re: a small C program to test xdm's /dev/mem reading on your architecture

[matthew green <mrg@eterna.com.au>]

   Be warned: on at least some architectures (notably IA-64), this sort of
   read has been known to cause untrapped machine checks (a.k.a., lockups
   or spontaneous reboots).  Arguably the kernel should trap this sort of
   nonsense, so you may be in the mood to file a bug against "kernel" after
   running this program.

wow, this is such a bad idea.  the kernel *can't* trap that sort of
thing in a lot of cases.  simply the hardware goes catatonic.  this
is true of ultrasparc machines as well. you may also access some random
"device" memory causing it do do something unexpected.  "read" can be
very destructive of device state...


why don't you use /dev/urandom if it exists, as it does on pretty
much all modern UNIX platforms?


*shudder*


.mrg.