From mboxrd@z Thu Jan  1 00:00:00 1970
From: ron minnich <rminnich@lanl.gov>
To: 9fans@cse.psu.edu
Message-ID: <Pine.LNX.4.44.0402292114020.1983-100000@maxroach.lanl.gov>
MIME-Version: 1.0
Content-Type: TEXT/PLAIN; charset=US-ASCII
Subject: [9fans] a sure easy way to try out kernel stuff
Date: Sun, 29 Feb 2004 21:16:52 -0700
Topicbox-Message-UUID: 05f7c418-eacd-11e9-9e20-41e7f4b1d025


I think I sent this before, but it's so nice I am sending it again.

Scenario: an EPIA with linuxbios and plan 9 in flash. cpu is named cpu50.

You want to muck with the kernel and debug it. Easy.

. bind_test_namespace
cd /sys/src/9/pc
mk 'CONF=whatever'
cpu -h cpu50
echo 'reboot /path/to/9whatever' > /dev/reboot

boom. 9 boots 9. takes 5 seconds. If it blows up, cpu is back in 10
seconds.

Add this to the 20 seconds build time (MAX!) for plan 9, and kernel
hackery is now as easy as normal program hackery -- almost.

Very very nice. Hats off to /dev/reboot.

ron