Microsoft Windows 95

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Windows 95
Lettering "Windows (R)" (bold) with addition "95" (normal printing without character spacing), over the first Windows letter the lettering "Microsoft (R)"
Windows 95 in German
The start menu , Windows Explorer (which shows the system C:\drive), the control panel and Windows Media Player 6.4 are shown
developer Microsoft
License (s) Microsoft EULA ( Closed Source )
Current  version 4.00.950 (RTM) / 4.03.1214 (Windows 95 C) (August 24, 1995 / November 26, 1997 )
Kernel MS-DOS
↳ Windows kernel
ancestry Windows 1.0 - Windows 3.x
↳ Windows 9x
timeline Windows 1.0
Windows 2.0
Windows 3.0
Windows 3.1
Windows 95
Windows 98
Windows Me
Others Development discontinued
Support discontinued on December 31, 2001
(no longer available)
Microsoft website:

Microsoft Windows 95 is an operating system with a graphical user interface for personal computers (PC). It was the first operating system in the Windows series from Microsoft that provided extensive support for 32-bit operation of the processor without sacrificing backward compatibility with the DOS programs that were still widely used at the time . These were (and still are) carried out under NT systems in a virtual DOS machine . B. direct hardware access, which many of these programs require, consistently prevented. Like Windows NT, Windows 95 is backwards compatible for 16-bit Windows programs .

After its introduction on August 24, 1995, Windows 95 developed into the most successful operating system on the market until then and founded the Windows 9x series.

Development history

Chicago 73g, an early pre-release version of Windows 95

February 1995 - Windows 95 is released

In February 1995, a test version of the previously secret Windows 95 was distributed to a handful of people. Before that it was only known as Windows 4.0 or under its working title Windows “Chicago”. Everyone who was allowed to take part in the test phases had to sign a confidentiality agreement. On August 24, 1995, Microsoft released the final version for sale after numerous further tests. Its version number was 4.00.950. Microsoft began the largest product launch in the company's history.


Microsoft thus heralded the end of the 16-bit architecture on a broad front. In the 16-bit mode of the x86 line , DOS and the first versions of Windows up to and including Windows 3.x run among others ( Windows 3.1 is partially 32-bit capable). Windows 95, like its direct successors Windows 98 and Windows Me , is based on MS-DOS , which is required for starting and for some important system processes and drivers.

It is controversial whether Windows 95 should be viewed as a "graphical user interface for DOS" or as a largely independent operating system:

  • In some areas it cannot work without routines from the “underlying DOS”.
  • Windows 95 is started from DOS and DOS remains loaded in the background, including all TSR programs . From this point of view, Windows does not differ from a DOS application that switches to Protected Mode .
  • Preemptive multitasking is still not possible with 16-bit applications (Windows 3.x / DOS) .
  • Because of the limited memory protection , a 32-bit program can block the entire system ("undoing" preemptive multitasking). Likewise, the DOS running in the background can still be paralyzed by faulty 16-bit accesses, which can also be DEBUG.EXEdemonstrated by.
  • It is independent and more powerful than DOS in important areas of an operating system:
    • Memory management , memory protection, CPU allocation / process scheduler
    • however, only for 32-bit applications that do not use the Windows 3.x / DOS compatibility behavior.
  • Many Windows components and system services that are available for applications are significantly more modern and far exceed the DOS operating system services.


Microsoft's official support for Windows 95 with updates and fixes ended on December 31, 2001.

Media introduction and starting melody

In August 1995 Microsoft introduced the product with its largest advertising campaign to date. The introduction of the “Start” button was accompanied by the song “Start me Up” by the Rolling Stones in TV spots .

The starting melody, created especially for Windows 95, was composed by Brian Eno in 1994 after he was approached by Mark Malamud and Erik Gavriluk (senior developer of the Microsoft Chicago project). Microsoft wanted a piece of music that was inspiring, universal, optimistic, futuristic, soulful and emotional, and should also do justice to other attributes. It should also be a maximum of 3¼ seconds. Eventually it turned into six seconds.

In order to enable both computer inexperienced users and users of older Windows versions to quickly get used to the new interface of the operating system, its operation and the new multimedia options, many pre-installed computers were provided with a CD-ROM entitled Windows 95 Start! bei, an interactive computer course.

Pen Services for Windows 95

The Pen Services are an operating system extension that was designed for input using a light pen and was executed on tablet PCs . The operation was mainly characterized by the fact that it introduced functions such as trainable handwriting recognition and gestures . Developed was Windows for Pen Computing into two versions together with the cooperation partners IBM and Compaq . After Compaq had discontinued its plans to release a PDA based on this operating system in 1994, i.e. before the appearance of Windows 95, Microsoft decided to develop the version for Windows 95 without the participation of cooperation partners, but also to license it exclusively to OEM customers.

Technical innovations

According to Microsoft, the following improvements over Windows 3.1 exist :

  • 32-bit protected mode operating system, in contrast to Windows 3.1 no separate DOS operating system installation required
  • Preemptive multitasking and multithreading ("concurrency") improves the reactivity of the operating system and allows programs to work in the background without any disruption
  • 32-bit file systems such as VFAT, CDFS, and Network redirectors
  • 32-bit device drivers for the entire system and thus extended address spaces
  • Operating system core completely in 32 bit, with memory management, process scheduling and management
  • More robust against program errors and better removal of program code after termination of the faulty program (thanks to memory protection and central memory management)
  • More dynamic system configuration, reduces the need for reconfiguration for the user

After Windows NT 3.1 and 3.5 (both with the Windows 3.x user interface), Windows 95 is the first Microsoft operating system that is largely based on the 32-bit architecture (in x86-compatible protection mode ). IBM with OS / 2 , which had mastered this technology for a long time, could not prevail on the market against Windows. Microsoft combined the 16-bit DOS, 16-bit Windows and 32-bit Windows architectures (with their specific memory protection modes) in a kind of symbiosis. Most of the software at that time still ran under DOS, which made consistent Windows NT development unattractive.

With Windows 95, a Win 3.x successor could now run several programs at the same time. Previously, programs (under Windows 3.x) had to wait until the previous program released the processor . Multitasking is already available in previous Windows versions, but there it is still cooperative multitasking , so only one program runs at a time, the others are only kept in memory and paused for as long. Preemptive multitasking in 32-bit mode now enables system-controlled quasi-parallel operation in the time slice procedure (see also Scheduling ), but only with limited memory protection for reasons of downward compatibility.

With the registration database , a central, system-wide unique and competitively accessible space for configuration information was introduced; it almost completely replaced the Windows 3.1 system of initialization files. However, even today, application programs occasionally use configuration files instead of registry entries, especially portable software .

File system

With the VFAT file system extension , the system allows longer file names to be used under Windows for the first time , which means that the DOS limit of 8 + 3 characters for names is no longer applicable. Now 255 characters are allowed, but including the path name , which can cause additional problems when copying into subfolders. Windows does not distinguish between uppercase and lowercase letters, but retains the spelling assigned by the user. With VFAT, Microsoft wanted to make the new file system compatible with the old one, so that every long name still receives an automatically generated DOS-compatible name, e.g. B. “DOCUME ~ 1.DOC” next to “Documentation of the new project.doc” (behind the tilde , names that exist multiple times are simply numbered consecutively). This means that all files created on VFAT can also be used by DOS users and users of Windows up to version 3.11 (if the underlying file system is FAT12 or FAT16 supported by DOS, but not FAT32).

Windows 95B supports FAT32 for the first time , which means that an extended address space is available. The improvement over FAT16 consists mainly in the support of larger hard disk partitions (more than 2 GB) and in smaller storage sectors, whereby the unused memory is reduced, especially for small files.

The DriveSpace online data compression from DOS 6.22 / DOS 7 can for the first time also be configured with a graphical user interface. Together with Microsoft Plus! the effectiveness of this compression was increased again by better algorithms (HiPack and UltraPack) in DriveSpace 3 (the third version) and integrated into the operating system in Windows 95B without additional software. The problematic data security and other disadvantages, however, meant that the program quickly lost its importance since the availability of large hard drives at low prices.

Graphic user interface (GUI) and user guidance

The innovations in the graphic area are also extensive, especially the Windows start menu . With Windows 95, Microsoft has further developed the graphical user interface so that it can be operated in a similar way to the OS / 2 operating system that was initially developed together with IBM. The taskbar at the bottom of the screen was also new in Windows. If the user clicks on “Start”, he gets a menu in which he can call up the available programs, call up the documents last used, change settings, call up help and switch off the computer (the strange-sounding request was often quoted: “Click on start to end ”). The task bar (the “ribbon” next to this “Start” button) shows the currently running programs, with one click you can switch between them. The old program manager from Windows 3.1 has been replaced by what is known as the desktop , a surface on which icons (“shortcuts”) associated with the relevant applications are located. The old program manager, like the old file manager, was still included in the scope of delivery, the corresponding program files are located as “Progman.exe” and “Winfile.exe” in the Windows installation directory. When the first Windows 95 operating system (Windows 95A) was installed, it was even possible to select the old user interface as an alternative to the standard user interface.

The file manager known from Windows 3.x has been replaced by the new Windows Explorer . In addition to the actual file management, he is also responsible for the icons (on the desktop), the windows , the taskbar and a lot more. The context menus are also new for Windows . So you can click practically everything with the right mouse button to see what actions you can carry out on the respective object; for example, there are differences in the possible actions in the context menu between text files and Word documents. Under Windows 3.x, the right mouse button - in contrast to many application programs, such as WordPerfect - is mostly without function.

Aside from the File Manager (a holdover from Windows 3.x), Windows 95 is fully Year 2000 compatible. However, an update for this has been released by Microsoft. Service Pack 1 (around February / March 1996) already includes Internet Explorer version 2.0, which can be installed later.

With Windows 95 there was WordPad for the first time , in all previous versions only the WordPad predecessor Microsoft Write was included.

Device support

In the beta version, the virtual device driver "cdfs.vxd" (size: 77.2 KB) can still open music CDs like a normal Windows folder. There the individual pieces of music are displayed as copied WAV files in mono and stereo, each with three quality levels. A ripping of music files was not necessary. The “cdfs.vxd” was replaced in the retail version by a file that is only 57.7 KB in size and only shows links (* .cda file names). The "cdfs.vxd" of the beta version was functional up to and including Windows ME. It was available for download from various computer magazines on enclosed CD-ROMs or online.

In addition to the new (and almost unusable due to errors) USB support, the B version of the operating system also supports AGP graphics cards for the first time .

Windows 95 has always had problems with the ever increasing performance of the hardware. Processors that were too fast led to a crash due to a timing error; this error was also called "AMD-K6-Bug" because it first appeared with the AMD K6 . Another bug in another system component that Microsoft did not fix causes a crash when the processor is faster than 2.1 GHz. Windows 95 does not support hard drives larger than 32 GB either.


Four versions of "Windows 95" were developed, the last of which is divided into different versions. However, only the first version was commercially available, optionally also as a set of floppy disks, all the others were only preinstalled as OEM versions and were available with newly purchased computers and on CD-ROM (not bootable, with an additional start disk).

Surname date designated
Build no. Service release CD code New functions and special features
Windows 95 (upgrade and original version) July 11, 1995 4.00.950 4.00.950 -
(retail version)
0795 FAT16 only; Service Pack 1 is available as a separate update.
Windows 95a February 14, 1996 4.00.950A 4.00.950 OSR 1 (for OEM and retail version  ) 0196 FAT16 only (FAT32 and USB cannot be retrofitted via updates - as in the original version)
Windows 95b August 24, 1996 4.00.950B 4.00.1111 OSR 2 (OEM version only) 0796 From here on with FAT32 support, faulty IO.SYS , Microsoft Internet Explorer (version 3) was integrated.
Windows 95b August 27, 1997 4.00.950B 4.03.1212 and 4.03.1214 OSR 2.1 (OEM versions only) 0397 From here on with optional but faulty USB support; A CD with Internet Explorer 4.0 (with web extensions ) is also included in delivery .
Windows 95c November 26, 1997 4.00.950C 4.03.1216 OSR 2.5 (OEM version only) 1297 Revised USB driver, but still faulty and can only be retrofitted using the installation CD; B and C output are identical, the "C" is changed in the registry under script control during the installation of Internet Explorer; Internet Explorer 4.0 is included as stand-alone software on the Windows CD and is automatically installed with the help of a script after Windows.
Windows 95 with Internet Explorer 3
Windows 95c with Internet Explorer 4

Under DOS, all OSR 2.x versions report with 4.00.1111. Also under Windows without USB support, they can only be recognized by the "B" or "C" entry.

After the development of Windows 95 (original or A version), a system update appeared under the code name "Nashville". It is a beta version that can be installed under Windows 95 and is identified as "Windows 96" in the software control panel. However, it later did not go on sale under this name, but was sold as an updated Windows 95B. The innovations mainly concerned the support of new hardware, such as infrared and USB interfaces.

System requirements

The following minimum system requirements apply to Windows 95 (original version) and Windows 95a ( OEM Service Release 1):

CPU : 386 DX
Hard disk space: 50 MB
Drives: floppy disk drive, with the CD version also CD-ROM drive

The following minimum system requirements apply to Windows 95b and Windows 95c (OEM Service Release 2, 2.1 and 2.5):

CPU: 486 DX
Hard disk space: 100 MB
Drives: CD-ROM and floppy disk drives


Windows 95 brought not only innovations, but also problems. The aim of the architecture was full 16-bit compatibility with Windows 3.11 and DOS while using the new 32-bit architecture, which was only partially achieved. Also because of this compatibility approach , Windows 95 did not come close to the stability of the Windows versions of the NT line .

Compared to Apple's Mac OS Classic , it was concluded that these operating systems in Windows 95 have had new features such as copying files by copying and pasting "for years". "No new era" is dawning, even if the operating system showed a high level of media presence even before sales started, thanks in part to major advertising work on the part of Microsoft (see the section " Media introduction and starting melody ").

By supporting both old 16-bit and new 32-bit programs, the kernel has become significantly more complex than in the previous version 3.1x, which results in a significantly lower execution speed of 16-bit program code - especially when it comes to screen layout. With 16-bit program code, the Windows kernel files continue to access the basic input / output functions of the DOS system kernel IO.SYS as they do with DOS or Windows 3.1 .

The B and C versions also have some problems with the previously non-existent USB support, which turned out to be faulty. Some graphics card drivers also refuse to work with version C, but run without problems with the older version B.


  • Matt Pietrek: Windows 95 System Programming Secrets. IDG Books, Foster City, CA, 1995. ISBN 1-56884-318-6 .

Web links

Commons : Microsoft Windows 95  - collection of pictures, videos and audio files

Individual evidence

  1. Microsoft Windows 95. Microsoft, May 16, 2001, archived from the original on December 17, 2001 ; accessed on April 9, 2010 (English). last Windows 95 product page from the official support period
  2. Microsoft Windows 95. Microsoft, October 31, 2002, archived from the original on May 21, 2007 ; accessed on April 9, 2010 (English). the last official product page
  3. Windows 95: 15 years ago today DOS disappeared
  4. does anyone remember ... (windows98 question). In: Strangetalk. January 3, 2003, accessed on June 2, 2012 (English, forum post ): “ How to BSOD win98 with debug.exe? "
  5. Georg Acher: Georg Acher's homepage. Notes on assembler. November 21, 2001, archived from the original on December 16, 2012 ; accessed on June 2, 2012 : "Under DOS, Windows 3.1, Windows 95 and Windows 98 you can crash the computer without any problems because of the limitations of these 'operating systems' with the wrong program or wrong entry in debug."
  6. Windows 95 Support: Contact Support. Microsoft, December 13, 2002, archived from the original on May 22, 2007 ; accessed on September 9, 2009 .
  7. Microsoft Press: Windows 95 Start! CD Rom. Item No. 000-23039
  8. ^ Anna-Martina Kröll: Interorganizational Networks: Use of Social Capital for Market Entry Strategies. Springer-Verlag, 2013. ISBN 3-322-81117-4 , ISBN 978-3-322-81117-2 ( excerpt online )
  9. ^ Windows 95 Architecture Components., accessed April 9, 2010 .
  10. Multitasking 16-bit / 32-bit Applications in Windows 95., August 27, 2002, accessed April 9, 2010 .
  11. Microsoft Technet: Windows 95 long filenames administration issues ( Memento of February 21, 2008 in the Internet Archive ) (English) - File names are limited to 255 characters, including the storage path
  12. Bugtraq -Article “Microsoft Windows Long Filename Extension Vulnerability” and “Malformed Filename Extensions causes Microsoft Windows modules to overflow” ( Memento of November 29, 2003 in the Internet Archive ) (both English) on the error of files with long filename extensions in Windows
  13. Online (English adjective, according to Babylon Translator stands for: "directly connected to the computer, usable immediately") refers to an automatically running background process, see also description texts e.g. B. from
  14. Microsoft Knowledge Base - Problems with an AMD K6-2 or Athlon Processor (CPU). Retrieved July 15, 2012 .
  15. Microsoft Knowledge Base - Windows protection errors in NDIS at a CPU speed higher than 2.1 GHz. Retrieved July 15, 2012 .
  16. Microsoft Knowledge Base - Windows 95 does not support hard drives larger than 32 GB. Retrieved July 13, 2012 .
  17. Windows versions and CD images ( Memento from August 30, 2017 in the Internet Archive ) at (in the web archive)
  18. Microsoft problem description and patch ( Memento from May 20, 2009 in the Internet Archive )
  19. Windows Nashville (Windows 95B Beta) -
  20. SRF Archive: Windows 95 (1995) | SRF archive. March 27, 2015, accessed March 12, 2019 .