>You'd hope that other paging systems would use the same scheme. It's >simple and it makes sense. Yup, BSD and the SunOS 4.x/System V Release 4 VM system (which is different from the paging S5R2/S5R3 system described) also give you zero-fill-on-demand pages when you "sbrk()". V6, V7 and non-paging S3 and S5 zeroed the data out explicitly, as I remember.