Windows 1.0x based on MS-DOS Executive
Windows 1.0 is the first major release of Microsoft Windows, a family of graphical operating systems for personal computers developed by Microsoft. It was first released to manufacturing in the United States on November 20, 1985, while the European version was released as Windows 1.02 in May 1986.
Its development began after the Microsoft co-founder and spearhead of Windows 1.0, Bill Gates, saw a demonstration of a similar software suite, Visi On, at COMDEX in 1982. The operating environment was showcased to the public in November 1983, although it ended up being released two years later. Windows 1.0 runs on MS-DOS, as a 16-bit shell program known as MS-DOS Executive, and it provides an environment which can run graphical programs designed for Windows, as well as existing MS-DOS software. It introduced multitasking and the use of the mouse, and various built-in programs such as Calculator, Paint, and Notepad. The operating environment does not allow its windows to overlap, and instead, the windows are tiled. Windows 1.0 also contains four releases, which contain minor updates to the system.
The system received lukewarm reviews; critics raised concerns about not fulfilling expectations, its compatibility with very little software, and its performance issues, while it has also received positive responses to Microsoft's early presentations and support from a number of hardware- and software-makers. Its last release was 1.04, and it was succeeded by Windows 2.0, which was released in December 1987. Microsoft ended its support for Windows 1.0 on December 31, 2001, making it the longest-supported out of all versions of Windows.Features
Windows 1.0 was built on the MS-DOS kernel, while it runs as a 16-bit shell program known as the MS-DOS Executive, and it offers limited multitasking of existing MS-DOS programs and concentrates on creating an interaction paradigm (cf. message loop), an execution model and a stable API for native programs for the future. The operating environment supports the use of a mouse, which allows users to perform click-and-drag operations. Contrary to modern Windows operating systems, the mouse button had to be kept pressed to display the selected menu.Opening .exe files in the MS-DOS Executive would open an application window. Windows 1.0 also includes programs such as the Calculator, Paint (then known as Paintbrush), Notepad, Write, Terminal, Clock, and utilities such as Clipboard and Print Spooler. Paint only supports monochrome graphics. The operating environment also has the Cardfile manager, a Clipboard, and a Print Spooler program. Initially, Puzzle and Chess were supposed to appear as playable video games, although Microsoft scrapped the idea; instead, it introduced Reversi as a commercially published video game. It was included in Windows 1.0 as a built-in application, and it relies on mouse control. The operating environment also introduced the Control Panel, which was used to configure the features of Windows 1.0. The operating environment does not allow overlapping windows, and instead, the windows are tiled. When a program gets minimized, its icon would appear on a horizontal line at the bottom of the screen, which resembles the modern-day Windows taskbar.It also consists of three dynamic-link libraries, which are located as files in the system under the names KERNEL.EXE, USER.EXE, and GDI.EXE. The Windows 1.0 SDK contains debugging versions of these files, which can be used to replace the corresponding files on the setup disks.: 13, 200  The setup program combines multiple system files into one, so that Windows boots faster. Using the debugging KERNEL.EXE provided by the Windows 1.0 SDK one can create a "slow boot" version of Windows, where the files are separate. Windows 1.0 includes a kernel, which performs functions such as task handling, memory management, and input and output of files, while the two other dynamic-link libraries are the user interface and Graphics Device Interface. The operating environment could also move the program code and data segments in memory, to allow programs to share code and data that are located in dynamic-link libraries. Windows 1.0 implemented the use of code segment swapping.Version 1.02 introduced drivers for European keyboards, as well as screen and print drivers. The last Windows 1.0 release, 1.04, introduced support for IBM PS/2 computers. Due to Microsoft's extensive support for backward compatibility, it is not only possible to execute Windows 1.0 binary programs on current versions of Windows to a large extent but also to recompile their source code into an equally functional "modern" application with just limited modifications.In March 2022, it was discovered that the operating environment also includes an easter egg that lists the developers who worked on the operating environment along with a message that says "Congrats!".