Dr. Dobb's Journal July 1998

The EvStack Kernel Enhancement

EvStack is an extremely flexible console system we designed to overcome some limitations of the current Linux-KGI kernel patch, which breaks some features and programs (notably XFree and SVGAlib). The basic idea behind EvStack is to pass events between independent modules instead of hardwiring the calls. This allows you to plug together a console and dynamically swap out parts, like the VT-emulation. Under EvStack, you can have xterm, Linux, and dumb consoles on the same machine as well as different fonts, screen sizes, and screen modes (for instance, graphical consoles) on the different virtual terminals. With the EvStack patch installed, you can do one of three things:

• Turn EvStack off at compile time, giving you traditional Linux console code.
• Turn EvStack on, but load or compile in the conlinux.o module, giving you traditional Linux behavior running on the new code.
• Turn EvStack on, but don't load conlinux.o, giving you pure EvStack behavior, with the additional conlinux API disabled and all configuration occurring via /proc.

-- A.B.