There is a 2 way upgrade mode for FreeBSD upgrade
1. Upgrade with source code based which is more steps and more difficult

2. Upgrade with binary which is less steps and simple to understand.

In this tutorial i will upgrade my freeBSD server from 7.0-RELEASE to 7.2-RELEASE with binary upgrade tools comes from freeBSD installation.

So i assume you already running FreeBSD 7.0-RELEASE
You need to login as root into the server
and type this command below to start update

#freebsd-update upgrade -r 7.2-RELEASE

What is Kernel ?

kernel is the essential center of a computer operating system, the core that provides basic services for all other parts of the operating system. A synonym is nucleus. A kernel can be contrasted with a shell, the outermost part of an operating system that interacts with user commands. Kernel and shell are terms used more frequently in Unix operating systems than in IBM mainframe or Microsoft Windows systems.

What is Realtime?

The Linux kernel and the distributions that package it typically provide very conservative defaults to certain network settings that affect networking parameters.

These settings can be tuned via the /proc filesystem or using the sysctl program. The latter is often better, as it reads the contents of /etc/sysctl.conf, which allows you to keep settings across reboots.

The following is a snippet from /etc/sysctl.conf that may improve network performance:

We need to prepare anything before we go ahead upgrading old FreeBSD 6.2 to FreeBSD 6.3

First, we need to have a box running old FreeBSD.
Login into your server and type this command and see what is your current FreeBSD version

[code]athena# uname -mrs
FreeBSD 6.2-RELEASE-p10 i386[/code]

This is mean your current FreeBSD version is 6.2-RELEASE-p10

IMPORTANT :
Before we start upgrade old FreeBSD 6.2 to FreeBSD 6.3 we need to make sure we have a FreeBSD GENERIC kernel running on it.

When a new version of FreeBSD is released, or there have been a number of security updates released it is necessary to update FreeBSD with Make World. The process may seem very complex if you have never done one before, but overall it is very straight forward and painless.

Getting New Sources With CVSup

If you don't know how to setup CVSup, you can follow this link to Get CVSup up and running first,
Here is the URL http://www.wowtutorial.org/en/tutorial/70.html

Building a New World Sources