ACE (compression file format)
This article relies largely or entirely on a single source. (February 2016)
|Internet media type||
|Developed by||e-merge GmbH|
|Type of format||data compression|
In computing, ACE is a proprietary data compression archive file format developed by Marcel Lemke, and later bought by e-merge GmbH. The peak of its popularity was 1999–2001, when it provided slightly better compression rates than RAR, which has since become more popular.
WinAce, maintained by e-merge GmbH, is used to compress and decompress ACE files under Microsoft Windows. When installed, it lets the user choose between paying for a registration or installing WhenU adware. e-merge GmbH also produces a Commandline ACE for DOS; and a freeware command-line decompression tool for Linux (i386) and Mac OS X called "Unace". e-merge GmbH also provides several libraries for developers, including a freeware decompression DLL called "UnACE.DLL". Some third-party archivers can read the format using this DLL. None of the above is open source free software.
An older version of an Unace 1.2b is free software and licensed under the GPL by the author Marcel Lemke, but it cannot extract ACE archives from version 2.0 and newer. A newer version of Unace 2.5 that supports ACE 2.0 archives is available under a restrictive open source license, also by Marcel Lemke.
On November 23, 2007, version 2.69 of WinACE was released, including a less intrusive adware application, MeMedia AdVantage, which replaces WhenU. No other major changes are in this release.
Packing of ACE files is licensed as proprietary information and only available through WinACE, while unpacking of ACE files is supported by a number of third-party archivers. However, virtually all of them (the ones that support ACE 2.x format) do this by using the proprietary "Unace.dll" from e-merge GmbH. Since 2017, there is a BSD licensed python module that supports unpacking of ACE 2.x format archives.