In chemistry, we studied something called dimensional analysis. Dimensional analysis is a method for converting from one unit to another. So first off we multiply the number of pixels by 1 over our DPI (in this case 300 DPI) then we multiply that by 25.4 by one inch (number of millimeters in an inch) Once everything cancels out we are left with a fairly nice, simple and easy to use formula.
mm = (pixels * 25.4) / dpi
In order to convert back from millimeters to pixels we simply reverse the formula using simple algebra.
pixels = (mm * dpi) / 25.4
There you have it. A very simple way to convert from pixels to millimeters. And then from millimeters back to pixels.

First of all you need to figure out what your IP Addresses are. If you are using private address (ie. 192.168.1.0/16, 10.0.0.0/8, etc) you can pretty much use whatever you want. If you are like me and have statically assigned IP addreses that are world viewable, then you will need to plan this out a little more. In my instance, I have a block of 16 address. They are 209.90.112.16 thru 209.90.112.31. I have already assigned my webserver to be 209.90.112.22, 209.90.112.23 is assigned to another server so I wanted to assign 209.90.112.24 as the secondary IP address.

To do this, it is quite simple, simply login as root to the server, you will need to edid the /etc/rc.conf file using your favorite editor. I personally use vim (or vi depending on which machine I am using) so we enter:


vi /etc/rc.conf


This command gets us into the file and allows us to make changes to it. The next thing that you will need to do is find the line that is similar to ifconfig_em0=”inet 209.90.112.22 netmask 255.255.255.240″ this line will differ on each machine simply because not all machines have the same ethernet cards and the IP subnet mask. Below this line you will need to add the following line:


ifconfig_em0_alias0="209.90.112.24 netmask 255.255.255.255"


This tells the networking system on FreeBSD to add a secondary IP address to the network interface. The subnet mask MUST mask out everything. Why? Well, in order for there to not be any conflicts between the two IP addresses one of them needs to only reference the single address. (this is because they are on the same subnet) This can turn into a big mess, so trust me, you need it this way.

Now, save your work on the file. (:wq if you are using vi or vim) Finally you are ready to restart the networking and routing systems to allow the IP address to actually function. We can do this by using the following command:


/etc/rc.d/netif restart && /etc/rc.d/routing restart


This forces the network interface to restart and pickup the additional IP address, it also restarts the local routing service, so that the system knows how to send packets out onto the network.

Now you can run the ifconfig command. You should get something that looks like the following:


sirius# ifconfig
em0: flags=8843 metric 0 mtu 1500
options=19b
ether 00:30:48:93:11:11
inet 209.90.112.22 netmask 0xfffffff0 broadcast 209.90.112.31
inet 209.90.112.24 netmask 0xffffffff broadcast 209.90.112.24
media: Ethernet autoselect (100baseTX )
status: active
lo0: flags=8049 metric 0 mtu 16384
inet6 fe80::1%lo0 prefixlen 64 scopeid 0x2
inet6 ::1 prefixlen 128
inet 127.0.0.1 netmask 0xff000000


One thing to be careful about though, FreeBSD starts at zero and counts up, so you can add as many as you want, be remember that if you skip a number, any of the aliases above that will be ignored. Also make sure that you are careful and don’t put in the wrong information or the wrong interface, this will cause the networking to stop functioning. If this happens, and you machine is on the other side of the world in some datacenter, you will be in big trouble because the networking won’t return.

Good luck!

$rounded = round(($initial_value / .5), 0) * .5

There you have it. A very simple (and quick way) of rounding to the nearest half dollar. To be able to round to the nearest quarter dollar, tenth of a dollar or anything else you feel like rounding to, simply change the .5 to .25 (for quarter dollar) or .1 (for tenth of a dollar) depending on what is needed.

FreeBSD uses two different methods. I am going to focus on the Ports collection since this way seems to be the most flexible, I must warn you though, compiling everything can become a pain in the neck if you have a slow machine. Fortunately for me, all of the servers I am using in the Server Migration are new and quite fast.

The Ports collection is relatively easy to use. Simply go into the ports collection.


server# cd /usr/ports

Now you will need to find the package you want to install (I will forgo the instructions on how to do this, as I am assuming that you know how to do that already.) In my case I started with MySQL 5

server# cd databases/mysql50-server
server# make install clean
server# mysql_install_db
server# chown -R mysql:mysql /var/db/mysql
server# /usr/local/bin/mysqld_safe -user=mysql&
server# mysqladmin -u root password <password>
server# vi /etc/rc.conf

Now you will need to tell the server to automatically start the MySQL daemon when the computer restarts. Add the following line to your rc.conf file (Which you will be editing if you have followed the previous steps.)

mysql_enable=”yes”

There you go, as long as no error messages show up, your MySQL 5.0 server will be running and will be usable.

mysql> ALTER tablename AUTO_INCREMENT=new_number

There you go, it is that easy to change the auto increment value for MySQL.

NOTE: I have discovered that MySQL will not allow you to set the auto_increment value to a number smaller that what is currently set. The data must be truncated and then set to get it to work properly.

This raises a wonderful questio, actually, it isn’t a question but it raises a point about who is liable for what. I believe that the manufacturer is the one liable. The casino should call it good and move on. You read it and tell me what you think.

Please return often and comment on my views. I love to hear about the way others think on these topics.