Microsoft Windows 95 was released on August 24, 1995.
What is Windows 95?
Windows 95 was Microsoft’s most popular 32-bit desktop operating system, which replaced the Windows 3.1 operating system. Windows 95 was designed as a desktop operating system for home, office, and business use that preserves full backward compatibility with applications for legacy 16-bit operating systems such as MS-DOS, Windows 3.1, and Windows for Workgroups.
Windows 95 includes the following features:
- A redesigned graphical user interface (GUI) with such features as a configurable desktop, taskbar, Start button, and context menus
- Compatibility with legacy hardware and with MS-DOS and 16-bit Windows applications
- 32-bit virtual device drivers (VxDs) for protected-mode management of devices and services
- Preemptive multitasking kernel that multitasks Win32 and MS-DOS-based applications, replacing the cooperative multitasking approach used by Windows 3.1
- Fully integrated 32-bit disk, network, and print subsystems
- Integrated built-in networking software for Microsoft Networks, Novell NetWare, and Banyan Vines
- Support for long filenames
- Support for plug and play automatic hardware installation and configuration
- Advanced Power Management (APM) support for mobile users
- Integrated Windows Messaging for e-mail
- Integrated dial-up networking for Internet connectivity and for Remote Access Service (RAS) connectivity
- Integrated support for multimedia sound and video applications
- Microsoft Internet Explorer, an integrated Web browser
- Support for advanced features for network administrators, including hardware profiles, user profiles, and system policies
How Windows 95 Works
The Windows 95 architecture evolved from Windows 3.1 and Windows for Workgroups, but in contrast to these 16-bit versions of Windows, which ran on top of MS-DOS, Windows 95 is a 32-bit operating system with a 32-bit kernel, VxDs, and an Installable File System (IFS) manager and does not require that MS-DOS be loaded on the computer. However, Windows 95 does includes some 16-bit code and 16-bit components to ensure backward compatibility with MS-DOS, Windows 3.1, and Windows for Workgroups. Windows 95 also supports multithreaded operation and preemptive multitasking operation and manages system resources more effectively than earlier versions of Windows, allowing more and larger applications to be multitasked.
For added protection against application crashes, Windows 95 supports virtual machines (VMs). VMs in Windows 95 are similar to those implemented in Windows 3.1 except for two differences: in Windows 95, 32-bit Windows applications (Win32 apps) can run within their own protected memory address space within the system VM, and 16-bit Windows applications (Win16 apps) also run in the system VM but share their own address space (since they must be cooperatively multitasked). MS-DOS applications run in individual VMs of their own.
Another change in Windows 95 is that system configuration information that was formerly stored in boot files (config.sys and autoexec.bat) and INI files is stored in a database structure called the registry. The registry is the central repository for all hardware and software configuration information. Boot and INI files are still supported for backward compatibility with legacy hardware and software.
Hardware Requirements
Windows 95 minimum system requirements were an Intel 80386DX CPU of any speed, 4 MB of system RAM and 50–55 MB of hard disk space depending on features selected. This configuration would rely heavily on virtual memory and was only optimal for productive use on single-tasking dedicated workstations. It was possible to run Windows 95 on a 386 SX, but this led to even less acceptable performance due to its 16-bit external data bus. To achieve optimal performance, Microsoft recommended an Intel 80486 or compatible CPU with at least 8 MB of RAM.
Most copies of Windows 95 were on CD-ROM, but a floppy version could also be had for older machines. The retail floppy disk version of Windows 95 came on 13 DMF formatted floppy disks.
Windows 95 Incremental Releases
| Version Number | Release |
| 4.00.950 | Original full retail version and upgrade from Windows 3.1. |
| 4.00.950A | Windows 95 with Service Pack 1, also called OEM Service Release 1 (OSR1). |
| 4.00.950B | OEM Service Release 2 (OSR2) or OEM Service Release 2.1 (OSR2.1). If “USB Supplement to OSR2” shows up as an installed program when you use the Add/Remove Programs utility in Control Panel, you have OSR2.1 installed. |
| 4.00.950C | OEM Service Release 2.5 (OSR2.5). |
Windows 95 OEM
If your 20-digit product ID number has “OEM” in it, you have an original equipment manufacturer (OEM) version of Windows 95 that was probably preinstalled on your computer.
Internet Explorer in Windows 95
Windows 95 originally shipped without Internet Explorer, and the default network installation did not install TCP/IP, the network protocol used on the Internet. At the release date of Windows 95, Internet Explorer 1.0 was available, but only in the Plus! add-on pack for Windows 95, which was a separate product. The Plus! Pack did not reach as many retail consumers as the operating system itself (it was mainly advertised for its non-Internet-related add-ons such as themes and better disk compression) but was usually included in pre-installed (OEM) sales, and at the time of Windows 95’s release, the web was being browsed mainly with a variety of early web browsers such as NCSA Mosaic and Netscape Navigator (promoted by products such as IBox).
Windows 95 OEM Service Release 1 was the first release of Windows to include Internet Explorer (version 2.0) with the OS. While there was no uninstaller, it could be deleted easily if desired. OEM Service Release 2 included Internet Explorer 3. The installation of Internet Explorer 4 on Windows 95 (or the OSR2.5 version preinstalled on a computer) gave Windows 95 Active Desktop and browser integration into Windows Explorer, known as the Windows Desktop Update. The CD version of the last release of Windows 95, OEM Service Release 2.5 (Version 4.00.950C), includes Internet Explorer 4, and installs it after Windows 95’s initial setup and first boot are complete.
Windows 95 Interactive Demo
Windows 95 official launch
The release of Microsoft’s much-anticipated new operating system was marked by midnight store launches and lines of customers worldwide.
The iconic system, which came on CDs and had a startup sound composed by Brian Eno, introduced the Start button and task bar, recycle bin and desktop shortcuts. It also added support for longer file names and new “plug and play” capability for installing hardware. Windows 95 sold 7 million copies in its first five weeks, becoming the world’s most popular operating system.
The official launch of Windows 95 was on August 24, 1995.
