Twm
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- The title of this article is incorrect because of technical limitations. The correct title is twm.
In computing, twm (Tom's Window Manager or Tab Window Manager) is the standard window manager for the X Window System, version X11R4 onwards. It is a re-parenting window manager that provides title bars, shaped windows and icon management, and is extensively configurable.
twm was a breakthrough achievement in its time, but has been largely superseded by other window managers and is no longer maintained. Despite being obsolete, it made a strong impact on the development of X window managers. Many others, such as swm (also by LaStrange), vtwm, tvtwm, ctwm, fvwm and their derivatives, were built on its code, while many others used concepts pioneered by it.
Although it is generally regarded as the window manager of last resort, a small but dedicated minority of users favor twm for its simplicity, light weight — rather than being written to a widget toolkit, it is written in C directly against Xlib — and tremendous customizability. twm is still standard with the X.Org reference implementation and is available as part of many X distributions.
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Using twm
twm's interface is very different to that of common X window managers and desktop environments of the present day, which tend to work similarly to the Apple Macintosh or the various versions of Microsoft Windows. New users often find twm difficult to understand without reading the manual page.
In the default configuration of twm, the title bar has two buttons:
- Resize button (nested squares): the user clicks here, drags the mouse pointer to the edge they wish to move, then releases when the window is the desired size.
- Iconify button (circle): reduces the window to an icon.
There is no title bar button to close a window. A left click on the desktop brings up a menu, which includes an option to kill a window.
A left click on the title bar brings the window to the top of the window stack; a middle click moves the window; a right click sends the window to the bottom of the window stack.
Window focus follows the mouse pointer (point-to-focus), rather than being on whichever window was clicked last (click-to-focus).
When a new window is created, a 3×3 grid is displayed following the mouse pointer, waiting for the user to click where they wish the window to appear — left-click to appear in that position with that size, middle-click to resize the window before its creation, right-click to appear in that position but long enough vertically to reach the bottom of the screen.
Note that any of the above may be changed with appropriate changes to the configuration file.
History
twm was written by Tom LaStrange, then at Solbourne Computer, starting in 1987, owing to frustration with the then-standard uwm: "I sat down at my monochrome Sun 3/50 and typed vi twm.c and then opened the X11 documentation. twm was my first X program. About six months later, I convinced my manager to let me send a copy to the comp.windows.x newsgroup." [1] (http://www.linuxplanet.com/linuxplanet/reports/3000/2/) A version for X11R1 was published on the Usenet newsgroup comp.unix.sources on June 13, 1988.
Nine months later, Jim Fulton of the MIT X Consortium approached Tom to request that he hand over the maintenance of the code to the X Consortium. After it was made compliant with the then new Inter-Client Communication Conventions Manual and support was added for shaped title bars, twm was released as the standard window manager for X11R4, replacing uwm.
twm originally stood for Tom's Window Manager. When the X Consortium took over its maintenance, and several other people had contributed substantially, its name was changed to Tab Window Manager. The vtwm.gamma man page says:
- To save Tom LaStrange from being blamed for any of the massive numbers of changes that have been done to twm since he gave up control of it, the name "twm" now stands for "Tab Window Manager".
The word "tab" was most likely picked because it started with T, but the official line of reasoning is that with appropriate configuration (the SqueezeTitle option), the window title bars can be squeezed, making the windows look like folders with tabs.
Authors
twm was originally written by Tom LaStrange. Later substantial contributors include Jim Fulton, Keith Packard and Dave Sternlicht, all three at the X Consortium at the time, Steve Pitschke, then at Stardent Computer, and Dave Payne, then at Apple Computer.
References
- twm — Tab Window Manager for the X Window System (http://www.x.org/X11R6.8.2/doc/twm.1.html) — man page (X.org)
- Tab Window Manager (http://xwinman.org/vtwm.html) (xwinman)
- Original comp.unix.sources posting (ftp://ftp.isc.org/usenet/comp.sources.unix/volume15/twm/)
- An Overview of twm (Tom's Window Manager) (http://www.lastrange.com/work/twm.pdf) (PDF) — Tom LaStrange, Xhibition '89 Conference Proceedings — concerning pre-ICCCM versions of twm
- From the Desktop: Tom LaStrange Speaks!: Talking with a Man Named Tom (http://www.linuxplanet.com/linuxplanet/reports/3000/2/) (Brian Proffitt, LinuxPlanet, Tuesday 6 February 2001)