Windows 95 (Chicago cipher ) is a consumer-oriented operating system developed by Microsoft. It was released on August 24, 1995. Windows 95 combines Microsoft that previously separated MS-DOS and Windows products. It displays significant improvements to its predecessor, Windows 3.1, especially in the graphical user interface (GUI) and in the simplified "plug-and-play" feature. There are also major changes made to core operating system components, such as switching from a 16-bit multitasking architecture that mostly works together to a multitasking preemptive multitasking 32-bit architecture.
Accompanied by an extensive marketing campaign, Windows 95 introduces the various functions and features featured in Windows versions, such as taskbar, "Start" button, and how users navigate.
Three years after its introduction, Windows 95 was replaced by Windows 98. Microsoft ended support for Windows 95 on December 31, 2001.
Video Windows 95
Development
The initial design and planning of Windows 95 can be traced back to around March 1992, right after the release of Windows 3.1. At this time, Windows for Workgroups 3.11 and Windows NT 3.1 is still under development and Microsoft plans for the future are focused in Cairo. Cairo will be Microsoft's next-generation operating system based on Windows NT and showcases new user interfaces and object-based file systems, but it was not planned to be shipped before 1994. However, Cairo will ship in July 1996 in the form of Windows NT 4.0, but without a system object-based files, which will then evolve into WinFS.
Along with the release of Windows 3.1, IBM started sending OS/2 2.0. Microsoft realizes that they need the latest version of Windows that can support 32-bit applications and preemptive multitasking, but can still run on lower-grade hardware (Windows NT does). So the development of Windows "Chicago" started and, as planned for late 1993 release, became known as Windows 93. Initially, the decision was made not including the new user interface, as it was planned for Cairo, and only focused on making installations, configurations, and network becomes easier. Windows 93 will ship with MS-DOS 7.0, offering a more integrated experience to users and making it useless for other companies to create DOS clones. MS-DOS 7.0 is under development at the time with the code name "Jaguar" and can be run optionally on a 32-bit protected Windows 3.1 kernel mode called "Cougar" in order to compete with DR-DOS better. The first version of the Chicago feature specification was completed on September 30, 1992. Cougar became a Chicago kernel.
Beta
Prior to the official release of Windows 95, users in the United States and the United Kingdom had the opportunity to preview it in the Windows 95 Preview Program. For US $ 19.95/Ã, £ 19.95, users will receive multiple 3.5-inch floppy disks to use to install Windows 95 either as an upgrade from Windows 3.1x or as a new installation. Participants were also given a free preview of Microsoft Network (MSN), an online service that Microsoft launched with Windows 95. During the preview period, Microsoft established various electronic distribution points for promotional and technical documentation in Chicago, including detailed documents for media reviewers explaining the new system highlighted. The preview version ended in November 1995, after which users had to buy their own copy of the final version of Windows 95.
Maps Windows 95
Architecture
Windows 95 is designed to be maximally compatible with existing MS-DOS and 16-bit Windows programs and device drivers, while offering a more stable and performing system better. The Windows 95 architecture is an evolution of Windows-enhanced mode for Workgroups' 386. The lowest level of the operating system consists of a large number of virtual device drivers (VxDs) running in 32-bit protected mode and one or more DOS virtual machines running in virtual 8086 mode. The virtual device driver is responsible for handling physical devices (such as video and network cards), emulating virtual devices used by virtual machines or providing various system services. The three most important virtual device drivers are:
- Virtual Machine Manager (VMM32.VXD)
- Responsible for memory management, event handling, interrupt handling, loading and initializing virtual device drivers, creating new virtual machines and thread scheduling.
- Configuration Manager (CONFIGMG)
- Responsible for implementing Plug and Play functionality; monitor hardware configuration changes; detect device using bus enumerator ; and allocate I/O ports, IRQ, DMA channels, and memory in conflict free mode.
- Installable File System Manager (Input/Output Subsystem)
- Coordinate access to supported file systems. Windows 95 was originally shipped with support for FAT12, FAT16, VFAT extensions, ISO 9660 (CDFS) and network redirectors, with later releases supporting FAT32.
Request access to physical media is sent to the Input/Output Supervisor , the component responsible for scheduling the request. Each physical medium has its own device driver: access to disk is done by port driver , while access to SCSI devices is handled by miniport drivers working on SCSI. layer. Ports and miniport drivers perform I/O operations in 32-bit shaded mode, bypassing MS-DOS and BIOS, delivering significant performance improvements. If there is no genuine Windows driver for a particular storage device, or if the device is forced to run in compatibility mode, Real Mode Scanner
The 32-bit Windows program has its own memory segment, which can be adjusted to whatever size you want. The memory area outside the segment can not be accessed by the program. If a program crashes, nothing else is harmed. Prior to this, programs using 64-KB segments remain non-exclusive. While the size of 64Ã, KB is a serious flaw in DOS and Windows 3.x, the lack of guaranteed exclusivity is the cause of stability issues because programs sometimes outdo each segment. Windows 3.x programs that crash can paralyze the process around it.
The Win32 API is implemented by three modules, each consisting of 16-bit and 32-bit components:
- Kernel
- Provides high level access to memory and process management, and access to the file system. Consists of KRNL386.EXE, KERNEL32.DLL, and VWIN32.VXD.
- Users
- Responsible for managing and drawing various user interface components, such as windows, menus, and buttons. Consists of USER.EXE and USER32.DLL.
- Graphical Device Interface (GDI)
- Responsible for drawing graphs in a device-free way. Consists of GDI.EXE and GDI32.DLL.
Dependency on MS-DOS
For end users, MS-DOS appears as a basic component of Windows 95. For example, it is possible to prevent the loading of the graphical user interface and boot the system into a real-mode MS-DOS environment. This sparked a debate among users and professionals over the question of the extent to which Windows 95 is the operating system or just a graphical shell that runs over MS-DOS.
When the graphical user interface starts, the virtual machine manager takes over the associated functions of the file system and disk. MS-DOS itself is downgraded to compatibility layer for 16-bit device drivers. This contrasts with previous versions of Windows that depend on MS-DOS to access files and disks (Windows for Workgroups 3.11 can also generally bypass MS-DOS when 32-bit file access and 32-bit disk access are enabled). Keeping MS-DOS in memory enables Windows 95 to use DOS device drivers when the corresponding Windows driver is unavailable. Windows 95 is capable of using all 16-bit Windows-3 drivers.
At startup, MS-DOS components in Windows 95 respond to
As a result of DOS-based, Windows 95 must maintain internal DOS data structures synchronized with Windows 95. When starting the program, even the original 32-bit Windows program, MS-DOS temporarily executes to create a data structure known as Program Segment Prefix. It's even possible for MS-DOS to run conventional memory while doing so, preventing programs from launching. Windows 3.x allocates fixed segments in conventional memory first. Because segments are allocated as fixed, Windows can not move them, which will prevent more programs from launching.
Microsoft removes some support for File Control Blocks (anchoring APIs from DOS 1.x and CP/M) in Windows 95 OSR2 (OEM Service Release 2). FCB function can only read FAT32 volume, but not write to them.
User interface
Windows 95 introduces a redesigned shell based on desktop metaphors; the desktop is redesigned to save shortcuts to apps, files, and folders. In contrast, the Windows 3.1 desktop is used to display the running app icons. On Windows 95, they are now displayed as buttons on the taskbar at the bottom of the screen, which also contains the notification area used to display icons for background apps, volume controls and current time. The Start menu, called by clicking the "Start" button on the taskbar, is introduced as an additional tool for launching applications or opening documents. While maintaining the program group used by its predecessor Program Manager, it now shows apps in a flowing sub-menu. The previous File Manager program was also replaced by Windows Explorer.
In 1994, Microsoft designers Mark Malamud and Erik Gavriluk approached Brian Eno to write music for the Windows 95 project. The result was a six-second start-up music sound from the Windows 95 operating system, The Microsoft Sound .
When released for Windows 95 and NT4, Internet Explorer 4 comes with an optional Windows Desktop Update, which modifies the shell to provide new features integrated with Internet Explorer, such as Active Desktop (which allows Internet content to be displayed directly on the desktop) and additional updates for Windows Explorer.
Some of the user interface elements introduced in Windows 95, such as desktops, taskbar, Start menu, and Windows Explorer file manager, remain unchanged on upcoming versions of Windows.
Technical upgrade
Windows 95 includes support for 255-character long filename mixes and multitasked protected-mode 32-bit applications preemptively.
Long filename
32-bit File Access is required for the long file name feature introduced with Windows 95 through the use of the VFAT file system extension. It is available for both Windows programs and MS-DOS programs starting from Windows (they need to be slightly customized, since accessing long file names requires using larger pathname buffers and hence different system calls). DOS-compatible operating systems released before Windows 95 can not see these names. Using older versions of DOS utilities to manipulate files means long names are invisible and lost if files are moved or renamed, as well as by copy (but not original), if the files are copied. During Windows 95 automatic upgrades of older Windows 3.1 systems, DOS and third-party disk utilities that could damage long file names are identified and made unavailable. When Windows 95 starts in DOS mode, e.g. to run DOS programs, low-level access to the disk is locked. If a need arises depending on a disk utility that does not recognize long file names, such as the MS-DOS 6.x defrag utility, a program called LFNBACK for backup and restore long filenames is provided on CD-ROM, specifically in the \ ADMIN \ APPTOOLS \ LFNBACK directory.
32-bit
Windows 95 follows Windows for Workgroups 3.11 with lack of support for older, 16-bit x86, requiring Intel 80386 (or compatible). While the OS kernel is 32-bit, much of the code (especially for the user interface) remains 16-bit for performance reasons as well as development time constraints. This has a somewhat detrimental effect on the stability of the system and causes the application to crash frequently.
The introduction of 32-bit file access in Windows for Workgroups 3.11 means that the MS-DOS 16-bit real-bit mode is not used to manage files while Windows is running, and the early introduction of 32-bit disk access means that PC BIOS is often no longer used to manage the hard disk. DOS can be used to run old-style drivers for compatibility, but Microsoft does not recommend its use, as it prevents proper multitasking and undermines system stability. Control Panel allows users to view MS-DOS components used by the system; optimal performance is achieved when skipped. The Windows kernel uses MS-DOS style real mode drivers in Safe Mode , which exists to allow users to fix issues related to loading original drivers, shielded mode.
System requirements
The official system requirements are Intel 80386DX CPU of any speed, 4M system RAM, and 50-55 MB of hard disk space depending on the selected feature. These minimal claims are made to maximize the available market from Windows 3.1 migration. This configuration will depend heavily on virtual memory and is only optimal for productive use on special workstations that have a single task. It was possible to run Windows 95 on 386 SX, but this caused less acceptable performance due to the 16-bit external data bus. To achieve optimal performance, Microsoft recommends Intel 80486 or a compatible CPU with at least 8 MB of RAM.
Windows 95 may fail to boot on a computer with more than approximately 480 MB of memory. In that case, reducing the file cache size or video memory size can help. The theoretical maximum according to Microsoft is 2 GB.
Windows 95 is replaced by Windows 98 and can still be directly upgraded by Windows 2000 Professional or Windows ME. Office 2000 is the latest version of Microsoft Office compatible with Windows 95. Similarly, Windows Media Player 7.1, released in May 2001, and DirectX 8.0a, released in February 2001, are the latest versions of Windows Media Player and DirectX available for Windows 95 , each. On December 31, 2001, Microsoft ended its support for Windows 95, making it "obsolete" in accordance with the Microsoft Lifecycle Policy. Although support for Windows 95 has ended, this software is sometimes still used on legacy systems for various purposes. In addition, some video game enthusiasts choose to use Windows 95 for their legacy systems to play old DOS games, although some other Windows versions like Windows 98 can also be used for this purpose.
Most copies of Windows 95 are on CD-ROM, but floppy versions can also be owned for older machines. The Windows 95 retail diskette version comes on 13 DMF format disks, while OSR 2.1 doubles the number of floppies to 26. Both versions exclude additional software that may have featured CD-ROM versions. Microsoft Plus! for Windows 95 is also available on the floppy disk. DMF is a special 21-sector format that Microsoft uses to store 1.68 MB on floppy disks instead of the usual 1.44 MB.
Internet Explorer
Windows 95 was originally shipped without Internet Explorer, and the default network installation did not install TCP/IP, the network protocol used on the Internet. On the Windows 95 release date, Internet Explorer 1.0 is available, but only on Plus! add-on pack for Windows 95, which is a separate product. The Plus! Pack does not reach as many retail consumers as the operating system itself (it's primarily advertised for Internet unrelated add-ons such as themes and better disk compression) but is usually included in pre-installed (OEM) sales, and at the time of release Windows 95, the web is being explored mainly with various early web browsers such as NCSA Mosaic and Netscape Navigator (promoted by products such as the Internet in the Box).
Windows 95 OEM Service Release 1 is the first Windows release that includes Internet Explorer (version 2.0) with the OS. Although there is no uninstaller, it can be deleted easily if desired. Release OEM Service 2 includes Internet Explorer 3. Installing Internet Explorer 4 on Windows 95 (or preinstalled OSR2.5 version) gives Windows 95 Active Desktop and browser integration into Windows Explorer, known as Windows Desktop Update. The CD version of the last release of Windows 95, OEM Service Release 2.5 (Version 4.00.950C), including Internet Explorer 4, and install it after the initial setup of Windows 95 and the first boot is completed.
Although only the 4.x browser version has an option to install the Windows Desktop Update feature, the next 5.x version has a hidden option. Editing the installer configuration file located in the temporary folder will make the feature available on the installer. Alternatively, users can install IE4 with a desktop update before installing a newer version of Internet Explorer. The latest version of Internet Explorer supported on Windows 95 was Internet Explorer 5.5, released in 2000. Windows 95 was shipped with Microsoft's own online dial-up service called The Microsoft Network (MSN).
Release and promotion
The Windows 95 release includes ads featuring The Rolling Stones' 1981 single "Start Me Up" (reference to the Start button). It is widely reported that Microsoft paid the Rolling Stones between US $ 8 and US $ 14 million for the use of songs in a Windows 95 ad campaign. However, Microsoft said that this was just rumors spread by the band to increase their market value, and the company actually paid a fraction of that amount. The 30 minute promotional video, labeled "cyber sitcom", featuring Jennifer Aniston and Matthew Perry, was also released to showcase Windows 95 features. Microsoft's $ 300 million advertising campaign featured the story of people lining up outside the store to get a copy.
In the UK, the largest PC World computer network receives a large number of material sales points; many branches opened midnight to sell the first copy of the product. The The Times copy is available for free, and Microsoft paid 1.5 million issues (twice daily circulation at the time).
In the United States, the Empire State Building in New York City is lit to match the colors of the Windows logo. In Canada, a 328-foot (100 m) banner is hung above the CN Tower in Toronto.
This release contains a number of "Fun Stuff" items on the CD, including Edie Brickell's "Good Times" and "Buddy Holly" music belonging to Weezer, a trailer for 1995 Rob Roy > Hover! .
The sales are strong, with one million copies delivered worldwide in just four days.
Edition
A number of Windows 95 editions have been released. Only genuine releases are sold as shrink wrapped products; the next edition is only given to OEM computers to be installed on a new PC. For this reason, this edition is known as OEM Service Release ( OSR ).
Together with the introduction of Windows 95, Microsoft released Microsoft Plus! for Windows 95 pack, which contains a number of optional components for high-end multimedia PCs, including Internet Explorer, DriveSpace, and additional themes.
The first service pack is made available half a year after the original release and fixes a number of small bugs.
The second service pack primarily introduces support for new hardware, especially support for hard drives larger than 2 GB in the form of FAT32 file systems. This release was never made available to end users directly and is only sold through OEMs with the purchase of a new PC.
The third full service pack was never released, but two smaller updates for the second were released in the form of a USB Supplement (OSR 2.1) and Windows Desktop Update (OSR 2.5). Both are available as stand-alone updates and as updated disk images are delivered by OEMs. OSR 2.5 is notorious for displaying a number of changes in Windows Explorer, integrating it with Internet Explorer 4.0 - this version of Internet Explorer looks very similar to the one shown in Windows 98.
Legacy
Many of the features that have become key components of the Microsoft Windows series, such as the Start menu and the taskbar, are from Windows 95. Neil MacDonald, a Gartner analyst, says that Windows 95 "is a quantum leap in the difference in technological capabilities and stability." Ina Fried of CNET says that "by the time Windows 95 was finally taken out of the market in 2001, it has become a fixture on desktop computers around the world."
See also
- Windows 9x
References
Further reading
Source of the article : Wikipedia
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