---EDIT
Now (V5.66.731, 2012-03-25) IdoswinPro is freeware as well, no more nag-screen on startup.
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Maybe a drawback for some of you: it is only available in german (as far as i know).
features:
- dual-pane, vertically or horizontally, with or without folder tree -- unfortunately no tabs
- folder size in bytes or kiB
- file comparison
- folder comparison/ synchronization
- file search and filtering
- view files in hex, binary, text or image format
- built-in editor
- shows file extensions (also pif ..., which are not shown in windows-explorer even if "hide known file extensions" is unchecked)
- keyboard shortcuts/ programme launcher
- customizable user interface
- file splitter
- read and extract zip, cab, rar and ace archives, edit zip-archives
Dependencies: none(?)
How to extract: Download the installer-exe and extract to a folder of your choice. Launch idoswin32.exe/ idoswinpro.exe. You can also install it normally to any location (see EDIT below).
Stealth [?]: (?)
License: Freeware
System Requirements: Win2K / WinXP / Vista / Win7 (see bottom of http://www.idoswin.de)
----EDIT
during normal installation according to info.rtf-file: icons in start-menu and on the desktop, registry entry for file type .split and entry for explorer context menu, no other changes in registry or file system, admin rights not necassary. All of these changes are OPTIONAL.
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screenshots: http://www.idoswin.de/idosview.htm
functions free/ pro: http://www.idoswin.de/idosfree.htm
download: http://www.idoswin.de/idosdnld.htm
Information from the auther: "Idoswin Free/ Pro starts from a stick without special installation."