The first thing to know about computers is that they are not magical and so far as we can tell, they are not sentient. They are electronic machines that execute long series of small commands at a very high speed. Without software telling the processor to accept input from the keyboard, the mouse and other peripherals, you would not be able to make your computer do anything. The software that is running when nothing else is running is called the Operating System.

The Operating System is the basic toolbox that controls all the standard functions of your computer. Your applications (the programs you run, like your word processor, your spreadsheet software or your Web browser) use the tools of the Operating System in order to do their work.

Have you noticed how, in Windows, when you issue the command "File: Open" you get a dialog box that looks pretty much the same no matter what application you are running? Well, that dialog box is created by the Operating System. It is a standard tool created so that when programmers write applications, they don't have to re-write the code for the File: Open dialog box. Instead, they make a "system call" for this standard dialog box and let the Operating System take care of presenting the dialog box, allowing you to browse your hard drive for the file you wish to open, and taking the input from you once you select the file you wish to open. The Operating System loads the file. Your application doesn't have to do anything again until the file is loaded.

Windows 3.11

If you have Windows 3.11, you also have DOS. Both of these are called operating systems, but they are somewhat interdependent. This is confusing to some people, but if you think of an operating system as a toolbox, consider DOS to be a very small toolbox and Windows 3.11 to be a larger toolbox which happens to be missing all the tools that already exist in the DOS toolbox. They sit next to each other and you and your software use tools from both boxes while you do your work.

If you were in a Windows program and issue the File: Open command, your application got out of the way and let Windows 3.11 pull up the standard dialog box. Windows allowed you to browse the drive, though it dipped back into the DOS toolbox in order to give you the list of file names. When you loaded a file, DOS had the tools that went to the drive and read the file into memory. Once that was done, Windows closed down the dialog box and returned you to your Windows-based application.

Windows 95

Windows 95 is a bigger toolbox that contains all the tools previously contained in both the DOS and Windows 3.11 toolboxes, plus a few new ones. Windows 95 is a whole operating system all by itself. With Windows 95, you don't jump back and forth between DOS and Windows 95 to access various tools, as you did in Windows 3.11

DOS did not directly deal with peripherals (like a printer). Instead DOS only had the ability to "see" as far as the ports, like the serial ports (also called COM ports, where your mouse or modem might be connected to your PC) and parallel port (also called a printer port). Without adding special modules into memory DOS could never see your mouse, for example. DOS, also, never knew what kind of printer you had, so if you had a DOS based word processor, it needed a printer driver in order to know how to make your printer underline or change font or use any of its special features. Your spreadsheet program would also need to be configured for your printer. Each separate application needed to be individually set up for your printer. If you changed printers, you needed to reconfigure each of your applications to talk to this new printer and acquire separate drivers for each application for that printer.

Windows 3.11 had printer drivers and mouse drivers built in. This meant that your mouse simply worked in Windows, and once you installed the printer driver to Windows 3.11, all your Windows based applications immediately knew how to use your new printer. If you change printers, you simply had to add the new printer driver and with that one installation change, all your Windows based programs simultaneously "learned" how to use your printer. Windows 3.11 did not, however, have modem drivers. Every program you used which required a modem had to be individually set up to understand how to send the right codes to your modem to use its features.

Windows 95 has mouse drivers, printer drivers and modem drivers. When you change printers or modems using Windows 95, just update your Windows drivers and all your applications that use your printer or modem will automatically become configured for this new device.

Since Windows 95 does not use DOS to access your hard drive, it can support features DOS would not understand, like filenames up to 255 uppercase and lowercase characters long that can contain blank spaces and some punctuation. You can write an entire sentence to describe your file in Windows 95, while DOS and Windows 3.11 require that you name your files with names from one to eight characters long and it made everything uppercase, so you could not use case or blank spaces in your filenames.

Windows 95 uses a more effective form of multitasking so that you can run programs simultaneously, without one of them hogging all the processor time. When you printed anything under Windows 3.11, you could observe the absence of this effect. Your computer stopped doing anything else while it printed. You got an hourglass and you had to wait for it to finish printing. Windows 95 allows you to continue working with your software while it prints in background.

Windows 95 has many tools to assist in troubleshooting hardware and software. It automatically detects most hardware and automatically configures itself to use that hardware most effectively. Unlike Windows 3.11, it has Internet access support built in as a standard feature. Dialup Networking is another standard feature.

Windows 98

Windows 98 is an incremental update of Windows 95. Its biggest advantage is that it provides better support to the hardware typical for newer computers.

Newer hardware components that benefit the most from Windows 98 include:

Since most older PCs do not have these new hardware components, there is little reason to upgrade an old system to Windows 98. An additional consideration is the fact that Windows 98 is a lot bigger and does a lot more stuff in background than Windows 95, which may seriously burden many old systems were they upgraded to Windows 98.

Windows 98 is, however, a very good operating system for newer computers. Adjusting to the more cosmetic changes to the interface may take a bit of time, but the improved support for the new hardware will be worth it.

Windows NT

Windows NT (New Technology) provides a far bigger set of tools than Windows 95. It is more powerful, more robust, more secure, more complex to configure, and much more complex to troubleshoot. It is extremely well suited to a specific kind of computer environment -- one in which a Network Administrator must manage a computer large network very closely. NT is specifically tuned to making the task of a Network Administrator for a large network easier to do. Using NT, an Administrator can install software from the server, control configuration of machines remotely, lock the machines down to whatever extent the Administrator chooses and generally control things in a very secure environment.

Many PCs around the University are not managed by a Network Administrator. These machines are not well suited to NT. As an example of how poorly NT is suited to these machines, NT requires that someone be declared Administrator and have their access controlled by a password. Most NT users will declare themselves Administrator. If they forget their passwords, the PC and its hard drive's contents will then become inaccessible to anyone until you reinstall the Operating System, which is not a trivial task.

NT lacks many of the "Plug'N'Play" features built into Windows 95, so installing and configuring hardware can be much more challenging with NT than Win95. It lacks Windows 95's Device Manager, which helps diagnose hardware problems easily.

Basically, as Bill Gates put it when Windows NT 4.0 was first released, "…if you don't already know why you want NT, you don't want NT..." The people who can use NT well already know why they prefer it. The security and remote administration features of it outweigh the troubleshooting and installation headaches it involves.

Windows 2000

This is essentially the first major attempt to bring the best parts of Windows 98 into Windows NT, plus add enough new features to coax people to leave Windows 98 to move to an NT environment. It comes close, though it is still best suited for corporate environments that are centrally administered by a well-trained Network Administrator. You should not casually decide to switch to Windows 2000 because it is newer. Learn about it first. It has substantial effects on the network to which it is attached and it is inconveniently "secure" in the same way NT 4.0 is secure. Meanwhile it is far better than NT for all laptop users and for anyone needing to troubleshoot hardware. If you needed NT for specific reasons in your past and your PC is powerful enough to run Windows 2000, it is a very good choice.