Online Acumen

13 pointless years on the net and counting

Compression Utilities

It seems you never hear about most "freeware" or "shareware" compression software programs. I can't remember ever reading a review in one of the popular computer magazines of a program that focused on the ARJ or RAR utilities.

The only compression utility they "inform" you of is the .zip file format. Unfortunately, you will find that you need two or three different utilities to handle all the formats on the net since no one utility can handle them all.

WINZIP

WINZIP is one compression utility that is constantly adding needed improvements while, at the same time, becoming simpler to use.

Version 8.1 supports plenty of features, one of which is virus scanning. WINZIP will also decompress the popular ARJ compression format, but you must have ARJ already installed on your computer.

Another cool feature is its ability to compress files while in Windows 95/98 Explorer. You simply highlight the desired files, right click and select Add to Zip. Winzip will even suggest a filename making this only a point and click process.

Winzip makes a big deal about the fact that they now, finally, support multi disk spanning. This is great when you want to zip up an entire directory that requires more space than that found on one floppy disk.

You can simultaneously uncompress several zipped files by highlighting them in Windows '95/98 Explorer, dragging them to a temp folder and then selecting the right-click "extract to folder" option.

The latest version is Winzip 10.0 and you can download it from here.

PKZIP/PKUNZIP

PKZIP is a great utility that includes a wealth of options, but is most powerful when the DOS version is used.

PKZIP and PKUNZIP perform tasks quickly, whether you need to zip or unzip multiple files and both can be added to batch files that handle these functions.

The text below is from my pkunzip.bat file that automates the process of unzipping a multiple number of files.

Note: In order to run this batch file you must have the PKUNZIP.EXE file in the same directory as the archive or in one of the folders listed in your autoexec.bat's PATH STATEMENT.

@echo off

mkdir D:\Newfiles

pkunzip -d -o *.zip D:\Newfiles

mkdir creates the Newfiles directory on the D letter drive.

(-d) unzips the files into a restored directory structure inside the D:\Newfiles folder.

(-o) overwrites duplicate files.

PKZIPFIX

Another great feature PKZIP has is its ability to fix corrupted zipped files. Due to the way modems retrieve data from the Internet, as well as, many other reasons, a file sometimes becomes corrupted during download. This is called a CRC error and renders the zip file unusable.

PKZIPFIX is the utility contained in PKZIP that allows you an opportunity to fix corrupted zip files. I have been able to salvage quite a few files with this program.

PKZIP also comes with outstanding documentation (over 100 pages) that explains in detail all of its many uses. This is really a must have for Internet users.

Download a copy of PKZ204G.EXE (198 kb)

How To Spot A Lamer

On some occasions you will come across files that have been archived using either ARJ or RAR.

Why, you ask? Well basically for two reasons:

Ease in archiving large file(s) down into several smaller files.

You achieve a greater compression ratio, meaning smaller overall file size, especially with RAR.

Note: Concerning RAR and ARJ, you may hear some negative comments about these utilities, the most common being they are too difficult or produce CRC errors - both of these statements are false.

Use this as a helpful way of identifying lamers.

WINRAR

The RAR compression format is probably the least publicized and is unknown to quite a few people who use the 'net. It offers great compression ratios however, as well as, many other benefits making it well worth the time spent learning to use it.

WINRAR is a superb windows port that easily matches WINZIP in ease of use.

Unlike WINARJ95 this version of WINRAR is faster and far more reliable than the DOS version of RAR, especially when archiving a large number of files.

WINRAR also allows you to test and repair damaged archives, although its success rate is dismal.

Download a copy of WINRAR 3.51 (620 kb)

RAR

This utility is kinda odd in that you can use both RAR.EXE and UNRAR.EXE to extract files.

Unlike ZIP files, RAR files can have ending extensions other than just .rar The most common extensions consist of (.rar, .r00, .r01, .r02 etc.) or the less common format of (.001, .002, .003 etc.)

Here is a batch file that shows you how to decompress one or more RAR files into a directory named temp. The file extension .001 replaces .rar in the batch file when applicable.

@echo off

mkdir temp

unrar x -v -y *.rar temp

( x) Extract files with full path.

(-v) Process all volumes from current.

(-y) Overwrites existing files.

Note: In order to run batch files using RAR you must have RAR.EXE/UNRAR.EXE in the same folder as the archive or in one of the folders listed in your autoexec.bat's PATH STATEMENT.

RAR is very powerful and easy to master. I know because I was able to learn it without having to buy a book on it, and believe me, I own a lot of books.

Download a copy of RAR 2.06 (268 kb)

CD-RIPPER

Say you wanted to split up a 10 MB file so that it would fit on multiple 1.44 MB size floppy disks.

The easiest way using RAR to accomplish this is with this great freeware utility called CD-Ripper.

Read all about the features found in the CD-Ripper(4 KB)

Download the CD-Ripper.(1 MB)

WINARJ

WINARJ95 is slow and unstable due to the vast number of options ARJ incorporates. The Windows user interface is poorly coded and seems to be only a "shell" sitting on top of the DOS version.

So while the interface is fairly straightforward and easy to use, WINARJ95 lacks speed and your never quite sure when its done. Basically the graphical interface just sucks up resources that could be used speeding up the decompression of your files.

Avoid this utility because the DOS version of ARJ is far superior.

ARJ

ARJ 2.60 is my favorite compression utility because it never bogs my system down by hogging resources and it's extremely fast.

To run an ARJ batch file from Win95 explorer all you have to do is copy the batch file to the directory of the files you want to decompress and double-click on it.

A DOS window will then open and you can observe the whole process. When it's finished you simply close the DOS window.

This assumes you have ARJ.exe in your path statement. If you don't, just copy ARJ.exe along with the ARJ.bat file to the directory that contains the files.

Just like RAR files, ARJ files can have ending extensions other than .arj consisting of .a01 or .001

Here is an example of an ARJ batch file.

@echo off

mkdir temp

arj x -v -y *.arj temp

( x) extracts the files to temp directory.

(-v) processes multiple zips or volumes in the archive.

(-y) Overwrites existing files.

Download ARJ version 2.60 (347 kb)

JAR

JAR is a JAVA application that combines multiple files into a single JAR archive file. JAR is a general purpose archiving and compression tool, based on ZIP and the ZLIB compression format.

However, JAR was designed mainly to facilitate the packaging of java applets or applications into a single archive.

When the components of an applet are combined into a single archive, they may be downloaded by a browser in a single HTTP transaction, rather than requiring a new connection for each piece.

This dramatically improves download times, in addition, to allowing individual entries in a file to be signed by the applet author so that their origin can be authenticated.

Here is the results of a comparison test of all the different compression formats that shows just how powerful the Jar archiver can be.

Download JAR102 (509 kb)