Will It Run Windows?

One of the most common questions involved with old garage sale or thrift store PCs is "Will It Run Windows?"

The answer is yes, depending on what you're willing to use.

Windows 3.0

The first version of Windows that most people consider really usable is Windows 3.0. Released in 1990, it will even run on the original IBM 5150 PC if you fill one of the five expansion slots with a hardware EMS (Expanded Memory System*) card. Windows 3.0 requires a minimum one megabyte of real RAM and will do much better with a meg or two of EMS. The main problem with running Windows 3.0 on an 8088- or 8086-based PC is that it only runs in Real Mode without virtual memory, and there very few programs were written that ran in Real Mode.

Windows 3.0 will run on a 286 in Standard Mode. Standard Mode is much better than Real Mode because it supports XMS (eXpanded Memory System*) RAM. A 286-based PC will support up to 16 MB of total RAM. That's the base 640K plus the 384K used for various "housekeeping" for the hardware and EMS/XMS memory plus 15 MB more RAM. A 286 PC will support virtual memory with Windows, but it's not as efficient as a 386 due to a "feature" (bug) in all 286 CPU chips.*

Windows 3.0 will run on a 386 in 386 Enhanced Mode.* (Wow. Original name for it.) 386 Enhanced Mode allows Windows to make better use of memory and also allows more efficient usage of virtual memory plus the option to have a fixed size virtual memory file (swap file) on the hard drive which doesn't get fragmented. The drawback to a fixed size swap file is that it doesn't get deleted when you exit Windows to run DOS programs. You have to give up a sizable chunk of drive space permanently. Most programs for Windows 3.0 require a 386 at least, running in Enhanced Mode. If you really need to, Windows 3.0 can be forced into Real Mode on a 286 or Real or Standard Mode on a 386.

Windows 3.1

The next version was Windows 3.1, which was released in 1992 with almost as much media coverage as Windows 95. This version dropped Real Mode and thus won't run on anything less than a 286. Several of the shortcut key combinations were altered to better match those on the Macintosh. For example Paste was now Control+V instead of Shift+Insert. The user interface was spiffed up a bit, and icons were changed some too. Under the surface it had better hardware support and various general improvements. A fairly huge amount of software was written for Windows 3.1. Operating modes and memory support for 286 and 386 or 486 CPUs remained the same as Windows 3.0.

A rarely mentioned version is Windows 3.11, which runs on a 286 on up and is mostly the same as 3.1. The main difference is an early foray into 32-bit land on the 386 that really didn't do much to improve performance.

The next and final version before 95 was Windows for Workgroups 3.11. It dropped Standard Mode, so it only ran on a 386 or higher. With that you got the first useful taste of 32-bit stuff with 32-bit Disk and File Access that improved performance. WFWG 3.11 was the first Windows version to include networking support, but you still had to configure DOS drivers for the network adaptor for it to work.

A significant add-on for the Windows 3.1x series was Win32s. This added a Subset of the upcoming 32-bit Windows 95 commands so that programmers could begin the move to 32-bit software. Chances are that if a program says it run under Windows 3.1x or Windows 95, it uses Win32s on 3.1x. Win32s was given away free by Microsoft and usually included with any software that needed it. Win32s requires at least Windows 3.1 running on a 386.

Windows 95

Windows 95 will run on as low-end a PC as a 386SX with 4 MB of RAM, but you really, really, really don't want to try that. The bare minimum I'd recommend is a 486DX2/66 with 16 MB, and even then it's slow going.

* Things I'll probably get to in a future article that will be loaded with technical stuff about various types of memory and possibly a DOS 6.22 Upgrade "gotcha" if it doesn't get too long.