What is an Archive?

Archives are files that contain other files.  Typically the files in an archive are compressed.  Archives usually have file names ending with ZIP, LZH, ARJ, or ARC, depending on how they were created.  Archives make it easy to group files and make transporting and copying these files faster.

Typical Uses for Archives:

·           Most files available in "file areas" on bulletin boards and electronic services like CompuServe and the Internet are distributed as archives.  Two benefits of using archives for electronic file distribution are that only one file transfer operation ("download") is required to obtain all related files, and file transfer time is minimized because the files in an archive are compressed.  See the sections titled Install/Try/Uninstall Feature and CheckOut Feature for information about WinZip features particularly suited for working with downloaded files.

·           It is often useful to send a group of related files to an associate.  Rather than distributing individual files it is often easier to distribute the files as an archive to benefit from the file grouping and compression.

·           Some files are important but not used often.  To save disk space simply compress these files into an archive when they are not used, and decompress them only when needed.

What is a Self-Extracting Zip File?

A self-extracting Zip file is an executable program file (.EXE file) that includes both a Zip file and software to extract or "unzip" the contents of the Zip file.  Users can extract the contents of a self-extracting Zip file by simply running it.  This is convenient, because the end user does not need an unzip program (like WinZip) to extract files from these self-extracting archives.

WinZip Self-Extractor Personal Edition, included with WinZip, creates native Windows self-extracting Zip files.  You can also create self-extracting ARJ and LZH files.  This, however, requires external programs, as described in the section System Requirements.

Archive formats:

·           Zip files are the most common archive format.  WinZip does not use external programs to work with Zip files.

·           ARJ files are another popular archive format.  ARJ files are manipulated by the ARJ program from ARJ Software, P.O. Box 249, Norwood, Massachusetts 02062.

·           LZH files are manipulated by the LHA program from Haruyasu Yoshizaki.  LHA won the October 1991 PC Magazine Editor's Choice award as the best data compression utility.

·           ARC is an older format.  ARC files can be manipulated by several programs, including the original ARC, ARCE (also known as ARC-E), PKXARC, and PKUNPAK.  Since almost all new archives are created in other formats and there is no single widely available program to manipulate ARC files, WinZip does not provide facilities to add to ARC files (however, all other WinZip functions are supported).

·           TAR, Z, GZ, TAZ, and TGZ files are often found on Unix-based Internet sites.  The relationship between these file types is less straightforward than the aforementioned file formats.  The important thing to remember is that WinZip handles all these formats the same way as Zip files, so you don't need to know the details.  Here is more information on these formats:  TAR stands for "Tape ARchive".  This is an old file format and does not provide compression; it is used only to group files.  Z files are compressed with gzip or the older Unix "compress" program.  GZ files are gzip files.  Z and GZ files cannot contain multiple files.  TAZ and TGZ files are TAR files compressed in "Z" or "GZ" format.  Since almost all new archives are created in Zip format WinZip does not provide facilities to add to or create files in these formats (however, all other WinZip functions are supported).  WinZip does not require external programs when working with files in these formats.

·           UUencoded, XXencoded, BinHex, and MIME files are used primarily to transfer binary files by Internet e-mail.  If you encounter one of these files, you can open it and extract its contents with WinZip.  You can UUencode an archive using the UUencode entry in the WinZip Actions pull-down menu.

·           WinZip also handles many files in the Microsoft Compress format (also known as LZEXPAND format).  However, there are several variations on this format, and Microsoft has not released documentation on these variations.  Therefore, you are limited to decompressing files supported by your version of Windows (Windows for Workgroups supports some files not supported by Windows 3.1).  WinZip issues an appropriate message if you attempt to decompress a file not supported by your version of Windows.  Microsoft Compress files usually end with a trailing underscore, for example, "commdlg.dl_".  Like Z and GZ files, Microsoft Compress format files contain only one file.  This format is used for many files on your Windows 3.x distribution disks and many other Microsoft products.  Note that not all files ending with an underscore are Microsoft Compress format files.

 

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