[Tfug] dumping physical memory

[Adrian]

Anyone dump their physical (volatile) memory to disk for review/diagnostics 
lately??? I use to due it from time to time to retrieve data when an 
application crashed or when I diagnosed a single bit memory error that was 
crashing my laptop... But something in the kernel appears to have changed!

I can no longer due a dd if=/dev/mem of=/tmp/mem_dump.raw. Instead, it dies at 
1M (of my 1G of memory) with a read error. Likewise, /proc/kcore refuses to 
allow me to read the core at all (yes, I have chanegd permissions). Any ideas 
when/what changed this???

Adrian