Development Release 5<< Go back
This is the earliest leaked build of Windows 1.0, and thus of Windows in general. It was compiled on 31st October 1984 and probably distributed to developers and testers in early November. It is also the only leaked Windows 1.0 build from before 1985.
As the name implies, this is the fifth release in the Development Release series, the goal of which was to provide software developers with an early look at application development for Windows. The phase began in May 1984, according to magazine articles, and presumably ended with this build.
It was distributed on three 5.25" 360 kB floppy disks with a simple batch installation procedure. The disks contain both the OS itself, as well as the development tools needed to develop applications for it, and some sample applications. Due to its early and unfinished nature, it requires a specific environment to work properly, so using an emulator for a PC/XT/AT class machine is mandatory. Only IBM CGA and Hercules displays are supported, neither in color.
The overall experience is rather lackluster, as the system tends to crash and/or hang after prolonged use, and feels fragile when performing certain actions. Application resources (such as icons, menus, etc.) are stored externally in .RES files. This is the first leaked build which uses the ICO icon format, though it's an earlier one that's different from the one we still use today. The user interface is all over the place, e.g. some applications use buttons for dialog actions, while others use menus.
Included are early version of Calculator, Clipboard, Clock, Control panel, Notepad and Reversi, as well as several sample applications (including their source code). The file extension for drivers is also .EXE. Windows configuration is managed via a USER.PRO file, which is an early version of WIN.INI. Running MS-DOS applications under Windows is not supported yet - the WINOLDAP module that facilitates this was first included with the Alpha several months later.