> This may vary by device type, I think I > heard Linux framebuffer driver source was most useful to developers > of one OS.
As a NetBSD user, I found the ISDN drivers in Linux considerably easier to read than the FreeBSD ones (NetBSD didn't include them at the time). I think NetBSD's philosophy of drawing a very clear boundary between machine-dependent and machine-indepndent comes closest to Plan 9; unfortunately, NetBSD is a bit more strict in its application: Plan 9 prefers the device drivers to be entirely in the machine-dependent space. Bottom line, both NetBSD and Plan 9 take their philosophy too far and neither can learn from the other. Which is why Linux drivers become the examples to follow :-) ++L
