Kyle Jones <kyle_jones(a)wonderworks.com&gt; writes: 66% of pure storage is strings. These cannot refer any anything so it is irrelevant for them, isn't it? Wy does it need to be enforced "by the OS"? Isn't it enough if we enforce it "by hand"? I still think the best solution would be to stop using purespace for conses and keep the checks for other things that can refer to lisp objects and can be changed (that would really be just the vectors) and even THAT is just another 14%. So my mistake was that the loss of 80K for not using pure store for cons cells is incurred on all systems, including modern ones. Jan