Microsoft Windows
** This page is a work in progress **
What's this? A page about Windows on DOS Days, you say?
Well, yes. The two lived side-by-side quite happily for a good 5 or so years, and during this time, Windows was somewhat clunky and not your everyday operating system, but it gradually found favour alongside the Intel 80386 and the power it could unleash. The lure of multitasking and mouse support would begin to sway business users away from the limiting DOS text modes and into Graphical User Interfaces.
This page aims to take you through the early history of the Windows operating system. If you want to, you can go to my dedicated Windows 3.1 article which looks at the installation, applications and device drivers.
Windows/386
Windows/386 launched in December 1987 for $195, and as the name implies it was designed specially for the Intel 80386 microprocessor. It's key selling point was its ability to mulitask (run more than one program simultaneously), but it also supported expanded memory (EMS) as well as 640 KB of virtual CPU support for existing DOS programs.
With its multitasking capabilities, you could run more than one DOS application at the same time, either in multiple windows or with a single application taking up the whole screen, and unlike some multitasking mechanisms that only ran a single active application at a time, Windows/386 ran them all simultaneously in their own running process. You could mix the running of DOS programs alongside Windows applications too (for which Windows/386 is fully backward compatible with earlier versions of Windows).
Not only did it support EMS but also XMS memory, emulating LIM 4.0 specification.
The only downside was that you needed an 80386 PC to run it, such as a Compaq Deskpro 386 or IBM PS/2 Model 80. It also required a minimum of 2 MB of memory and either EGA or VGA graphics.
Multitasking operating systems were not new. Concurrent DOS 386, by Digital Research, was already on the store shelves long before Windows/386 arrived. It combined CP/M compatibility with DOS compatibility, allowing you to run up to four applications at the same time.

Concurrent DOS 386, by Digital Research, Inc. (1987)
Hard Disk Space Needed for Windows
The table below shows how much hard disk space you might need to install various versions of Windows as well as some applications:
| Windows 3.1 | 8.2 MB |
| Windows 98 | 110 MB - 289 MB |
Applications:
| Word for Windows 6.0a (1993) | 6.1 MB - 30 MB |
| Excel 5.0a (1994) | 7.6 MB - 24.6 MB |