Date: Mon, 22 Jan 1996 16:24:34 +0100 (MET) From: Luigi Rizzo <luigi@labinfo.iet.unipi.it> To: mpp@mpp.minn.net (Mike Pritchard) Cc: bugs@FreeBSD.org Subject: Re: dd /dev/mem ... Message-ID: <199601221524.QAA05424@labinfo.iet.unipi.it> In-Reply-To: <199601221436.IAA00318@mpp.minn.net> from "Mike Pritchard" at Jan 22, 96 08:35:41 am
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> Luigi Rizzo wrote: > > > > Running 2.1R, I tried the following running as root: > > > > dd if=/dev/mem bs=32k skip=512 count=1 | dd bs=32 count=1 | hexdump > > > > and my P100 w/ 16MB was frozen: no keyboard, no mouse, everything > > still on the X screen. > > Funny you should mention this -- I just crashed my machine trying > the same thing trying to verify PR# 383. As near as I can tell, it > only locks up the machine when you run it from X *and* the current > vty is the X window. If you do something like: > sleep 30; dd if=/dev/mem ... > and then switch to vty0, the machine won't lock up. Running from > an ordinary syscons vty doesn't seem to be a problem. Right, I think it worked yesterday from a syscons vty. and I believe I have read from /dev/mem with a C program from an xterm with no problems either. Luigi ==================================================================== Luigi Rizzo Dip. di Ingegneria dell'Informazione email: luigi@iet.unipi.it Universita' di Pisa tel: +39-50-568533 via Diotisalvi 2, 56126 PISA (Italy) fax: +39-50-568522 http://www.iet.unipi.it/~luigi/ ====================================================================
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