-;;; without any documentation. However, there have been a few changes
-;;; since the fork:
-;;; * The FreeBSD STATIC-SPACE-START value was bumped up
-;;; from #x28000000 to #x30000000 when FreeBSD ld.so dynamic linking
+;;; without any documentation. However, there were a few explanatory
+;;; comments in the CMU CL sources:
+;;; * On Linux,
+;;; ** The space 0x08000000-0x10000000 is "C program and memory allocation".
+;;; ** The space 0x40000000-0x48000000 is reserved for shared libs.
+;;; ** The space >0xE0000000 is "C stack - Alien stack".
+;;; * On FreeBSD,
+;;; ** The space 0x0E000000-0x10000000 is "Foreign segment".
+;;; ** The space 0x20000000-0x30000000 is reserved for shared libs.
+;;; And there have been some changes since the fork from CMU CL:
+;;; * The OpenBSD port is new since the fork. We started with
+;;; the FreeBSD address map, which actually worked until the
+;;; Alpha port patches, for reasons which in retrospect are rather
+;;; mysterious. After the Alpha port patches were added, the
+;;; OpenBSD port suffered memory corruption problems. While
+;;; debugging those, it was discovered that src/runtime/trymap
+;;; failed for the control stack region #x40000000-#x47fff000.
+;;; After the control stack was moved upward out of this region
+;;; (stealing some bytes from dynamic space) the problems went
+;;; away.
+;;; * The FreeBSD STATIC-SPACE-START value was bumped up from
+;;; #x28000000 to #x30000000 when FreeBSD ld.so dynamic linking