nits

README

-xv6 is a re-implementation of Unix Version 6 (v6), which was developed
-by Dennis Ritchie and Ken Thompson. xv6 follows the structure and
-style of v6, but is implemented for a modern x86-based multiprocessor
-using ANSI C.
+xv6 is a re-implementation of Dennis Ritchie's and Ken Thompson's Unix
+Version 6 (v6).  xv6 loosely follows the structure and style of v6,
+but is implemented for a modern x86-based multiprocessor using ANSI C.
 
-xv6 is inspired by the following work by Lions about Unix version 6:
+xv6 is inspired by John Lions' Commentary on UNIX 6th Edition (Peer
+to Peer Communications; ISBN: 1-57398-013-7; 1st edition (June 14,
+2000)). See also http://pdos.csail.mit.edu/6.828/2006/v6.html, which
+provides pointers to on-line resources for v6.
 
-- Lions' Commentary on UNIX' 6th Edition, John Lions, Peer to Peer
-Communications; ISBN: 1-57398-013-7; 1st edition (June 14, 2000). See
-also http://pdos.csail.mit.edu/6.828/2006/v6.html, which provides
-pointers to on-line resources for v6.
-
-Code was used from the following sources:
-    JOS (asm.h, elf.h, mmu.h, bootasm.S, ide.c, and others)
+xv6 borrows code from the following sources:
+    JOS (asm.h, elf.h, mmu.h, bootasm.S, ide.c, console.c, and others)
     Plan 9 (bootother.S, mp.h, mp.c, ioapic.h, lapic.c)
     FreeBSD (ioapic.c)
+    NetBSD (console.c)
 
 The following people made contributions:
     Russ Cox (context switching, locking)

kalloc.c

@@ -38,7 +38,7 @@ kinit(void)
   initlock(&kalloc_lock, "kalloc");
   start = (char *) &end;
   start = (char *) (((uint)start + PAGE) & ~(PAGE-1));
-  mem = 256; // XXX
+  mem = 256; // assume 256 pages of RAM
   cprintf("mem = %d\n", mem * PAGE);
   kfree(start, mem * PAGE);
 }