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Dmitriy Kostiuk
Type devroom
Starts on day 2 (2021-02-07) at 10:30 (Brussels time, UTC+1) in room Retro (duration 00:30)
Matrix room #retro:fosdem.org
Running old-time OS in a virtual machine often comes with a problem of non-coinciding cursors. A relative positioning device (mouse and trackball) provides the operating system with a vector of the cursor movement instead of its coordinates. As a result, different cursor acceleration formulas are breaking the coincidence of host and guest systems cursor. Fortunately, modern guest operating systems support absolute positioning devices (tablets), which provide real cursor coordinates. Desktop virtualization systems emulate such devices (USB Wacom tablet in case of QEMU), allowing the host cursor to control guest systems in so-called "mouse integration mode".
Until recent times mouse integration was available only if guest OS either has a driver from the virtual machine vendor or supports USB tablet. In all other situations, desktop virtual machines use "mouse lock mode". The host cursor is hidden, and the user can only interact with the guest system until some dedicated keypress.
Starting from version 1.9, QEMU had accepted our GSOC-developed patch intended for the osimeline project (HTML-based live demo of historical operating systems) and can emulate the RS-232 Wacom tablet as a "wctablet" character device backend.
Currently, QEMU is the only virtualization system with such capabilities.