Finding a machine for EmStar Development

If you're developing with EmStar, you have two choices. First, you can use the CENS computers. This is easier because we configure and manage the computers for you. But, we have a limited number of machines, and only one group can use one at a time. Your second choice is to set up your own EmStar development workstation at home; this can be tricky to set up, but gives you your own private resource.

Using CENS Development Machines

The easiest way to do EmStar development is to use the computers we've already set up and configured to run EmStar. These three computers, tako, dragon and tobiko, are Linux machines maintained by CENS folks. To access them:

  1. Get yourself a CENS account; contact Eric (eoster at cens dot ucla dot edu) if you didn't already sign up for one in class.

  2. Access the CENS network using our gateway host, toro.cens.ucla.edu. (To access (almost) any CENS computer, you must first log into Toro using SSH, then SSH into your desired target machine.)

  3. From Toro, ssh to either Dragon or Tobiko. Use "w" to see if anyone else is logged in who might be interfering with your work.

  4. Once you're on Dragon or Tobiko, check out the CENS source code into your home directory, using the following commands: 
    cvs -d :pserver:anoncvs@cvs.cens.ucla.edu:/home/cvs/cvsroot login
(When prompted for a password, type anoncvs)

cvs -z9 -d :pserver:anoncvs@cvs.cens.ucla.edu:/home/cvs/cvsroot checkout emstar
    (More detailed instructions on accessing the cvs repository can be found here.)

  5. cd into your new emstar directory and type "make". The instructions elsewhere on this site give more detail on how to use the build system, and what the heck to do with all this software once it's compiled (see the sections on Emrun and My First API).

Using LECS Lab Machines

If you are a member of the LECS laboratory, most workstations in the lab can be used as EmStar workstations. The only trick is to make sure you're using the latest version of the FUSD kernel module -- remove kfusd.o using rmmod (if it's inserted), and insmod kfusd.o that you compile from the CENS CVS repository. If the module has trouble inserting the first time, and you've recently used the old version of the kernel module, try rebooting -- this works around a bug in the devfs code of the kernel.

Gamayun, our 4-processor simulator machine, is configured with the latest kfusd.o kernel module and can be used for EmStar simulations.

Using the LECS IPAQ Testbed

The testbed of 60-odd Compaq IPAQs set up in the LECS lab, which is extensively described here, is capable of running EmStar. The only problem is that most of them have the old version of the FUSD kernel module installed. So, before using emstar, make sure to remove the kfusd.o kernel module the IPAQs are running, and insert a new version of kfusd.o that you compile from the source in the CENS repository. Once you have the CENS sources checked out, type "make ARCH=arm-linux" to cross-compile EmStar for the IPAQs.

Setting up your own computer for EmStar use

If you are an experienced Linux user, and know how to compile your own kernel, it shouldn't be too painful to set up. Using your own computer for development frees you from contending with other people for our currently somewhat limited resources. It also lets you do local development, rather than doing everything over the network.

Please don't try to do this on your own unless you already know how to compile and install the Linux kernel.

In theory, EmStar should be able to run on top of almost any standard Linux distribution, but We have only used RedHat, and can't guarantee that anything else will work. Use only Redhat 7.2 or later.

There is one tricky thing you need to do to your Redhat 7.2 or better installation: recompile your kernel to enable devfs, the device filesystem. This is a feature that lets the kernel dynamically create and destroy device-files under /dev, instead of relying on device files sitting on a physical filesystem created by mknod. We need this feature so that all of the various devices used by EmStar programs can be created automatically.

The basic steps are:

  1. Install Redhat v 7.2 or better

  2. Get the latest version of the 2.4 kernel from kernel.org. 2.4.20 works very nicely. Unpack the sources into /usr/src/linux. Configure the kernel with whatever drivers are required for your computer (e.g. using "make xconfig"). However, make one important change: under filesystems, choose "devfs - device filesystem". You might need to check the "show experimental options" dialog to be given this choice. Compile the kernel but don't install it yet.

  3. Get the source for devfsd, the devfs control daemon, e.g. from here. Use the latest version, e.g. 1.3.25.

  4. Important, before you build devfsd, make sure you look at the Makefile, and make sure it's pointing to the kernel sources you just unpacked and compiled (e.g. the 2.4.20 sources in /usr/src/linux). Build and install devfsd.

  5. Now install the kernel. In your grub.conf, add the option "devfs=mount" to the kernel boot options. Also, you might need to explicitly add a "root=/dev/hda1" or similar argument to tell the kernel where to find its root partition.

  6. Reboot and pray.
If the system seems to generally work, check out and compile the CENS CVS repository as described elsewhere. The kfusd.o module should compile without complaint. Use insmod to insert obj.i686-linux/fusd/kfusd.o; again, it should insert with no errors. If this works, try running "obj.i686-linux/fusd/torturetest 10" and make sure it exits with no errors.

If all that works -- celebrate! You now have an EmStar-Capable(TM) system.


Last modified by jelson, 28 January 2003