About Archive Files

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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, RAR, ARC, ARJ, ACE, LZH etc., 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 on the Internet and on electronic services like America Online and CompuServe 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.

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


Archive formats:


Zip files are the most common archive format.  Zip files can span multiple disks, and provide both compression and file grouping. IZArc does not use external programs to work with Zip files.

TAR, Z, GZ, TAZ, and TGZ files are often found on Unix-based Internet sites.  TAR stands for "Tape Archive".  The TAR format does not provide compression; it is used only to group files. GZ and Z files are gzip files.  GZ and Z files cannot contain multiple files.  TAZ and TGZ files are TAR files compressed in the gzip format.


File formats such as Uuencoded, XXencoded, BinHex, and MIME 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 IZArc.


IZArc also handles most files in the old 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. IZArc 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 the Windows 3.1 distribution disks and many older Microsoft products.  Note that not all files ending with an underscore are Microsoft Compress format files. IZArc does not use external programs when working with files in these formats.


The Microsoft CAB (short for Cabinet) format is used by most Microsoft setup programs, including those used to install Windows.  CAB files provide both file compression and file grouping.  You can use IZArc to open and extract the contents of CAB files. IZArc will handle most self-extracting CAB files. IZArc does not use external programs when working with CAB files.


RAR, ARC, ARJ, ACE, LZH and etc. are older formats that provide both grouping and compression, like Zip files.

IZArc does not use external programs when working with these files.