Software Patches | Network+ Study Guide

Patches, fixes, service packs, and updates are all the same thing—free software revisions. These are intermediary solutions until a new version of the product is released. A patch may solve a particular problem, as does a security patch, or change the way your system works, as does an update. You can apply a so-called hot patch without rebooting your computer; in other cases, applying a patch requires that the server go down.

Is It Necessary?

Because patches are designed to fix problems, it would seem that you would want to download the most current patches and apply them immediately. That is not always the best thing to do. Patches can sometimes cause problems with existing, older software. Different philosophies exist regarding the application of the newest patches. The first philosophy is to keep your systems only as up-to-date as necessary to keep them running. This is the “if it ain’t broke, don’t fix it” approach. After all, the point of a patch is to fix your software. Why fix it if it isn’t broken? The other philosophy is to keep the software as up-to-date as possible because of the additional features that a patch will sometimes provide.

You must choose the approach that is best for your situation. If you have little time to devote to chasing down and fixing problems, go with the first philosophy. If you always need the latest and greatest features, even at the expense of stability, go with the second.

Where to Get Patches

Patches are available from several locations:

The manufacturer’s website
The manufacturer’s CD or DVD
The manufacturer’s support subscriptions on CD or DVD
The manufacturer’s bulletin (less frequently an option)

You’ll notice in every case that the source of the patch, regardless of the medium being used to distribute it, is the manufacturer. You cannot be sure that patches available through online magazines, other companies, and shareware websites are safe. Also, patches for the operating system are sometimes included when you purchase a new computer.

How to Apply Patches

Just as you always need to plan for an upgrade, you need to plan for a patch. Never blindly install patches (or any other new software) without examining the potential impact on the network. Although patches are designed to fix known problems, they may create new ones. It is best to try patches on a test network or system before installing them on all systems on the network.

Follow these steps to apply a patch:

Research the enhancements and changes that the patch provides. Go to the manufacturer’s website, or take a look at the official documentation.
Download the patch and related documentation to an isolated test network (or computer if you don’t have an entire test network).
Decompress any documentation files and read them. (Yes, the manual is something you read before installation, not after things crash.)
Note the changes, and define a way to test the new features.
Install the patch on a test workstation/server.
Select the installation method that allows you to save previous configurations so that you can uninstall if necessary.
Record any options and your selections, such as retaining or replacing drivers.
Reboot the computer.
If the operating system does not load or work properly, start over with a clean test machine. Select to keep your original drivers. (NIC drivers are commonly updated and may not work.)
Try out the new features. Test all patches to see if they work as advertised.
Run the test workstation/server for two weeks. Reboot it and try different tasks during this time.
If all goes well, do a limited rollout of the update to your support staff’s personal computers and applicable servers, and have them test the patch.
After the IS support staff determines the product is safe, do a limited rollout to some users’ workstations and applicable servers.
Roll out the patch to all production servers and all workstations via an automated procedure.
Ensure proper revision control. Make sure that all equipment has the same approved patch.

Note

Remember that these are general steps. Refer to the documentation that comes with the patch (most likely a README.TXT file) for specific instructions on installing a specific patch.

You can see that this process can take a long time, even with multiple test machines and people helping you. The process can be speeded up a little, but do not skip any steps. If at any point you cannot get a system to work, even with changing the install options, stop the installation and refer to the support documentation for the patch to see if you are doing something wrong. Do not roll out a patch until it has been proven stable in all test environments.

Warning

If you use your operating system or application CDs to make changes to the operating system or an application after applying the patch, you may overwrite the updates made by the patch. You will need to reapply the patch after accessing these files.