# Retro7zip for DOS

Retro7zip is a native backport of 7-Zip for DOS that runs on old Microsoft
operating systems.


## System Requirements

* DOS 3.3
* 386 CPU
* 4MB RAM (for 7zm.exe)

* https://github.com/dajhorn/retro7zip/wiki/System-Requirements


## Downstream Support

* https://github.com/dajhorn/retro7zip/issues
* https://github.com/dajhorn/retro7zip/discussions


## FreeDOS Installation

On FreeDOS, do this:

	RENAME 7zip-24.09+3_dos.zip 7zip.zip
	FDNPKG INSTALL 7zip.zip

On any other platform, unzip the release file and put the EXE files anywhere in
the %PATH%.


## 7-Zip Program Variants

This DOS package contains four executable files:

This release package for DOS contains four executable files:

  1.  `7zm.exe` Mini for DOS

Runs on computers that have less than 8 megabytes of memory.  Implements only
the BCJ2 filter, LZMA2 codec, and 7Z container that are used in regular 7-Zip
archives.

  2.  `7zr.exe` Reduced for DOS

Runs best on computers that have at least 8 megabytes of memory.  Implements
all filters, codecs, and containers for the archive formats that 7-Zip can
read and write.  (7z, bz2, gz, tar, xz, zip.)

  3.  `7za.exe` Aggregated for DOS

Contains all upstream features, including support for filesystem images and
exotic archive formats.  Requires more than 8 megabytes of memory to unpack
some complex files.  (Run `7za i` for a complete list of supported types.)

  4.  `7zdec.exe` Minimalistic for DOS

The smallest possible 7z unpacker. 
