[hdgvhicv]

My first machine with a mouse had 1 meg of ram. Mouse.sys was loaded into himem from memory and used something like 30kb of precious memory.

My first wheel mouse which looks exactly like my current mouse ran on my 4meg 486.

[Anamon]

Even back then we were looking for alternative mouse drivers with lower memory footprints, though =D some wouldn't load high (or not work im games when they were). Conventional memory was such a precious resource in DOS. With a bad mouse driver, you might've had to choose between having sound or mouse control in your game.

For emulated systems, I mostly use CuteMouse now, which occupies less than 4 kB. It sure would've been nice to have had that back in the day.