Windows 95

Windows 95

File:Am windows95 desktop.png Screenshot of Windows 95
Developer	Microsoft
OS family	Microsoft Windows
Source model	Closed source
Released to manufacturing	24 August 1995 –
Latest release	OEM Service Release 2.5 / 26 November 1997 –
Kernel type	Monolithic kernel
License	Microsoft EULA
Official website	www.microsoft.com/windows95
Support status
Unsupported as of 31 December 2001.

Windows 95 is a consumer-oriented graphical user interface-based operating system. It was released on August 24 1995 by Microsoft, and was a significant progression from the company's previous Windows products. During development it was referred to as Windows 4.0 or by the internal codename Chicago.

Windows 95 was intended to integrate Microsoft's formerly separate MS-DOS and Windows products and includes an enhanced version of DOS, often referred to as MS-DOS 7.0. It features significant improvements over its predecessor, Windows 3.1, most visibly in the graphical user interface (GUI), where the basic elements of the interface remain largely unchanged in later versions of Windows, such as Windows Server 2008. There were also major changes made at lower levels of the operating system, including support for 255-character mixed-case long filenames and preemptively multitasked pseudo protected-mode 32-bit applications. Whereas its predecessors are optional "operating environments" requiring the MS-DOS operating system (usually available separately), by incorporating MS-DOS into Windows 95 itself, it is made into a consolidated operating system, which was a significant marketing change. The release of Windows 95 also marked wider acceptance of Plug and Play standards on the IBM PC platform.

User interface

In the marketplace, Windows 95 was an unqualified success, and within a year or two of its release had become the most successful operating system ever produced. It also had the effect of driving other major players in the DOS-compatible operating system out of business, something which would later be used in court against Microsoft.

Internet Explorer 4.0 came with an optional shell update known as Windows Desktop Update that gave Windows 95 (and NT 4.0) a user interface and several updated shell features that would become the graphical user interface of Windows 98. The last release of Windows 95, that is, OEM Service Release 2.5 (Version 4.00.950C) includes IE4 on the Setup CD (but not in slipstreamed form) and installs it after Windows 95's initial setup and first boot is complete.

Only the 4.x series of the browser contained the shell update, so those that wanted the new shell had to install IE4 with the desktop update before installing a newer version of Internet Explorer.

Windows 95 marked the introduction of the Start button and taskbar to Microsoft's GUI, both of which have remained fixtures of all subsequent versions of Windows, although the word "Start" was dropped from the button in Windows Vista, with the company preferring to label the button with the Windows logo ("Start" is still present as a tooltip and in the classic UI mode).

Long file names

32-bit File Access is necessary for the long file names feature introduced with Windows 95 through the use of the VFAT file system. It is available to both Windows programs and MS-DOS programs started from Windows (they have to be adapted slightly, since accessing long file names requires using larger pathname buffers and hence different system calls). Competing DOS-compatible operating systems released before Windows 95 cannot see these names. Using older versions of DOS utilities to manipulate files means that the long names are not visible and are lost if files are moved or renamed, as well as by the copy (but not the original), if the file is copied. During a Windows 95 automatic upgrade of an older Windows 3.1 system, DOS and third-party disk utilities which can destroy long file names are identified and made unavailable (Microsoft Anti-Virus for Windows indicated that the upgrade program was itself a computer virus). When Windows 95 is started in DOS mode, e.g. for running DOS games, low-level access to disks is locked out. In case the need arises to depend on disk utilities that do not recognize long file names, such as MS-DOS 6.x's defrag utility, a program called LFNBACK for backup and restoration of long file names is provided on the CD-ROM. The program is in the \ADMIN\APPTOOLS\LFNBACK directory of the Windows 95 CD-ROM.

32-bit

Windows 95 followed Windows for Workgroups 3.11 with its lack of support for older, 16-bit x86 processors, thus requiring an Intel 80386 (or compatible).

The introduction of 32-bit File Access in Windows for Workgroups 3.11 meant that 16-bit real mode MS-DOS is not used for managing the files while Windows is running, and the earlier introduction of the 32-bit Disk Access means that the PC BIOS is not used for managing hard disks. This essentially reduces MS-DOS to the role of a boot loader for the protected-mode Windows kernel. DOS can be used for running old-style drivers for compatibility, but Microsoft discourages using them, as this prevents proper multitasking and impairs system stability. Control Panel allows a user to see what MS-DOS components are used by the system; optimal performance is achieved when they are all bypassed. The Windows kernel uses MS-DOS style real-mode drivers in Safe Mode, which exists to allow a user to fix problems relating to loading native, protected-mode drivers.

Protected mode

Although running in protected mode and not being well documented, Windows 95 does not correctly implement protected mode, as can be seen with trivial probing of memory -- which often does not result in the appropriate hooked IVT being called for a segmentation fault -- resulting in a BSOD or other, undefined arbitrary behaviour.

Attempting to execute the following code on Windows 95 will result in said behaviour:

   int main(void) 
   {
       for(int *p = (int *)0x00010000;;*(p++) = 0);
   }

Release

Beta

File:Winchicagodesktop.png

Microsoft Chicago Build 58 desktop. Note the three buttons in the lower left.

Several Windows 95 betas were released before the final launch.

Build 58 introduced a Start menu prototype. It divided the functions of the Windows 95 Start menu up into three buttons. Future Chicago builds combined these three into the Start button still recognized today.

Build 58 included a new File Manager, Chicago Explorer, which remained relatively unchanged in the initial version of Windows 95 and in Windows NT 4.0. Build 58 still included Program Manager as found in Windows 3.1, although this application was supplemented by the new desktop and taskbar/Start menu designs.

This build also introduced shortcuts (Chicago referred to them as Links) and native right click functionality, which Windows 3.1 lacked. It also introduced long file name support.

Prior to the official release, the American public was given a chance to preview Windows 95 in the Windows 95 Preview Program. For US$19.95, users were sent a set of 3½" floppy diskettes that would install Windows 95 either as an upgrade to Windows 3.1x or as a fresh install on a clean computer. Users who bought into the program were also given a free preview of The Microsoft Network (MSN), the online service that Microsoft launched with Windows 95. The preview versions expired in November 1995, after which the user would have to purchase their own copy of the final version of Windows 95.

Final

File:Windows95BOXSHOT.png

Microsoft Windows 95 operating system cover shot

Windows 95 was released with great fanfare, including a commercial featuring the Rolling Stones song "Start Me Up" (a reference to the Start button). It was widely reported that Microsoft paid the Rolling Stones between US$8 and US$14 million for the use of the song (from the 1981 album Tattoo You) in the '95 advertising campaign. According to sources at Microsoft, however, this was just a rumor spread by the Stones to increase their market value, and Microsoft actually paid a fraction of that amount. A 30 minute promotional video, labeled a "cyber sitcom", featuring Jennifer Aniston and Matthew Perry, was also released to showcase the features of Windows 95. Microsoft's US$300 million dollar advertising campaign featured stories of people waiting in line outside stores to get a copy.

In the UK, the largest computer chain PC World received a large number of oversized Windows 95 boxes, posters and point of sale material, and many branches opened at midnight to sell the first copies of the product, although these customers were far fewer in number than publicity had suggested.

In the United States, the Empire State Building in New York City was lit to match the colors of the Windows logo. In Canada, a 300-foot banner was hung from the top of the CN Tower in Toronto. Copies of The Times were available for free in the United Kingdom where Microsoft paid for 1.5 million issues (twice the daily circulation at the time).

The release included a number of "Fun Stuff" items on the CD, including music videos from Edie Brickell and Weezer.

Internet Explorer

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 add-ons such as themes and better disk compression) but was usually included in OEM sales, and at the time of Windows 95 release, the web was being browsed mainly with a variety of early web browsers such as Netscape (promoted by products such as Internet in a Box).

Windows 95 OEM Service Release 1 was the first release of Windows to include Internet Explorer (Codenamed O'Hare) with the OS, including version 2.0. While there was no uninstaller, it could be deleted easily if the user so desired. The included version switched to Internet Explorer 3 when it came out. 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. The last version of Internet Explorer supported on Windows 95 is Internet Explorer 5.5 which was released in 2000. Windows 95 shipped with Microsoft's own dial-up online service called The Microsoft Network.

Editions

Release	Version	Release Date	Internet Explorer	USB Support	FAT32 Support	UDMA Support
Windows 95 Retail	4.00.950	1995	✗	✗	✗	✗
Windows 95 Retail SP1	4.00.950a	31 December 1995	2.0	✗	✗	✗
OEM Service Release 1	4.00.950A	1996	2.0	✗	✗	✗
OEM Service Release 2	4.00.950B (4.00.1111)	1996	3.0	✗	✓	✓
OEM Service Release 2.1	4.00.950B (4.03.1212 or 4.03.1214)	1996	3.0	✓	✓	✓
OEM Service Release 2.5	4.00.950C (4.03.1214)	1997	4.0	✓	✓	✓

While Windows 95 was originally sold as a shrink-wrapped product, later editions were provided only to computer OEMs for installation on new PCs. The term OEM Service Release is frequently abbreviated OSR, as in OSR1 or OSR2.1. Thus, for example, OSR1 was the OEM release that was identical to Windows 95 retail with Service Pack 1 applied (with the addition of Internet Explorer). In order to maintain compatibility with existing programs, Windows 95 has an internal version number of "4.00.950", regardless of the internal build number, thus reflecting Windows 95's alternative identity as "Windows 4.0" (similarly, the original edition of Windows 98 has an internal version number of Windows 4.10.1998.) Later versions are sometimes referred to by the trailing letter appended to this version string, such as Windows 95 B for OSR2 and OSR2.1.

Windows 95 partially supports USB as of OSR 2.1, though it is disabled by default and is limited by driver availability.

System requirements

File:DesignedforWindows95.jpg

Designed for Windows 95 computer hardware logo

Official system requirements were an Intel 80386 DX CPU of any speed, 4 MB of system RAM, and 50 MB of hard drive space. These minimal claims were made in order to maximize the available market of Windows 3.1 converts. This configuration was distinctly suboptimal for any productive use on anything but single tasking dedicated workstations due to the heavy reliance on virtual memory. Also, in some cases, if any networking or similar components were installed the system would refuse to boot with 4 megabytes of RAM. 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 recommends an Intel 80486 or compatible microprocessor with at least 8 MB of RAM.

Windows 95 was superseded by Windows 98 and could still be directly upgraded by both Windows 2000 and Windows Me. On 31 December 2001, Microsoft ended its support for Windows 95, making it an "obsolete" product according to the Microsoft Lifecycle Policy. Even though support for Windows 95 has ended, the software still remains in use on some home and school computers because of budget issues, a lack of knowledge or lack of desire to upgrade to newer editions of Windows. In addition, some video game enthusiasts choose to use Windows 95 for their legacy system to play old DOS games, although some other versions of Windows such as Windows 98 can also be used for this purpose.

Windows 95 has been released on both floppy disks and on CD-ROM, as some computer systems at the time did not include a CD-ROM drive. The retail floppy disk version of Windows 95 came on 13 DMF formatted floppy disks, while OSR 2.1 doubled the floppy count to 26. Both versions exclude additional software that CD-ROM might have featured. Microsoft Plus! for Windows 95 was also available on floppy disks.

References

• Windows 95: The hype and beyond, Guardian Unlimited
• With Windows 95's Debut, Microsoft Scales Heights of Hype, Washington Post
• Windows 95 Installation Requirements, Microsoft
• Windows 95 end of support date, Microsoft
• Schulman, Andrew (1994). Unauthorized Windows 95: A Developer's Guide to Exploring the Foundations of Windows "Chicago". IDG Books. ISBN 1-56884-169-8 (paperback). {{cite book}}: Check |isbn= value: invalid character (help)

External links

• GUIdebook: Windows 95 Gallery - A website dedicated to preserving and showcasing Graphical User Interfaces
• Windows timeline
• Description of Windows 95 OEM Service Release 1
• HPC: Factor Windows 95 Patches & Updates Guide
• Win95 Support Site
• Windows 95 Commercial on YouTube