First Steps with Player/Stage Software

As with any software that I'm learning for the first time it helps tremendously if I start with example programs and build on what is taught there.  For this project, the Player/Stage/Gazebo robot simulation software will be used.  After installing it in Ubuntu 9.04 Jaunty (which in itself is not exactly an easy task with multiple libraries needing to be compiled and installed), I ran the most basic example.

So what's going on is the red spot moving on the left window is a mobile robot equipped with a laser range scanner.  The blue field emanating out from the robot is the laser scanner that looks for objects along the path of the robot and if it comes within a certain threshold that object is avoided.  The tail behind the robot is just the recent path that the robot took and is good for noticing trajectory changes.  On the right window, we have the output of the sensor in respect to the robot.  So in essence, it is the robot view of the world around itself using the available sensor data.

This is a really simple example and I will build on it to create what I hope is a great project.

Boot Directly into Windows Using GRUB

I'm using the Ubuntu linux distribution for my project and I also run Windows Vista for other work that I do.  As a result, I'm dual booting my computer.  Most of the time I work in Windows so I want to be able to boot into Windows as the default setting.  When Ubuntu gets installed, the bootloader GRUB uses Ubuntu as the default operating system.  I changed this and here is how.

Boot into Ubuntu and open up a terminal window.

Start off by creating a backup of the file that we're going to change just in case things get messed up.  Type the command

sudo cp /boot/grub/menu.lst /boot/grub/menu.lst.bck

Next, type in the command

sudo gedit /boot/grub/menu.lst

This will open up a gedit window where you can modify the file.  The part we need to get to is at the bottom of this file.  All the way down at the bottom you should see a block of text that looks something like this

# This is a divider, added to separate the menu items below from the Debian

# ones.

title        Other operating systems:

root

# This entry automatically added by the Debian installer for a non-linux OS

# on /dev/sdb1

title        Windows Vista (loader)

rootnoverify    (hd1,0)

savedefault

map        (hd0) (hd1)

map        (hd1) (hd0)

chainloader    +1

 The information may be different inside but the key part is that you're grabbing the Windows loader.  We want to move this block above the Ubuntu loader because what happens is when Ubuntu is updated a new entry is added to the list of Ubuntu loaders.  So move this block to just before the following

### BEGIN AUTOMAGIC KERNELS LIST

At this point you can either keep the block of text that has "Other Operating Systems", or delete it.  Just keep this:

# This entry automatically added by the Debian installer for a non-linux OS
# on /dev/sdb1
title        Windows Vista (loader)
rootnoverify    (hd1,0)
savedefault
map        (hd0) (hd1)
map        (hd1) (hd0)
chainloader    +1

If you elect to keep the divider you will need to change the default number in the text

## default num
# Set the default entry to the entry number NUM. Numbering starts from 0, and
# the entry number 0 is the default if the command is not used.
#
# You can specify 'saved' instead of a number. In this case, the default entry
# is the entry saved with the command 'savedefault'.
# WARNING: If you are using dmraid do not use 'savedefault' or your
# array will desync and will not let you boot your system.
default        0

Change the last line from a 0 to 1 if you kept the divider.

Be sure to save the new file and now your computer will default boot into Windows.