I love it and would never go back to Windows.
I would have to say Mac OS X 10.4 Tiger , Or Leopard
Mac OS X (say Mac OS Ten) is the tenth version of the operating system (OS) that controls a Macintosh computer (known as a Mac for short). The equivalent for some other computers would be the Windows operating system. Mac OS X has been around for nearly ten years and replaced Mac OS 9 which was the last version of what is known as the "classic" Mac OS. Although a few Macs still use Mac OS 9 all Macs sold since 2002 have come with Mac OS X and would now be considered a regular Mac. (See links below)
I have a Mac OS X but I know Mac OS is a computer made by the brand/company, Apple.
The second name of Mac OS X v10.4.5 is Mac OS X v10.4 Intel.Mac OS X 10.4 was known as Mac OS X Tiger.
You cannot without erasing your hard drive and installing Mac OS 9 from scratch. Even then Mac OS 9 may not run on modern Mac hardware because Mac OS 9 needs the ROM chip to boot. Modern Mac OS X hardware uses EFI to boot the system instead of a ROM chip to boot. Mac OS X v10.0 - Mac OS X v10.4 support Mac OS 9 applications and can run them, you just need to install the Mac OS 9 compatibility program which can be found on the Mac OS X Install CD.
Well, there's classic Mac OS (Mac OS 1 -> Mac OS 9), and then there's Mac OS X (Mac OS 10.0 -> Mac OS 10.6 (to be released in 2 days)).If you're wondering what kind of editions there are, like how Windows has Basic, Premium, Ultimate, etc, there are two: Client and Server. Client is what is usually used, but Server is if you need to do special internet related activities, such as hosting a website.Client is $129 (Leopard)Server is $1000, I believe (Leopard)Again, Client is the primary version (it is often just referred to as Mac OS X, not Mac OS X Client), and Server is strictly for computers that need server-like capabilities, so it is often regarded. Many people will say that there is only one version of Mac OS X, referring to Mac OS X Client.
The oldest mac OS is System 1
Mac OS Leopard
Mac OS X 10.4 (Tiger) needs to be purchased as it is not possible to update from Mac OS X 10.2.8
Unless the disc is damaged and so needs reformatting you can run the Mac OS installer over an existing Mac OS.
Mac OS X is an operating system released by Apple Inc. It is designed for Apple branded computers, which is why you will never see a Dell, or an HP computer run Mac OS X. There are only two important versions of Mac OS X, Mac OS X Server, and regular Mac OS X. Mac OS X server was designed for servers, while regular Mac OS X was designed for most computers. The current version of Mac OS X (10.6) is named Snow Leopard.
The Mac OS comes free with a Mac. New versions have a small charge.