users prefer its clean and straightforward approach over those of the commercial applications, some of which have so many icons and menu options that they can be rather intimidating and time consuming to figure out how to use, especially for anyone unfamiliar with file compression or the new user.

7-Zip File Manager
Figure 2. 7-Zip File Manager

Viewing the contents of a sample ZIP file, the 7-Zip File Manager displays all of the needed information about the files contained within the archive: its name, size (unpacked and packed), last-modified datetime, file attributes, whether it is encrypted, any comment, its cyclic redundancy check (CRC) value, compression method, and file system. In addition to its own file manager, 7-Zip integrates with the Windows shell, which means that when you right-click on one or more files in Windows Explorer, you have immediate access to 7-Zip's commands, listed in the context menu that pops up.

7-Zip is fast and lightweight. You can use it on a Windows command line, making it ideal for use by Windows shell scripts or Perl scripts. It supports optional encryption using the strong AES-256 algorithm, when creating 7z and ZIP archive files. 7-Zip is truly international, with its support for 74 languages ("localizations"). It also offers an outstanding compression performance that is better than that of some of the paid products. According to its website, "for ZIP and GZIP formats, 7-Zip provides a compression ratio that is 2-10 % better than the ratio provided by PKZip and WinZip."


Italy may be known much more for its achievements in art than in software development, but that has not prevented some resourceful programmers (in Reggio Calabria, a city in southern Italy) from creating ZipGenius.

ZipGenius homepage
Figure 3. ZipGenius homepage

ZipGenius is free of any purchase price, licensing fee, advertisements, or spyware. It supports more archive formats than possibly any other free compression program (including some formats specific to multimedia players): ZIP, CZIP, EXE (ZIP SFX), JAR, EAR, WAR, DSFZ, BSZ, MSKIN, CBZ, PCV, XPI, SXW, SXI, SXC, SXD, STW, STD, STC, STI, SXG, SXM, OD*, ( 2.x documents), TAR, TAR.GZ, TAR.BZ2, TAZ, TGZ, ACE, RAR, R00, R01, EXE (RAR SFX), CBR, 7Z, ARJ, CAB, LZH, LHA, SQX, YZ1, RPM, ISO, NRG, CMI, WAL, and WMZ.

ZipGenius is available in two different editions — Standard and Suite — although the website does not appear to explain the differences between them. Nonetheless, combined they have apparently been downloaded over 3 million times, so there must be some qualities of this program that make it so popular. Immediately one will notice its attractive icons and interface (to be expected in a product from Italy).

ZipGenius interface empty
Figure 4. ZipGenius interface empty

If you decide to take this application for a test drive, you should find the installation process to be fast and easy. However, if you have an outbound firewall in place, it probably will detect that ZipGenius periodically tries to connect to the server "". This connection does not seem to be required, so you can choose to have your firewall block it in the future.

The site's overview page displays almost a dozen screenshots, but for a fair comparison with 7-Zip, see the figure below to compare the ZipGenius interface with that of 7-Zip when opening the same archival file.

ZipGenius interface with file
Figure 5. ZipGenius interface with file

For each file in the archive, ZipGenius reports most of the same details as does 7-Zip, except it is lacking any comment or file system indicator — although it does add file type, compression ratio, path, and a peculiar string of characters ("3...") at the end.

ZipGenius has garnered over three dozen awards, and has attracted an active community of users, who gather in the online forum.

Regardless of which of these two programs you may decide to use for your file compression needs, either one of them should give you better performance and speed than the native Windows functionality.

Copyright © 2010 Michael J. Ross. All rights reserved.

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