[User-mode-linux-user] the user-mode kernel and expect

[Jeff Dike <jdike@ka...>]

Unsurprisingly, they work well together.  

I'm chasing the fsck crash.  Since it only happens when fsck needs to fix up a 
dirty filesystem, and, even then, most of the time, it works, I needed to 
repeatedly boot the system, log in, cause some file activity, and crash it.

After a fair amount of experimentation and learning tcl, I ended up with this 
expect script:

set send_slow {1 .2}
for {} 1 {} {
    set timeout -1
    spawn linux fhd0=../../root_fs_deb fhd1=swap
    expect "usermode login:" 
    send -s "root\r"
    expect "Password:"
    send -s "root\r"
    expect "usermode:~#"
    send -s "dd if=/dev/disk/0 of=/mnt/data &\r"
    expect "usermode:~#"
    sleep 1
    system "kill -9 `ps uax | grep linux | awk '{print \$2}'`"
}

Pretty clean and simple once you know the syntax.

				Jeff

[User-mode-linux-user] Stupid (user-mode) kernel tricks

[Jeff Dike <jdike@ka...>]

Boot the kernel, and log in on two or three consoles.
As simultaneously as possible, start a "ls -alR /" in each one.
Watch the system switch from one to the other every few seconds...

This looks like a good way to graphically demonstrate time-sharing.  Most 
kernels switch too fast for time-sharing to be visible.  Not mine :-)

				Jeff