+The Magic SysRq Keys (SysReq or Sys Req, short for System Request):
+
+To reboot your system using the SysRq keys just hold down the Alt and
+SysRq (Print Screen) key while pressing the keys REISUB ("Raising
+Elephants Is So Utterly Boring").
+
+R = take the keyboard out of raw mode
+E = terminates all processes (except init)
+I = kills all processes (except init)
+S = synchronizes the disk(s)
+U = remounts all filesystems read-only
+B = reboot the system
+
+Notice: use O instead of B for poweroff.
+
+Or write the sequence to /proc/sysrq-trigger instead:
+
+# for i in r e i s u b ; do echo $i > /proc/sysrq-trigger ; done
+
+To enable or disable SysRq calls:
+
+# echo 0 > /proc/sys/kernel/sysrq
+# echo 1 > /proc/sys/kernel/sysrq
+
+See http://en.wikipedia.org/wiki/Magic_SysRq_key for more details.
+--
+Memtest / memcheck:
+
+Just boot your grml Live-CD with "memtest" to execute a memcheck/memtest
+with Memtest86+.
+--