The Twentieth Anniversary Macintosh comes shipped in several different configurations containing either system 7.6.1 or system 8.0. There are only a few items that distinguish these configurations from the standard systems:
Apple Video Player 1.6.5
ATI Graphics Driver 1.0.15
Movie Player 2.5.1 *
QuickTime MPEG Extension 1.0 *
QuickTime VR 2.0 *
System Enabler 704 1.0 (8.0 has enabler 1.0.1)
Twentieth Anniversary Mac Color Sync Profile
Video Startup 1.6.5
* Items with asterisk became part of the standard software distribution for all macs with 8.0
It is important to note that the CD drive in the twentieth anniversary mac only works properly with Apple CD-ROM extension version 5.3.3 or Apple CD/DVD Driver 1.0.1. These versions will allow you to push the button on the front panel and have the CD properly put away and the door will open. Version 5.4 of this driver loses this capability, and you have to drag the CD to the trash in order to open the door. I have also seen version 5.4.2 work properly with the twentieth, although it can be sporadic.
OS 9.0 works great on the Twentieth Anniversary Mac, but there are few things to watch out for. First off, you MUST do an easy install of the system itself for things to work properly. The installer is very nice, and very customizable, but if you do not do an easy install the front panel buttons will not work, AVP will crash frequently, and the machine will behave very poorly. Strange but true. Another important note is that you should zap your pram (command-option-p-r on startup) and rebuild the desktop (command-option as the finder is loading) after installing Mac OS 9.1.
You will want to hang on to the Apple Video Player 1.6.5 and Video Startup 1.6.5, as they are still necessary to get the best performance from the TV Tuner and Video In. One nice thing is that the freeze frame bug was fixed in Quicktime 4.0, and works with AVP 1.6.5, so you don't need to keep newer versions around for this purpose.
I was at first very unhappy with the OS9 upgrade until I redid it all with an easy install of the system. Personally, I really don't care for Sherlock 2, and I don't like the interface for Quicktime 4, but OS 9 seems quite stable. Frankly I really don't find the upgrade worth the money, and wouldn't recommend it. If you haven't already bought OS9, wait for the next release. It also appears to take quite a bit more memory. If you only have 32MB of RAM, do NOT install OS9.
To keep up with updates for OS9.1 I recommend Version Tracker.
That said, my recommendation for the twentieth anniversary mac at this time is OS 8.6.
For systems 7.6.1, 8.0 and 8.1 please see the older systems page.
Copy the items Video Startup 1.6.5, Apple Video Player 1.6.5 from your system 7.6.1 system folder to a safe place. Purchase the 8.5 upgrade CD from Apple. Do an easy install (I recommend a "clean" install) of system 8.5. After you have done this, copy the two items you saved over the new installed versions from 8.5. This will give you the tone and balance controls in Apple Video Player. Next install the following updates (available on Apple's ftp servers):
Apple System Profiler 2.1.2 - Installed by 8.6
Internet Address Detectors 1.0.2
Apple Telecom 3.1.3 (Should be available on the 8.5 CD - be sure you remove objectsupportlib AFTER this install)
If you use an Iomega drive such as a Zip or a Jaz, you should update to Iomega 6.0.4.
Upgrade your ATI Drivers to the latest versions. This will give you the software you need to run your ATI Rage II hardware, which works on games like Nanosaur, Havoc and a handful of others. Do a custom install and tell the installer that you have an Xclaim 3D. When you are finished, you should have the following files:
ATI Driver Update 1.4.6
ATI 3D Accelerator 4.3.6
ATI Graphics Accelerator 3.4.3
ATI Video Accelerator 3.1.4
ATI Video Memory Manager 7.5
There is now an ATI installer 4.0.1 which will have some newer versions than this. The important things are the file names. Open GL 1.1 also installs some newer versions of certain ATI software.
You can safely throw away (or store in a separate folder if you like) any other ATI software in your system folder. This includes the control panel and a few others.
If you use the FM Radio, and you also use Appearance Sounds (a new feature in 8.5), you will need the FM Radio Launcher.
Also, be sure to install ATM 4.0.2. This is available on the 8.5 CD.
You will need DiskCopy to install many of these. If you already have DiskCopy, be sure you have version 6.3.3.
Note: If you try to do freeze frame captures with the Apple Video Player 1.6.5 and Quicktime 3.0.x your machine will crash. This bug was fixed in AVP 1.7.2, which removes the tone and balance controls for some odd reason which is why I recommend sticking with 1.6.5. AVP 1.6.5 works very well with Quicktime 4.0.x, which also fixes the bug.
If you are like me and you want double arrows at both ends of your scrollbars, you want DubDubScrollbars. This is a simple Applescript that accesses an otherwise unaccessable feature of MacOS 8.5.
I do recommend the 8.6 upgrade for MacOS 8.5. It provides multiple bug fixes and is a good, stable release of the Mac OS. Be sure to download the Font Manager Update, as it solves some crashes related to 8.6. For more information about updates to 8.6, see Version Tracker.