You can comfortably read and comprehend the Unix v6 kernel source code in a day or two. The printed form of Lyons Notes is about half a centimeter thick, maybe

You can comfortably read and comprehend the Unix v6 kernel source code in a day or two. The printed form of Lyons Notes is about half a centimeter thick, maybe 150 pages. Machines were smaller then, too. 64K of code on a PDP-11, small ROMs (hundreds of KB) for the larger embedded systems. My belabored point: Systems were smaller. There was a lot less typing involved :-)