The information on this page is mainly for UML developers. Users of SBUML do not have to know the following details, because the SBUML command scripts handle them.
SBUML runs a patched version of the kernel that simply takes one additional parameter: sndir. If that parameter is not on the command line, then the kernel should run exactly like the normal UML kernel. (If it does not then it is a bug that should be trivial to fix.) So if you have unpacked the core SBUML distribution, you can boot toms filesystem in the normal UML way like this:
[(sbumldemo subshell) sbumldemo]$ ./kernel/linux \
ubd0=/tmp/tom.cow,./bases/toms-dcbb7d918c4814b7184f90d1a846ecd5/tomsfs
The sndir parameter specifies the machine directory, which if empty boots a new machine. To use it, the current directory must first be changed to the directory of the base distribution.
[(sbumldemo subshell) sbumldemo]$ mkdir /tmp/test
[(sbumldemo subshell) sbumldemo]$ cd bases/toms-dcbb7d918c4814b7184f90d1a846ecd5/
[(sbumldemo subshell) toms-dcbb7d918c4814b7184f90d1a846ecd5]$ ../../kernel/linux ubd0=tomsfs sndir=/tmp/test
To suspend the machine, use another terminal to send it the "halteverything" command using a rather ad-hoc interface that miraculously still survives:
[(sbumldemo subshell) sbumldemo]$ echo halteverything >>/tmp/test/console
[(sbumldemo subshell) sbumldemo]$ kill -USR1 $(cat /tmp/test/ctpid)
To resume, issue the same command used to boot the machine. Since there is already a status file in the directory, the machine is resumed from the existing state. But first, remove the mconsole socket, which will be recreated:
[(sbumldemo subshell) toms-dcbb7d918c4814b7184f90d1a846ecd5]$ rm /tmp/test/mconsole
[(sbumldemo subshell) toms-dcbb7d918c4814b7184f90d1a846ecd5]$ ../../kernel/linux ubd0=tomsfs sndir=/tmp/test
The machine is now frozen, so send it a continue command:
[(sbumldemo subshell) sbumldemo]$ echo continue >>/tmp/test/console
[(sbumldemo subshell) sbumldemo]$ kill -USR1 $(cat /tmp/test/ctpid)
The UML machine should now be restored and running normally.
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