Re: 16 MB -> 32 MB, a memory problem resolved!

Michael K. Johnson (johnsonm@nigel.vnet.net)
Thu, 18 Apr 1996 10:38:25 -0400


Alan Cox writes:
>> The easiest way to crash Linux is specifying more RAM than you have.
>> What about a very quick and dirty test of the memory size
>> (read-modify-read at the highest address)?
>
>The motherboard may well just lock up if you reference such addresses. Boards
>with video devices mapped just above RAM will also get trampled blindly
>and wrongly.

Well, it's better to freeze or trample the machine at boot than to do
it at some random time after boot when there's unwritten data in the
cache...

The point that Ulrich was making was, I think, that Linux should do a
read-modify-read cycle on the highest address *that was specified as
legal* either by the BIOS or by command-line arguments. That will make
problems show up earlier.

I think his suggestion makes sense. Your reply doesn't seem to address
his concern or suggestion, at least as I read it.

michaelkjohnson