The Mouse!

I've always thought the mouse was 'jumpy' under Windows.... Now I have proof!

Mouse update frequency and syncronicity. On the mac, it depends on you monitor verticle refresh frequency (as set in the montiors control panel) and could anywhere from 50Hz (Only on my Amiga MacOs PAL emulation) to way up 70,80, 100Hz. The mouse is totally smooth and tracks beustifully as a result. Unfortunately, Windows 3.1 and Win95 both have very dumb thing called a "software polled" mouse pointer update. The CPU sends the initiative to check the mouse using a pre-emptive time-scheduling facility (yes even on Win3.1 - it's called an interupt). But it wasn't synced to the monitor like the MacOS, Amiga Workbench, and The Atari Pointer, and as a result the pointer jerks and bumps across the screen. The software polled/timed approach is also used on X Windows (Silicon Graphics also suffers the same problem), WindowsNT, and OS/2. An Example: Mouse movement = 75 pixels Screen Refresh Rate = 75 Hz On the Mac: 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, = smooth movement On Windows: (assuming a mouse refresh of 51, which is good for windoze) 0.68 - a fraction comes out as 0, 1, 1, 0, 1, 1, 0, 1, 1 = jerky movement 0.68, 1.36, 2.04, 2.72, 3.4, 4.08, 4.08, 5.44 you get the idea, its very very jerky. Source: http://funk.co.nz/windoze-vs-mac.html