An old and inefficient format. But to exchange files with older operating systems or read old files, you may need an ARC program.

ARJ [suffix .arj; for archiving and compression]

ARJ, developed by Robert Jung was very popular in the 1980s, and common on DOS machines. Fairly slow, but sometimes achieved better compression than gZip, Zip, and StuffIt formats.

BinHex [suffix .hqx; for encoding]

BinHex converts binary data to text data for transmission over text-based systems such as e-mail attachments and Internet news.

gZIP [suffix .gz, .z, .Z; for compression]

gZIP is a UNIX compression utility similar to ZIP on the PC, but it can only compress single files [it does not combine multiple files into an archive]. It can decompress the older UNIX "Compress" format as well.

DMS [suffix .dms]

Popular disk archiver that compresses the 'image' of a disk to a single file. Ideal for transfering non-standard media and maintaining original format.

LHA/LZH [suffix .lha, .lzh; for compression and archiving]

LHA was a fast compressor and produced tight archives. LHA and LZH formats are usually [but not always] interchangeable.

MIME [encoding]

The primary use of MIME [Multipurpose Internet Mail Extensions] encoding is to convert binary data to text for transmission over e-mail or as Net news. Some e-mail and newsreader programs handle this conversion automatically.

RAR [suffix .rar; for compression and archiving]

A popular compression format developed by Eugene Roshal, RAR is available for DOS, Windows 3.x, Windows 95, OS/2 and UNIX.

StuffIt [suffix .sit; for compression and archiving]

The primary compression program for Macintoshes, Stuffit is a universal favorite on Macs.

ShrinkIt [suffix .shk; for compression and archiving]

This is the primary Apple II compression program. ShrinkIt GS can read .arc, .zoo, and .sit [the ancient 1.51 format only] files if you need to transfer files to the Apple II from some other platform.

TAR [suffix .tar; for archiving]

The .tar format can archive files [combine many files into one file] but not compress, so tar files are usually gZipped, leading to the common file suffix .tar .gz.

UUEncode [suffix .uu; for encoding]

The primary use of UUEncode is to convert binary data to text for transmission over e-mail or Net news.

ZIP [suffix .Zip; for compression and archiving]

ZIP is the de facto standard. It's speed and compression are excellent, and it is now available for DOS, Win 3.x and OS/2. Many other compression tools give ZIP compatibility.

Zoo [suffix .zoo; for archiving and compression]